Sample records for ratio wings subject

  1. Winglets on low aspect ratio wings

    Kuhlman, John M.; Liaw, Paul


    The drag reduction potentially available from the use of winglets at the tips of low aspect ratio (1.75-2.67) wings with pronounced (45-60 deg) leading edge sweep is assessed numerically for the case of a cruise design point at Mach of 0.8 and a lift coefficient of 0.3. Both wing-winglet and wing-alone design geometries are derived from a linear-theory, minimum induced drag design methodology. Relative performance is evaluated with a nonlinear extended small disturbance potential flow analysis code. Predicted lift coefficient/pressure drag coefficient increases at equal lift for the wing-winglet configurations over the wing-alone planform are of the order of 14.6-15.8, when boundary layer interaction is included.

  2. Low Aspect-Ratio Wings for Wing-Ships

    Filippone, Antonino; Selig, M.


    Flying on ground poses technical and aerodynamical challenges. The requirements for compactness, efficiency, manouverability, off-design operation,open new areas of investigations in the fieldof aerodynamic analysis and design. A review ofthe characteristics of low-aspect ratio wings, in- and out...

  3. Vortex Interaction on Low Aspect Ratio Membrane Wings

    Waldman, Rye M.; Breuer, Kenneth S.


    Inspired by the flight of bats and by recent interest in Micro Air Vehicles, we present measurements on the steady and unsteady behavior of low aspect ratio membrane wings. We conduct wind tunnel experiments with coupled force, kinematic, and flow field measurements, both on the wing and in the near wake. Membrane wings interact strongly with the vortices shed from the leading- and trailing-edges and the wing tips, and the details of the membrane support play an important role in the fluid-structure interaction. Membranes that are supported at the wing tip exhibit less membrane flutter, more coherent tip vortices, and enhanced lift. The interior wake can exhibit organized spanwise vortex shedding, and shows little influence from the tip vortex. In contrast, membranes with an unsupported wing tip show exaggerated static deformation, significant membrane fluttering and a diffuse, unsteady tip vortex. The unsteady tip vortex modifies the behavior of the interior wake, disrupting the wake coherence.

  4. Effect of torsional stiffness and inertia on the dynamics of low aspect ratio flapping wings.

    Xiao, Qing; Hu, Jianxin; Liu, Hao


    Micro air vehicle-motivated aerodynamics in biological flight has been an important subject in the past decade. Inspired by the novel flapping wing mechanisms in insects, birds and bats, we have carried out a numerical study systematically investigating a three-dimensional flapping rigid wing with passively actuated lateral and rotational motion. Distinguishing it from the limited existing studies, this work performs a systematic examination on the effects of wing aspect ratio (AR = 1.0 to infinity), inertia (density ratio σ = 4-32), torsional stiffness (frequency ratio F = 1.5-10 and infinity) and pivot point (from chord-center to leading edge) on the dynamics response of a low AR rectangular wing under an initial zero speed flow field condition. The simulation results show that the symmetry breakdown of the flapping wing results in a forward/backward motion with a rotational pitching. When the wing reaches its stable periodic state, the induced pitching frequency is identical to its forced flapping frequency. However, depending on various kinematic and dynamic system parameters, (i.e. flapping frequency, density ratio and pitching axis), the lateral induced velocity shows a number of different oscillating frequencies. Furthermore, compared with a one degree of freedom (DoF) wing in the lateral direction only, the propulsion performance of such a two DoF wing relies very much on the magnitude of torsional stiffness adding on the pivot point, as well as its pitching axis. In all cases examined here, thrust force and moment generated by a long span wing is larger than that of a short wing, which is remarkably linked to the strong reverse von Kármán vortex street formed in the wake of a wing.

  5. Aeroelastic stability analysis of high aspect ratio aircraft wings

    Banerjee, J. R.; Liu, X.; Kassem, H. I.


    Free vibration and flutter analyses of two types of high aspect ratio aircraft wings are presented. The wing is idealised as an assembly of bending-torsion coupled beams using the dynamic stiffness method leading to a nonlinear eigenvalue problem. This problem is solved using the Wattrick-Williams algorithm yielding natural frequencies and mode shapes. The flutter analysis is carried out using the normal mode method in conjunction with generalised coordinates and two-dimensional unsteady aero...

  6. A review on non-linear aeroelasticity of high aspect-ratio wings

    Afonso, Frederico; Vale, José; Oliveira, Éder; Lau, Fernando; Suleman, Afzal


    Current economic constraints and environmental regulations call for design of more efficient aircraft configurations. An observed trend in aircraft design to reduce the lift induced drag and improve fuel consumption and emissions is to increase the wing aspect-ratio. However, a slender wing is more flexible and subject to higher deflections under the same operating conditions. This effect may lead to changes in dynamic behaviour and in aeroelastic response, potentially resulting in instabilities. Therefore, it is important to take into account geometric non-linearities in the design of high aspect-ratio wings, as well as having accurate computational codes that couple the aerodynamic and structural models in the presence of non-linearities. Here, a review on the state-of-the-art on non-linear aeroelasticity of high aspect-ratio wings is presented. The methodologies employed to analyse high aspect-ratio wings are presented and their applications discussed. Important observations from the state-of-the-art studies are drawn and the current challenges in the field are identified.

  7. Flight Loads Prediction of High Aspect Ratio Wing Aircraft Using Multibody Dynamics

    Michele Castellani


    Full Text Available A framework based on multibody dynamics has been developed for the static and dynamic aeroelastic analyses of flexible high aspect ratio wing aircraft subject to structural geometric nonlinearities. Multibody dynamics allows kinematic nonlinearities and nonlinear relationships in the forces definition and is an efficient and promising methodology to model high aspect ratio wings, which are known to be prone to structural nonlinear effects because of the high deflections in flight. The multibody dynamics framework developed employs quasi-steady aerodynamics strip theory and discretizes the wing as a series of rigid bodies interconnected by beam elements, representative of the stiffness distribution, which can undergo arbitrarily large displacements and rotations. The method is applied to a flexible high aspect ratio wing commercial aircraft and both trim and gust response analyses are performed in order to calculate flight loads. These results are then compared to those obtained with the standard linear aeroelastic approach provided by the Finite Element Solver Nastran. Nonlinear effects come into play mainly because of the need of taking into account the large deflections of the wing for flight loads computation and of considering the aerodynamic forces as follower forces.

  8. High lift generation of low-aspect-ratio wings

    Devoria, Adam; Mohseni, Kamran


    The time-averaged flow field in the center-span of low-aspect-ratio rectangular wings is experimentally measured. It is shown that lift stall is preceded by shedding of strong trailing-edge vorticity. The induced downwash of the tip vortices delays the growth of the attached boundary layer as well as leading-edge separation. Reattached flow occurs for sufficiently low aspect ratios and results in a smooth merging of the flow at the trailing edge thus assisting in satisfying a Kutta condition there. As a consequence, the strength of vorticity shed from the trailing edge is decreased and allows for continued lift generation at high angles of attack. When the reattachment point passes beyond the trailing edge, a strong shear layer is generated there and represents negative lift, leading to stall with a slight increase in angle of attack or aspect ratio.

  9. Power reduction and the radial limit of stall delay in revolving wings of different aspect ratio

    Kruyt, J.W.; Heijst, Van G.F.; Altshuler, D.L.; Lentink, David


    Airplanes and helicopters use high aspect ratio wings to reduce the power required to fly, but must operate at low angle of attack to prevent flow separation and stall. Animals capable of slow sustained flight, such as hummingbirds, have low aspect ratio wings and flap their wings at high angle o

  10. Power reduction and the radial limit of stall delay in revolving wings of different aspect ratio

    Kruyt, J.W.; Heijst, Van G.F.; Altshuler, D.L.; Lentink, David


    Airplanes and helicopters use high aspect ratio wings to reduce the power required to fly, but must operate at low angle of attack to prevent flow separation and stall. Animals capable of slow sustained flight, such as hummingbirds, have low aspect ratio wings and flap their wings at high angle o

  11. Active Aeroelastic Tailoring of High-Aspect-Ratio Composite Wings


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  12. Effect of tip vortices on membrane vibration of flexible wings with different aspect ratios

    Genç Mustafa Serdar


    Full Text Available In this study, the effect of the aspect ratio on the aerodynamics characteristic of flexible membrane wings with different aspect ratios (AR = 1 and AR = 3 is experimentally investigated at Reynolds number of 25000. Time accurate measurements of membrane deformation using Digital Image Correlation system (DIC is carried out while normal forces of the wing will be measured by helping a load-cell system and flow on the wing was visualized by means of smoke wire technic. The characteristics of high aspect ratio wings are shown to be affected by leading edge separation bubbles at low Reynolds number. It is concluded that the camber of membrane wing excites the separated shear layer and this situation increases the lift coefficient relatively more as compared to rigid wings. In membrane wings with low aspect ratio, unsteadiness included tip vortices and vortex shedding, and the combination of tip vortices and vortex shedding causes complex unsteady deformations of these membrane wings. The characteristic of high aspect ratio wings was shown to be affected by leading edge separation bubbles at low Reynolds numbers whereas the deformations of flexible wing with low aspect ratio affected by tip vortices and leading edge separation bubbles.

  13. Effects of wing shape, aspect ratio and deviation angle on aerodynamic performance of flapping wings in hover

    Shahzad, Aamer; Tian, Fang-Bao; Young, John; Lai, Joseph C. S.


    This numerical study is focused on assessing the effect on the aerodynamic hovering performance of wing shapes defined by the radius of the first moment of the wing area ( r 1 ¯ ) and aspect ratio (AR). In addition, the effect of introducing a deviation angle in the kinematics is examined. The performance of r 1 ¯ = 0 . 43 , 0.53, and 0.63 wings with AR of 1.5, 2.96, 4.5, and 6.0 is investigated at Reynolds numbers (Re) = 12, 400, and 13 500. The performance trends of the wing shapes have been observed to be independent of Re for both 2-angle and 3-angle kinematics. This is because high suction pressures associated with the leading-edge vortex are predominantly spread in the distal (away from the wing root) and leeward regions (towards the trailing-edge) of high flapping velocities for all the cases. While the deviation angle is detrimental to the production of lift and power economy (PE, defined as the ratio of the mean lift coefficient to the mean aerodynamic power coefficient) at Re = 12 due to strong viscous effects, it improves PE at Re = 400 and 13 500. A high instantaneous angle of attack at the stroke reversal results in high lift peak for 3-angle kinematics but its effect at Re = 400 and 13 500 is attenuated by strong vortical structures on the underside of the wing. Maximum PE is achieved at AR = 2.96, as a low AR wing does not produce enough lift and high AR wings consume more aerodynamic power. Although the lift is maximized using high r 1 ¯ and AR wings, our results show that low r 1 ¯ and high AR wings are best for maximizing PE for a given lift in insects.

  14. A Stationary Vortex Phenomenon above a Low-Aspect-Ratio Wing

    TANG Jian; ZHU Ke-Qin; TAN Guang-Kun


    @@ A stationary vortex phenomenon above a nondelta low-aspect-ratio wing was obtained in three-dimensional unsteady numerical simulation. Flow visualization is conducted in water channel using hydrogen bubbles. The results verify that there is a vortex trapped above the low-aspect-ratio wing and the stationary vortex consisted of two semi-balls and anti-rotation vortices which are different from the leading edge vortices on the delta wing.

  15. Nonlinear Dynamic Characteristics and Optimal Control of SMA Composite Wings Subjected to Stochastic Excitation

    Zhi-Wen Zhu


    Full Text Available A kind of high-aspect-ratio shape memory alloy (SMA composite wing is proposed to reduce the wing’s fluttering. The nonlinear dynamic characteristics and optimal control of the SMA composite wings subjected to in-plane stochastic excitation are investigated where the great bending under the flight loads is considered. The stochastic stability of the system is analyzed, and the system’s response is obtained. The conditions of stochastic Hopf bifurcation are determined, and the probability density of the first-passage time is obtained. Finally, the optimal control strategy is proposed. Numerical simulation shows that the stability of the system varies with bifurcation parameters, and stochastic Hopf bifurcation appears in the process; the reliability of the system is improved through optimal control, and the first-passage time is delayed. Finally, the effects of the control strategy are proved by experiments. The results of this paper are helpful for engineering applications of SMA.

  16. Strong geographical variation in wing aspect ratio of a damselfly, Calopteryx maculata (Odonata: Zygoptera

    Christopher Hassall


    Full Text Available Geographical patterns in body size have been described across a wide range of species, leading to the development of a series of fundamental biological rules. However, shape variables are less well-described despite having substantial consequences for organism performance. Wing aspect ratio (AR has been proposed as a key shape parameter that determines function in flying animals, with high AR corresponding to longer, thinner wings that promote high manoeuvrability, low speed flight, and low AR corresponding to shorter, broader wings that promote high efficiency long distance flight. From this principle it might be predicted that populations living in cooler areas would exhibit low AR wings to compensate for reduced muscle efficiency at lower temperatures. I test this hypothesis using the riverine damselfly, Calopteryx maculata, sampled from 34 sites across its range margin in North America. Nine hundred and seven male specimens were captured from across the 34 sites (mean = 26.7 ± 2.9 SE per site, dissected and measured to quantify the area and length of all four wings. Geometric morphometrics were employed to investigate geographical variation in wing shape. The majority of variation in wing shape involved changes in wing aspect ratio, confirmed independently by geometric morphometrics and wing measurements. There was a strong negative relationship between wing aspect ratio and the maximum temperature of the warmest month which varies from west-east in North America, creating a positive relationship with longitude. This pattern suggests that higher aspect ratio may be associated with areas in which greater flight efficiency is required: regions of lower temperatures during the flight season. I discuss my findings in light of research of the functional ecology of wing shape across vertebrate and invertebrate taxa.

  17. Lift-optimal aspect ratio of a revolving wing at low Reynolds number

    Jardin, Thierry; Colonius, Tim


    Lentink & Dickinson (2009) showed that rotational acceleration stabilized the leading-edge vortex on revolving, low-aspect-ratio wings, and hypothesized that a Rossby number of around 3, which is achieved during each half-stroke for a variety of hovering insects, seeds, and birds, represents a convergent high-lift solution across a range of scales in nature. Subsequent work has verified that, in particular, the Coriolis acceleration is responsible for LEV stabilization. Implicit in these results is that there exists an optimal aspect ratio for wings revolving about their root, because it is otherwise unclear why, apart from possible physiological reasons, the convergent solution would not occur for an even lower Rossby number. We perform direct numerical simulations of the flow past revolving wings where we vary the aspect ratio and Rossby numbers independently by displacing the wing root from the axis of rotation. We show that the optimal lift coefficient represents a compromise between competing trends where the coefficient of lift increases monotonically with aspect ratio, holding Rossby number constant, but decreases monotonically with Rossby number, when holding aspect ratio constant. For wings revolving about their root, this favors wings of aspect ratio between 3 and 4. The authors gratefully acknowledge support from Fondation ISAE-Supaero.

  18. Golden Ratio-Based and Tapered Diptera Inspired Wings: Their Design and Fabrication Using Standard MEMS Technology

    X. Q. Bao; E. Cattan


    This work presents our understanding of insect wings, and the design and micromachining of artificial wings with golden ratio-based and tapered veins. The geometric anisotropy of Leading Edge Veins (LEVs) selected by Diptera has a function able to evade impact. As a Diptera example, the elliptic hollow LEVs of cranefly wings are mechanically and aerodynamically significant. In this paper, an artificial wing was designed to be a fractal structure by mimicking cranefly wings and incorporating cross-veins and discal cell. Standard technologies of Microelectromechanical Systems (MEMS) were employed to materialize the design using the selected material. One SU-8 wing sample, light and stiff enough to be comparable to fresh cranefly wings,was presented. The as-prepared SU-8 wings are faithful to real wings not only in weight and vein pattern, but also in flexural stiffness and mass distribution. Thus our method renders possible mimicking with good fidelity of natural wings with complex geometry and morphology.

  19. A small perturbation based optimization approach for the frequency placement of high aspect ratio wings

    Goltsch, Mandy

    Design denotes the transformation of an identified need to its physical embodiment in a traditionally iterative approach of trial and error. Conceptual design plays a prominent role but an almost infinite number of possible solutions at the outset of design necessitates fast evaluations. The corresponding practice of empirical equations and low fidelity analyses becomes obsolete in the light of novel concepts. Ever increasing system complexity and resource scarcity mandate new approaches to adequately capture system characteristics. Contemporary concerns in atmospheric science and homeland security created an operational need for unconventional configurations. Unmanned long endurance flight at high altitudes offers a unique showcase for the exploration of new design spaces and the incidental deficit of conceptual modeling and simulation capabilities. Structural and aerodynamic performance requirements necessitate light weight materials and high aspect ratio wings resulting in distinct structural and aeroelastic response characteristics that stand in close correlation with natural vibration modes. The present research effort evolves around the development of an efficient and accurate optimization algorithm for high aspect ratio wings subject to natural frequency constraints. Foundational corner stones are beam dimensional reduction and modal perturbation redesign. Local and global analyses inherent to the former suggest corresponding levels of local and global optimization. The present approach departs from this suggestion. It introduces local level surrogate models to capacitate a methodology that consists of multi level analyses feeding into a single level optimization. The innovative heart of the new algorithm originates in small perturbation theory. A sequence of small perturbation solutions allows the optimizer to make incremental movements within the design space. It enables a directed search that is free of costly gradients. System matrices are decomposed

  20. Computational design of low aspect ratio wing-winglets for transonic wind-tunnel testing

    Kuhlman, John M.; Brown, Christopher K.


    A computational design has been performed for three different low aspect ratio wing planforms fitted with nonplanar winglets; one of the three planforms has been selected to be constructed as a wind tunnel model for testing in the NASA LaRC 7 x 10 High Speed Wind Tunnel. A design point of M = 0.8, CL approx = 0.3 was selected, for wings of aspect ratio equal to 2.2, and leading edge sweep angles of 45 and 50 deg. Winglet length is 15 percent of the wing semispan, with a cant angle of 15 deg, and a leading edge sweep of 50 deg. Winglet total area equals 2.25 percent of the wing reference area. This report summarizes the design process and the predicted transonic performance for each configuration.

  1. A study of high-altitude manned research aircraft employing strut-braced wings of high-aspect-ratio

    Smith, P. M.; Deyoung, J.; Lovell, W. A.; Price, J. E.; Washburn, G. F.


    The effect of increased wing aspect ratio of subsonic aircraft on configurations with and without strut bracing. Results indicate that an optimum cantilever configuration, with a wing aspect ratio of approximately 26, has a 19% improvement in cruise range when compared to a baseline concept with a wing aspect ratio of approximately 10. An optimum strut braced configuration, with a wing aspect ratio of approximately 28, has a 31% improvment in cruise range when compared to the same baseline concept. This improvement is mainly due to the estimated reduction in wing weight resulting from use of lifting struts. All configurations assume the same mission payload and fuel. The drag characteristics of the wings are enhanced with the use of laminar flow airfoils. A method for determining the extent of attainable natural laminar flow, and methods for preliminary structural design and for aerodynamic analysis of wings lifting struts are presented.

  2. Gust response analysis and wind tunnel test for a high-aspect ratio wing

    Liu Yi


    Full Text Available A theoretical nonlinear aeroelastic response analysis for a flexible high-aspect ratio wing excited by harmonic gust load is presented along with a companion wind tunnel test. A multidisciplinary coupled numerical calculation is developed to simulate the flexible model wing undergoing gust load in the time domain via discrete nonlinear finite element structural dynamic analysis and nonplanar unsteady vortex lattice aerodynamic computation. A dynamic perturbation analysis about a nonlinear static equilibrium is also used to determine the small perturbation flutter boundary. A novel noncontact 3-D camera measurement analysis system is firstly used in the wind tunnel test to obtain the spatial large deformation and responses. The responses of the flexible wing under different static equilibrium states and frequency gust loads are discussed. The fair to good quantitative agreements between the theoretical and experimental results demonstrate that the presented analysis method is an acceptable way to predict the geometrically nonlinear gust response for flexible wings.

  3. Aeroelastic Wing Shaping Control Subject to Actuation Constraints.

    Swei, Sean Shan-Min; Nguyen, Nhan


    This paper considers the control of coupled aeroelastic aircraft model which is configured with Variable Camber Continuous Trailing Edge Flap (VCCTEF) system. The relative deflection between two adjacent flaps is constrained and this actuation constraint is accounted for when designing an effective control law for suppressing the wing vibration. A simple tuned-mass damper mechanism with two attached masses is used as an example to demonstrate the effectiveness of vibration suppression with confined motion of tuned masses. In this paper, a dynamic inversion based pseudo-control hedging (PCH) and bounded control approach is investigated, and for illustration, it is applied to the NASA Generic Transport Model (GTM) configured with VCCTEF system.

  4. Hummingbird wing efficacy depends on aspect ratio and compares with helicopter rotors

    Kruyt, J.W.; Quicazan Rubio, E.M.; Heijst, van G.J.F.; Altshuler, D.L.; Lentink, D.


    Hummingbirds are the only birds that can sustain hovering. This unique flight behaviour comes, however, at high energetic cost. Based on helicopter and aeroplane design theory, we expect that hummingbird wing aspect ratio (AR), which ranges from about 3.0 to 4.5, determines aerodynamic efficacy. Pre

  5. Gust response analysis and wind tunnel test for a high-aspect ratio wing

    Liu Yi; Xie Changchuan; Yang Chao; Cheng Jialin


    A theoretical nonlinear aeroelastic response analysis for a flexible high-aspect ratio wing excited by harmonic gust load is presented along with a companion wind tunnel test. A multidisci-plinary coupled numerical calculation is developed to simulate the flexible model wing undergoing gust load in the time domain via discrete nonlinear finite element structural dynamic analysis and nonplanar unsteady vortex lattice aerodynamic computation. A dynamic perturbation analysis about a nonlinear static equilibrium is also used to determine the small perturbation flutter bound-ary. A novel noncontact 3-D camera measurement analysis system is firstly used in the wind tunnel test to obtain the spatial large deformation and responses. The responses of the flexible wing under different static equilibrium states and frequency gust loads are discussed. The fair to good quanti-tative agreements between the theoretical and experimental results demonstrate that the presented analysis method is an acceptable way to predict the geometrically nonlinear gust response for flex-ible wings.

  6. Dihedral influence on lateral-directional dynamic stability on large aspect ratio tailless flying wing aircraft

    Song Lei; Yang Hua; Zhang Yang; Zhang Haoyu; Huang Jun


    The influence of dihedral layout on lateral-directional dynamic stability of the tailless flying wing aircraft is discussed in this paper. A tailless flying wing aircraft with a large aspect ratio is selected as the object of study, and the dihedral angle along the spanwise sections is divided into three segments. The influence of dihedral layouts is studied. Based on the stability derivatives cal-culated by the vortex lattice method code, the linearized small-disturbance equations of the lateral modes are used to determine the mode dynamic characteristics. By comparing 7056 configurations with different dihedral angle layouts, two groups of stability optimized dihedral layout concepts are created. Flight quality close to Level 2 requirements is achieved in these optimized concepts without any electric stability augmentation system.

  7. Construction of a Ca II Core-to-Wing Ratio Image

    Roberts, H.


    To understand Earth's climate, we must first understand the Sun. However, there are still significant uncertainties associated with both the fundamental mechanisms of solar variability and how they enter into the Earth's climate system. An important method to study the causes of solar variability can be found through the analysis of solar images. The Precision Solar Photometric Telescope (PSPT) located at the Mauna Loa Solar Observatory (MLSO) acquires images of the Sun in three different photometric bands to monitor the evolution of solar surface features that change over the course of a solar cycle. These images provide a complete knowledge about the Sun by targeting different layers of the solar atmosphere. Though raw images are meaningful and important, precision image processing is required to remove instrumental artifacts and false features that may appear in these images prior to usage for scientific purposes. A scientific application of the high precision solar images is investigated by analyzing a set of narrow band of Calcium II K core and wing images. The Core and Wing images are processed to remove the influence of the center-to-limb variation; the resultant core-to-wing ratio image enhances the appearance of network structures on the entire solar disk along with the more obvious facula and plage brightening associated with the passage of active regions.

  8. Geometrical Nonlinear Aeroelastic Stability Analysis of a Composite High-Aspect-Ratio Wing

    Chang Chuan Xie


    Full Text Available A composite high-aspect-ratio wing of a high-altitude long-endurance (HALE aircraft was modeled with FEM by MSC/NASTRAN, and the nonlinear static equilibrium state is calculated under design load with follower force effect, but without load redistribution. Assuming the little vibration amplitude of the wing around the static equilibrium state, the system is linearized and the natural frequencies and mode shapes of the deformed structure are obtained. Planar doublet lattice method is used to calculate unsteady aerodynamics in frequency domain ignoring the bending effect of the deflected wing. And then, the aeroelastic stability analysis of the system under a given load condition is successively carried out. Comparing with the linear results, the nonlinear displacement of the wing tip is higher. The results indicate that the critical nonlinear flutter is of the flap/chordwise bending type because of the chordwise bending having quite a large torsion component, with low critical speed and slowly growing damping, which dose not appear in the linear analysis. Furthermore, it is shown that the variation of the nonlinear flutter speed depends on the scale of the load and on the chordwise bending frequency. The research work indicates that, for the very flexible HALE aircraft, the nonlinear aeroelastic stability is very important, and should be considered in the design progress. Using present FEM software as the structure solver (e.g. MSC/NASTRAN, and the unsteady aerodynamic code, the nonlinear aeroelastic stability margin of a complex system other than a simple beam model can be determined.

  9. Effect of wing aspect ratio and flap span on aerodynamic characteristics of an externally blown jet-flap STOL model

    Smith, C. C., Jr.


    An investigation has been conducted to determine the effects of flap span and wing aspect ratio on the static longitudinal aerodynamic characteristics and chordwise and spanwise pressure distributions on the wing and trailing-edge flap of a straight-wing STOL model having an externally blown jet flap without vertical and horizontal tail surfaces. The force tests were made over an angle-of-attack range for several thrust coefficients and two flap deflections. The pressure data are presented as tabulated and plotted chordwise pressure-distribution coefficients for angles of attack of 1 and 16. Pressure-distribution measurements were made at several spanwise stations.

  10. Experiments on a low aspect ratio wing at low Reynolds numbers

    Morse, Daniel R.

    At the start of the 21st century much of the focus of aircraft design has been turned to unmanned aerial vehicles (UAVs) which generally operate at much lower speeds in higher risk areas than manned aircraft. One subset of UAVs are Micro Air Vehicles (MAVs) which usually are no larger than 20cm and rely on non-traditional shapes to generate lift at very low velocities. This purpose of this work is to describe, in detail with experimental methods, the flow field around a low aspect ratio wing operating at low Reynolds numbers and at high angles of attack. Quantitative measurements are obtained by Three Component Time Resolved Particle Image Velocimetry (3C TR PIV) which describe the mean and turbulent flow field. This research focuses on the leading edge separation zone and the vortex shedding process which occurs at the leading edge. Streamwise wing tip vortices which dominate the lift characteristics are described with flow visualization and 3C TR PIV measurements. Turbulent Kinetic Energy (TKE) is described at the leading edge over several angles of attack. Turbulent Reynolds stresses in all three directions are described over the wing span and several Reynolds numbers. Two primary cyclic processes are observed within the flow field; one low frequency oscillation in the separated region and one high frequency event associated with leading edge vortex formation and convection. Two length scales are proposed and are shown to match well with each other, one based on leading edge vortex shedding frequency and convective velocity and the other based on mean vortex separation distance. A new method of rendering velocity frequency content over large data sets is proposed and used to illustrate the different frequencies observed at the leading edge.

  11. Aeroelastic response of an aircraft wing with mounted engine subjected to time-dependent thrust

    Mazidi, A.; Kalantari, H.; Fazelzadeh, S. A.


    In this paper, the aeroelastic response of a wing containing an engine subjected to different types of time-dependent thrust excitations is presented. In order to precisely consider the spanwise and chordwise locations of the engine and the time-dependent follower force in governing equations, derived through Lagrange's method, the generalized function theory is used. Unsteady aerodynamic lift and moment in the time domain are considered in terms of Wagner's function. Numerical simulations of the aeroelastic response to different types of time-dependent thrust excitation and comparisons with the previously published results are supplied. Effects of the engine mass and location and also the type of time-dependent thrust on the wing aeroelastic response are studied and pertinent conclusions are outlined.

  12. Design and Simulation of BTT Missile with High-Aspect-Ratio Wing Robust H∞ Autopilot

    CUI Sheng-wang; LIU Li; MA Chun-yan


    For the strong coupling among the channels of bank-to-turn (BTT) missile with high-aspect-ratio wing,an autopilot is designed with a two loop control structure robust autopilot design methods.By the inner loop design,the question of pole-zero cancellation is solved,and the stabilization of structured uncertainty is achieved.Through the outer loop of H∞ controller design,the flying performance and robustness can be guaranteed.The nonlinear simulation results show that the autopilot designed has perfect time domain response,and can suppress bad influence of the inertial and kinematics couplings.It can make the missile fly stably in the large flying areas.The control is very effective.

  13. A model for roll stall and the inherent stability modes of low aspect ratio wings at low Reynolds numbers

    Shields, Matt

    The development of Micro Aerial Vehicles has been hindered by the poor understanding of the aerodynamic loading and stability and control properties of the low Reynolds number regime in which the inherent low aspect ratio (LAR) wings operate. This thesis experimentally evaluates the static and damping aerodynamic stability derivatives to provide a complete aerodynamic model for canonical flat plate wings of aspect ratios near unity at Reynolds numbers under 1 x 105. This permits the complete functionality of the aerodynamic forces and moments to be expressed and the equations of motion to solved, thereby identifying the inherent stability properties of the wing. This provides a basis for characterizing the stability of full vehicles. The influence of the tip vortices during sideslip perturbations is found to induce a loading condition referred to as roll stall, a significant roll moment created by the spanwise induced velocity asymmetry related to the displacement of the vortex cores relative to the wing. Roll stall is manifested by a linearly increasing roll moment with low to moderate angles of attack and a subsequent stall event similar to a lift polar; this behavior is not experienced by conventional (high aspect ratio) wings. The resulting large magnitude of the roll stability derivative, Cl,beta and lack of roll damping, Cl ,rho, create significant modal responses of the lateral state variables; a linear model used to evaluate these modes is shown to accurately reflect the solution obtained by numerically integrating the nonlinear equations. An unstable Dutch roll mode dominates the behavior of the wing for small perturbations from equilibrium, and in the presence of angle of attack oscillations a previously unconsidered coupled mode, referred to as roll resonance, is seen develop and drive the bank angle? away from equilibrium. Roll resonance requires a linear time variant (LTV) model to capture the behavior of the bank angle, which is attributed to the

  14. Subsonic and transonic pressure measurements on a high-aspect-ratio supercritical-wing model with oscillating control surfaces

    Sandford, M. C.; Ricketts, R. H.; Watson, J. J.


    A high aspect ratio supercritical wing with oscillating control surfaces is described. The semispan wing model was instrumented with 252 static orifices and 164 in situ dynamic pressure gases for studying the effects of control surface position and sinusoidal motion on steady and unsteady pressures. Data from the present test (this is the second in a series of tests on this model) were obtained in the Langley Transonic Dynamics Tunnel at Mach numbers of 0.60 and 0.78 and are presented in tabular form.

  15. The flow over a 'high' aspect ratio gothic wing at supersonic speeds

    Narayan, K. Y.


    Results are presented of an experimental investigation on a nonconical wing which supports an attached shock wave over a region of the leading edge near the vertex and a detached shock elsewhere. The shock detachment point is determined from planform schlieren photographs of the flow field and discrepancies are shown to exist between this and the one calculated by applying the oblique shock equations normal to the leading edge. On a physical basis, it is argued that the shock detachment has to obey the two-dimensional law normal to the leading edges. From this, and from other measurements on conical wings, it is thought that the planform schlieren technique may not be particularly satisfactory for detecting shock detachment. Surface pressure distributions are presented and are explained in terms of the flow over related delta wings which are identified as a vertex delta wing and a local delta wing.

  16. The effects of winglets on low aspect ratio wings at supersonic Mach numbers. M.S. Thesis Report Feb. 1989 - Apr. 1991

    Keenan, James A.; Kuhlman, John M.


    A computational study was conducted on two wings, of aspect ratios 1.244 and 1.865, each having 65 degree leading edge sweep angles, to determine the effects of nonplanar winglets at supersonic Mach numbers. A Mach number of 1.62 was selected as the design value. The winglets studied were parametrically varied in alignment, length, sweep, camber, thickness, and dihedral angle to determine which geometry had the best predicted performance. For the computational analysis, an available Euler marching technique was used. The results indicated that the possibility existed for wing-winglet geometries to equal the performance of wing-alone bodies in supersonic flows with both bodies having the same semispan. The first wing with winglet used NACA 1402 airfoils for the base wing and was shown to have lift-to-pressure drag ratios within 0.136 percent to 0.360 percent of the NACA 1402 wing-alone. The other base wing was a natural flow wing which was previously designed specifically for a Mach number of 1.62. The results obtained showed that the natural wing-alone had a slightly higher lift-to-pressure drag than the natural wing with winglets.

  17. Supersonic aerodynamic characteristics of a low-aspect-ratio missile model with wing and tail controls and with tails in line and interdigitated

    Graves, E. B.


    A study has been made to determine the aerodynamic characteristics of a low-aspect ratio cruciform missile model with all-movable wings and tails. The configuration was tested at Mach numbers from 1.50 to 4.63 with the wings in the vertical and horizontal planes and with the wings in a 45 deg roll plane with tails in line and interdigitated.

  18. Gust load alleviation wind tunnel tests of a large-aspect-ratio flexible wing with piezoelectric control

    Ying Bi


    Full Text Available An active control technique utilizing piezoelectric actuators to alleviate gust-response loads of a large-aspect-ratio flexible wing is investigated. Piezoelectric materials have been extensively used for active vibration control of engineering structures. In this paper, piezoelectric materials further attempt to suppress the vibration of the aeroelastic wing caused by gust. The motion equation of the flexible wing with piezoelectric patches is obtained by Hamilton’s principle with the modal approach, and then numerical gust responses are analyzed, based on which a gust load alleviation (GLA control system is proposed. The gust load alleviation system employs classic proportional-integral-derivative (PID controllers which treat piezoelectric patches as control actuators and acceleration as the feedback signal. By a numerical method, the control mechanism that piezoelectric actuators can be used to alleviate gust-response loads is also analyzed qualitatively. Furthermore, through low-speed wind tunnel tests, the effectiveness of the gust load alleviation active control technology is validated. The test results agree well with the numerical results. Test results show that at a certain frequency range, the control scheme can effectively alleviate the z and x wingtip accelerations and the root bending moment of the wing to a certain extent. The control system gives satisfying gust load alleviation efficacy with the reduction rate being generally over 20%.

  19. Transonic steady- and unsteady-pressure measurements on a high-aspect-ratio supercritical-wing model with oscillating control surfaces

    Sandford, M. C.; Ricketts, R. H.; Cazier, F. W., Jr.


    A supercritical wing with an aspect ratio of 10.76 and with two trailing-edge oscillating control surfaces is described. The semispan wing is instrumented with 252 static orifices and 164 in situ dynamic-pressure gages for studying the effects of control-surface position and motion on steady- and unsteady-pressures at transonic speeds. Results from initial tests conducted in the Langley Transonic Dynamics Tunnel at two Reynolds numbers are presented in tabular form.

  20. Mechanical Design of High Lift Systems for High Aspect Ratio Swept Wings

    Rudolph, Peter K. C.


    The NASA Ames Research Center is working to develop a methodology for the optimization and design of the high lift system for future subsonic airliners with the involvement of two partners. Aerodynamic analysis methods for two dimensional and three dimensional wing performance with flaps and slats deployed are being developed through a grant with the aeronautical department of the University of California Davis, and a flap and slat mechanism design procedure is being developed through a contract with PKCR, Inc., of Seattle, WA. This report documents the work that has been completed in the contract with PKCR on mechanism design. Flap mechanism designs have been completed for seven (7) different mechanisms with a total of twelve (12) different layouts all for a common single slotted flap configuration. The seven mechanisms are as follows: Simple Hinge, Upside Down/Upright Four Bar Linkage (two layouts), Upside Down Four Bar Linkages (three versions), Airbus A330/340 Link/Track Mechanism, Airbus A320 Link/Track Mechanism (two layouts), Boeing Link/Track Mechanism (two layouts), and Boeing 767 Hinged Beam Four Bar Linkage. In addition, a single layout has been made to investigate the growth potential from a single slotted flap to a vane/main double slotted flap using the Boeing Link/Track Mechanism. All layouts show Fowler motion and gap progression of the flap from stowed to a fully deployed position, and evaluations based on spanwise continuity, fairing size and number, complexity, reliability and maintainability and weight as well as Fowler motion and gap progression are presented. For slat design, the options have been limited to mechanisms for a shallow leading edge slat. Three (3) different layouts are presented for maximum slat angles of 20 deg, 15 deg and 1O deg all mechanized with a rack and pinion drive similar to that on the Boeing 757 airplane. Based on the work of Ljungstroem in Sweden, this type of slat design appears to shift the lift curve so that

  1. Torg ratios based on cervical lateral plain films in normal subjects

    David Tjahjadi


    Full Text Available Stenosis of the spinal canal can be caused by trauma, degenerative processes, and tumors, causing a neurological deficit. If the neurological deficit could be detected or diagnosed earlier, the late complications such as quadriparesis could be prevented. The Torg ratio can be used to find evidence of cervical canal stenosis on lateral plain film, as it has the advantage of not being affected by magnification. The purpose of this study was to determine the Torg ratio for normal subjects using lateral plain films of cervical vertebrae. This cross-sectional study was done at the Department of Radiology FKUI/RSUPN-CM Jakarta, starting from September 16 – 20, 2008. The study included 98 subjects, aged 20 – 40 years, were the mean age of the subjects was 27.4 years (SD ± 5.4. All participants were subjected to measurement of the Torg ratio by cervical lateral plain film. The mean Torg ratio of normal subjects was 0.99 for males and 1.06 for females. The mean Torg ratio of several ethnicities were 1.04 for Javanese, 1.02 for Sundanese, 1.01 for Betawi, and 0.99 for other ethnicities. The mean Torg ratio of our subjects is different from that of other people, such as Pakistanis, Singaporeans, and Koreans. The mean Torg ratios of ethnicities are not significantly different from one another. Therefore, the Torg ratio can be relied upon to predict narrowing of the cervical spinal canal in the sagittal plane.

  2. Charts for Determining Preliminary Values of Span-load, Shear, Bending-moment, and Accumulated-torque Distributions of Swept Wings of Various Taper Ratios

    Wollner, Bertram C


    Contains charts for use in determining preliminary values of the spanwise-load, shear, bending-moment, and accumulated-torque distributions of swept wings. The charts are based on strip theory and include four aerodynamic-load distributions, two section-moment distributions, and two inertia-load distributions. The taper ratios considered cover the range from 1.0 to 0 and the results are applicable to any angle of sweep.

  3. High triglyceride-to-HDL cholesterol ratio associated with albuminuria in type 2 diabetic subjects.

    Lee, I Te; Wang, Chih-Yuan; Huang, Chien-Ning; Fu, Chen-Chung; Sheu, Wayne H H


    Emerging evidence indicates that metabolic syndrome (MetS) predisposes diabetic subjects to nephropathy. Aside from hypertension and hyperglycemia, it is unclear which component of MetS also contributes to increased urinary albumin excretion (UAE). We compared the MetS profiles of subjects divided into two groups based on their UAE. The Asia Pacific Real-Life Effectiveness and Care Patterns of Diabetes Management (AP RECAP-DM) study is a cross-sectional survey in which type 2 diabetic subjects using oral anti-hyperglycemic drugs were enrolled. We analyzed the data of 162 type 2 diabetic subjects with normotension or taking antihypertensive medications. There were 123 subjects with normal UAE (HDL) cholesterol (odds ratio=3.27, P=0.022) were both independently associated with abnormal UAE. Using 3.4 as a cut-off value, a high triglyceride-to-HDL cholesterol ratio was a useful marker (odds ratio=15.05, PHDL cholesterol ratio was found to be an important risk factor for nephropathy in type 2 diabetic subjects. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. Lipid Peroxidation, Nitric Oxide Metabolites, and Their Ratio in a Group of Subjects with Metabolic Syndrome

    Gregorio Caimi


    Full Text Available Our aim was to evaluate lipid peroxidation, expressed as thiobarbituric acid-reactive substances (TBARS, nitric oxide metabolites (nitrite + nitrate expressed as NOx, and TBARS/NOx ratio in a group of subjects with metabolic syndrome (MS. In this regard we enrolled 106 subjects with MS defined according to the IDF criteria, subsequently subdivided into diabetic (DMS and nondiabetic (NDMS and also into subjects with a low triglycerides/HDL-cholesterol (TG/HDL-C index or with a high TG/HDL-C index. In the entire group and in the four subgroups of MS subjects we found an increase in TBARS and NOx levels and a decrease in TBARS/NOx ratio in comparison with normal controls. Regarding all these parameters no statistical difference between DMS and NDMS was evident, but a significant increase in NOx was present in subjects with a high TG/HDL-C index in comparison with those with a low index. In MS subjects we also found a negative correlation between TBARS/NOx ratio and TG/HDL-C index. Considering the hyperactivity of the inducible NO synthase in MS, these data confirm the altered redox and inflammatory status that characterizes the MS and suggest a link between lipid peroxidation, inflammation, and insulin resistance, evaluated as TG/HDL-C index.

  5. Multi-Objective Flight Control for Drag Minimization and Load Alleviation of High-Aspect Ratio Flexible Wing Aircraft

    Nguyen, Nhan; Ting, Eric; Chaparro, Daniel; Drew, Michael; Swei, Sean


    As aircraft wings become much more flexible due to the use of light-weight composites material, adverse aerodynamics at off-design performance can result from changes in wing shapes due to aeroelastic deflections. Increased drag, hence increased fuel burn, is a potential consequence. Without means for aeroelastic compensation, the benefit of weight reduction from the use of light-weight material could be offset by less optimal aerodynamic performance at off-design flight conditions. Performance Adaptive Aeroelastic Wing (PAAW) technology can potentially address these technical challenges for future flexible wing transports. PAAW technology leverages multi-disciplinary solutions to maximize the aerodynamic performance payoff of future adaptive wing design, while addressing simultaneously operational constraints that can prevent the optimal aerodynamic performance from being realized. These operational constraints include reduced flutter margins, increased airframe responses to gust and maneuver loads, pilot handling qualities, and ride qualities. All of these constraints while seeking the optimal aerodynamic performance present themselves as a multi-objective flight control problem. The paper presents a multi-objective flight control approach based on a drag-cognizant optimal control method. A concept of virtual control, which was previously introduced, is implemented to address the pair-wise flap motion constraints imposed by the elastomer material. This method is shown to be able to satisfy the constraints. Real-time drag minimization control is considered to be an important consideration for PAAW technology. Drag minimization control has many technical challenges such as sensing and control. An initial outline of a real-time drag minimization control has already been developed and will be further investigated in the future. A simulation study of a multi-objective flight control for a flight path angle command with aeroelastic mode suppression and drag

  6. Low-Speed Investigation of a Full-Span Internal-Flow Jet-Augmented Flap on a High-Wing Model with a 35 deg Swept Wing of Aspect Ratio 7.0

    Turner, Thomas R.


    An investigation of a full-span 17-percent-chord internal-flow jet-augmented flap on an aspect-ratio-7.0 wing with 35 deg of sweepback has been made in the Langley 300-MPH 7- by 10-foot tunnel. Blowing over the conventional elevator and blowing down from a nose jet were investigated as a means of trimming the large diving moments at the high momentum and high lift coefficients. The results of the investigation showed that the model with the horizontal tail 0.928 mean aerodynamic chord above the wing-chord plane was stable to the maximum lift coefficient. The large diving-moment coefficients could be trimmed either with a downward blowing nose jet or by blowing over the elevator. Neither the downward blowing nose jet nor blowing over the elevator greatly affected the static longitudinal stability of the model. Trimmed lift coefficients up to 8.8 with blowing over the elevator and up to 11.4 with blowing down at the nose were obtained when the flap was deflected 70 deg and the total momentum coefficients were 3.26 and 4.69.

  7. Can body mass index, waist circumference, waist-hip ratio and waist-height ratio predict the presence of multiple metabolic risk factors in Chinese subjects?

    Lu Liping; Tong Weiwei; Tong Guanghui; Liu Yong; Qin Xiaosong


    Abstract Background Obesity is associated with metabolic risk factors. Body mass index (BMI), waist circumference, waist-hip ratio (WHR) and waist-height ratio (WHtR) are used to predict the risk of obesity related diseases. However, it has not been examined whether these four indicators can detect the clustering of metabolic risk factors in Chinese subjects. Methods There are 772 Chinese subjects in the present study. Metabolic risk factors including high blood pressure, dyslipidemia, and gl...

  8. Myelination process in preterm subjects with periventricular leucomalacia assessed by magnetization transfer ratio

    Xydis, Vassilios; Astrakas, Loukas; Gassias, Dimitrios; Argyropoulou, Maria [University of Ioannina, Department of Radiology, Medical School, Ioannina (Greece); Drougia, Aikaterini; Andronikou, Styliani [University of Ioannina, Neonatology Clinic, Child Health Department, Medical School, Ioannina (Greece)


    Magnetization transfer imaging assesses the myelination status of the brain. To study the progress of myelination in children with periventricular leucomalacia (PVL) by measuring the magnetization transfer ratio (MTR) and to compare the MTR values with normal values. Brain MTR in 28 PVL subjects (16 males, 12 females, gestational age 30.7{+-}2.5 weeks, corrected age 3.1{+-}2.9 years) was measured using a 3D gradient echo sequence (TR/TE 32/8 ms, flip angle 60 , 4 mm/2 mm overlapping sections) without and with magnetization transfer prepulse and compared with normal values for preterm subjects. MTR of white-matter structures followed a monoexponential function model (y=A-B*exp(-x/C)) while the thalamus and caudate nucleus had a poor goodness of fit. MTR of the splenium of the corpus callosum reached a final value lower than normal (0.67 versus 0.70) at a younger age [t(99%) at 10.32 versus 18.90 months; P<0.05]. MTR of the normal-appearing occipital white matter and of the genu of the corpus callosum reached a normal final MTR but at a younger age than normal preterm infants [t(99%) at 8.51 versus 14.50 months and 12.51 versus 20.85 months, respectively]. In PVL subjects, myelination of the splenium is characterized by early arrest and deficient maturation. Accelerated myelination in unaffected white matter might suggest a compensatory process of reorganization. (orig.)

  9. Diagnostic Role of Captopril Challenge Test in Korean Subjects with High Aldosterone-to-Renin Ratios

    Jung Hee Kim


    Full Text Available BackgroundDiagnosis of primary aldosteronism (PA begins with aldosterone-to-renin ratio (ARR measurement followed by confirmative tests. However, the ARR has high false positive rates which led to unnecessary confirmatory tests. Captopril challenge test (CCT has been used as one of confirmatory tests, but the accuracy of it in the diagnosis of PA is still controversial. We aimed to examine the clinical efficacy of CCT as a post-screening test in PA.MethodsIn a prospective study, we enrolled subjects with suspected PA who had hypertension and ARR >20 (ng/dL/(ng/mL/hr. Sixty-four patients who underwent both the saline infusion test and the CCT were included.ResultsThe diagnostic performance of plasma aldosterone concentration (PAC post-CCT was greater than that of ARR post-CCT and ARR pre-CCT in PA (area under the curve=0.956, 0.797, and 0.748, respectively; P=0.001. A cut-off value of 13 ng/dL showed the highest diagnostic odds ratio considering PAC post-CCT at 60 and 90 minutes. A PAC post-CCT of 19 ng/dL had a specificity of 100%, which can be used as a cut-off value for the confirmative test. Determining the diagnostic performance of PAC post-CCT at 90 minutes was sufficient for PA diagnosis. Subjects with PAC post-CCT at 90 minutes <13 ng/dL are less likely to have PA, and those with PAC post-CCT at 90 minutes ≥13 but <19 ng/dL should undergo secondary confirmatory tests.ConclusionThe CCT test may be a reliable post-screening test to avoid the hospitalization in the setting of falsely elevated ARR screening tests.

  10. Reproductive and behavioral aspects of red-winged tinamous (Rhynchotus rufescens in groups with different sex ratios

    VU Cromberg


    Full Text Available The aim of this research study was to evaluate the reproductive performance of tinamous submitted to five different male:female ratios. The study was carried out with 72 birds in a randomized experimental design with 4 replications. Tinamous were housed in cages, using the ratios of one (1:1, two (2:1, three (3:1 and four (4:1 females per male, and also one male was housed with three females individually (3R:1, in a rotational system. Reproductive records of the breeding season from September 2004 to March 2005 were used. The reproductive traits studied were: number of eggs laid, fertility, and percentage of eggs damaged and cracked by pecking. Nonparametric analyses of these traits were performed using Kruskal-Wallis test. Two replications of treatments 1:1 and 4:1, and one of treatment 2:1 were video-taped for three days, 12 hours/day. The videotapes were sampled according to the scan method to fit an ethogram. Birds were also watched for one hour per day to study dominance and agonistic behavior. None of the reproductive traits was affected by mating sex ratio (p<0.05. Female dominance could be related to displacement behavior (r=1.00, and male sitting in immobility plus sitting in activity behaviors were related to lower number of damaged eggs (r=-0.90. Social dominance was indirectly determined by displacement behavior in the study situation. A large number of damaged eggs occurred in all treatments, thereby not allowing a clear conclusion on the best male:female ratio.

  11. Optimization of composite tiltrotor wings with extensions and winglets

    Kambampati, Sandilya

    Tiltrotors suffer from an aeroelastic instability during forward flight called whirl flutter. Whirl flutter is caused by the whirling motion of the rotor, characterized by highly coupled wing-rotor-pylon modes of vibration. Whirl flutter is a major obstacle for tiltrotors in achieving high-speed flight. The conventional approach to assure adequate whirl flutter stability margins for tiltrotors is to design the wings with high torsional stiffness, typically using 23% thickness-to-chord ratio wings. However, the large aerodynamic drag associated with these high thickness-to-chord ratio wings decreases aerodynamic efficiency and increases fuel consumption. Wingtip devices such as wing extensions and winglets have the potential to increase the whirl flutter characteristics and the aerodynamic efficiency of a tiltrotor. However, wing-tip devices can add more weight to the aircraft. In this study, multi-objective parametric and optimization methodologies for tiltrotor aircraft with wing extensions and winglets are investigated. The objectives are to maximize aircraft aerodynamic efficiency while minimizing weight penalty due to extensions and winglets, subject to whirl flutter constraints. An aeroelastic model that predicts the whirl flutter speed and a wing structural model that computes strength and weight of a composite wing are developed. An existing aerodynamic model (that predicts the aerodynamic efficiency) is merged with the developed structural and aeroelastic models for the purpose of conducting parametric and optimization studies. The variables of interest are the wing thickness and structural properties, and extension and winglet planform variables. The Bell XV-15 tiltrotor aircraft the chosen as the parent aircraft for this study. Parametric studies reveal that a wing extension of span 25% of the inboard wing increases the whirl flutter speed by 10% and also increases the aircraft aerodynamic efficiency by 8%. Structurally tapering the wing of a tiltrotor

  12. Comparison of subjective and objective methods to determine the retinal arterio-venous ratio using fundus photography

    Heitmar, Rebekka; Kalitzeos, Angelos A.; Patel, Sunni R.; Prabhu-Das, Diana; Cubbidge, Robert P.


    Purpose: To assess the inter and intra observer variability of subjective grading of the retinal arterio-venous ratio (AVR) using a visual grading and to compare the subjectively derived grades to an objective method using a semi-automated computer program. Methods: Following intraocular pressure and blood pressure measurements all subjects underwent dilated fundus photography. 86 monochromatic retinal images with the optic nerve head centred (52 healthy volunteers) were obtained using a Zeis...

  13. High total-to-HDL cholesterol ratio predicting deterioration of ankle brachial index in Asian type 2 diabetic subjects.

    Lee, I-Te; Huang, Chien-Ning; Lee, Wen-Jane; Lee, Hong-Shen; Sheu, Wayne Huey-Herng


    We conducted a prospective study to determine the risk factors for decrease in ABI in Chinese subjects with type 2 diabetes during a 3-year period. Type 2 diabetic subjects with normal ABI were enrolled in this study. The risk factors for PVD and ABI were examined before and after the follow-up period. A total of 107 type 2 diabetic subjects completed the assessment. Based on the change of ABI, the study subjects were divided into two groups. Forty subjects, in Group 1, had a decrease in ABI; 67 subjects, in Group 2, had no decrease in ABI after the 3-year follow-up. The baseline total-to-HDL cholesterol ratio (4.5+/-1.2 vs. 3.9+/-1.0, P=0.018) and serum creatinine (99.0+/-18.0micromol/L vs. 88.8+/-15.7micromol/L, P=0.004) were significantly higher, and the HDL cholesterol concentration was significantly lower (1.11+/-0.26mmol/L vs. 1.27+/-0.39mmol/L, P=0.011) in Group 1 than in Group 2. Furthermore, total-to-HDL cholesterol ratio was the variable showed an inverse correlation and independent predictor for the change in ABI after the 3-year follow-up. Total-to-HDL cholesterol ratio is a major risk factor for PVD and showed an inverse trend to change in ABI in Asian type 2 diabetic subjects.

  14. Effect of Subject Rotation on Assessment of Esthetic Dental Ratios: A Simulation Study

    Rajesh Gyawali


    Full Text Available Objective. This study aimed to find out the change in esthetic ratios during rotation of patient’s head using a simulation. Materials and Methods. A plaster study model was photographed placing its midline along the long axis of the camera. Then a series of photographs were taken by rotating the model each degree till 10° on both right and left sides. These photographs were digitally measured and the ratio of the maxillary anterior teeth at zero-degree rotation was compared with that at various degrees of rotation. Results. As the model was rotated to the right side till 10°, the ratio of the right lateral to central incisor gradually decreased while the ratio of the left lateral to central incisor gradually increased. However, the ratio of the canine to lateral incisor on both sides gradually increased. Similar results were obtained when the model was rotated to the left side. The ratio of the lateral to central incisor deviated from the acceptable range (±10% when there was rotation of more than 7°, whereas the ratio of the canine to lateral incisor was within the acceptable range till 10° rotation on either side. Conclusions. Rotation of the model by more than 7° leads to a substantial change in the esthetic ratio.

  15. Avian Wings

    Liu, Tianshu; Kuykendoll, K.; Rhew, R.; Jones, S.


    This paper describes the avian wing geometry (Seagull, Merganser, Teal and Owl) extracted from non-contact surface measurements using a three-dimensional laser scanner. The geometric quantities, including the camber line and thickness distribution of airfoil, wing planform, chord distribution, and twist distribution, are given in convenient analytical expressions. Thus, the avian wing surfaces can be generated and the wing kinematics can be simulated. The aerodynamic characteristics of avian airfoils in steady inviscid flows are briefly discussed. The avian wing kinematics is recovered from videos of three level-flying birds (Crane, Seagull and Goose) based on a two-jointed arm model. A flapping seagull wing in the 3D physical space is re-constructed from the extracted wing geometry and kinematics.

  16. Is an objective refraction optimised using the visual Strehl ratio better than a subjective refraction?

    Hastings, Gareth D; Marsack, Jason D; Nguyen, Lan Chi; Cheng, Han; Applegate, Raymond A


    To prospectively examine whether using the visual image quality metric, visual Strehl (VSX), to optimise objective refraction from wavefront error measurements can provide equivalent or better visual performance than subjective refraction and which refraction is preferred in free viewing. Subjective refractions and wavefront aberrations were measured on 40 visually-normal eyes of 20 subjects, through natural and dilated pupils. For each eye a sphere, cylinder, and axis prescription was also objectively determined that optimised visual image quality (VSX) for the measured wavefront error. High contrast (HC) and low contrast (LC) logMAR visual acuity (VA) and short-term monocular distance vision preference were recorded and compared between the VSX-objective and subjective prescriptions both undilated and dilated. For 36 myopic eyes, clinically equivalent (and not statistically different) HC VA was provided with both the objective and subjective refractions (undilated mean ± S.D. was -0.06 ± 0.04 with both refractions; dilated was -0.05 ± 0.04 with the objective, and -0.05 ± 0.05 with the subjective refraction). LC logMAR VA provided by the objective refraction was also clinically equivalent and not statistically different to that provided by the subjective refraction through both natural and dilated pupils for myopic eyes. In free viewing the objective prescription was preferred over the subjective by 72% of myopic eyes when not dilated. For four habitually undercorrected high hyperopic eyes, the VSX-objective refraction was more positive in spherical power and VA poorer than with the subjective refraction. A method of simultaneously optimising sphere, cylinder, and axis from wavefront error measurements, using the visual image quality metric VSX, is described. In myopic subjects, visual performance, as measured by HC and LC VA, with this VSX-objective refraction was found equivalent to that provided by subjective refraction, and was typically preferred

  17. Span morphing using the GNATSpar wing


    Rigid wings usually fly at sub-optimal conditions generating unnecessary aerodynamic loses represented in flight time, fuel consumption, and unfavourable operational characteristics. High aspect ratio wings have good range and fuel efficiency, but lack manoeuvrability. On the other hand, low aspect ratio wings fly faster and are more manoeuvrable, but have poor aerodynamic performance. Span morphing technology allows integrating both features in a single wing design and allows continuously ad...

  18. When wings touch wakes: understanding locomotor force control by wake wing interference in insect wings.

    Lehmann, Fritz-Olaf


    Understanding the fluid dynamics of force control in flying insects requires the exploration of how oscillating wings interact with the surrounding fluid. The production of vorticity and the shedding of vortical structures within the stroke cycle thus depend on two factors: the temporal structure of the flow induced by the wing's own instantaneous motion and the flow components resulting from both the force production in previous wing strokes and the motion of other wings flapping in close proximity. These wake-wing interactions may change on a stroke-by-stroke basis, confronting the neuro-muscular system of the animal with a complex problem for force control. In a single oscillating wing, the flow induced by the preceding half stroke may lower the wing's effective angle of attack but permits the recycling of kinetic energy from the wake via the wake capture mechanism. In two-winged insects, the acceleration fields produced by each wing may strongly interact via the clap-and-fling mechanism during the dorsal stroke reversal. Four-winged insects must cope with the fact that the flow over their hindwings is affected by the presence of the forewings. In these animals, a phase-shift between the stroke cycles of fore- and hindwing modulates aerodynamic performance of the hindwing via leading edge vortex destruction and changes in local flow condition including wake capture. Moreover, robotic wings demonstrate that phase-lag during peak performance and the strength of force modulation depend on the vertical spacing between the two stroke planes and the size ratio between fore- and hindwing. This study broadly summarizes the most prominent mechanisms of wake-wing and wing-wing interactions found in flapping insect wings and evaluates the consequences of these processes for the control of locomotor forces in the behaving animal.

  19. Low-speed aerodynamic performance of an aspect-ratio-10 supercritical-wing transport model equipped with a full-span slat and part-span and full-span double-slotted flaps

    Morgan, H. L., Jr.


    An investigation was conducted in the Langley 4 by 7 Meter Tunnel to determine the static longitudinal and lateral directional aerodynamic characteristics of an advanced aspect ratio 10 supercritical wing transport model equipped with a full span leading edge slat as well as part span and full span trailing edge flaps. This wide body transport model was also equipped with spoiler and aileron roll control surfaces, flow through nacelles, landing gear, and movable horizontal tails. Six basic wing configurations were tested: (1) cruise (slats and flaps nested), (2) climb (slats deflected and flaps nested), (3) part span flap, (4) full span flap, (5) full span flap with low speed ailerons, and (6) full span flap with high speed ailerons. Each of the four flapped wing configurations was tested with leading edge slat and trailing edge flaps deflected to settings representative of both take off and landing conditions. Tests were conducted at free stream conditions corresponding to Reynolds number of 0.97 to 1.63 x 10 to the 6th power and corresponding Mach numbers of 0.12 to 0.20, through an angle of attack range of 4 to 24, and a sideslip angle range of -10 deg to 5 deg. The part and full span wing configurations were also tested in ground proximity.

  20. Time-varying wing-twist improves aerodynamic efficiency of forward flight in butterflies.

    Lingxiao Zheng

    Full Text Available Insect wings can undergo significant chordwise (camber as well as spanwise (twist deformation during flapping flight but the effect of these deformations is not well understood. The shape and size of butterfly wings leads to particularly large wing deformations, making them an ideal test case for investigation of these effects. Here we use computational models derived from experiments on free-flying butterflies to understand the effect of time-varying twist and camber on the aerodynamic performance of these insects. High-speed videogrammetry is used to capture the wing kinematics, including deformation, of a Painted Lady butterfly (Vanessa cardui in untethered, forward flight. These experimental results are then analyzed computationally using a high-fidelity, three-dimensional, unsteady Navier-Stokes flow solver. For comparison to this case, a set of non-deforming, flat-plate wing (FPW models of wing motion are synthesized and subjected to the same analysis along with a wing model that matches the time-varying wing-twist observed for the butterfly, but has no deformation in camber. The simulations show that the observed butterfly wing (OBW outperforms all the flat-plate wings in terms of usable force production as well as the ratio of lift to power by at least 29% and 46%, respectively. This increase in efficiency of lift production is at least three-fold greater than reported for other insects. Interestingly, we also find that the twist-only-wing (TOW model recovers much of the performance of the OBW, demonstrating that wing-twist, and not camber is key to forward flight in these insects. The implications of this on the design of flapping wing micro-aerial vehicles are discussed.

  1. 大展弦比飞翼布局飞机的三轴稳定特性%Three-axis stability characteristics of flying wing with high aspect ratio

    张子军; 王磊; 王立新; 王晋军


    飞翼布局飞机取消了平尾和垂尾,构型的改变和阻力方向舵的使用使其呈现出与常规布局飞机不同的三轴稳定特性.以大展弦比飞翼布局飞机为研究对象,开展了其三轴静、动稳定特性的研究;通过与常规大展弦比飞机进行对比,揭示了飞翼构型参数、典型飞行状态对其稳定性的影响规律;分析了阻力方向舵的偏转对此类飞机稳定性的影响.研究结果表明,大展弦比飞翼布局飞机的本体稳定性存在诸多的不足.%A flying wing cancels horizontal and vertical tails, but the changes of configuration and the use of drag rudder make it differ much from the conventional configuration aircraft in three-axis stability characteristics. The aircraft chosen for the study is a flying wing with high aspect ratio. Its three-axis static and dynamic stability characteristics are studied. Comparing with the conventional configuration aircraft with high aspect ratio, the effects of configuration parameters and typical flight condition on the stabilities of the flying wing are discussed. The impact of the drag rudder on the stabilities of such aircraft types is also analyzed. Results show that there are many deficiencies in the inherent three-axis stabilities of the high aspect ratio flying wing.

  2. Low-speed aerodynamic performance of a high-aspect-ratio supercritical-wing transport model equipped with full-span slat and part-span double-slotted flaps

    Morgan, H. L., Jr.; Paulson, J. W., Jr.


    An investigation was conducted in the Langley V/STOL tunnel to determine the static longitudinal and lateral-directional aerodynamic characteristics of an advanced high-aspect-ratio supercritical-wing transport model equipped with a full-span leading-edge slat and part-span double-slotted trailing-edge flaps. This wide-body transport model was also equipped with spoiler and aileron control surfaces, flow-through nacelles, landing gear, movable horizontal tails, and interchangeable wing tips with aspect ratios of 10 and 12. The model was tested with leading-edge slat and trailing-edge flap combinations representative of cruise, climb, takeoff, and landing wing configurations. The tests were conducted at free-stream conditions corresponding to Reynolds numbers (based on mean geometric chord) of 0.97 to 1.63 x 10 to the 6th power and corresponding Mach numbers of 0.12 to 0.20, through an angle-of-attack range of -2 deg to 24 deg and a sideslip-angle range of -10 deg to 5 deg.

  3. Use of the plasma triglyceride/high-density lipoprotein cholesterol ratio to identify cardiovascular disease in hypertensive subjects.

    Salazar, Martin R; Carbajal, Horacio A; Espeche, Walter G; Aizpurúa, Marcelo; Leiva Sisnieguez, Carlos E; Leiva Sisnieguez, Betty C; March, Carlos E; Stavile, Rodolfo N; Balbín, Eduardo; Reaven, Gerald M


    This analysis evaluated the hypothesis that the plasma triglyceride (TG)/high-density lipoprotein cholesterol (HDL-C) concentration ratio can help identify patients with essential hypertension who are insulin-resistant, with the cardiovascular disease (CVD) risk profile associated with that defect. Data from a community-based study developed between 2003 and 2012 were used to compare CVD risk factors and outcome. Plasma TG/HDL-C cut-points of 2.5 (women) and 3.5 (men) subdivided normotensive (n = 574) and hypertensive (n = 373) subjects into "high" and "low" risk groups. Metabolic syndrome criteria (MetS) were also used to identify "high" and "low" risk groups. The baseline cardio-metabolic profile was significantly more adverse in 2003 in "high" risk subgroups, irrespective of BP classification or definition of risk (TG/HDL-C ratio vs. MetS criteria). Crude incidence of combined CVD events increased across risk groups, ranging from 1.9 in normotensive-low TG/HDL-C subjects to 19.9 in hypertensive-high TG/HDL-C ratio individuals (P for trends <.001). Adjusted hazard ratios for CVD events also increased with both hypertension and TG/HDL-C. Comparable findings were seen when CVD outcome was predicted by MetS criteria. The TG/HDL-C concentration ratio and the MetS criteria identify to a comparable degree hypertensive subjects who are at greatest cardio-metabolic risk and develop significantly more CVD.

  4. Bat flight with bad wings: is flight metabolism affected by damaged wings?

    Voigt, Christian C


    Infection of North American bats with the keratin-digesting fungus Geomyces destructans often results in holes and ruptures of wing membranes, yet it is unknown whether flight performance and metabolism of bats are altered by such injuries. I conducted flight experiments in a circular flight arena with Myotis albescens and M. nigricans individuals with an intact or ruptured trailing edge of one of the plagiopatagial membranes. In both species, individuals with damaged wings were lighter, had a higher aspect ratio (squared wing span divided by wing area) and an increased wing loading (weight divided by wing area) than conspecifics with intact wings. Bats with an asymmetric reduction of the wing area flew at similar speeds to conspecifics with intact wings but performed fewer flight manoeuvres. Individuals with damaged wings showed lower metabolic rates during flight than conspecifics with intact wings, even when controlling for body mass differences; the difference in mass-specific metabolic rate may be attributable to the lower number of flight manoeuvres (U-turns) by bats with damaged wings compared with conspecifics with intact wings. Possibly, bats compensated for an asymmetric reduction in wing area by lowering their body mass and avoiding flight manoeuvres. In conclusion, it may be that bats suffer from moderate wing damage not directly, by experiencing increased metabolic rate, but indirectly, by a reduced manoeuvrability and foraging success. This could impede a bat's ability to gain sufficient body mass before hibernation.

  5. Stiffness of desiccating insect wings

    Mengesha, T E; Vallance, R R [Department of Mechanical Engineering, The George Washington University, 738 Phillips Hall, 801 22nd St NW, Washington, DC 20052 (United States); Mittal, R, E-mail: [Department of Mechanical Engineering, Johns Hopkins University, 126 Latrobe Hall, 3400 N Charles Street, Baltimore, MD 21218 (United States)


    The stiffness of insect wings is typically determined through experimental measurements. Such experiments are performed on wings removed from insects. However, the wings are subject to desiccation which typically leads to an increase in their stiffness. Although this effect of desiccation is well known, a comprehensive study of the rate of change in stiffness of desiccating insect wings would be a significant aid in planning experiments as well as interpreting data from such experiments. This communication presents a comprehensive experimental analysis of the change in mass and stiffness of gradually desiccating forewings of Painted Lady butterflies (Vanessa cardui). Mass and stiffness of the forewings of five butterflies were simultaneously measured every 10 min over a 24 h period. The averaged results show that wing mass declined exponentially by 21.1% over this time period with a time constant of 9.8 h, while wing stiffness increased linearly by 46.2% at a rate of 23.4 {mu}N mm{sup -1} h{sup -1}. For the forewings of a single butterfly, the experiment was performed over a period of 1 week, and the results show that wing mass declined exponentially by 52.2% with a time constant of 30.2 h until it reached a steady-state level of 2.00 mg, while wing stiffness increased exponentially by 90.7% until it reached a steady-state level of 1.70 mN mm{sup -1}. (communication)

  6. Twenty-four-hour plasma tryptophan concentrations and ratios are below normal in obese subjects and are not normalized by substantial weight reduction

    Breum, Leif; Rasmussen, Michael H; Hilsted, Jannik


    subjects. Blood samples were drawn frequently throughout the 24-h period. An insulin tolerance test was also used to determine whether weight loss altered the ability of insulin to modify plasma concentrations of tryptophan and of the other large neutral amino acids. RESULTS: Plasma tryptophan......BACKGROUND: Plasma tryptophan concentrations and the ratio of tryptophan to other large neutral amino acids (plasma tryptophan ratio) are reportedly low in obese subjects. The plasma tryptophan ratio predicts brain tryptophan uptake and serotonin production. If this ratio is low in obese subjects...... concentrations and ratios in obese subjects were low at all times; these effects persisted after weight reduction. Plasma concentrations of all the large neutral amino acids decreased during insulin infusion in all the groups. CONCLUSIONS: The low 24-h plasma tryptophan ratios in obese and formerly obese...

  7. Parametric weight evaluation of joined wings by structural optimization

    Miura, Hirokazu; Shyu, Albert T.; Wolkovitch, Julian


    Joined-wing aircraft employ tandem wings having positive and negative sweep and dihedral, arranged to form diamond shapes in both plan and front views. An optimization method was applied to study the effects of joined-wing geometry parameters on structural weight. The lightest wings were obtained by increasing dihedral and taper ratio, decreasing sweep and span, increasing fraction of airfoil chord occupied by structural box, and locating the joint inboard of the front wing tip.

  8. Magnetization transfer ratio in the brain of preterm subjects: age-related changes during the first 2 years of life

    Xydis, Vassilios; Astrakas, Loukas; Zikou, Anastasia; Argyropoulou, Maria I. [University of Ioannina, Department of Radiology, Medical School, Ioannina (Greece); Pantou, Kostandina; Andronikou, Styliani [Medical School University of Ioannina, Neonatology Clinic, Child Health Department, Ioannina (Greece)


    To study the progress of myelination in preterm-born subjects by measuring the MT ratio (MTR) from birth, up to 24 months of corrected age.One hundred twenty-five preterm subjects (64 males and 61 females of gestational age 33{+-}2.4 weeks with chronologic and corrected age of 9.3{+-}5.1 and 7.7{+-}5.1 months, respectively) with normal brain MR using classic sequences were further evaluated for MTR by using a three-dimensional gradient-echo sequence (TR=32/TE=8/flip angle=6 4 mm/2 mm overlapping sections) with and without magnetization transfer prepulse. The magnetization transfer ratio was calculated as: MTR=(SIo-SIm)/SIo x 100%, where SIm refers to signal intensity from an image acquired with a MT prepulse and SIo the signal intensity from the image acquired without a MT prepulse. MTR increased asymptotically in the genu (R{sup 2}=0.85) and splenium (R{sup 2}=0.85) of the corpus callosum, the white matter of the frontal lobe (R{sup 2}=0.91) and occipital lobe (R{sup 2}=0.82), thalamus (R{sup 2}=0.86), caudate nucleus (R{sup 2}=0.67) and putamen (R{sup 2}=0.71), reaching the 95% of the final value at the corrected age 18.7, 17.7, 15.6, 12.9, 10.4, 9.2 and 6.4 months, respectively. This study shows age-related changes of the brain MTR and provides data that may be useful to assess disturbances in the progress of myelination. (orig.)

  9. Angel's Wings


    @@ Angel's wings had fallen off. It started slowly,a couple of feathers breaking loose in the wind,floating away in carefree spirals, then in clumps in the shower, matted wet and clogging the drain,until one day he woke in a thick layer of white plumage, quills snagging on the stained sheets.

  10. Topology of Vortex-Wing Interaction

    McKenna, Chris; Rockwell, Donald


    Aircraft flying together in an echelon or V formation experience aerodynamic advantages. Impingement of the tip vortex from the leader (upstream) wing on the follower wing can yield an increase of lift to drag ratio. This enhancement is known to depend on the location of vortex impingement on the follower wing. Particle image velocimetry is employed to determine streamline topology in successive crossflow planes, which characterize the streamwise evolution of the vortex structure along the chord of the follower wing and into its wake. Different modes of vortex-follower wing interaction are created by varying both the spanwise and vertical locations of the leader wing. These modes are defined by differences in the number and locations of critical points of the flow topology, and involve bifurcation, attenuation, and mutual induction. The bifurcation and attenuation modes decrease the strength of the tip vortex from the follower wing. In contrast, the mutual induction mode increases the strength of the follower tip vortex. AFOSR.

  11. 小展弦比飞翼标模纵航向气动特性低速实验研究%Low speed experiment on longitudinal and lateral aerodynamic characteristics of the low aspect ratio flying wing calibration model

    吴军飞; 秦永明; 黄湛; 魏忠武; 贾毅


    对小展弦比飞翼气动布局外形,通过常规测力风洞实验方法得到其纵向气动特性和偏航控制特性,在分析其气动特性后,选取典型的状态采用 PIV 实验方法对其流动机理进行研究,研究表明小展弦比飞翼在较小的迎角下即出现前缘分离涡,随着迎角的增大,前缘分离涡强度增大,且逐渐往机体对称面方向移动,随着迎角进一步增大,分离涡变得不稳定,涡核开始摆动,最终破裂,破裂位置从后缘开始,逐渐前移。对小展弦比飞翼气动布局飞机的控制难点偏航控制进行研究,结果表明该飞翼布局模型在实验迎角范围内偏航方向是静稳定的,在小迎角下具有可操纵性,迎角大于6°后嵌入面处于破裂的前缘涡尾迹之中,操纵性降低。%longitudinal and lateral aerodynamic characteristics of the low aspect ratio flying wing calibration model are investigated in a low speed wind tunnel.Normal force measuring ex-periment is conducted to gain the longitudinal aerodynamic characteristics and yaw control charac-teristics,and the PIV test is also conducted to investigate the flow mechanism of the low aspect ratio flying wing.The results indicate that the leading-edge separation vortex appears on the wing’s spine surface when the attack angle is at 6 degree.The vortex intensity increases and the vortex core shifts to the symmetric plane of flying wing with the increase of attack angle.Increas-ing the attack angle further,the vortex core becomes unsteady and begins to oscillate,finally break entirely.The broken position shifts from the ending edge to the leading edge.Yaw control characteristics of low aspect ratio flying wing is also studied in this paper.The results indicate that the flying wing is static stabile at the test attack angle.When the attack angle is less than 6 degree,it is controllable in yaw direction.And when attack angle is more than 6 degree,the yaw control

  12. Study on Static Test Technology for High-Aspect Ratio Wing of Full Scale Aircraft%全尺寸飞机大展弦比机翼静力试验技术研究

    刘兴科; 刘冰; 张建锋


    In the bearing capability static test of wing structure,because of the high-aspect ratio, the large deformation will arouse load direction changed.Taking the full scale aircraft structure as research obj ect,a test loading technology is proposed,which can realize the extractive wing loading.The static test of a certain type aircraft structure solves the problems of large deforma-tion loading,which has great realistic significance and application value.%在大展弦比飞机的机翼承载能力试验中,试验加载方向会因其大变形发生变化。本文以全尺寸结构机翼为研究对象,提出一种试验加载技术,最大程度实现机翼载荷的准确施加。通过此静强度试验,很好地解决了机翼试验大变形加载问题,具有较大的现实意义和应用价值。

  13. Aeroelastic response for straight wing with high aspect ratio due to sharp edge gust%锐边突风对大展弦比机翼的气动弹性响应影响

    刘伏虎; 马晓平


    基于Theodorsen非定常气动力理论,以大展弦比均匀直机翼为研究对象,建立了系统的气动弹性响应方程.选取二阶弯曲和二阶扭转模态,采用V-g法求解了系统的颤振速度.基于Kussner函数,建立了锐边突风系统模型,并推导了在弯曲和扭转模态阶数为Nw和Na下的系统状态方程,仿真研究了加入突风后系统的气动弹性响应.结果表明,加入突风后翼尖响应振幅增大.%Based on Theodorsen unsteady aerodynamics theory, the equation of aeroelastic response for straight wing with high aspect ratio is established. Flutter speed is determined for two bending modes and two torsional modes using V-g methods. The sharp edge gust system model is established and the system state equations are derived with Nw bending modes and Na torsional modes wing systems based on the function Kussner. The aeroelastic response of system shows that the amplitude oscillation becomes higher. The modeling method may offer reference for research of gust response.

  14. 大型客机发动机振动载荷传递特性研究%Exploring Wing-Mounted Engine Vibration Transmission for New Generation Airplanes with Turbofan Engines of High Bypass Ratio

    陈熠; 贺尔铭; 扈西枝; 韩峰


    The use of turbofan engines of high bypass ratio has caused the low-frequency structure-borne noise. To investigate the medium and low frequency vibration transmission through wing structure to airframe, we introduce the double-beam dynamic model of a wing and build the "pylon-wing-airframe" dynamic half model of a full airplane, which takes into account the dynamics of an actual airplane. Sections 1 through 4 of the full paper explain the exploration mentioned in the title; their core consists of; ( 1) we use the vibration spectrum of the turbofan engines to calculate the vibration load of the airplane at each section of the airframe transmitted from wing to the air-frame , which provides the input data for estimating the noise level of the pressurized cabin; (2) through simulation , we identify the main path of engines' vibration transmission to the airframe; the simulation results, given in Figs. 6 and 7, and their analysis form, in our opinion, a useful preparation for pylon structure vibration reduction, engine vibration isolation mounting and the acoustic design inside the cabin.%高涵道比涡扇发动机的振动冲击频段向低频转移,使得飞机舱内噪声频率分布中的低频结构传递噪声变得更加突出.为了研究发动机振动载荷通过机翼向机身传递的中低频振动特性,文章针对真实客机的结构动力特性,创新地提出了机翼双梁动力学模型概念,建立了“吊架-机翼-机身”全机动力学有限元模型;基于发动机的振动载荷谱,分析了发动机振动通过机翼向机身结构传递的载荷特性,为后续舱内噪声预计提供了数据输入;并仿真辨识了发动机振动传递的主路径,为舱内声学设计及发动机隔振安装提供了基础数据.文中研究结果对我国大型客机的减振降噪设计工作有重要的工程参考价值.

  15. Average values and racial differences of neutrophil lymphocyte ratio among a nationally representative sample of United States subjects.

    Basem Azab

    Full Text Available Several studies reported the negative impact of elevated neutrophil/lymphocyte ratio (NLR on outcomes in many surgical and medical conditions. Previous studies used arbitrary NLR cut-off points according to the average of the populations under study. There is no data on the average NLR in the general population. The aim of this study is to explore the average values of NLR and according to race in adult non-institutional United States individuals by using national data.The National Health and Nutrition Examination Survey (NHANES of aggregated cross-sectional data collected from 2007 to 2010 was analyzed; data extracted included markers of systemic inflammation (neutrophil count, lymphocyte count, and NLR, demographic variables and other comorbidities. Subjects who were prescribed steroids, chemotherapy, immunomodulators and antibiotics were excluded. Adjusted linear regression models were used to examine the association between demographic and clinical characteristics and neutrophil counts, lymphocyte counts, and NLR.Overall 9427 subjects are included in this study. The average value of neutrophils is 4.3 k cells/mL, of lymphocytes 2.1k cells/mL; the average NLR is 2.15. Non-Hispanic Black and Hispanic participants have significantly lower mean NLR values (1.76, 95% CI 1.71-1.81 and 2.08, 95% CI 2.04-2.12 respectively when compared to non-Hispanic Whites (2.24, 95% CI 2.19-2.28-p<0.0001. Subjects who reported diabetes, cardiovascular disease, and smoking had significantly higher NLR than subjects who did not. Racial differences regarding the association of smoking and BMI with NLR were observed.This study is providing preliminary data on racial disparities in a marker of inflammation, NLR, that has been associated with several chronic diseases outcome, suggesting that different cut-off points should be set according to race. It also suggests that racial differences exist in the inflammatory response to environmental and behavioral risk factors.

  16. Analysis of bat wings for morphing

    Leylek, Emily A.; Manzo, Justin E.; Garcia, Ephrahim


    The morphing of wings from three different bat species is studied using an extension of the Weissinger method. To understand how camber affects performance factors such as lift and lift to drag ratio, XFOIL is used to study thin (3% thickness to chord ratio) airfoils at a low Reynolds number of 100,000. The maximum camber of 9% yielded the largest lift coefficient, and a mid-range camber of 7% yielded the largest lift to drag ratio. Correlations between bat wing morphology and flight characteristics are covered, and the three bat wing planforms chosen represent various combinations of morphological components and different flight modes. The wings are studied using the extended Weissinger method in an "unmorphed" configuration using a thin, symmetric airfoil across the span of the wing through angles of attack of 0°-15°. The wings are then run in the Weissinger method at angles of attack of -2° to 12° in a "morphed" configuration modeled after bat wings seen in flight, where the camber of the airfoils comprising the wings is varied along the span and a twist distribution along the span is introduced. The morphed wing configurations increase the lift coefficient over 1000% from the unmorphed configuration and increase the lift to drag ratio over 175%. The results of the three different species correlate well with their flight in nature.

  17. Wind-tunnel investigation of longitudinal and lateral-directional stability and control characteristics of a 0.237-scale model of a remotely piloted research vehicle with a thick, high-aspect-ratio supercritical wing

    Byrdsong, T. A.; Brooks, C. W., Jr.


    A 0.237-scale model of a remotely piloted research vehicle equipped with a thick, high-aspect-ratio supercritical wing was tested in the Langley 8-foot transonic tunnel to provide experimental data for a prediction of the static stability and control characteristics of the research vehicle as well as to provide an estimate of vehicle flight characteristics for a computer simulation program used in the planning and execution of specific flight-research mission. Data were obtained at a Reynolds number of 16.5 x 10 to the 6th power per meter for Mach numbers up to 0.92. The results indicate regions of longitudinal instability; however, an adequate margin of longitudinal stability exists at a selected cruise condition. Satisfactory effectiveness of pitch, roll, and yaw control was also demonstrated.

  18. Cerebral PET glucose hypometabolism in subjects with mild cognitive impairment and higher EEG high-alpha/low-alpha frequency power ratio.

    Moretti, Davide Vito; Pievani, Michela; Pini, Lorenzo; Guerra, Ugo Paolo; Paghera, Barbara; Frisoni, Giovanni Battista


    In Alzheimer's disease (AD) research, both 2-deoxy-2-((18)F)fluoro-D-glucose (FDG) positron emission tomography (PET) and electroencephalography (EEG) are reliable investigational modalities. The aim of this study was to investigate the associations between EEG High-alpha/Low-alpha (H-alpha/L-alpha) power ratio and cortical glucose metabolism. A total of 23 subjects with mild cognitive impairment (MCI) underwent FDG-PET and EEG examinations. H-alpha/L-alpha power ratio was computed for each subject and 2 groups were obtained based on the increase of the power ratio. The subjects with higher H-alpha/L-alpha power ratio showed a decrease in glucose metabolism in the hub brain areas previously identified as typically affected by AD pathology. In subjects with higher H-alpha/L-alpha ratio and lower metabolism, a "double alpha peak" was identified in the EEG spectrum and a U-shaped correlation between glucose metabolism and increase of H-alpha/L-alpha power ratio has been found. Moreover, in this group, a conversion rate of 62.5% at 24 months was detected, significantly different from the chance percentage expected. The neurophysiological meaning of the interplay between alpha oscillations and glucose metabolism and the possible interest of the H-alpha/L-alpha power ratio as a clinical biomarker in AD have been discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Analysis of Grey Matter in Thalamus and Basal Ganglia Based on EEG α3/α2 Frequency Ratio Reveals Specific Changes in Subjects with Mild Cognitive Impairment

    Davide V Moretti


    Full Text Available GM (grey matter changes of thalamus and basal ganglia have been demonstrated to be involved in AD (Alzheimer's disease. Moreover, the increase of a specific EEG (electroencephalogram marker, α3/α2, have been associated with AD-converters subjects with MCI (mild cognitive impairment. To study the association of prognostic EEG markers with specific GM changes of thalamus and basal ganglia in subjects with MCI to detect biomarkers (morpho-physiological early predictive of AD and non-AD dementia. Seventy-four adult subjects with MCI underwent EEG recording and high-resolution 3D MRI (three-dimensional magnetic resonance imaging. The α3/α2 ratio was computed for each subject. Three groups were obtained according to increasing tertile values of α3/α2 ratio. GM density differences between groups were investigated using a VBM (voxel-based morphometry technique. Subjects with higher α3/α2 ratios when compared with subjects with lower and middle α3/α2 ratios showed minor atrophy in the ventral stream of basal ganglia (head of caudate nuclei and accumbens nuclei bilaterally and of the pulvinar nuclei in the thalamus; The integrated analysis of EEG and morpho-structural markers could be useful in the comprehension of anatomo-physiological underpinning of the MCI entity.

  20. Effect of wing mass in free flight by a butterfly-like 3D flapping wing-body model

    Suzuki, Kosuke; Okada, Iori; Yoshino, Masato


    The effect of wing mass in free flight of a flapping wing is investigated by numerical simulations based on an immersed boundary-lattice Boltzmann method. We consider a butterfly-like 3D flapping wing-model consisting of two square wings with uniform mass density connected by a rod-shaped body. We simulate free flights of the wing-body model with various mass ratios of the wing to the whole of the model. As a result, it is found that the lift and thrust forces decrease as the mass ratio increases, since the body with a large mass ratio experiences large vertical and horizontal oscillations in one period and consequently the wing tip speed relatively decreases. In addition, we find the critical mass ratio between upward flight and downward flight for various Reynolds numbers. This work was supported by JSPS KAKENHI Grant Number JP16K18012.

  1. Veins improve fracture toughness of insect wings.

    Jan-Henning Dirks

    Full Text Available During the lifetime of a flying insect, its wings are subjected to mechanical forces and deformations for millions of cycles. Defects in the micrometre thin membranes or veins may reduce the insect's flight performance. How do insects prevent crack related material failure in their wings and what role does the characteristic vein pattern play? Fracture toughness is a parameter, which characterises a material's resistance to crack propagation. Our results show that, compared to other body parts, the hind wing membrane of the migratory locust S. gregaria itself is not exceptionally tough (1.04±0.25 MPa√m. However, the cross veins increase the wing's toughness by 50% by acting as barriers to crack propagation. Using fracture mechanics, we show that the morphological spacing of most wing veins matches the critical crack length of the material (1132 µm. This finding directly demonstrates how the biomechanical properties and the morphology of locust wings are functionally correlated in locusts, providing a mechanically 'optimal' solution with high toughness and low weight. The vein pattern found in insect wings thus might inspire the design of more durable and lightweight artificial 'venous' wings for micro-air-vehicles. Using the vein spacing as indicator, our approach might also provide a basis to estimate the wing properties of endangered or extinct insect species.

  2. The effect of the elliptical ratio on the tubular energy absorber subjected to lateral loading under quasistatic conditions

    Olabi A.G.; Baroutaji A.


    Tubular systems are proposed to be used as energy absorber because they are cheap and easy to manufacture; recently some researchers use the elliptical tube as energy absorber. In this work, the influence of elliptical ratio (r =D1/D2) on energy absorption capability and load carrying capacity and stress of mild steel elliptical tubes has been investigated both experimentally and numerically, the experimental analyses conducted by using Zwick Type BT1-FB050TN testing instrument. This m...

  3. Design and aerodynamic characteristics of a span morphing wing

    Yu, Yuemin; Liu, Yanju; Leng, Jinsong


    Flight vehicles are often designed to function around a primary operating point such as an efficient cruise or a high maneuverability mode. Performance and efficiency deteriorate rapidly as the airplane moves towards other portions of the flight envelope. One solution to this quandary is to radically change the shape of the aircraft. This yields both improved efficiency and a larger flight envelope. This global shape change is an example of morphing aircraft . One concept of morphing is the span morphing wing in which the wingspan is varied to accommodate multiple flight regimes. This type of design allows for at least two discreet modes of the aircraft. The original configuration, in which the extensible portion of the wing is fully retracted, yields a high speed dash mode. Fully extending the wing provides the aircraft with a low speed mode tailored for fine tracking and loiter tasks. This paper discusses the design of a span morphing wing that permits a change in the aspect ratio while simultaneously supporting structural wing loads. The wing cross section is maintained by NACA 4412 rib sections . The span morphing wing was investigated in different configurations. The wing area and the aspect ratio of the span morphing wing increase as the wings pan increases. Computational aerodynamics are used to estimate the performance and dynamic characteristics of each wing shape of this span morphing wing as its wingspan is changed. Results show that in order to obtain the same lift, the conventional wing requires a larger angle of attach(AOA) than that of the span morphing wing.The lift of the span morphing wing increases as the wing span ,Mach number and AOA increases.

  4. The effect of the elliptical ratio on the tubular energy absorber subjected to lateral loading under quasistatic conditions

    Baroutaji, A.; Olabi, A. G.


    Tubular systems are proposed to be used as energy absorber because they are cheap and easy to manufacture; recently some researchers use the elliptical tube as energy absorber. In this work, the influence of elliptical ratio (r =D1/D2) on energy absorption capability and load carrying capacity and stress of mild steel elliptical tubes has been investigated both experimentally and numerically, the experimental analyses conducted by using Zwick Type BT1-FB050TN testing instrument. This machine is universal instrument for performing tensile test and compression test, Fig (1) and bending test and it is consider as an important machine for measuring the mechanical properties of materials and structures. The loading frame consist of two vertical lead screws, a moving crosshead and an upper and lower bearing plate which bears the load of the lead screws. The maximum capacity of the loading frame attached to the table mounted unit is 50KN In this study a velocity between 310mm/min was applied to the moving component to ensure the quasistatic conditions whereas velocities between 0.5mm/min and 15 mm/min have been used by many researchers to simulate the quasi-static lateral compression of tubes between various indenters [1-2]. In addition to the experimental work, computational method using ANSYS is used to predict the loading and response of such tubes where series of models was performed with elliptical ratios ranging from 0.5 to 1.5. Comparison of numerical and experimental forcedeflection response is presented. It has been found that with changing the elliptical ratio of the tube the loaddeflection curve change and this leads to change the energy absorbed by tube, the changing of the geometrical shape of the tube leads to change the volume of this tube and hence the mass. By reducing the elliptical ratio to 0.5 the tube will absorb 43.3% more energy and the system will gain 102% more in terms of specific energy, fig (2).

  5. The effect of the elliptical ratio on the tubular energy absorber subjected to lateral loading under quasistatic conditions

    Olabi A.G.


    Full Text Available Tubular systems are proposed to be used as energy absorber because they are cheap and easy to manufacture; recently some researchers use the elliptical tube as energy absorber. In this work, the influence of elliptical ratio (r =D1/D2 on energy absorption capability and load carrying capacity and stress of mild steel elliptical tubes has been investigated both experimentally and numerically, the experimental analyses conducted by using Zwick Type BT1-FB050TN testing instrument. This machine is universal instrument for performing tensile test and compression test, Fig (1 and bending test and it is consider as an important machine for measuring the mechanical properties of materials and structures. The loading frame consist of two vertical lead screws, a moving crosshead and an upper and lower bearing plate which bears the load of the lead screws. The maximum capacity of the loading frame attached to the table mounted unit is 50KN In this study a velocity between 310mm/min was applied to the moving component to ensure the quasistatic conditions whereas velocities between 0.5mm/min and 15 mm/min have been used by many researchers to simulate the quasi-static lateral compression of tubes between various indenters [1-2]. In addition to the experimental work, computational method using ANSYS is used to predict the loading and response of such tubes where series of models was performed with elliptical ratios ranging from 0.5 to 1.5. Comparison of numerical and experimental forcedeflection response is presented. It has been found that with changing the elliptical ratio of the tube the loaddeflection curve change and this leads to change the energy absorbed by tube, the changing of the geometrical shape of the tube leads to change the volume of this tube and hence the mass. By reducing the elliptical ratio to 0.5 the tube will absorb 43.3% more energy and the system will gain 102% more in terms of specific energy, fig (2.

  6. Use of T1-weighted/T2-weighted magnetic resonance ratio to elucidate changes due to amyloid β accumulation in cognitively normal subjects

    Fumihiko Yasuno


    Full Text Available The ratio of signal intensity in T1-weighted (T1w and T2-weighted (T2w magnetic resonance imaging (MRI was recently proposed to enhance the sensitivity of detecting changes in disease-related signal intensity. The objective of this study was to test the effectiveness of T1w/T2w image ratios as an easily accessible biomarker for amyloid beta (Aβ accumulation. We performed the T1w/T2w analysis in cognitively normal elderly individuals. We applied [11C] Pittsburgh Compound B (PiB-PET to the same individuals, and Aβ deposition was quantified by its binding potential (PiB-BPND. The subjects were divided into low and high PiB-BPND groups, and group differences in regional T1w/T2w values were evaluated. In the regions where we found a significant group difference, we conducted a correlation analysis between regional T1w/T2w values and PiB-BPND. Subjects with high global cortical PiB-BPND showed a significantly higher regional T1w/T2w ratio in the frontal cortex and anterior cingulate cortex. We found a significant positive relationship between the regional T1w/T2w ratio and Aβ accumulation. Moreover, with a T1w/T2w ratio of 0.55 in the medial frontal regions, we correctly discriminated subjects with high PiB-BPND from the entire subject population with a sensitivity of 84.6% and specificity of 80.0%. Our results indicate that early Aβ-induced pathological changes can be detected using the T1w/T2w ratio on MRI. We believe that the T1w/T2w ratio is a prospective stable biological marker of early Aβ accumulation in cognitively normal individuals. The availability of such an accessible marker would improve the efficiency of clinical trials focusing on the initial disease stages by reducing the number of subjects who require screening by Aβ-PET scan or lumbar puncture.

  7. Aerodynamics on a transport aircraft type wing-body model

    Schmitt, V.


    The DFLR-F4 wing-body combination is studied. The 1/38 model is formed by a 9.5 aspect ratio transonic wing and an Airbus A 310 fuselage. The F4 wing geometrical characteristics are described and the main experimental results obtained in the S2MA wind tunnel are discussed. Both wing-fuselage interferences and viscous effects, which are important on the wing due to a high rear loading, are investigated by performing 3D calculations. An attempt is made to find their limitations.

  8. Investigation and design of a C-Wing passenger aircraft

    Karan BIKKANNAVAR; Scholz, Dieter


    A novel nonplanar wing concept called C-Wing is studied and implemented on a commercial aircraft to reduce induced drag which has a significant effect on fuel consumption. A preliminary sizing method which employs an optimization algorithm is utilized. The Airbus A320 aircraft is used as a reference aircraft to evaluate design parameters and to investigate the C-Wing design potential beyond current wing tip designs. An increase in aspect ratio due to wing area reduction at 36m span results in...

  9. Whey protein improves HDL/non-HDL ratio and body weight gain in rats subjected to the resistance exercise

    Kely Raspante Teixeira


    Full Text Available The aim of this study was to evaluate the effects of resistance exercise, such as weight-lifting (WL on the biochemical parameters of lipid metabolism and cardiovascular disease risk in the rats fed casein (control or whey protein (WP diets. Thirty-two male Fisher rats were randomly assigned to sedentary or exercise-trained groups and were fed control or WP diets. The WL program consisted of inducing the animals to perform the sets of jumps with weights attached to the chest. After seven weeks, arteriovenous blood samples were collected for analysis. The WL or WP ingestion were able to improve the lipid profile, reducing the TC and non-HDL cholesterol concentrations, but only WP treatment significantly increased the serum HDL concentrations, thereby also affecting the TC/HDL and HDL/non-HDL ratios. However, WL plus WP was more effective in improving the HDL/non-HDL ratio than the exercise or WP ingestion alone and the body weight gain than exercise without WP ingestion.

  10. The Realization and Study of Optical Wings

    Artusio-Glimpse, Alexandra Brae

    Consider the airfoil: a carefully designed structure capable of stable lift in a uniform air flow. It so happens that air pressure and radiation (light) pressure are similar phenomena because each transfer momentum to flow-disturbing objects. This, then, begs the question: does an optical analogue to the airfoil exist? Though an exceedingly small effect, scientists harness radiation pressure in a wide gamut of applications from micromanipulation of single biological particles to the propulsion of large spacecrafts called solar sails. We introduce a cambered, refractive rod that is subjected to optical forces analogous to those seen in aerodynamics, and I call this analogue the optical wing. Flight characteristics of optical wings are determined by wing shape and material in a uniform radiation field. Theory predicts the lift force and axial torque are functions of the wing's angle of attack with stable and unstable orientations. These structures can operate as intensity-dependent, parametrically driven oscillators. In two-dimensions, the wings exhibit bistability when analyzed in an accelerating frame. In three-dimensions, the motion of axially symmetric spinning hemispherical wings is analogous to a spinning top. Experiments on semi-buoyant wings in water found semicylindrically shaped, refractive microparticles traversed a laser beam and rotated to an illumination-dependent stable orientation. Preliminary tests aid in the development of a calibrated force measurement experiment to directly evaluate the optical forces and torque on these samples. A foundational study of the optical wing, this work contributes to future advancements of flight-by-light.

  11. The ratio of the subjective audiometry in patients with acoustic trauma and “noisy” production workers

    Shydlovska T.А.


    Full Text Available Introduction: The problem of diagnosis and treatment of sensorineural hearing loss (SHL, including forms developed under the influence of noise, takes one of the leading places in ot¬olaryngology. However, there are not many studies on acoustic trauma, although this problem has recently become more and more important. Objective: A comparison of subjective audiometry in patients with sensorineural hearing loss after acute acoustic trauma and chronic noise exposure. Materials and methods. In the work the results of exa¬mination of 84 patients with acoustic trauma, 15 healthy as the control group and 15 workers employed on 'noise' occupations as a comparison group are given. Subjective audiometry was fully carried out by clinical audiometer AC-40 «Interacoustics» (Denmark. Hearing indices were investigated in the conventional (0,125-8 kHz and extended (9-16 kHz frequency bands. Results: Subjective audiometry showed a reduction in sound perception in all patients. Ac¬cor¬ding to the threshold tone audiometry in patients with acoustic trauma hearing thresholds were authentically (P <0,05 increased by 4, 6 and 8 kHz tones of conventional (0,125-8 kHz frequency band and by 14-16 kHz tones of the extended (9-16 kHz in comparison with the control group, as with workers employed on noise occupations. All the examined patients had deterioration of speech-test audiometry and above-threshold audiometry. Conclusions: According to su¬b¬jective audiometry, the type similar disorders of auditory function are in patients with acoustic trauma as in patients with long-term noise exposure, but they are more pronounced and develop much faster. The most informative features which show the origin and progression of hearing loss in patients with acoustic trauma are: increasing hearing thresholds by 14 and 16 kHz tones of the extended (9-16 kHz frequency band and by 4, 6 and 8 kHz tones of con¬ven¬tional (0,125-8 kHz frequency band plus the reduction of

  12. Vortices around Dragonfly Wings

    Kweon, Jihoon; Choi, Haecheon


    Dragonfly beats its wings independently, resulting in its superior maneuverability. Depending on the magnitude of phase difference between the fore- and hind-wings of dragonfly, the vortical structures and their interaction with wings become significantly changed, and so does the aerodynamic performance. In this study, we consider hovering flights of modelled dragonfly with three different phase differences (phi=-90, 90, 180 degrees). The three-dimensional wing shape is based on that of Aesch...

  13. Electron-ion temperature ratio estimations in the summer polar mesosphere when subject to HF radio wave heating

    Pinedo, H.; La Hoz, C.; Havnes, O.; Rietveld, M.


    We have inferred the electron temperature enhancements above mesospheric altitudes under Polar Mesospheric Summer Echoes (PMSE) conditions when the ionosphere is exposed to artificial HF radio wave heating. The proposed method uses the dependence of the radar cross section on the electron-to-ion temperature ratio to infer the heating factor from incoherent scatter radar (ISR) power measurements above 90 km. Model heating temperatures match our ISR estimations between 90 and 130 km with 0.94 Pearson correlation index. The PMSE strength measured by the MORRO MST radar is about 50% weaker during the heater-on period when the modeled electron-to-ion mesospheric temperature is approximately 10 times greater than the unperturbed value. No PMSE weakening is found when the mesospheric temperature enhancement is by a factor of three or less. The PMSE weakening and its absence are consistent with the modeled mesospheric electron temperatures. This consistency supports to the proposed method for estimating mesospheric electron temperatures achieved by independent MST and ISR radar measurements.

  14. Wing-Alone Aerodynamic Characteristics to High Angles of Attack at Subsonic and Transonic Speeds.


    indicators of symmetry since the wings were unbanked within the limits of tolerances and flow angularity. Longitudinal, spanwise, and vertical... unbanked wings at subsonic and transonic speeds from low to high angles of attack. The wing planforms varied in aspect ratio and taper ratio with

  15. The effect of water loading on the urinary ratio of cortisone to cortisol in healthy subjects and a new approach to the evaluation of the ratio as an index for in vivo human 11β-hydroxysteroid dehydrogenase 2 activity.

    Yokokawa, Akitomo; Takasaka, Toru; Shibasaki, Hiromi; Kasuya, Yasuji; Kawashima, Soko; Yamada, Akira; Furuta, Takashi


    Factors that give rise to a large variation in the urinary ratio of free cortisone to cortisol (UFE/UFF) were investigated to accurately estimate 11β-hydroxysteroid dehydrogenase 2 (11β-HSD2) activity in humans in vivo. A water loading test was first carried out in two healthy subjects to examine the effect of water intake or urine volume on the urinary ratio of free cortisone to cortisol (UFE/UFF). The ratio was found to increase by water loading. We also examined urinary concentrations and amounts of cortisol, cortisone, creatinine, Na(+), K(+), and Cl(-), and urine volume, as possible factors affecting the urinary ratio (UFE/UFF), in 60 urine samples obtained from 15 healthy volunteers. Among these factors tested, the urinary concentration of cortisol was most highly correlated with the UFE/UFF ratio (r=-0.858), indicating that the in vivo activity of 11β-HSD2 (UFE/UFF) should fluctuate with the changes of the urinary concentration of cortisol. Based on the findings, we proposed a new estimation method of in vivo activity of 11β-HSD2 in humans, using the UFE/UFF ratio correlated with the urinary concentration of cortisol (UFE/UFF-cortisol concentration). Taking into consideration the intra-individual variabilities in the urinary concentration of cortisol, there were no significant within-day variations in 11β-HSD2 activity. The findings indicate that 11β-HSD2 activities can be accurately evaluated by simply measuring free cortisol and cortisone concentrations in spot urine samples. Furthermore, administrations of glycyrrhetinic acid in three healthy volunteers were performed to confirm the usefulness of the present assessment for the activity of 11β-HSD2. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. Cephalometric evaluation of adenoids, upper airway, maxilla, velum length, need ratio for determining velopharyngeal incompetency in subjects with unilateral cleft lip and palate

    Avinash Gohilot


    Full Text Available Objectives: Children with cleft lip and palate (CLP are seen to have reduced airway size and large adenoids, which might lead to different characteristics in the upper airway and surrounding tissues from both morphological and functional perspectives. Decrease in adenoid size and increase in need ratio in cleft patients might lead to velopharyngeal incompetency (VPI and development of nasality in adulthood. No studies have been conducted on the Indian population with variables contributing to VPI. So the aim was to evaluate the size and position of the adenoids, upper airway, maxilla, velum length and need ratio contributing to VPI in subjects with and without unilateral cleft lip and palate (UCLP during juvenile and adolescent stages. Materials and Methods: Cephalograms of 120 subjects with 6-17 years were taken and various linear and angular measurements were measured and data was analyzed using the unpaired t test. Results: Adenoids were significantly larger and the upper airway smaller in the juvenile and adolescent cleft group than in the non-cleft group. In the adolescent cleft group, airway was larger than that in the adolescent non-cleft group. The maxilla was small and retropositioned in juvenile and adolescent subjects as compared to non cleft cases. Length of velum was smaller and need ratio was larger in both juvenile and adolescent groups as compared to the non-cleft group, suggestive of velopharyngeal incompetence. Conclusion: Decreased Adenoids, restricted airway, small, retruded maxilla, smaller velum length and larger need ratio larger were seen in the cleft group as compared to the non-cleft group, which was suggestive of VPI.

  17. [Study of ventricular function by means of echocardiographic quantification of the thickness/radius (h/r) ratio of the left ventricle in healthy subjects].

    Guadalajara, J F; Martínez, C; Gutiérrez, E; Zamora, C; Huerta, D


    We studied 72 healthy subjects; 31 of them were adults and 41 children. By means of two-dimensional echocardiography we obtained a short axis view at the papillary muscle level of the ratio of the thickness (h) of the ventricular wall and the radius (r) of the cavity. We analysed ventricular performance determinants (pre-load, after-load and contractility). This non-invasive method gives information similar to pressure-volume curves. Thus, we propose it for the study of left ventricular overloads.

  18. Increased Risk of Progression of Coronary Artery Calcification in Male Subjects with High Baseline Waist-to-Height Ratio: The Kangbuk Samsung Health Study.

    Oh, Hyung Geun; Nallamshetty, Shriram; Rhee, Eun Jung


    The waist-to-height ratio (WHtR) is an easy and inexpensive adiposity index that reflects central obesity. In this study, we examined the association of baseline WHtR and progression of coronary artery calcification (CAC) over 4 years of follow-up in apparently healthy Korean men. A total of 1,048 male participants (mean age, 40.9 years) in a health-screening program in Kangbuk Samsung Hospital, Seoul, Korea who repeated a medical check-up in 2010 and 2014 were recruited. Baseline WHtR was calculated using the value for the waist in 2010 divided by the value for height in 2010. The CAC score (CACS) of each subject was measured by multi-detector computed tomography in both 2010 and 2014. Progression of CAC was defined as a CACS change over 4 years greater than 0. During the follow-up period, progression of CAC occurred in 278 subjects (26.5%). The subjects with CAC progression had slightly higher but significant baseline WHtR compared to those who did not show CAC progression (0.51±0.04 vs. 0.50±0.04, P<0.01). The proportion of subjects with CAC progression significantly increased as the baseline WHtR increased from the 1st quartile to 4th quartile groups (18.3%, 18.7%, 28.8%, and 34.2%; P<0.01). The risk for CAC progression was elevated with an odds ratio of 1.602 in the 4th quartile group of baseline WHtR even after adjustment for confounding variables (95% confidence interval, 1.040 to 2.466). Increased baseline WHtR was associated with increased risk for CAC progression. WHtR might be a useful screening tool to identify individuals at high risk for subclinical atherosclerosis.

  19. Slotted Aircraft Wing

    McLean, James D. (Inventor); Witkowski, David P. (Inventor); Campbell, Richard L. (Inventor)


    A swept aircraft wing includes a leading airfoil element and a trailing airfoil element. At least one full-span slot is defined by the wing during at least one transonic condition of the wing. The full-span slot allows a portion of the air flowing along the lower surface of the leading airfoil element to split and flow over the upper surface of the trailing airfoil element so as to achieve a performance improvement in the transonic condition.

  20. The effects of corrugation and wing planform on the aerodynamic force production of sweeping model insect wings

    Guoyu Luo; Mao Sun


    The effects of corrugation and wing planform (shape and aspect ratio) on the aerodynamic force production of model insect wings in sweeping (rotating after an initial start) motion at Reynolds number 200 and 3500 at angle of attack 40° are investigated, using the method of computational fluid dynamics. A representative wing corrugation is considered. Wing-shape and aspect ratio (AR) of ten representative insect wings are considered; they are the wings of fruit fly, cranefly, dronefly, hoverfly, ladybird, bumblebee, honeybee, lacewing (forewing), hawkmoth and dragonfly (forewing), respectively (AR of these wings varies greatly,from 2.84 to 5.45). The following facts are shown.(1) The corrugated and flat-plate wings produce approximately the same aerodynamic forces. This is because for a sweeping wing at large angle of attack, the length scale of the corrugation is much smaller than the size of the separated flow region or the size of the leading edge vortex (LEV). (2) The variation in wing shape can have considerable effects on the aerodynamic force; but it has only minor effects on the force coefficients when the velocity at r2 (the radius of the second moment of wing area) is used as the reference velocity; i.e.the force coefficients are almost unaffected by the variation in wing shape. (3) The effects of AR are remarkably small:when AR increases from 2.8 to 5.5, the force coefficients vary only slightly; flowfield results show that when AR is relatively large, the part of the LEV on the outer part of the wings sheds during the sweeping motion. As AR is increased, on one hand,the force coefficients will be increased due to the reduction of 3-dimensional flow effects; on the other hand, they will be decreased due to the shedding of pan of the LEV; these two effects approximately cancel each other, resulting in only minor change of the force coefficients.

  1. Flexibility and inertia of flapping wings in forward flight

    Tian, Fang-Bao; Luo, Haoxiang; Lu, Xi-Yun


    Insect wings typically deform passively in flight under the combined aerodynamic force and inertia of the wing. To study the effect of the wing flexibility on the aerodynamic performance, a two-dimensional numerical study is employed to simulate the fluid-structure interaction of an elastic plate performing forward flight. The leading edge of the plate is clamped, while the rest of the chord is free to deform, leading to passive pitching and a dynamic camber. The wing stiffness and mass ratio are varied, and their effects on the lift, thrust, and aerodynamic power are investigated. The results shows that the moderate chordwise deformation can improve both lift and thrust performance significantly. The instantaneous passive pitching angle and consequently the forces are largely affected by the mass ratio that determines whether the deformation is caused by the wing inertia or the aerodynamic force. The high mass ratio wings, whose deformation is due to the wing inertia, can produce more thrust than the low mass ratio wing at the same amount of deformation. However, the high thrust is gained at a price of more power requirement. This work is sponsored by the U.S. NSF and the NSF of China.

  2. The ratio of animal protein intake to potassium intake is a predictor of bone resorption in space flight analogues and in ambulatory subjects

    Zwart, Sara R.; Hargens, Alan R.; Smith, Scott M.


    BACKGROUND: Bone loss is a critical concern for space travelers, and a dietary countermeasure would be of great benefit. Dietary protein and potassium-associated bicarbonate precursors may have opposing effects on the acid-base balance in the body and therefore on bone loss. OBJECTIVE: In 2 studies, we examined the ability of dietary protein and potassium to predict markers of bone metabolism. DESIGN: In the first study, 8 pairs of male identical twins were assigned to 1 of 2 groups: bed rest (sedentary, or SED, group) or bed rest with supine treadmill exercise in a lower-body negative pressure chamber (EX group). In a second study, groups of 4 subjects lived in a closed chamber for 60 or 91 d, and dietary data were collected for two or three 5-d sessions. Urinary calcium, N-telopeptide, and pyridinium cross-links were measured before bed rest; on bed rest days 5-6, 12-13, 19-20, and 26-27; and daily during the chamber studies. Data were analyzed by Pearson's correlation (P protein intake to potassium intake was significantly correlated with N-telopeptide in the SED group during bed rest weeks 3 and 4 (r = 0.77 and 0.80) and during the 91-d chamber study (r = 0.75). The ratio of animal protein intake to potassium intake was positively correlated with pyridinium cross-links before bed rest in the EX group (r = 0.83), in the EX group during bed rest week 1 (r = 0.84), and in the SED group during bed rest week 2 (r = 0.72) but not during either chamber study. In both studies, these relations were not significant with the ratio of vegetable protein intake to potassium intake. CONCLUSIONS: The ratio of animal protein intake to potassium intake may affect bone in ambulatory and bed-rest subjects. Changing this ratio may help to prevent bone loss on Earth and during space flight.

  3. Multi-objective Aerodynamic and Stealthy Performance Optimization for Large- aspect- ratio Forward- swept Wings%大展弦比前掠翼气动隐身多目标优化

    廖炎平; 刘莉; 龙腾


    Forward- Swept wing (FSW) configuration provides a now direction for the aerodynamic configuration desigu of UAV benause its excellent aerodynamic characteristics. The Class-Shape function Transformation (CST) method is used to describe the parameterized airfoil geometry. The parameterized models for aerodynamic and stealthy performance of FSW are constructed. The aerodynamic analysis model of FSW is constructed by computational fluid dynamics method basod on N - S equations. Tbe stealthy performance analysis model of FSW is constructed by computational electromagnetics method based Method of Moments ( MoM ). The multi - objective aerodynamic and stealthy performance optimization method for FSW using Kriging model is presented. The Latin hypercube method is employed to get a set of sample points. The aerodynamic and stealthy perfomance Kriging models are built. The multi-objective aerodynamic and stealthy performance optimization of FSW is optimized by combining Pareto genetic algorithm with Krigthg model. The results of the investigation show that the constructed analysis models are reasonable and the presented multi- objective optimization design method is feasible ,which can improve the performance of large- aspect- ratio FSW and the efficiency of optimization effiectively.%前掠翼布局优越的气动性能为无人机气动布局设计提供了一条新的方向.采用CST方法对翼型几何外形进行参数化描述,实现前掠翼气动和隐身多学科优化设计模型的参数化描述.建立了基于N-S方程的计算流体力学方法的前掠翼气动分析模型和基于矩量法的计算电磁学方法的前掠翼隐身分析模型.提出了基于Kriging模型的前掠翼气动隐身多目标优化方法,采用拉丁超方试验设计方法获取样本点,建立前掠翼气动和隐身的Kriging代理模型.将Pareto多目标遗传算法与Kriging代理模型结合进行大展弦比前掠翼的气动隐身多目标优化设计.研究结果表

  4. Investigation and design of a C-Wing passenger aircraft



    Full Text Available A novel nonplanar wing concept called C-Wing is studied and implemented on a commercial aircraft to reduce induced drag which has a significant effect on fuel consumption. A preliminary sizing method which employs an optimization algorithm is utilized. The Airbus A320 aircraft is used as a reference aircraft to evaluate design parameters and to investigate the C-Wing design potential beyond current wing tip designs. An increase in aspect ratio due to wing area reduction at 36m span results in a reduction of required fuel mass by 16%. Also take-off mass savings were obtained for the aircraft with C-Wing configuration. The effect of a variations of height to span ratio (h/b of C-Wings on induced drag factor k, is formulated from a vortex lattice method and literature based equations. Finally the DOC costing methods used by the Association of European Airlines (AEA was applied to the existing A320 aircraft and to the C-Wing configuration obtaining a reduction of 6% in Direct Operating Costs (DOC for the novel concept resulted. From overall outcomes, the C-Wing concept suggests interesting aerodynamic efficiency and stability benefits.

  5. Wetting Characteristics of Insect Wing Surfaces

    Doyoung Byun; Jongin Hong; Saputra; Jin Hwan Ko; Young Jong Lee; Hoon Cheol Park; Bong-Kyu Byun; Jennifer R. Lukes


    Biological tiny structures have been observed on many kinds of surfaces such as lotus leaves, which have an effect on the coloration of Morpho butterflies and enhance the hydrophobicity of natural surfaces. We investigated the micro-scale and nano-scale structures on the wing surfaces of insects and found that the hierarchical multiple roughness structures help in enhancing the hydrophobicity. After examining 10 orders and 24 species of flying Pterygotan insects, we found that micro-scale and nano-scale structures typically exist on both the upper and lower wing surfaces of flying insects. The tiny structures such as denticle or setae on the insect wings enhance the hydrophobicity, thereby enabling the wings to be cleaned more easily. And the hydrophobic insect wings undergo a transition from Cassie to Wenzel states at pitch/size ratio of about 20. In order to examine the wetting characteristics on a rough surface, a biomimetic surface with micro-scale pillars is fabricated on a silicon wafer,which exhibits the same behavior as the insect wing, with the Cassie-Wenzel transition occurring consistently around a pitch/width value of 20.

  6. Prediction of span loading of straight-wing/propeller combinations up to stall. [propeller slipstreams and wing loading

    Mcveigh, M. A.; Gray, L.; Kisielowski, E.


    A method is presented for calculating the spanwise lift distribution on straight-wing/propeller combinations. The method combines a modified form of the Prandtl wing theory with a realistic representation of the propeller slipstream distribution. The slipstream analysis permits calculations of the nonuniform axial and rotational slipstream velocity field of propeller/nacelle combinations. This nonuniform field was then used to calculate the wing lift distribution by means of the modified Prandtl wing theory. The theory was developed for any number of nonoverlapping propellers, on a wing with partial or full-span flaps, and is applicable throughout an aspect ratio range from 2.0 and higher. A computer program was used to calculate slipstream characteristics and wing span load distributions for a number of configurations for which experimental data are available, and favorable comparisons are demonstrated between the theoretical predictions and the existing data.

  7. Experimental Methods to Characterize Nonlinear Vibration of Flapping Wing Micro Air Vehicles


    the following terminology when referring to flapping wing MAVs; bird flight machines are also known as ornithopters and robotic insects are also...15. SUBJECT TERMS Flapping Wing Micro Air Vehicle, flapping-wing MAV, MAV, ornithopter , entomopter, nonlinear vibration, beam resonance

  8. Computational wing optimization and comparisons with experiment for a semi-span wing model

    Waggoner, E. G.; Haney, H. P.; Ballhaus, W. F.


    A computational wing optimization procedure was developed and verified by an experimental investigation of a semi-span variable camber wing model in the NASA Ames Research Center 14 foot transonic wind tunnel. The Bailey-Ballhaus transonic potential flow analysis and Woodward-Carmichael linear theory codes were linked to Vanderplaats constrained minimization routine to optimize model configurations at several subsonic and transonic design points. The 35 deg swept wing is characterized by multi-segmented leading and trailing edge flaps whose hinge lines are swept relative to the leading and trailing edges of the wing. By varying deflection angles of the flap segments, camber and twist distribution can be optimized for different design conditions. Results indicate that numerical optimization can be both an effective and efficient design tool. The optimized configurations had as good or better lift to drag ratios at the design points as the best designs previously tested during an extensive parametric study.

  9. Experimental investigations of the functional morphology of dragonfly wings

    H.Rajabi; A.Darvizeh


    Nowadays,the importance of identifying the flight mechanisms of the dragonfly,as an inspiration for designing flapping wing vehicles,is well known.An experimental approach to understanding the complexities of insect wings as organs of flight could provide significant outcomes for design purposes.In this paper,a comprehensive investigation is carried out on the morphological and microstructural features of dragonfly wings.Scanning electron microscopy (SEM) and tensile testing are used to experimentally verify the functional roles of different parts of the wings.A number of SEM images of the elements of the wings,such as the nodus,leading edge,trailing edge,and vein sections,which play dominant roles in strengthening the whole structure,are presented.The results from the tensile tests indicate that the nodus might be the critical region of the wing that is subjected to high tensile stresses.Considering the patterns of the longitudinal corrugations of the wings obtained in this paper,it can be supposed that they increase the load-bearing capacity,giving the wings an ability to tolerate dynamic loading conditions.In addition,it is suggested that the longitudinal veins,along with the leading and trailing edges,are structural mechanisms that further improve fatigue resistance by providing higher fracture toughness,preventing crack propagation,and allowing the wings to sustain a significant amount of damage without loss of strength.

  10. A Brief Study, Research, Design, Analysis on Multi Section Variable Camber Wing



    Full Text Available Minimizing fuel consumption is one of the major concerns in the aviation industry. In the past decade, there have been many attempts to improve the fuel efficiency of aircraft. One of the methods proposed is to vary the lift-to-drag ratio of the aircraft in different flight conditions. To achieve this, the wing of the airplane must be able to change its configuration during flight, corresponding to different flight regimes.In the research presented in this thesis, the aerodynamic characteristics of a multisection, variable camber wing were investigated. The model used in this research had a 160mm chord and a 200mm wingspan, with the ribs divided into 4 sections. Each section was able to rotate approximately 5 degrees without causing significant discontinuity on the wing surface. Two pneumatic actuators located at the main spar were used to morph the wing through mechanical linkages. The multi-section variable camber wing model could provide up to 10 percent change in camber from the baseline configuration, which had a NACA0015 section.The wing was tested in the free-jet wind tunnel at three different Reynolds numbers: 322000, 48000, and 636000. Static tests were performed to obtain lift and drag data for different configurations. Two rigid wings in baseline and camber configuration were built and tested to compare the test data with variable camber wing. The wind tunnel test results indicated that the multisection variable camber wing provided a higher lift than the rigid wing in both configurations whereas high drag was also generated on the variable camber wing due to friction drag on the wing skin. The larger drag value appeared on variable camber wing in baseline configuration than in cambered configuration resulting in lower lift-to-drag ratio as compared to the baseline rigid wing whereas the variable camber wing in cambered configuration had higher lift-to-drag ratio than the cambered rigid wing.

  11. Wing Warping, Roll Control and Aerodynamic Optimization of Inflatable Wings

    Simpson, Andrew


    The research presents work on aerodynamic control by warping inflatable wings. Inflatable wings are deformable by their nature. Mechanical manipulation of the wing's shape has been demonstrated to alter the performance and control the vehicle in flight by deforming the trailing edge of the wing near the wing tip. Predicting and correlating the forces required in deforming the wings to a particular shape and the deformation generated for a given internal pressure were conducted through the use of photogrammetry. This research focuses on optimizing the roll moments and aerodynamic performance of the vehicle, given the current level of wing warping ability. Predictions from lifting line theory applied to wing shape changes are presented. Comparisons from the experimental results are made with lifting line analysis for wings with arbitrary twist and the solutions are used to determine rolling moment and optimum L/D. Results from flight tests will also be presented.

  12. Conceptual design for a laminar-flying-wing aircraft

    Saeed, T. I.

    The laminar-flying-wing aircraft appears to be an attractive long-term prospect for reducing the environmental impact of commercial aviation. In assessing its potential, a relatively straightforward initial step is the conceptual design of a version with restricted sweep angle. Such a design is the topic of this thesis. Subject to constraints, this research aims to; provide insight into the parameters affecting practical laminar-flow-control suction power requirements; identify a viable basic design specification; and, on the basis of this, an assessment of the fuel efficiency through a detailed conceptual design study. It is shown that there is a minimum power requirement independent of the suction system design, associated with the stagnation pressure loss in the boundary layer. This requirement increases with aerofoil section thickness, but depends only weakly on Mach number and (for a thick, lightly-loaded laminar flying wing) lift coefficient. Deviation from the optimal suction distribution, due to a practical chamber-based architecture, is found to have very little effect on the overall suction coefficient. In the spanwise direction, through suitable choice of chamber depth, the pressure drop due to frictional and inertial effects may be rendered negligible. Finally, it is found that the pressure drop from the aerofoil surface to the pump collector ducts determines the power penalty. To identify the viable basic design specification, a high-level exploration of the laminar flying wing design space is performed. The characteristics of the design are assessed as a function of three parameters: thickness-to-chord ratio, wingspan, and unit Reynolds number. A feasible specification, with 20% thickness-to-chord, 80 m span and a unit Reynolds number of 8 x 106 m-1, is identified; it corresponds to a 187 tonne aircraft which cruises at Mach 0.67 and altitude 22,500 ft, with lift coefficient 0.14. On the basis of this specification, a detailed conceptual design is

  13. Flapping wing aerodynamics: from insects to vertebrates.

    Chin, Diana D; Lentink, David


    More than a million insects and approximately 11,000 vertebrates utilize flapping wings to fly. However, flapping flight has only been studied in a few of these species, so many challenges remain in understanding this form of locomotion. Five key aerodynamic mechanisms have been identified for insect flight. Among these is the leading edge vortex, which is a convergent solution to avoid stall for insects, bats and birds. The roles of the other mechanisms - added mass, clap and fling, rotational circulation and wing-wake interactions - have not yet been thoroughly studied in the context of vertebrate flight. Further challenges to understanding bat and bird flight are posed by the complex, dynamic wing morphologies of these species and the more turbulent airflow generated by their wings compared with that observed during insect flight. Nevertheless, three dimensionless numbers that combine key flow, morphological and kinematic parameters - the Reynolds number, Rossby number and advance ratio - govern flapping wing aerodynamics for both insects and vertebrates. These numbers can thus be used to organize an integrative framework for studying and comparing animal flapping flight. Here, we provide a roadmap for developing such a framework, highlighting the aerodynamic mechanisms that remain to be quantified and compared across species. Ultimately, incorporating complex flight maneuvers, environmental effects and developmental stages into this framework will also be essential to advancing our understanding of the biomechanics, movement ecology and evolution of animal flight.

  14. Active Control of Flapping Wings Using Wing Deformation

    Tokutake, Hiroshi; Sunada, Shigeru; Ohtsuka, Yukio

    A new method for the attitude control of a flapping-wing aircraft is proposed. In this method, the variations in wing deformation, that is, the feathering angle and the camber, are controlled by pulling the wing at a certain point with a thread connected to a servomotor. The experimental setup for verifying the practicability of this method was developed, and aerodynamic forces and wing deformation were measured. It was concluded that thread control caused effective wing deformation, and the variation in the deformation generated the pitching moment that controls the attitude of a flapping-wing aircraft.

  15. On the vein-stiffening membrane structure of a dragonfly hind wing

    Zhong-xue LI; Wei SHEN; Gen-shu TONG; Jia-meng TIAN; Loc VU-QUOC


    Aiming at exploring the excellent structural performance of the vein-stiffening membrane structure of dragonfly hind wings, we analyzed two planar computational models and three 3D computational models with cambered corrugation based on the finite element method. It is shown that the vein size in different zones is proportional to the magnitude of the vein internal force when the wing structure is subjected to uniform out-of-plane transverse loading. The membrane contributes little to the flexural stiffness of the planar wing models, while exerting an immense impact upon the stiffness of the 3D wing models with cambered corrugation. If a lumped mass of 10% of the wing is fixed on the leading edge close to the wing tip, the wing fundamental fre-quency decreases by 10.7%~13.2%; ifa lumped mass is connected to the wing via multiple springs, the wing fundamental fre-quency decreases by 16.0%~18.0%. Such decrease in fundamental frequency explains the special function of the wing pterostigma in alleviating the wing quivering effect. These particular features of dragonfly wings can be mimicked in the design of new-style reticulately stiffening thin-walled roof systems and flapping wings in novel intelligent aerial vehicles.

  16. Dynamics and control of robotic aircraft with articulated wings

    Paranjape, Aditya Avinash

    , and compare the steady state performance of rigid and flexible-winged aircraft. We present an intuitive but very useful notion, called the effective dihedral, which allows us to extend some of the stability and performance results derived for rigid aircraft to flexible aircraft. In the process, we identify the extent of flexibility needed to induce substantial performance benefits, and conversely the extent to which results derived for rigid aircraft apply to a flexible aircraft. We demonstrate, interestingly enough, that wing flexibility actually causes a deterioration in the maximum achievable turn rate when the sideslip is regulated. We also present experimental results which help demonstrate the capability of wing dihedral for control and for executing maneuvers such as slow, rapid descent and perching. Open loop as well as closed loop experiments are performed to demonstrate (a) the effectiveness of symmetric dihedral for flight path angle control, (b) yaw control using asymmetric dihedral, and (c) the elements of perching. Using a simple order of magnitude analysis, we derive conditions under which the wing is structurally statically stable, as well as conditions under which there exists time scale separation between the bending and twisting dynamics. We show that the time scale separation depends on the geometry of the wing cross section, the Poisson's ratio of the wing material, the flight speed and the aspect ratio of the wing. We design independent control laws for bending and twisting. A key contribution of this thesis is the formulation of a partial differential equation (PDE) boundary control problem for wing deformation. PDE-backstepping is used to derive tracking and exponentially stabilizing boundary control laws for wing twist which ensure that a weighted integral of the wing twist (net lift or the rolling moment) tracks the desired time-varying reference input. We show that a control law which only ensures tracking of a weighted integral improves the

  17. Unsteady flow past wings having sharp-edge separation

    Atta, E. H.; Kandil, O. A.; Mook, D. T.; Nayfeh, A. H.


    A vortex-lattice technique is developed to model unsteady, incompressible flow past thin wings. This technique predicts the shape of the wake as a function of time; thus, it is not restricted by planform, aspect ratio, or angle of attack as long as vortex bursting does not occur and the flow does not separate from the wing surface. Moreover, the technique can be applied to wings of arbitrary curvature undergoing general motion; thus, it can treat rigid-body motion, arbitrary wing deformation, gusts in the freestream, and periodic motions. Numerical results are presented for low-aspect rectangular wings undergoing a constant-rate, rigid-body rotation about the trailing edge. The results for the unsteady motion are compared with those predicted by assuming quasi-steady motion. The present results exhibit hysteretic behavior.

  18. Numerical simulation of X-wing type biplane flapping wings in 3D using the immersed boundary method.

    Tay, W B; van Oudheusden, B W; Bijl, H


    The numerical simulation of an insect-sized 'X-wing' type biplane flapping wing configuration is performed in 3D using an immersed boundary method solver at Reynolds numbers equal to 1000 (1 k) and 5 k, based on the wing's root chord length. This X-wing type flapping configuration draws its inspiration from Delfly, a bio-inspired ornithopter MAV which has two pairs of wings flapping in anti-phase in a biplane configuration. The objective of the present investigation is to assess the aerodynamic performance when the original Delfly flapping wing micro-aerial vehicle (FMAV) is reduced to the size of an insect. Results show that the X-wing configuration gives more than twice the average thrust compared with only flapping the upper pair of wings of the X-wing. However, the X-wing's average thrust is only 40% that of the upper wing flapping at twice the stroke angle. Despite this, the increased stability which results from the smaller lift and moment variation of the X-wing configuration makes it more suited for sharp image capture and recognition. These advantages make the X-wing configuration an attractive alternative design for insect-sized FMAVS compared to the single wing configuration. In the Reynolds number comparison, the vorticity iso-surface plot at a Reynolds number of 5 k revealed smaller, finer vortical structures compared to the simulation at 1 k, due to vortices' breakup. In comparison, the force output difference is much smaller between Re = 1 k and 5 k. Increasing the body inclination angle generates a uniform leading edge vortex instead of a conical one along the wingspan, giving higher lift. Understanding the force variation as the body inclination angle increases will allow FMAV designers to optimize the thrust and lift ratio for higher efficiency under different operational requirements. Lastly, increasing the spanwise flexibility of the wings increases the thrust slightly but decreases the efficiency. The thrust result is similar to one of the

  19. Effects of Wing-Cuff on NACA 23015 Aerodynamic Performances

    Meftah S.M.A


    Full Text Available The main subject of this work is the numerical study control of flow separation on a NACA 23015 airfoil by using wing cuff. This last is a leading edge modification done to the wing. The modification consists of a slight extension of the chord on the outboard section of the wings. Different numerical cases are considered for the baseline and modified airfoil NACA 23015 according at different angle of incidence. The turbulence is modeled by two equations k-epsilon model. The results of this numerical investigation showed several benefits of the wing cuff compared with a conventional airfoil and an agreement is observed between the experimental data and the present study. The most intriguing result of this research is the capability for wing cuff to perform short take-offs and landings.

  20. Folding in and out: passive morphing in flapping wings.

    Stowers, Amanda K; Lentink, David


    We present a new mechanism for passive wing morphing of flapping wings inspired by bat and bird wing morphology. The mechanism consists of an unactuated hand wing connected to the arm wing with a wrist joint. Flapping motion generates centrifugal accelerations in the hand wing, forcing it to unfold passively. Using a robotic model in hover, we made kinematic measurements of unfolding kinematics as functions of the non-dimensional wingspan fold ratio (2-2.5) and flapping frequency (5-17 Hz) using stereo high-speed cameras. We find that the wings unfold passively within one to two flaps and remain unfolded with only small amplitude oscillations. To better understand the passive dynamics, we constructed a computer model of the unfolding process based on rigid body dynamics, contact models, and aerodynamic correlations. This model predicts the measured passive unfolding within about one flap and shows that unfolding is driven by centrifugal acceleration induced by flapping. The simulations also predict that relative unfolding time only weakly depends on flapping frequency and can be reduced to less than half a wingbeat by increasing flapping amplitude. Subsequent dimensional analysis shows that the time required to unfold passively is of the same order of magnitude as the flapping period. This suggests that centrifugal acceleration can drive passive unfolding within approximately one wingbeat in small and large wings. Finally, we show experimentally that passive unfolding wings can withstand impact with a branch, by first folding and then unfolding passively. This mechanism enables flapping robots to squeeze through clutter without sophisticated control. Passive unfolding also provides a new avenue in morphing wing design that makes future flapping morphing wings possibly more energy efficient and light-weight. Simultaneously these results point to possible inertia driven, and therefore metabolically efficient, control strategies in bats and birds to morph or recover

  1. 大涵道比翼吊发动机喷流气动干扰研究%Interference effects of wing-mounted high bypass ratio nacelle with engine power

    乔磊; 白俊强; 华俊; 陈迎春; 张淼; 张美红


    研究了涡扇动力翼吊布局飞机考虑动力效应时的流场数值模拟和气动干扰的若干问题。在数值模拟方法方面,介绍了便于实际工程应用的发动机进排气边界状态参数设定算法;通过设定无总温总压增量的喷口边界模拟发动机的无动力状态,避免了研究喷流效应时由通气短舱和喷气构型之间的几何外形差异带来的网格差异对计算结果的影响,提高了复杂构型流场数值模拟结果的可信度。通过数值模拟发现,发动机喷流的引射虽然可使气流加速从而降低翼面压力,但发动机做功导致的翼面压力抬升亦不可忽视。发动机喷流可能引发强烈的挂架气动干扰,其原因是由机身、发动机、机翼和挂架构成的收缩-扩张流道引起的气流加速。通过适当延长和增厚挂架可以削弱这种干扰。%Numerical simulation method and aerodynamic interference effects of wing-mounted nacelle aircraft were studied.In aspect of numerical simulation,a practical engineering compatible algorithm for the determination of engine intake and exhaust boundary parameters directly from free stream and engine work-ing conditions was developed.Mesh difference arises from geometry inconsistency between powered and un-powered nacelle,which is a confounding factor when estimating power effect,is eliminated via set up a zero-energy-increase exhaust boundary condition.Then,the credibility of numerical simulation result of complex configuration in aircraft design was improved.The numerical simulation results shown that the engine power has two opposite aspects of effects on wing surface pressure,one is that engine ejection speed the flow up and bring the pressure down,the other is that the engine increasesd the pressure near the nuzzle.The numerical simulation result also revealed that engine jet stream can induce severe flow interferences on surface of pylon, duel to the flow acceleration through the

  2. Aerodynamics of a rigid curved kite wing

    Maneia, Gianmauro; Tordella, Daniela; Iovieno, Michele


    A preliminary numerical study on the aerodynamics of a kite wing for high altitude wind power generators is proposed. Tethered kites are a key element of an innovative wind energy technology, which aims to capture energy from the wind at higher altitudes than conventional wind towers. We present the results obtained from three-dimensional finite volume numerical simulations of the steady air flow past a three-dimensional curved rectangular kite wing (aspect ratio equal to 3.2, Reynolds number equal to 3x10^6). Two angles of incidence -- a standard incidence for the flight of a tethered airfoil (6{\\deg}) and an incidence close to the stall (18{\\deg}) -- were considered. The simulations were performed by solving the Reynolds Averaged Navier-Stokes flow model using the industrial STAR-CCM+ code. The overall aerodynamic characteristics of the kite wing were determined and compared to the aerodynamic characteristics of the flat rectangular non twisted wing with an identical aspect ratio and section (Clark Y profil...

  3. A structural dynamics study of a wing-pylon-tiltrotor system

    Khader, N.; Abu-Mallouh, R.


    A simple structural model for a three-bladed tiltrotor-pylon-wing assembly is presented, which accounts for chordwise, transverse, and torsional wing deformations, rigid pylon pitching motion with respect to the wing tip cross-section in its deformed position, lead-lag, flap, and torsional deformations of rotor blades. The model considers equivalent viscous damping associated with blade and wing elastic deformations and with rigid pylon pitching motion. It is established that blade-to wing bending rigidity ratio, pylon pitching frequency, equivalent viscous damping associated with blade elastic deformations, and rotational speed, are the most important design parameters, whose effect on system frequencies and stability boundaries is evaluated.

  4. Unsteady Aerodynamics of Flapping Wing of a Bird

    M. Agoes Moelyadi


    Full Text Available The unsteady flow behavior and time-dependent aerodynamic characteristics of the flapping motion of a bird’s wing were investigated using a computational method. During flapping, aerodynamic interactions between bird wing surfaces and surrounding flow may occur, generating local time-dependent flow changes in the flow field and aerodynamic load of birds. To study the effect of flapping speed on unsteady aerodynamic load, two kinds of computational simulations were carried out, namely a quasi-steady and an unsteady simulation. To mimic the movement of the down-stroke and the upstroke of a bird, the flapping path accorded to a sinus function, with the wing attitude changing in dihedral angle and time. The computations of time-dependent viscous flow were based on the solution of the Reynolds Averaged Navier-Stokes equations by applying the k-e turbulence model. In addition, the discretization for the computational domain around the model used multi-block structured grid to provide more accuracy in capturing viscous flow, especially in the vicinity of the wing and body surfaces, to obtain a proper wing-body geometry model. For this research, the seagull bird was chosen, which has high aspect ratio wings with pointed wing-tips and a high camber wing section. The results include mesh movement, velocity contours as well as aerodynamic coefficients of the flapping motion of the bird at various flapping frequencies.

  5. The Aerodynamics of Deforming Wings at Low Reynolds Number

    Medina, Albert

    responsive to flexibility satisfying an inverse proportionality to stiffness. In hover, an effective pitch angle can be defined in a flexible wing that accounts for deflection which shifts results toward trend lines of rigid wings. Three-dimensional simulations examining the effects of two distinct deformation modes undergoing prescribed deformation associated with root and tip deflection demonstrated a greater aerodynamic response to tip deflection in hover. Efficiency gains in flexion wings over rigid wing counterpart were shown to be dependent on Reynolds number with efficiency in both modes increasing with increased Reynolds number. Additionally, while the leading-edge vortex axis proved insensitive to deformation, the shape and orientation of the LEV core is modified. Experiments on three-dimensional dynamically-scaled fruit fly wings with passive deformation operating in the bursting limit Reynolds number regime revealed enhanced leading-edge vortex bursting with tip deflection promoting greater LEV core flow deceleration in stroke. Experimental studies on rotary wings highlights a universal formation time of the leading-edge vortex independent of Reynolds number, acceleration profile and aspect ratio. Efforts to replicate LEV bursting phenomena of higher aspect ratio wings in a unity aspect ratio wing such that LEV growth is no limited by span but by the LEV traversing the chord revealed a flow regime of oscillatory lift generation reminiscent of behavior exhibited in translating wings that also maintains magnitude peak to peak.

  6. Aeroelastic optimization design for wing with maneuver load uncertainties


    An aeroelastic optimization design methodology for air vehicle considering the uncertainties in maneuver load conditions is presented and applied to a structural design process of low-aspect-ratio wing. An aerodynamic load correction model is developed and used to predict the critical load conditions with the perturbations of theoretical linear aerodynamic forces and experimental aerodynamic forces from wind-tunnel test, when concerning the uncertainties in use of theoretical linear and experimental aerodynamic forces. Three objective functions of critical loads are defined. The load evaluations for three wing sections are investigated in four characteristic maneuvers, and the most critical load conditions are confirmed by using the sequential quadratic programming method. On this basis, the aeroelastic optimization design employing the genetic-gradient hybrid algorithm is conducted, in which the objective is to minimize structural mass subject to the constraints of stress, deformation and flutter speed. The resulting optimal structure is heavier than the one simply based on the theoretical linear or experimental aerodynamic forces. However, it is more robust when encountering the critical load conditions in actual flight due to the consideration of uncertainties in aerodynamic forces in the early design phase, thereby, the risk of structural redesign can be reduced.

  7. Flapping Wings of an Inclined Stroke Angle: Experiments and Reduced-Order Models in Dual Aerial/Aquatic Flight

    Izraelevitz, Jacob; Triantafyllou, Michael


    Flapping wings in nature demonstrate a large force actuation envelope, with capabilities beyond the limits of static airfoil section coefficients. Puffins, guillemots, and other auks particularly showcase this mechanism, as they are able to both generate both enough thrust to swim and lift to fly, using the same wing, by changing the wing motion trajectory. The wing trajectory is therefore an additional design criterion to be optimized along with traditional aircraft parameters, and could possibly enable dual aerial/aquatic flight. We showcase finite aspect-ratio flapping wing experiments, dynamic similarity arguments, and reduced-order models for predicting the performance of flapping wings that carry out complex motion trajectories.


    Davide v Moretti


    Full Text Available Background: several biomarkers have been proposed for detecting Alzheimer's disease (AD in its earliest stages, that is, in the predementia stage. In an attempt to find noninvasive biomarkers, researchers have investigated the feasibility of neuroimaging tools, such as MRI, SPECT as well as neurophysiological measurements using EEG. Moreover, the increase of EEG alpha3/alpha2 frequency power ratio has been associated with AD-converters subjects with mild cognitive impairment (MCI.Objective: to study the association of alpha3/alpha2 frequency power ratio with regional cerebral blood flow (rCBF changes in subjects with MCI .Methods: 27 adult subjects with MCI underwent EEG recording and perfusion single-photon emission computed tomography (SPECT evaluation. The alpha3/alpha2 frequency power ratio was computed for each subject. Two groups were obtained according to the median values of alpha3/alpha2, at a cut-off of 1.17. Correlation between brain perfusion and EEG markers were detected.Results: subjects with higher alpha3/alpha2 frequency power ratio showed a constant trend to a lower perfusion than low alpha3/alpha2 group. The two groups were significantly different as about the hippocampal volume and correlation with the theta frequency activity.Conclusion: there is a complex interplay between cerebral blood flow, theta frequency activity and hippocampal volume in MCI patients with prodromal Alzheimer's disease, characterized by higher EEG alpha3 /alpha2 frequency power ratio.

  9. Geometric design of the best performing auto-rotating wing

    Liu, Yucen; Vincent, Lionel; Kanso, Eva


    Many plants use gravity and aerodynamics to disperse their seeds away from the parent plant. Various seed designs result in different dispersal modes from gliding to auto-rotating. Here, we are interested in understanding the effect of geometric design of auto-rotating seedpods on their aerodynamic performance. As an experimentally tractable surrogate to real seedpods, we investigate auto-rotating paper wings of various shape designs. We compare these designs to a control case consisting of the canonical rectangular wing. Inspired by aerodynamics, we begin by considering the benefit of an elliptical planform, and test the effect of aspect ratio on flight range and descent angle. We find the elliptical planform improves the tumbling rate and the aspect ratio has a positive effect on the flight performance of the wings. We then test two families of more complex shapes: one of tapered planform and one of a planform with sharp tips. We look for an optimal flight performance while constraining either the mass or the maximum length and width of the wing. We find that wings with sharper tips and larger length have higher auto-rotation rates and improved performance. The results imply that both the planform and length of the wing contribute to the wing's flight performance.

  10. Variable camber wing based on pneumatic artificial muscles

    Yin, Weilong; Liu, Libo; Chen, Yijin; Leng, Jinsong


    As a novel bionic actuator, pneumatic artificial muscle has high power to weight ratio. In this paper, a variable camber wing with the pneumatic artificial muscle is developed. Firstly, the experimental setup to measure the static output force of pneumatic artificial muscle is designed. The relationship between the static output force and the air pressure is investigated. Experimental result shows the static output force of pneumatic artificial muscle decreases nonlinearly with increasing contraction ratio. Secondly, the finite element model of the variable camber wing is developed. Numerical results show that the tip displacement of the trailing-edge increases linearly with increasing external load and limited with the maximum static output force of pneumatic artificial muscles. Finally, the variable camber wing model is manufactured to validate the variable camber concept. Experimental result shows that the wing camber increases with increasing air pressure and that it compare very well with the FEM result.

  11. The efficient solution of transonic wing flow fields

    Holst, T. L.; Subramanian, N. R.; Thomas, S. D.


    An evaluation of the transonic-wing-analysis computer code TWING is presented. TWING utilizes a fully implicit, approximate-factorization iteration scheme to solve the full-potential equation in conservative form. A numerical elliptic-solver grid-generation scheme is used to generate the required finite-difference mesh. Several wing configurations have been analyzed, and comparisons of computed results have been made with available experimental data. Results indicate that the code is robust, accurate (when significant viscous effects are not present), and efficient. TWING generally produces solutions an order of magnitude faster than other conservative, full-potential codes using successive-line overrelaxation. The present method is applicable to a wide range of isolated wing configurations, including high-aspect-ratio transport wings and low-aspect-ratio, high-sweep, fighter configurations.

  12. Recent applications of the transonic wing analysis computer code, TWING

    Subramanian, N. R.; Holst, T. L.; Thomas, S. D.


    An evaluation of the transonic-wing-analysis computer code TWING is given. TWING utilizes a fully implicit approximate factorization iteration scheme to solve the full potential equation in conservative form. A numerical elliptic-solver grid-generation scheme is used to generate the required finite-difference mesh. Several wing configurations were analyzed, and the limits of applicability of this code was evaluated. Comparisons of computed results were made with available experimental data. Results indicate that the code is robust, accurate (when significant viscous effects are not present), and efficient. TWING generally produces solutions an order of magnitude faster than other conservative full potential codes using successive-line overrelaxation. The present method is applicable to a wide range of isolated wing configurations including high-aspect-ratio transport wings and low-aspect-ratio, high-sweep, fighter configurations.


    任智毅; 金海波; 丁运亮


    A method was presented to analyze the nonlinear flutter.Based on this method,the flutter character-istics of the high aspect wing were illustrated.The numerical results show that the flutter speed is decreased when the first horizontal bending mode involved.Secondly,this study discussed how the main direction of the compos-ite influenced the character of the nonlinear vibration and flutter,and established the method of the flutter clip-ping to the high aspect wing.And the result shows that the stiffness of structure can be changed by changing the main direction of the composite.It mainly changes the horizontal bending mode,makes the main direction tend to the trailing edge,and then makes the section line move to the leading edge.Further analyzing the nonlinear flut-ter reveals that it is the changing of the horizontal bending mode that causes the flutter speed change obviously. And by the section line of this mode moves ahead,the flutter speed will become larger.In the study,two exam-ples were illustrated to validate its truthiness.%针对大展弦比机翼水平弯曲模态参与耦合颤振问题,首先用考虑几何非线性的颤振分析方法研究了某大展弦比机翼的颤振特性,结果表明水平一弯模态参与耦合降低了机翼传统模式的线性颤振速度;然后研究了复合材料的铺层主刚度方向角对机翼非线性振动特性和颤振特性的影响规律,提出了大展弦比机翼非线性颤振剪裁设计的新方法。结果表明主刚度方向角的变化主要引起了水平一弯模态振型的改变,一般表现为主刚度方向角从机翼后梁向后缘偏转,该阶模态的相对扭转振型节线位置向前缘移动;反之,该节线位置后移。进一步非线性颤振分析,发现水平一弯模态振型的变化引起了该阶模态参与耦合颤振速度的明显改变,主要表现为该颤振型的颤振速度随该阶模态的相对扭转振型节线位置前移量的增加而增

  14. Twin Flavor Chicken Wings


    Ingredients:1000g chicken wings,about,100g Shredded rape-seedleaves,100g black sesame seeds,7g salt,5g sugar,3gMSG,10g cooking wine,5g cassia bark,1000g cookingoil(actual consumption only 100 grams),one egg,anoptional amount of scallion,ginger root,starch and

  15. Simulating Bird Strike on Aircraft Composite Wing Leading Edge.

    Ericsson, Max


    In this master thesis project the possibility to model the response of a wing when subjected to bird strike using finite elements is analyzed. Since this transient event lasts only a few milliseconds the used solution method is explicit time integration. The wing is manufactured using carbon fiber laminate. Carbon fiber laminates have orthotropic material properties with different stiffness in different directions. Accordingly, there are damage mechanisms not considered when using metal that ...

  16. Simulating Bird Strike on Aircraft Composite Wing Leading Edge.

    Ericsson, Max


    In this master thesis project the possibility to model the response of a wing when subjected to bird strike using finite elements is analyzed. Since this transient event lasts only a few milliseconds the used solution method is explicit time integration. The wing is manufactured using carbon fiber laminate. Carbon fiber laminates have orthotropic material properties with different stiffness in different directions. Accordingly, there are damage mechanisms not considered when using metal that ...

  17. The Correlation between the Triglyceride to High Density Lipoprotein Cholesterol Ratio and Computed Tomography-Measured Visceral Fat and Cardiovascular Disease Risk Factors in Local Adult Male Subjects.

    Park, Hye-Rin; Shin, Sae-Ron; Han, A Lum; Jeong, Yong Joon


    We studied the association between the triglyceride to high-density lipoprotein cholesterol ratio and computed tomography-measured visceral fat as well as cardiovascular risk factors among Korean male adults. We measured triglycerides, high density lipoprotein cholesterol, body mass, waist circumference, fasting plasma glucose, hemoglobin A1c, systolic blood pressure, diastolic blood pressure, visceral fat, and subcutaneous fat among 372 Korean men. The visceral fat and subcutaneous fat areas were measured by computed tomography using a single computed tomography slice at the L4-5 lumbar level. We analyzed the association between the triglyceride to high density lipoprotein cholesterol ratio and visceral fat as well as cardiovascular risk factors. A positive correlation was found between the triglyceride to high density lipoprotein cholesterol ratio and variables such as body mass index, waist circumference, fasting plasma glucose, hemoglobin A1c, visceral fat, and the visceral-subcutaneous fat ratio. However, there was no significant correlation between the triglyceride to high density lipoprotein cholesterol ratio and subcutaneous fat or blood pressure. Multiple logistic regression analyses revealed significant associations between a triglyceride to high density lipoprotein cholesterol ratio ≥3 and diabetes, a body mass index ≥25 kg/m(2), a waist circumference ≥90 cm, and a visceral fat area ≥100 cm(2). The triglyceride to high density lipoprotein cholesterol ratio was not significantly associated with hypertension. There were significant associations between the triglyceride to high density lipoprotein cholesterol ratio and body mass, waist circumference, diabetes, and visceral fat among a clinical sample of Korean men. In the clinical setting, the triglyceride to high density lipoprotein cholesterol ratio may be a simple and useful indicator for visceral obesity and cardiovascular disease.

  18. SMA actuators for morphing wings

    Brailovski, V.; Terriault, P.; Georges, T.; Coutu, D.

    An experimental morphing laminar wing was developed to prove the feasibility of aircraft fuel consumption reduction through enhancement of the laminar flow regime over the wing extrados. The morphing wing prototype designed for subsonic cruise flight conditions (Mach 0.2 … 0.3; angle of attack - 1 … +2∘), combines three principal subsystems: (1) flexible extrados, (2) rigid intrados and (3) an actuator group located inside the wing box. The morphing capability of the wing relies on controlled deformation of the wing extrados under the action of shape memory alloys (SMA) actuators. A coupled fluid-structure model of the morphing wing was used to evaluate its mechanical and aerodynamic performances in different flight conditions. A 0.5 m chord and 1 m span prototype of the morphing wing was tested in a subsonic wind tunnel. In this work, SMA actuators for morphing wings were modeled using a coupled thermo-mechanical finite element model and they were windtunnel validated. If the thermo-mechanical model of SMA actuators presented in this work is coupled with the previously developed structureaerodynamic model of the morphing wing, it could serve for the optimization of the entire morphing wing system.

  19. The Effect of Height, Wing Length, and Wing Symmetry on Tabebuia rosea Seed Dispersal

    Yasmeen Moussa


    Full Text Available The relationship between the vertical drop height and the horizontal distance traveled (dispersal ratio was investigated for a sample of fifty Tabebuia rosea seeds by dropping the seeds from five heights ranging from 1.00 to 2.00 meters. The dispersal ratio was found to be a constant 0.16 m/m for these heights. The effects of total seed length and asymmetry of seed wings on dispersal ratio were also measured using separate samples of fifty Tabebuia rosea seeds. It was found that neither seed length nor asymmetry had a significant effect on the dispersal ratio.

  20. Modeling the Motion of a Flapping Wing Aerial Vehicle

    Vorochaeva L.Y.


    Full Text Available The article discusses the vertical flight of a flapping wing aerial vehicle, which is also called an ornithopter. The robot is a chain of five links connected in series by active cylindrical hinges with the central link being the body and the remainder forming folding wings in pairs. The distinctive feature of this device is that the flaps of its wings imitate those of a seagull i.e. the device has a biological prototype. We construct a mathematical model of this device; much attention is given to the model of the interaction of the wings with the air environment and we determine the positions and velocities of points of application of the reduced aerodynamic forces to each of the links. Based on the results of numerical modelling of the vertical flight of the robot three modes of flight were established: ascent, hovering at a certain height and descent. The device can operate in these modes based on the oscillation parameters of the wings in particular flapping frequency and amplitude, the ratio of the amplitudes of two links and one wing and the shift of the equilibrium oscillation position of the wings relative to zero.

  1. Design optimization of deployable wings

    Gaddam, Pradeep

    Morphing technology is an important aspect of UAV design, particularly in regards to deployable systems. The design of such system has an important impact on the vehicle's performance. The primary focus of the present research work was to determine the most optimum deployable wing design from 3 competing designs and develop one of the deployable wing designs to test in the research facility. A Matlab code was developed to optimize 3 deployable wing concepts inflatable, inflatable telescopic and rigid-folding wings based on a sequential optimization strategy. The constraints that were part of the code include the packaging constraints during its stowed state, fixed length of the deployed section and the minimum L/D constraint. This code resulted in determining the optimum weight of all the 3 designs, the most optimum weight design is the inflatable wing design. This is a result of the flexible skin material and also due to no rigid parts in the deployed wing section. Another goal of the research involved developing an inflatable telescopic wing. The prototype was tested in a wind tunnel, while the actual wing was tested in the altitude chamber to determine the deployment speed, input pressure, analyze and predict the deployment sequence and behavior of the wing at such high wind speeds and altitudes ranging from 60,000 ft to 90,000 ft. Results from these tests allowed us to conclude the deployment sequence of the telescopic wing followed from the root to the tip section. The results were used to analyze the deployment time of the wing. As expected the deployment time decreased with an increase in input pressure. The results also show us that as the altitude increases, the deployment speed of the wing also increased. This was demonstrated when the wing was tested at a maximum altitude pressure of 90,000ft, well above the design altitude of 60,000ft.

  2. Sectional lift coefficient of a rotating wing at low Reynolds numbers

    Kim, Ji Eun [Hyundai Motor Company, Hwaseong (Korea, Republic of); Kweon, Ji Hoon [Asan Medical Center, Seoul (Korea, Republic of); Choi, Hae Cheon [Seoul National University, Seoul (Korea, Republic of)


    We study the characteristics of the sectional lift coefficient (C{sub L,S}) of low-aspect-ratio wings in rotating motion at low Reynolds number (Re = 136), by conducting three-dimensional numerical simulations. Three different shapes of thin-plate wings (fruit-fly, rectangular, and triangular wings) are considered but keeping their aspect ratio (wing span/wing chord) the same at 3.74. Each wing rotates at a constant angular velocity and the angle of attack (α) is fixed during rotation. During rotation, the wing is exposed to the downward flows generated from the previous rotation, and thus C{sub L,S} is overall reduced due to the decrease in the effective angle of attack. At low α's, C{sub L,S} becomes almost constant on the whole span. At high α's, C{sub L,S} on the wing mid-section is inversely proportional to the radial position. The radial distribution of the sectional lift coefficient is less affected by the wing planform, while the lift coefficient significantly depends on the wing planforms. Finally, we show that the effect of the Reynolds number on the sectional lift coefficient is insignificant at low angle of attack but becomes important at high angle of attack.

  3. The Aerodynamic Forces on Slender Plane- and Cruciform-Wing and Body Combinations

    Spreiter, John R


    The load distribution, forces, and moments are calculated theoretically for inclined slender wing-body combinations consisting of a slender body of revolution and either a plane or cruciform arrangement of low-aspect-ratio pointed wings. The results are applicable at subsonic and transonic speeds, and at supersonic speeds, provided the entire wing-body combination lies near the center of the Mach cone.

  4. Unsteady flow over flexible wings at different low Reynolds numbers

    Genç Mustafa Serdar


    Full Text Available In this study, unsteady flow around flexible membrane wing which had aspect ratio of 1 (AR=1 was investigated experimentally at various Reynolds numbers (Re = 25000 and Re = 50000. Smoke-wire technique for flow visualization over the flexible membrane wing was utilized in the experiments. Digital Image Correlation system (DIC was used for measuring deformation of AR = 1 flexible membrane wing. Instantaneous deformation measurements of membrane wing were combined with the flow field measurements. In low aspect ratio flexible membrane wings, unsteadiness includes tip vortices and vortex shedding, and the combination of tip vortices. In these types of wings, complex unsteady deformations occurred due to vortex shedding. The results showed that the increasing angle of attack results in increase of membrane deformation. Moreover, it was concluded that analysis of the instantaneous deformation revealed chordwise and spanwise, modes which were due to the shedding of leading-edge vortices as well as tip vortices. Consequently, vibrational mode decreased and maximum standard deviation location approached to the trailing edge by reason of increasing angle of attack.

  5. Unsteady flow over flexible wings at different low Reynolds numbers

    Genç, Mustafa Serdar; Özden, Mustafa; Hakan Açikel, Halil; Demir, Hacımurat; Isabekov, Iliasbek


    In this study, unsteady flow around flexible membrane wing which had aspect ratio of 1 (AR=1) was investigated experimentally at various Reynolds numbers (Re = 25000 and Re = 50000). Smoke-wire technique for flow visualization over the flexible membrane wing was utilized in the experiments. Digital Image Correlation system (DIC) was used for measuring deformation of AR = 1 flexible membrane wing. Instantaneous deformation measurements of membrane wing were combined with the flow field measurements. In low aspect ratio flexible membrane wings, unsteadiness includes tip vortices and vortex shedding, and the combination of tip vortices. In these types of wings, complex unsteady deformations occurred due to vortex shedding. The results showed that the increasing angle of attack results in increase of membrane deformation. Moreover, it was concluded that analysis of the instantaneous deformation revealed chordwise and spanwise, modes which were due to the shedding of leading-edge vortices as well as tip vortices. Consequently, vibrational mode decreased and maximum standard deviation location approached to the trailing edge by reason of increasing angle of attack.

  6. Spatial Disorientation Training in the Rotor Wing Flight Simulator.

    Powell-Dunford, Nicole; Bushby, Alaistair; Leland, Richard A

    This study is intended to identify efficacy, evolving applications, best practices, and challenges of spatial disorientation (SD) training in flight simulators for rotor wing pilots. Queries of a UK Ministry of Defense research database and Pub Med were undertaken using the search terms 'spatial disorientation,' 'rotor wing,' and 'flight simulator.' Efficacy, evolving applications, best practices, and challenges of SD simulation for rotor wing pilots were also ascertained through discussion with subject matter experts and industrial partners. Expert opinions were solicited at the aeromedical physiologist, aeromedical psychologist, instructor pilot, aeromedical examiner, and corporate executive levels. Peer review literature search yielded 129 articles, with 5 relevant to the use of flight simulators for the spatial disorientation training of rotor wing pilots. Efficacy of such training was measured subjectively and objectively. A preponderance of anecdotal reports endorse the benefits of rotor wing simulator SD training, with a small trial substantiating performance improvement. Advancing technologies enable novel training applications. The mobile nature of flight students and concurrent anticollision technologies can make long-range assessment of SD training efficacy challenging. Costs of advanced technologies could limit the extent to which the most advanced simulators can be employed across the rotor wing community. Evidence suggests the excellent training value of rotor wing simulators for SD training. Objective data from further research, particularly with regards to evolving technologies, may justify further usage of advanced simulator platforms for SD training and research. Powell-Dunford N, Bushby A, Leland RA. Spatial disorientation training in the rotor wing flight simulator. Aerosp Med Hum Perform. 2016; 87(10):890-893.

  7. A Conceptual Wing Flutter Analysis Tool for Systems Analysis and Parametric Design Study

    Mukhopadhyay, Vivek


    An interactive computer program was developed for wing flutter analysis in the conceptual design stage. The objective was to estimate flutt er instability boundaries of a typical wing, when detailed structural and aerodynamic data are not available. Effects of change in key flu tter parameters can also be estimated in order to guide the conceptual design. This userfriendly software was developed using MathCad and M atlab codes. The analysis method was based on non-dimensional paramet ric plots of two primary flutter parameters, namely Regier number and Flutter number, with normalization factors based on wing torsion stiffness, sweep, mass ratio, taper ratio, aspect ratio, center of gravit y location and pitch-inertia radius of gyration. These parametric plo ts were compiled in a Chance-Vought Corporation report from database of past experiments and wind tunnel test results. An example was prese nted for conceptual flutter analysis of outer-wing of a Blended-Wing- Body aircraft.

  8. Automated measurement of Drosophila wings

    Mezey Jason


    Full Text Available Abstract Background Many studies in evolutionary biology and genetics are limited by the rate at which phenotypic information can be acquired. The wings of Drosophila species are a favorable target for automated analysis because of the many interesting questions in evolution and development that can be addressed with them, and because of their simple structure. Results We have developed an automated image analysis system (WINGMACHINE that measures the positions of all the veins and the edges of the wing blade of Drosophilid flies. A video image is obtained with the aid of a simple suction device that immobilizes the wing of a live fly. Low-level processing is used to find the major intersections of the veins. High-level processing then optimizes the fit of an a priori B-spline model of wing shape. WINGMACHINE allows the measurement of 1 wing per minute, including handling, imaging, analysis, and data editing. The repeatabilities of 12 vein intersections averaged 86% in a sample of flies of the same species and sex. Comparison of 2400 wings of 25 Drosophilid species shows that wing shape is quite conservative within the group, but that almost all taxa are diagnosably different from one another. Wing shape retains some phylogenetic structure, although some species have shapes very different from closely related species. The WINGMACHINE system facilitates artificial selection experiments on complex aspects of wing shape. We selected on an index which is a function of 14 separate measurements of each wing. After 14 generations, we achieved a 15 S.D. difference between up and down-selected treatments. Conclusion WINGMACHINE enables rapid, highly repeatable measurements of wings in the family Drosophilidae. Our approach to image analysis may be applicable to a variety of biological objects that can be represented as a framework of connected lines.

  9. Comparative Analysis of the Wing Geometry Design for an Aerodynamic Gondola of a Recoverable and Reusable Probe Balloon

    David Rubio Forero


    Full Text Available The present paper describes two conceptual wing designs that maintain equals the wing area, the aspect ratio, the wing span and the aerodynamic profiles, varying wing shape by changing the length of the root and tip chord of each model, in order to determinate the most efficient wing geometry design of an aerodynamic nacelle than could be implemented in a recoverable and reusable radio probe. The lift and drag coefficients are analyzed in function of the angle of attack, as a comparative parameter, finding an improvement on the lift when the tip chord has more length.

  10. Structural modeling and optimization of a joined-wing configuration of a High-Altitude Long-Endurance (HALE) aircraft

    Kaloyanova, Valentina B.

    Recent research trends have indicated an interest in High-Altitude, Long-Endurance (HALE) aircraft as a low-cost alternative to certain space missions, such as telecommunication relay, environmental sensing and military reconnaissance. HALE missions require a light vehicle flying at low speed in the stratosphere at altitudes of 60,000-80,000 ft, with a continuous loiter time of up to several days. To provide high lift and low drag at these high altitudes, where the air density is low, the wing area should be increased, i.e., high-aspect-ratio wings are necessary. Due to its large span and lightweight, the wing structure is very flexible. To reduce the structural deformation, and increase the total lift in a long-spanned wing, a sensorcraft model with a joined-wing configuration, proposed by AFRL, is employed. The joined-wing encompasses a forward wing, which is swept back with a positive dihedral angle, and connected with an aft wing, which is swept forward. The joined-wing design combines structural strength, high aerodynamic performance and efficiency. As a first step to study the joined-wing structural behavior an 1-D approximation model is developed. The 1-D approximation is a simple structural model created using ANSYS BEAM4 elements to present a possible approach for the aerodynamics-structure coupling. The pressure loads from the aerodynamic analysis are integrated numerically to obtain the resultant aerodynamic forces and moments (spanwise lift and pitching moment distributions, acting at the aerodynamic center). These are applied on the 1-D structural model. A linear static analysis is performed under this equivalent load, and the deformed shape of the 1-D model is used to obtain the deformed shape of the actual 3-D joined wing, i.e. deformed aerodynamic surface grid. To date in the existing studies, only simplified structural models have been examined. In the present work, in addition to the simple 1-D beam model, a semi-monocoque structural model is

  11. Flow Modulation and Force Control of Flapping Wings


    species from fruit flies and dragonflies all the way up to hummingbirds. The summary of parameter levels is shown in Table I. Figure 30...such as this one. In our study, the mass ratio, given by (1) is 0.2. The mass ratio of a cranefly and dragonfly is estimated to be 0.34 (Ishihara...this choice of parameters. Reviewing the kinematics and known frequency ratios of dragonfly wings, this optimal MAV design parameter choice

  12. Modal analysis of sailplane and transport aircraft wings using the dynamic stiffness method

    Banerjee, J. R.


    The purpose of this paper is to provide theory, results, discussion and conclusions arising from an in-depth investigation on the modal behaviour of high aspect ratio aircraft wings. The illustrative examples chosen are representative of sailplane and transport airliner wings. To achieve this objective, the dynamic stiffness method of modal analysis is used. The wing is represented by a series of dynamic stiffness elements of bending-torsion coupled beams which are assembled to form the overall dynamic stiffness matrix of the complete wing. With cantilever boundary condition applied at the root, the eigenvalue problem is formulated and finally solved with the help of the Wittrick-Williams algorithm to yield the eigenvalues and eigenmodes which are essentially the natural frequencies and mode shapes of the wing. Results for wings of two sailplanes and four transport aircraft are discussed and finally some conclusions are drawn

  13. Aerodynamic Optimization of an Over-the-Wing-Nacelle-Mount Configuration

    Daisuke Sasaki


    Full Text Available An over-the-wing-nacelle-mount airplane configuration is known to prevent the noise propagation from jet engines toward ground. However, the configuration is assumed to have low aerodynamic efficiency due to the aerodynamic interference effect between a wing and a nacelle. In this paper, aerodynamic design optimization is conducted to improve aerodynamic efficiency to be equivalent to conventional under-the-wing-nacelle-mount configuration. The nacelle and wing geometry are modified to achieve high lift-to-drag ratio, and the optimal geometry is compared with a conventional configuration. Pylon shape is also modified to reduce aerodynamic interference effect. The final wing-fuselage-nacelle model is compared with the DLR F6 model to discuss the potential of Over-the-Wing-Nacelle-Mount geometry for an environmental-friendly future aircraft.

  14. Endplate effect on aerodynamic characteristics of threedimensional wings in close free surface proximity

    Jung, Jae Hwan; Kim, Mi Jeong; Yoon, Hyun Sik; Hung, Pham Anh; Chun, Ho Hwan; Park, Dong Woo


    We investigated the aerodynamic characteristics of a three-dimensional (3D) wing with an endplate in the vicinity of the free surface by solving incompressible Navier-Stokes equations with the turbulence closure model. The endplate causes a blockage effect on the flow, and an additional viscous effect especially near the endplate. These combined effects of the endplate significantly reduce the magnitudes of the velocities under the lower surface of the wing, thereby enhancing aerodynamic performance in terms of the force coefficients. The maximum lift-to-drag ratio of a wing with an endplate is increased 46% compared to that of wing without an endplate at the lowest clearance. The tip vortex of a wing-with-endplate (WWE) moved laterally to a greater extent than that of a wing-without-endplate (WOE). This causes a decrease in the induced drag, resulting in a reduction in the total drag.

  15. Features of owl wings that promote silent flight.

    Wagner, Hermann; Weger, Matthias; Klaas, Michael; Schröder, Wolfgang


    Owls are an order of birds of prey that are known for the development of a silent flight. We review here the morphological adaptations of owls leading to silent flight and discuss also aerodynamic properties of owl wings. We start with early observations (until 2005), and then turn to recent advances. The large wings of these birds, resulting in low wing loading and a low aspect ratio, contribute to noise reduction by allowing slow flight. The serrations on the leading edge of the wing and the velvet-like surface have an effect on noise reduction and also lead to an improvement of aerodynamic performance. The fringes at the inner feather vanes reduce noise by gliding into the grooves at the lower wing surface that are formed by barb shafts. The fringed trailing edge of the wing has been shown to reduce trailing edge noise. These adaptations to silent flight have been an inspiration for biologists and engineers for the development of devices with reduced noise production. Today several biomimetic applications such as a serrated pantograph or a fringed ventilator are available. Finally, we discuss unresolved questions and possible future directions.

  16. Flying Wings. A New Paradigm for Civil Aviation?

    R. Martinez-Val


    Full Text Available Over the last 50 years, commercial aviation has been mainly based what is currently called the conventional layout, characterized by a slender fuselage mated to a high aspect ratio wing, with aft-tail planes and pod-mounted engines under the wing. However, it seems that this primary configuration is approaching an asymptote in its productivity and performance characteristics. One of the most promising configurations for the future is the flying wing in its distinct arrangements: blended-wing-body, C-wing, tail-less aircraft, etc. These layouts might provide significant fuel savings and, hence, a decrease in pollution. This configuration would also reduce noise in take-off and landing. All this explains the great deal of activity carried out by the aircraft industry and by numerous investigators to perform feasibility and conceptual design studies of this aircraft layout to gain better knowledge of its main characteristics: productivity, airport compatibility, passenger acceptance, internal architecture, emergency evacuation, etc. The present paper discusses the main features of flying wings, their advantages over conventional competitors, and some key operational issues, such as evacuation and vortex wake intensity. 

  17. A Model for Selection of Eyespots on Butterfly Wings.

    Toshio Sekimura

    observed in nature.We therefore conclude that changes in the proximal boundary conditions are sufficient to explain the empirically observed distribution of eyespot focus points on the entire wing surface. The model predicts, subject to experimental verification, that the source strength of the activator at the proximal boundary should be lower in wing cells in which focus points form than in those that lack focus points. The model suggests that the number and locations of eyespot foci on the wing disc could be largely controlled by two kinds of gradients along two different directions, that is, the first one is the gradient in spatially varying parameters such as the reaction rate along the anterior-posterior direction on the proximal boundary of the wing cells, and the second one is the gradient in source values of the activator along the veins in the proximal-distal direction of the wing cell.

  18. Beetle wings are inflatable origami

    Chen, Rui; Ren, Jing; Ge, Siqin; Hu, David


    Beetles keep their wings folded and protected under a hard shell. In times of danger, they must unfold them rapidly in order for them to fly to escape. Moreover, they must do so across a range of body mass, from 1 mg to 10 grams. How can they unfold their wings so quickly? We use high-speed videography to record wing unfolding times, which we relate to the geometry of the network of blood vessels in the wing. Larger beetles have longer unfolding times. Modeling of the flow of blood through the veins successfully accounts for the wing unfolding speed of large beetles. However, smaller beetles have anomalously short unfolding times, suggesting they have lower blood viscosity or higher driving pressure. The use of hydraulics to unfold complex objects may have implications in the design of micro-flying air vehicles.




    Full Text Available Observers have always been fascinated by soaring birds. An interesting feature of these birds is the existence of few feathers extending from the tip of the wing. In this paper, small lifting surfaces were fitted to the tip of a NACA0012 wing in a fashion similar to that of wing tip feathers. Experimental measurements of induced drag, longitudinal static stability and trailing vortex structure were obtained.The tests showed that adding wing tip surfaces (sails decreased the induced drag factor and increased the longitudinal static stability. Results identified two discrete appositely rotated tip vortices and showed the ability of wing tip surfaces to break them down and to diffuse them.

  20. Interactive flutter analysis and parametric study for conceptual wing design

    Mukhopadhyay, Vivek


    An interactive computer program was developed for wing flutter analysis in the conceptual design stage. The objective was to estimate the flutter instability boundary of a flexible cantilever wing, when well defined structural and aerodynamic data are not available, and then study the effect of change in Mach number, dynamic pressure, torsional frequency, sweep, mass ratio, aspect ratio, taper ratio, center of gravity, and pitch inertia, to guide the development of the concept. The software was developed on MathCad (trademark) platform for Macintosh, with integrated documentation, graphics, database and symbolic mathematics. The analysis method was based on nondimensional parametric plots of two primary flutter parameters, namely Regier number and Flutter number, with normalization factors based on torsional stiffness, sweep, mass ratio, aspect ratio, center of gravity location and pitch inertia radius of gyration. The plots were compiled in a Vaught Corporation report from a vast database of past experiments and wind tunnel tests. The computer program was utilized for flutter analysis of the outer wing of a Blended Wing Body concept, proposed by McDonnell Douglas Corporation. Using a set of assumed data, preliminary flutter boundary and flutter dynamic pressure variation with altitude, Mach number and torsional stiffness were determined.

  1. Theoretical-Numerical Study of Feasibility of Use of Winglets on Low Aspect Ration Wings at Subsonic and Transonic Mach Numbers to Reduce Drag

    Kuhlman, John M.; Liaw, Paul; Cerney, Michael J.


    A numerical design study was conducted to assess the drag reduction potential of winglets installed on a series of low aspect ratio wings at a design point of M=0.8, C sub L=0.3. Wing-winglet and wing-alone design geometries were obtained for wings of aspect ratios between 1.75 and 2.67, having leading edge sweep angles between 45 and 60 deg. Winglet length was fixed at 15% of wing semispan. To assess the relative performance between wing-winglet and wing-alone configurations, the PPW nonlinear extended small disturbance potential flow code was utilized. This model has proven to yield plausible transonic flow field simulations for the series of low aspect ratio configurations selected. Predicted decreases in pressure drag coefficient for the wing-winglet configurations relative to the corresponding wing-alone planform are about 15% at the design point. Predicted decreases in wing-winglet total drag coefficient are about 12%, relative to the corresponding wing-alone design. Longer winglets (25% of the wing semispan) yielded decreases in the pressure drag of up to 22% and total drag of up to 16.4%. These predicted drag coefficient reductions are comparable to reductions already demonstrated by actual winglet designs installed on higher aspect ratio transport type aircraft.

  2. Study on flow over finite wing with respect to F-22 raptor, Supermarine Spitfire, F-7 BG aircraft wing and analyze its stability performance and experimental values

    Ali, Md. Nesar; Alam, Mahbubul


    , and the induced drag increases, reducing overall efficiency. To complement the high aspect ratio wing case, a slender wing model is formulated so that the lift and drag can be estimated for this limiting case as well. We analyze the stability performance of F-22 raptor, Supermarine Spitfire, F-7 BG Aircraft wing by using experimental method and simulation software. The experimental method includes fabrication of F-22 raptor, Supermarine Spitfire, F-7 BG Aircraft wing which making material is Gamahr wood. Testing this model wing in wind tunnel test and after getting expected data we also compared this value with analyzing software data for furthermore experiment.

  3. Three-dimensional flow past rotating wing at low Reynolds number: a computational study

    Ruifeng, Hu, E-mail: [School of Mechano-Electronic Engineering, Xidian University, Xi’an 710071 (China)


    In this work, we performed a computational study on the three-dimensional (3D) flow past a rotating wing at a low Reynolds number (Re = 200). The 3D vortical structures and aerodynamic performances of the rotating wing with different aspect ratios and rotating speeds are computed and analyzed. A quasi-steady model is adopted for prediction of aerodynamic performances of the wing, and its applicability is evaluated by the computation. It is found that there exists a periodic vortex shedding pattern at a low rotating speed, while vortices may cluster near the wing when rotating speed is high enough. The wake vortex topology is also affected by the aspect ratio. The current quasi-steady aerodynamic model could only be used for rotating wing aerodynamics at a low rotating speed when regularly periodic vortex shedding exists. (paper)

  4. Assembly modes of dragonfly wings.

    Zhao, Hong-Xiao; Yin, Ya-Jun; Zhong, Zheng


    The assembly modes of dragonfly wings are observed through FEG-ESEM. Different from airplane wings, dragonfly wings are found to be assembled through smooth transition mode and global package mode. First, at the vein/membrane conjunctive site, the membrane is divided into upper and lower portions from the center layer and transited smoothly to the vein. Then the two portions pack the vein around and form the outer surface of the vein. Second, at the vein/spike conjunctive site, the vein and spike are connected smoothly into a triplet. Last, at the vein/membrane/spike conjunctive site, the membrane (i.e., the outer layer of the vein) transits smoothly to the spike, packs it around, and forms its outer layer. In short, the membrane looks like a closed coat packing the wing as a whole. The smooth transition mode and the global package mode are universal assembly modes in dragonfly wings. They provide us the references for better understanding of the functions of dragonfly wings and the bionic manufactures of the wings of flights with mini sizes.

  5. Structural Analysis of a Dragonfly Wing

    Jongerius, S.R.; Lentink, D.


    Dragonfly wings are highly corrugated, which increases the stiffness and strength of the wing significantly, and results in a lightweight structure with good aerodynamic performance. How insect wings carry aerodynamic and inertial loads, and how the resonant frequency of the flapping wings is tuned

  6. Force generation and wing deformation characteristics of a flapping-wing micro air vehicle 'DelFly II' in hovering flight.

    Percin, M; van Oudheusden, B W; de Croon, G C H E; Remes, B


    The study investigates the aerodynamic performance and the relation between wing deformation and unsteady force generation of a flapping-wing micro air vehicle in hovering flight configuration. Different experiments were performed where fluid forces were acquired with a force sensor, while the three-dimensional wing deformation was measured with a stereo-vision system. In these measurements, time-resolved power consumption and flapping-wing kinematics were also obtained under both in-air and in-vacuum conditions. Comparison of the results for different flapping frequencies reveals different wing kinematics and deformation characteristics. The high flapping frequency case produces higher forces throughout the complete flapping cycle. Moreover, a phase difference occurs in the variation of the forces, such that the low flapping frequency case precedes the high frequency case. A similar phase lag is observed in the temporal evolution of the wing deformation characteristics, suggesting that there is a direct link between the two phenomena. A considerable camber formation occurs during stroke reversals, which is mainly determined by the stiffener orientation. The wing with the thinner surface membrane displays very similar characteristics to the baseline wing, which implies the dominance of the stiffeners in terms of providing rigidity to the wing. Wing span has a significant effect on the aerodynamic efficiency such that increasing the span length by 4 cm results in a 6% enhancement in the cycle-averaged X-force to power consumption ratio compared to the standard DelFly II wings with a span length of 28 cm.

  7. Wings and Flying in Immersive VR - Controller Type, Sound Effects and Experienced Ownership and Agency

    Sikström, Erik; Götzen, Amalia De; Serafin, Stefania

    An experiment investigated the subjective experiences of ownership and agency of a pair of virtual wings attached to a motion controlled avatar in an immersive virtual reality setup. A between groups comparison of two ways of controlling the movement of the wings and flight ability. One where...... their experienced embodiment of the wings on a body ownership and agency questionnaire. The results shows significant differences between the controllers in some of the questionnaire items and that adding self-produced sounds to the avatar, slightly changed the subjects evaluations....... the subjects achieved the wing motion and flight ability by using a hand-held video game controller and the other by moving the shoulder. Through four repetitions of a flight task with varying amounts of self-produced audio feedback (from the movement of the virtual limbs), the subjects evaluated...

  8. Incompressible Turbulent Wing-Body Junction Flow

    Krishnamurthy, R.; Cagle, Corey D.; Chandra, S.


    The overall objective of this study is to contribute to the optimized design of fan bypass systems in advanced turbofan engines. Increasing the engine bypass ratios have provided a major boost in engine performance improvement over the last fifty years. An engine with high bypass ratio (11-16:1) such as the Advanced Ducted Propulsion (ADP) is being developed and is expected to provide an additional 25% improvement in overall efficiency over the early turbofans. Such significant improvements in overall efficiency would reduce the cost per seat mile, which is a major government and Industry challenge for the 21th century. The research is part of the Advanced Subsonic Technology (AST) program that involves a NASA, U.S. Industry and FAA partnership with the goal of a safe and highly productive global air transportation system. The immediate objective of the study is to perform numerical simulation of duct-strut interactions to elucidate the loss mechanisms associated with this configuration that is typical of advanced turbofan engines such as ADP. However, at present experimental data for a duct-strut configuration are not available. Thus, as a first step a wing-body junction flow would be studied and is the specific objective of the present study. At the outset it is to be recognized that while duct-strut interaction flow is similar to that of wing-body junction flows, there are some differences owing to the presence of a wall at both ends of the strut. Likewise, some differences are due to the sheared inflow (as opposed to a uniform inflow) velocity profile. It is however expected that some features of a wing-body junction flow would persist. Next, some of the salient aspects of the complex flow near a wing-body junction, as revealed by various studies reported in the literature will be reviewed. One of the principle characteristics of the juncture flow, is the presence of the mean flow components in a plane perpendicular to the direction of the oncoming free

  9. Unsteady Flow Structure on Low Aspect Ratio Wings


    following, the flow structure is addressed in further detail for excitation at fe = fo/2. Figures A4a through A4c compare the flow structure on the...shown in Figure A4a , irrespective of the spanwise location , the effect of excitation is to substantially decrease the streamwise extent of the high

  10. The influence of flight style on the aerodynamic properties of avian wings as fixed lifting surfaces

    John J. Lees


    Full Text Available The diversity of wing morphologies in birds reflects their variety of flight styles and the associated aerodynamic and inertial requirements. Although the aerodynamics underlying wing morphology can be informed by aeronautical research, important differences exist between planes and birds. In particular, birds operate at lower, transitional Reynolds numbers than do most aircraft. To date, few quantitative studies have investigated the aerodynamic performance of avian wings as fixed lifting surfaces and none have focused upon the differences between wings from different flight style groups. Dried wings from 10 bird species representing three distinct flight style groups were mounted on a force/torque sensor within a wind tunnel in order to test the hypothesis that wing morphologies associated with different flight styles exhibit different aerodynamic properties. Morphological differences manifested primarily as differences in drag rather than lift. Maximum lift coefficients did not differ between groups, whereas minimum drag coefficients were lowest in undulating flyers (Corvids. The lift to drag ratios were lower than in conventional aerofoils and data from free-flying soaring species; particularly in high frequency, flapping flyers (Anseriformes, which do not rely heavily on glide performance. The results illustrate important aerodynamic differences between the wings of different flight style groups that cannot be explained solely by simple wing-shape measures. Taken at face value, the results also suggest that wing-shape is linked principally to changes in aerodynamic drag, but, of course, it is aerodynamics during flapping and not gliding that is likely to be the primary driver.

  11. The influence of flight style on the aerodynamic properties of avian wings as fixed lifting surfaces

    Dimitriadis, Grigorios; Nudds, Robert L.


    The diversity of wing morphologies in birds reflects their variety of flight styles and the associated aerodynamic and inertial requirements. Although the aerodynamics underlying wing morphology can be informed by aeronautical research, important differences exist between planes and birds. In particular, birds operate at lower, transitional Reynolds numbers than do most aircraft. To date, few quantitative studies have investigated the aerodynamic performance of avian wings as fixed lifting surfaces and none have focused upon the differences between wings from different flight style groups. Dried wings from 10 bird species representing three distinct flight style groups were mounted on a force/torque sensor within a wind tunnel in order to test the hypothesis that wing morphologies associated with different flight styles exhibit different aerodynamic properties. Morphological differences manifested primarily as differences in drag rather than lift. Maximum lift coefficients did not differ between groups, whereas minimum drag coefficients were lowest in undulating flyers (Corvids). The lift to drag ratios were lower than in conventional aerofoils and data from free-flying soaring species; particularly in high frequency, flapping flyers (Anseriformes), which do not rely heavily on glide performance. The results illustrate important aerodynamic differences between the wings of different flight style groups that cannot be explained solely by simple wing-shape measures. Taken at face value, the results also suggest that wing-shape is linked principally to changes in aerodynamic drag, but, of course, it is aerodynamics during flapping and not gliding that is likely to be the primary driver.

  12. The Redder the Better: Wing Color Predicts Flight Performance in Monarch Butterflies

    Davis, Andrew K.; Chi, Jean; Bradley, Catherine; Altizer, Sonia


    The distinctive orange and black wings of monarchs (Danaus plexippus) have long been known to advertise their bitter taste and toxicity to potential predators. Recent work also showed that both the orange and black coloration of this species can vary in response to individual-level and environmental factors. Here we examine the relationship between wing color and flight performance in captive-reared monarchs using a tethered flight mill apparatus to quantify butterfly flight speed, duration and distance. In three different experiments (totaling 121 individuals) we used image analysis to measure body size and four wing traits among newly-emerged butterflies prior to flight trials: wing area, aspect ratio (length/width), melanism, and orange hue. Results showed that monarchs with darker orange (approaching red) wings flew longer distances than those with lighter orange wings in analyses that controlled for sex and other morphometric traits. This finding is consistent with past work showing that among wild monarchs, those sampled during the fall migration are darker in hue (redder) than non-migratory monarchs. Together, these results suggest that pigment deposition onto wing scales during metamorphosis could be linked with traits that influence flight, such as thorax muscle size, energy storage or metabolism. Our results reinforce an association between wing color and flight performance in insects that is suggested by past studies of wing melansim and seasonal polyphenism, and provide an important starting point for work focused on mechanistic links between insect movement and color. PMID:22848463

  13. Beyond the wing planform: morphological differentiation between migratory and nonmigratory dragonfly species.

    Suárez-Tovar, C M; Sarmiento, C E


    Migration is a significant trait of the animal kingdom that can impose a strong selective pressure on several structures to overcome the amount of energy that the organism invests in this particular behaviour. Wing linear dimensions and planform have been a traditional focus in the study of flying migratory species; however, other traits could also influence aerodynamic performance. We studied the differences in several flight-related traits of migratory and nonmigratory Libellulid species in a phylogenetic context to assess their response to migratory behaviour. Wings were compared by linear measurements, shape, surface corrugations and microtrichia number. Thorax size and pilosity were also compared. Migratory species have larger and smoother wings, a larger anal lobe that is reached through an expansion of the discoidal region, and longer and denser thoracic pilosity. These differences might favour gliding as an energy-saving displacement strategy. Most of the changes were identified in the hind wings. No differences were observed for the thorax linear dimensions, wetted aspect ratio, some wing corrugations or the wing microtrichiae number. Similar changes in the hind wing are present in clades where migration evolved. Our results emphasize that adaptations to migration through flight may extend to characteristics beyond the wing planform and that some wing characteristics in libellulids converge in response to migratory habits, whereas other closely related structures remain virtually unchanged. Additionally, we concluded that despite a close functional association and similar selective pressures on a structure, significant differences in the magnitude of the response may be present in its components.

  14. The redder the better: wing color predicts flight performance in monarch butterflies.

    Andrew K Davis

    Full Text Available The distinctive orange and black wings of monarchs (Danaus plexippus have long been known to advertise their bitter taste and toxicity to potential predators. Recent work also showed that both the orange and black coloration of this species can vary in response to individual-level and environmental factors. Here we examine the relationship between wing color and flight performance in captive-reared monarchs using a tethered flight mill apparatus to quantify butterfly flight speed, duration and distance. In three different experiments (totaling 121 individuals we used image analysis to measure body size and four wing traits among newly-emerged butterflies prior to flight trials: wing area, aspect ratio (length/width, melanism, and orange hue. Results showed that monarchs with darker orange (approaching red wings flew longer distances than those with lighter orange wings in analyses that controlled for sex and other morphometric traits. This finding is consistent with past work showing that among wild monarchs, those sampled during the fall migration are darker in hue (redder than non-migratory monarchs. Together, these results suggest that pigment deposition onto wing scales during metamorphosis could be linked with traits that influence flight, such as thorax muscle size, energy storage or metabolism. Our results reinforce an association between wing color and flight performance in insects that is suggested by past studies of wing melansim and seasonal polyphenism, and provide an important starting point for work focused on mechanistic links between insect movement and color.

  15. Data and analysis procedures for improved aerial applications mission performance. [agricultural aircraft wing geometry

    Holmes, B. J.; Morris, D. K.; Razak, K.


    An analysis procedure is given and cases analyzed for the effects of wing geometry on lateral transport of a variety of agricultural particles released in the wake of an agricultural airplane. The cases analyzed simulate the release of particles from a fuselage centerline-mounted dry material spreader; however, the procedure applies to particles released anywhere along the wing span. Consideration is given to the effects of taper ratio, aspect ratio, wing loading, and deflected flaps. It is noted that significant lateral transport of large particles can be achieved using high-lift devices positioned to create a strong vortex near the location of particle release.

  16. Investigation of Load and Pressure Distribution onWing with Wake Rollup for Low Speed Aircraft

    Laith W. Ismail


    Full Text Available The presented work shows a preliminary analytic method for estimation of load and pressure distributions on low speed wings with flow separation and wake rollup phenomena’s. A higher order vortex panel method is coupled with the numerical lifting line theory by means of iterative procedure including models of separation and wake rollup. The computer programs are written in FORTRAN which are stable and efficient. The capability of the present method is investigated through a number of test cases with different types of wing sections (NACA 0012 and GA(W-1 for different aspect ratios and angles of attack, the results include the lift and drag curves, lift and pressure distributions along the wing span taking into the consideration the effect of the angles of attack and the aspect ratios on the wake rollup. The pressure distribution on the wings shows that there is a region of constant pressure on the upper surface of the wings near the trailing edge in the middle of the wing, also there is a region of flow separation on the upper surface of the wings. A good agreement is found between the presented work results and other from previous researches. These results show that the presented method is able to capture much of flow over wings feature like separation and wake rollup.

  17. Wing-kinematics measurement and aerodynamics in a small insect in hovering flight.

    Cheng, Xin; Sun, Mao


    Wing-motion of hovering small fly Liriomyza sativae was measured using high-speed video and flows of the wings calculated numerically. The fly used high wingbeat frequency (≈265 Hz) and large stroke amplitude (≈182°); therefore, even if its wing-length (R) was small (R ≈ 1.4 mm), the mean velocity of wing reached ≈1.5 m/s, the same as that of an average-size insect (R ≈ 3 mm). But the Reynolds number (Re) of wing was still low (≈40), owing to the small wing-size. In increasing the stroke amplitude, the outer parts of the wings had a "clap and fling" motion. The mean-lift coefficient was high, ≈1.85, several times larger than that of a cruising airplane. The partial "clap and fling" motion increased the lift by ≈7%, compared with the case of no aerodynamic interaction between the wings. The fly mainly used the delayed stall mechanism to generate the high-lift. The lift-to-drag ratio is only 0.7 (for larger insects, Re being about 100 or higher, the ratio is 1-1.2); that is, although the small fly can produce enough lift to support its weight, it needs to overcome a larger drag to do so.

  18. Conceptual design and optimization methodology for box wing aircraft

    Jemitola, Paul Olugbeji


    A conceptual design optimization methodology was developed for a medium range box wing aircraft. A baseline conventional cantilever wing aircraft designed for the same mis- sion and payload was also optimized alongside a baseline box wing aircraft. An empirical formula for the mass estimation of the fore and aft wings of the box wing aircraft was derived by relating conventional cantilever wings to box wing aircraft wings. The results indicate that the fore and aft wings would ...

  19. Limb disparity and wing shape in pterosaurs.

    Dyke, G J; Nudds, R L; Rayner, J M V


    The limb proportions of the extinct flying pterosaurs were clearly distinct from their living counterparts, birds and bats. Within pterosaurs, however, we show that further differences in limb proportions exist between the two main groups: the clade of short-tailed Pterodactyloidea and the paraphyletic clades of long-tailed rhamphorhynchoids. The hindlimb to forelimb ratios of rhamphorhynchoid pterosaurs are similar to that seen in bats, whereas those of pterodactyloids are much higher. Such a clear difference in limb ratios indicates that the extent of the wing membrane in rhamphorhynchoids and pterodactyloids may also have differed; this is borne out by simple ternary analyses. Further, analyses also indicate that the limbs of Sordes pilosus, a well-preserved small taxon used as key evidence for inferring the extent and shape of the wing membrane in all pterosaurs, are not typical even of its closest relatives, other rhamphorhynchoids. Thus, a bat-like extensive hindlimb flight membrane, integrated with the feet and tail may be applicable only to a small subset of pterosaur diversity. The range of flight morphologies seen in these extinct reptiles may prove much broader than previously thought.

  20. Leading-edge vortex shedding from rotating wings

    Kolomenskiy, Dmitry; Schneider, Kai


    The paper presents a numerical investigation of the leading-edge vortices generated by rotating triangular wings at Reynolds number $Re=250$. A series of three-dimensional numerical simulations have been carried out using a Fourier pseudo-spectral method with volume penalization. The transition from stable attachment of the leading-edge vortex to periodic vortex shedding is explored, as a function of the wing aspect ratio and the angle of attack. It is found that, in a stable configuration, the spanwise flow in the recirculation bubble past the wing is due to the centrifugal force, incompressibility and viscous stresses. For the flow outside of the bubble, an inviscid model of spanwise flow is presented.

  1. Geometric and structural properties of a rectangular supercritical wing oscillated in pitch for measurement of unsteady transonic pressure distributions

    Ricketts, R. H.; Watson, J. J.; Sandford, M. C.; Seidel, D. A.


    Wind-tunnel tests to measure unsteady aerodynamic data in the transonic region have been completed on an aspect ratio 2.0 rectangular wing with a supercritical airfoil. The geometric and structural properties of the wing are presented. (Other references contain the measured aerodynamic data.) Both measured and design airfoil coordinates are presented and compared. In addition, measured wing bending and torsional stiffness distributions and some trailing-edge flexibility influence coefficients are presented.

  2. Qualitative skeletal correlates of wing shape in extant birds (Aves: Neoaves).

    Hieronymus, Tobin L


    Among living fliers (birds, bats, and insects), birds display relatively high aspect ratios, a dimensionless shape variable that distinguishes long and narrow vs. short and broad wings. Increasing aspect ratio results in a functional tradeoff between low induced drag (efficient cruise) and increased wing inertia (difficult takeoff). Given the wide scope of its functional effects, the pattern of aspect ratio evolution is an important factor that contributes to the substantial ecological and phylogenetic diversity of living birds. However, because the feathers that define the wingtip (and hence wingspan and aspect ratio) often do not fossilize, resolution in the pattern of avian wing shape evolution is obscured by missing information. Here I use a comparative approach to investigate the relationship between skeletal proxies of flight feather attachment and wing shape. An accessory lobe of the internal index process of digit II-1, a bony correlate of distal primary attachment, shows weak but statistically significant relationships to aspect ratio and mass independent of other skeletal morphology. The dorsal phalangeal fossae of digit II-1, which house distal primaries VIII and IX, also show a trend of increased prominence with higher aspect ratio. Quill knobs on the ulna are examined concurrently, but do not show consistent signal with respect to wing shape. Although quill knobs are cited as skeletal correlates of flight performance in birds, their relationship to wing shape is inconsistent among extant taxa, and may reflect diverging selection pressures acting on a conserved architecture. In contrast, correlates of distal primary feather attachment on the major digit show convergent responses to increasing aspect ratio. In light of the diversity of musculoskeletal and integumentary mophology that underlies wing shape in different avian clades, it is unlikely that a single skeletal feature will show consistent predictive power across Neoaves. Confident inference of

  3. a New Efficient Control Method for Blended Wing Body

    Wu, Wenhua; Chen, Dehua; Qin, Ning; Peng, Xin; Tang, Xinwu

    The blended wing body (BWB) is the hottest one of the aerodynamic shapes of next generation airliner because of its' high lift-drag ratio, but there are still some flaws that cut down its aerodynamical performance. One of the most harmful flaws is the low efficiency of elevator and direction rudder, this makes the BWB hard to be controlled. In this paper, we proposed a new control method to solve this problem by morphing wing—that is, to control the BWB only by changing its wing shape but without any rudder. The pitching moments, rolling moments and yawing moments are plotted versus the parameters section and the wing shape in figures and are discussed in the paper. The result shows that the morphing wing can control the moments of BWB more precisely and in wider range. The pitching moments, rolling moments and yawing moments increases or decreases linearly or almost linearly, with the value of the selected parameters. These results show that using morphing wing is an excellent aerodynamic control way for a BWB craft.

  4. Wing Warping and Its Impact on Aerodynamic Efficiency

    Loh, Ben; Jacob, Jamey


    Inflatable wings have been demonstrated in many applications such as UAVs, airships, and missile stabilization surfaces. A major concern presented by the use of an inflatable wing has been the lack of traditional roll control surfaces. This leaves the designer with several options in order to have control about the roll axis. Since inflatable wings have a semi-flexible structure, wing warping is the obvious solution to this problem. The current method is to attach servos and control linkages to external surface of the wing that results in variation of profile chamber and angle of attack from leading edge or trailing edge deflection. Designs using internal muscles will also be discussed. This creates a lift differential between the half-spans, resulting in a roll moment. The trailing edge on the other half-span can also be deflected in the opposite direction to increase the roll moment as well as to reduce roll-yaw coupling. Comparisons show that higher L/D ratios are possible than using traditional control surfaces. An additional benefit is the ability to perform symmetric warping to achieve optimum aerodynamic performance. Via warping alone, an arbitrary span can be warped such that it has the same aerodynamic characteristics as an elliptical planform. Comparisons between lifting line theory and test results will be presented.

  5. WINGS Data Release

    Moretti, A.; Poggianti, B. M.; Fasano, G.;


    Context. To effectively investigate galaxy formation and evolution, it is of paramount importance to exploit homogeneous data for large samples of galaxies in different environments. Aims. The WIde-field Nearby Galaxy-cluster Survey (WINGS) project aim is to evaluate physical properties of galaxies......, and on the cluster redshift, reaching on average 90% at V ≲ 21.7. Near-infrared photometric catalogs for 26 (in K) and 19 (in J) clusters are part of the database and the number of sources is 962 344 in K and 628 813 in J. Here again the completeness depends on the data quality, but it is on average higher than 90......% for J ≲ 20.5 and K ≲ 19.4. The IR subsample with a Sersic fit comprises 71 687 objects. A morphological classification is available for 39 923 galaxies. We publish spectroscopic data, including 6132 redshifts, 5299 star formation histories, and 4381 equivalent widths. Finally, a calculation of local...

  6. Static aeroelastic analysis of composite wing

    Lee, IN; Hong, Chang Sun; Miura, Hirokazu; Kim, Seung KO


    A static aeroelastic analysis capability that can predict aerodynamic loads for the deformed shape of the composite wing has been developed. The finite element method (FEM) was used for composite plate structural analysis, and the linear vortex lattice method (VLM) was used for steady aerodynamic analysis. The final deformed shape of the wing due to applied forces is determined by iterative manner using FEM and VLM. FEM and VLM analysis are related by a surface spline interpolation procedure. The wing with Gr/Ep composite material has been investigated to see the wing deformation effect. Aerodynamic load change due to wing flexibility has been investigated. Also, the effect of fiber orientation and sweep angle on the deformation pattern and aerodynamic coefficients are examined. For a certain fiber orientation, the deflection and aerodynamic loading of the composite wing is very much reduced. The swept forward wing has more significant effect of wing flexibility on aerodynamic coefficient than the swept back wing does.

  7. Study on bird's & insect's wing aerodynamics and comparison of its analytical value with standard airfoil

    Ali, Md. Nesar; Alam, Mahbubul; Hossain, Md. Abed; Ahmed, Md. Imteaz


    Flight is the main mode of locomotion used by most of the world's bird & insect species. This article discusses the mechanics of bird flight, with emphasis on the varied forms of bird's & insect's wings. The fundamentals of bird flight are similar to those of aircraft. Flying animals flap their wings to generate lift and thrust as well as to perform remarkable maneuvers with rapid accelerations and decelerations. Insects and birds provide illuminating examples of unsteady aerodynamics. Lift force is produced by the action of air flow on the wing, which is an airfoil. The airfoil is shaped such that the air provides a net upward force on the wing, while the movement of air is directed downward. Additional net lift may come from airflow around the bird's & insect's body in some species, especially during intermittent flight while the wings are folded or semi-folded. Bird's & insect's flight in nature are sub-divided into two stages. They are Unpowered Flight: Gliding and Soaring & Powered Flight: Flapping. When gliding, birds and insects obtain both a vertical and a forward force from their wings. When a bird & insect flaps, as opposed to gliding, its wings continue to develop lift as before, but the lift is rotated forward to provide thrust, which counteracts drag and increases its speed, which has the effect of also increasing lift to counteract its weight, allowing it to maintain height or to climb. Flapping flight is more complicated than flight with fixed wings because of the structural movement and the resulting unsteady fluid dynamics. Flapping involves two stages: the down-stroke, which provides the majority of the thrust, and the up-stroke, which can also (depending on the bird's & insect's wings) provide some thrust. Most kinds of bird & insect wing can be grouped into four types, with some falling between two of these types. These types of wings are elliptical wings, high speed wings, high aspect ratio wings and soaring wings with slots. Hovering is used

  8. An experimental study of spanwise flow effects on lift generation in flapping wings

    Hong, Youngsun

    Using a combination of force transducer measurement to quantify net lift force, a high frame rate camera to quantify and subtract inertial contributions, and Digital Particle Image Velocimetry (DPIV) to calculate aerodynamic contributions in the spanwise plane, the contribution of spanwise flow to the generation of lift force in wings undergoing a pure flapping motion in hover is shown as a function of flapping angle throughout the flapping cycle. When flapping a flat plate wing and a wing of identical wing area and aspect ratio, but cambered in span (both wings in hover with no change in pitch), the spanwise cambered wing was found to generate a greater mean lift force through the whole flap cycle under the same acceleration. However, depending on the angle in flapping arc, the spanwise cambered wing can generate less lift than the flat wing. Additionally, since the lift force generated by the wingtip vortex in the spanwise plane resulting from the flapping motion has yet to be directly quantified, the wingtip vortex is investigated to determine precisely how it augments the lift force through the various phases in the flapping motion. Vortices in the vicinity of the wingtip generate lift force in the spanwise plane of flapping wings. In classical fixed wing aerodynamics, the presence of wing tip vortices has been shown to increase the lift locally near the tip. Also, the impingement of large vortices on the upper surface of delta wings is considered to contribute largely to the lift force at higher angles of attack. This study determined that vortices in the spanwise plane (streamwise vorticity) generate lift in a similar manner in flapping wings. Using a mechanical ornithopter with wings fabricated in-house, vortices were identified at several different locations along the span of the wing, and at numerous different points throughout the flapping cycle under a variety of operating conditions. The lift generated by these spanwise planar oriented vortices was

  9. Flapping states of an el astically anchored wing in a uniform flow

    Orchini, A; Guerrero, J; Festa, R; Boragno, C


    Linear stability analysis of an elastically anchored wing in a uniform flow is investigated both analytically and numerically. The analytical formulation explicitly takes into account the effect of the wake on the wing by means of Theodorsen's theory. Three different parameters non-trivially rule the observed dynamics: mass density ratio between wing and fluid, spring elastic constant and distance between the wing center of mass and the spring anchor point on the wing. We found relationships between these parameters which rule the transition between stable equilibrium and fluttering. The shape of the resulting marginal curve has been successfully verified by high Reynolds number direct numerical simulations. Our findings are of interest in applications related to energy harvesting by fluid-structure interaction, a problem which has recently attracted a great deal of attention. The main aim in that context is to identify the optimal physical/geometrical system configuration leading to large sustained motion, w...

  10. Installation effects of wing-mounted turbofan nacelle-pylons on a 1/17-scale, twin-engine, low-wing transport model

    Pendergraft, Odis C., Jr.; Ingraldi, Anthony M.; Re, Richard J.; Kariya, Timmy T.


    A twin-engine, low-wing transport model, with a supercritical wing of aspect ratio 10.8 designed for a cruise Mach number of 0.77 and a lift coefficient of 0.55, was tested in the Langley 16-Foot Transonic Tunnel. The purpose of this test was to compare the wing-nacelle interference effects of flow-through nacelles simulating superfan engines (very high bypass ratio (BPR is approx. = 18) turbofan engines) with the wing-nacelle interference effects of current-technology turbofans (BPR is approx. = 6). Forces and moments on the complete model were measured with a strain-gage balance, and extensive external static-pressure measurements (383 orifice locations) were made on the wing, nacelles, and pylons of the model. Data were taken at Mach numbers from 0.50 to 0.80 and at model angles of attack from -4 deg to 8 deg. Test results indicate that flow-through nacelles with a very high bypass ratio can be installed on a low-wing transport model with a lower installation drag penalty than for a conventional turbofan nacelle at a design cruise Mach number of 0.77 and lift coefficient of 0.55.

  11. Optimum Wing Shape Determination of Highly Flexible Morphing Aircraft for Improved Flight Performance

    Su, Weihua; Swei, Sean Shan-Min; Zhu, Guoming G.


    In this paper, optimum wing bending and torsion deformations are explored for a mission adaptive, highly flexible morphing aircraft. The complete highly flexible aircraft is modeled using a strain-based geometrically nonlinear beam formulation, coupled with unsteady aerodynamics and six-degrees-of-freedom rigid-body motions. Since there are no conventional discrete control surfaces for trimming the flexible aircraft, the design space for searching the optimum wing geometries is enlarged. To achieve high performance flight, the wing geometry is best tailored according to the specific flight mission needs. In this study, the steady level flight and the coordinated turn flight are considered, and the optimum wing deformations with the minimum drag at these flight conditions are searched by utilizing a modal-based optimization procedure, subject to the trim and other constraints. The numerical study verifies the feasibility of the modal-based optimization approach, and shows the resulting optimum wing configuration and its sensitivity under different flight profiles.

  12. Falling with Style: Bats Perform Complex Aerial Rotations by Adjusting Wing Inertia.

    Attila J Bergou

    Full Text Available The remarkable maneuverability of flying animals results from precise movements of their highly specialized wings. Bats have evolved an impressive capacity to control their flight, in large part due to their ability to modulate wing shape, area, and angle of attack through many independently controlled joints. Bat wings, however, also contain many bones and relatively large muscles, and thus the ratio of bats' wing mass to their body mass is larger than it is for all other extant flyers. Although the inertia in bat wings would typically be associated with decreased aerial maneuverability, we show that bat maneuvers challenge this notion. We use a model-based tracking algorithm to measure the wing and body kinematics of bats performing complex aerial rotations. Using a minimal model of a bat with only six degrees of kinematic freedom, we show that bats can perform body rolls by selectively retracting one wing during the flapping cycle. We also show that this maneuver does not rely on aerodynamic forces, and furthermore that a fruit fly, with nearly massless wings, would not exhibit this effect. Similar results are shown for a pitching maneuver. Finally, we combine high-resolution kinematics of wing and body movements during landing and falling maneuvers with a 52-degree-of-freedom dynamical model of a bat to show that modulation of wing inertia plays the dominant role in reorienting the bat during landing and falling maneuvers, with minimal contribution from aerodynamic forces. Bats can, therefore, use their wings as multifunctional organs, capable of sophisticated aerodynamic and inertial dynamics not previously observed in other flying animals. This may also have implications for the control of aerial robotic vehicles.

  13. Aircraft wing structural detail design (wing, aileron, flaps, and subsystems)

    Downs, Robert; Zable, Mike; Hughes, James; Heiser, Terry; Adrian, Kenneth


    The goal of this project was to design, in detail, the wing, flaps, and ailerons for a primary flight trainer. Integrated in this design are provisions for the fuel system, the electrical system, and the fuselage/cabin carry-through interface structure. This conceptual design displays the general arrangement of all major components in the wing structure, taking into consideration the requirements set forth by the appropriate sections of Federal Aviation Regulation Part 23 (FAR23) as well as those established in the statement of work.

  14. Study of vortex generator influence on the flow in the wake of high-lift system wing

    Bragin, N. N.; Ryabov, D. I.; Skomorokhov, S. I.; Slitinskaya, A. Yu.


    Passive vortex generators (VG) are known as one of the ways to improve the flow of the wings and other surfaces in the presence of flow separation. In particular, the VG are installed on the wings and nacelles of many foreign airplanes, including the most recent ones (for example, Boeing 787, Airbus A-350). The principle of the passive VG effects on flow is to transfer the kinetic energy of the external flow separation region by the vortices system arising from the flow VG themselves. For example, by increasing the angle of attack of the wing separation it is highly three-dimensional picture of the flow and sufficiently sensitive to external influences. Thus separated flow can be controlled when using the VG destroy large separation vortices. The VG effectiveness depends on many parameters. This is primarily the relative position of the second harmonic and the separation region on the wing and their size and position relative to each other, the orientation of the second harmonic relative to the local flow direction of the external flow, etc. Obviously, the VG effect will depend essentially on the intensity ratio of the second harmonic vortexes and nature of flow separation in the separation area. In the presence of intense flow separation the effect of conventional VG may be reduced or not occur at all. Until recently, investigations and selection of position of conventional VG were made only experimentally. Currently, the possibilities of calculation methods allow estimating the VG effect on the flow in the separation area. However, due to the phenomenon complexity the accuracy of these calculations is low. The experimental data are required to validate the computational methods, including information not only about the total impact, but also about the flow structure in the separation area. To obtain such information is the subject of this paper. In the test model of high-lift devices swept wing with modern supercritical profile the parametric studies were

  15. The Efficiency of a Hybrid Flapping Wing Structure—A Theoretical Model Experimentally Verified

    Yuval Keren


    Full Text Available To propel a lightweight structure, a hybrid wing structure was designed; the wing’s geometry resembled a rotor blade, and its flexibility resembled an insect’s flapping wing. The wing was designed to be flexible in twist and spanwise rigid, thus maintaining the aeroelastic advantages of a flexible wing. The use of a relatively “thick” airfoil enabled the achievement of higher strength to weight ratio by increasing the wing’s moment of inertia. The optimal design was based on a simplified quasi-steady inviscid mathematical model that approximately resembles the aerodynamic and inertial behavior of the flapping wing. A flapping mechanism that imitates the insects’ flapping pattern was designed and manufactured, and a set of experiments for various parameters was performed. The simplified analytical model was updated according to the tests results, compensating for the viscid increase of drag and decrease of lift, that were neglected in the simplified calculations. The propelling efficiency of the hovering wing at various design parameters was calculated using the updated model. It was further validated by testing a smaller wing flapping at a higher frequency. Good and consistent test results were obtained in line with the updated model, yielding a simple, yet accurate tool, for flapping wings design.

  16. Formation Flight: Upstream Influence of a Wing on a Streamwise Vortex

    McKenna, Chris; Rockwell, Donald; Lehigh University Fluids Lab Team


    Aircraft flying together in formation can experience aerodynamic advantages. Impingement of the tip vortex of the leader wing on the trailer wing can increase the lift to drag ratio L/D and the unsteady loading on the trailer wing. These increases are sensitive to the impingement location of the vortex on the wing. Particle image velocimetry is employed to determine patterns of velocity and vorticity on successive crossflow planes along the vortex, which lead to volume representations and thereby characterization of the streamwise evolution of the vortex structure as it approaches the trailer wing. This evolution of the incident vortex is affected by the upstream influence of the trailer wing, and is highly dependent on the location of vortex impingement. As the spanwise impingement location of the vortex moves from outboard of the wing tip to inboard, the upstream influence on the development of the vortex increases. For spanwise locations close to or intersecting the vortex core, the effects of upstream influence of the wing on the vortex are to: increase the streamwise velocity deficit; decrease the streamwise vorticity; increase the in-plane vorticity; decrease the downwash; and increase the root-mean-square of both streamwise velocity and vorticity.

  17. Formation Flight: Modes of Interaction of a Streamwise Vortex with a Wing

    McKenna, Chris; Bross, Matthew; Rockwell, Donald


    Aircraft flying together in an echelon or V formation experience aerodynamic advantages. Impingement of the tip vortex of the leader (upstream) wing on the follower wing can yield an increase of lift to drag ratio. This enhancement is known to be sensitive to the location of vortex impingement on the follower wing. Particle image velocimetry is employed to determine patterns of velocity and vorticity in successive crossflow planes, which characterize the streamwise evolution of the vortex structure along the chord of the follower wing and into its wake. Different modes of vortex-follower wing interaction are created by varying the spanwise location of the leader wing. These modes are defined by differences in the development of, and interaction between, the incident tip vortex from the leader wing and the tip vortex along the follower wing. Modes of development/interaction of the tip vortices include bifurcation, attenuation, and mutual induction. The bifurcation and attenuation modes decrease the strength of the follower tip vortex. In contrast, the mutual induction mode increases the strength of the follower tip vortex.

  18. Wing Configuration Impact on Design Optimums for a Subsonic Passenger Transport

    Wells, Douglas P.


    This study sought to compare four aircraft wing configurations at a conceptual level using a multi-disciplinary optimization (MDO) process. The MDO framework used was created by Georgia Institute of Technology and Virginia Polytechnic Institute and State University. They created a multi-disciplinary design and optimization environment that could capture the unique features of the truss-braced wing (TBW) configuration. The four wing configurations selected for the study were a low wing cantilever installation, a high wing cantilever, a strut-braced wing, and a single jury TBW. The mission that was used for this study was a 160 passenger transport aircraft with a design range of 2,875 nautical miles at the design payload, flown at a cruise Mach number of 0.78. This paper includes discussion and optimization results for multiple design objectives. Five design objectives were chosen to illustrate the impact of selected objective on the optimization result: minimum takeoff gross weight (TOGW), minimum operating empty weight, minimum block fuel weight, maximum start of cruise lift-to-drag ratio, and minimum start of cruise drag coefficient. The results show that the design objective selected will impact the characteristics of the optimized aircraft. Although minimum life cycle cost was not one of the objectives, TOGW is often used as a proxy for life cycle cost. The low wing cantilever had the lowest TOGW followed by the strut-braced wing.

  19. Vortexlet models of flapping flexible wings show tuning for force production and control

    Mountcastle, A M [Department of Organismic and Evolutionary Biology, Harvard University, Concord Field Station, Bedford, MA 01730 (United States); Daniel, T L, E-mail: mtcastle@u.washington.ed [Department of Biology, University of Washington, Seattle, WA 98195 (United States)


    Insect wings are compliant structures that experience deformations during flight. Such deformations have recently been shown to substantially affect induced flows, with appreciable consequences to flight forces. However, there are open questions related to the aerodynamic mechanisms underlying the performance benefits of wing deformation, as well as the extent to which such deformations are determined by the boundary conditions governing wing actuation together with mechanical properties of the wing itself. Here we explore aerodynamic performance parameters of compliant wings under periodic oscillations, subject to changes in phase between wing elevation and pitch, and magnitude and spatial pattern of wing flexural stiffness. We use a combination of computational structural mechanics models and a 2D computational fluid dynamics approach to ask how aerodynamic force production and control potential are affected by pitch/elevation phase and variations in wing flexural stiffness. Our results show that lift and thrust forces are highly sensitive to flexural stiffness distributions, with performance optima that lie in different phase regions. These results suggest a control strategy for both flying animals and engineering applications of micro-air vehicles.

  20. A computational study of the wing-wing and wing-body interactions of a model insect

    Xin Yu; Mao Sun


    The aerodynamic interaction between the contralateral wings and between the body and wings of a model insect are studied, by using the method of numerically solving the Navier-Stokes equations over moving overset grids, under typical hovering and forward flight conditions. Both the interaction between the contralateral wings and the interaction between the body and wings are very weak, e.g. at hovering, changes in aerodynamic forces of a wing due to the present of the other wing are less than 3% and changes in aerodynamic forces of the wings due to presence of thebody are less than 2%. The reason for this is as following. During each down-or up-stroke, a wing produces a vortexring, which induces a relatively large jet-like flow inside the ring but very small flow outside the ring. The vortex tings of the left and right wings are on the two sides of the body. Thus one wing is outside vortex ring of the other wing and the body is outside the vortex rings of the left and right wings, resulting in the weak interactions.

  1. Effects of ornamentation and phylogeny on the evolution of wing shape in stalk-eyed flies (Diopsidae).

    Husak, J F; Ribak, G; Baker, R H; Rivera, G; Wilkinson, G S; Swallow, J G


    Exaggerated male ornaments are predicted to be costly to their bearers, but these negative effects may be offset by the correlated evolution of compensatory traits. However, when locomotor systems, such as wings in flying species, evolve to decrease such costs, it remains unclear whether functional changes across related species are achieved via the same morphological route or via alternate changes that have similar function. We conducted a comparative analysis of wing shape in relation to eye-stalk elongation across 24 species of stalk-eyed flies, using geometric morphometrics to determine how species with increased eye span, a sexually selected trait, have modified wing morphology as a compensatory mechanism. Using traditional and phylogenetically informed multivariate analyses of shape in combination with phenotypic trajectory analysis, we found a strong phylogenetic signal in wing shape. However, dimorphic species possessed shifted wing veins with the result of lengthening and narrowing wings compared to monomorphic species. Dimorphic species also had changes that seem unrelated to wing size, but instead may govern wing flexion. Nevertheless, the lack of a uniform, compensatory pattern suggests that stalk-eyed flies used alternative modifications in wing structure to increase wing area and aspect ratio, thus taking divergent morphological routes to compensate for exaggerated eye stalks.

  2. Aerodynamic control with passively pitching wings

    Gravish, Nick; Wood, Robert

    Flapping wings may pitch passively under aerodynamic and inertial loads. Such passive pitching is observed in flapping wing insect and robot flight. The effect of passive wing pitch on the control dynamics of flapping wing flight are unexplored. Here we demonstrate in simulation and experiment the critical role wing pitching plays in yaw control of a flapping wing robot. We study yaw torque generation by a flapping wing allowed to passively rotate in the pitch axis through a rotational spring. Yaw torque is generated through alternating fast and slow upstroke and and downstroke. Yaw torque sensitively depends on both the rotational spring force law and spring stiffness, and at a critical spring stiffness a bifurcation in the yaw torque control relationship occurs. Simulation and experiment reveal the dynamics of this bifurcation and demonstrate that anomalous yaw torque from passively pitching wings is the result of aerodynamic and inertial coupling between the pitching and stroke-plane dynamics.

  3. Insect Evolution: The Origin of Wings.

    Ross, Andrew


    The debate on the evolution of wings in insects has reached a new level. The study of primitive fossil insect nymphs has revealed that wings developed from a combination of the dorsal part of the thorax and the body wall.

  4. New aeroelastic studies for a morphing wing

    Ruxandra Mihaela BOTEZ*


    Full Text Available For this study, the upper surface of a rectangular finite aspect ratio wing, with a laminar airfoil cross-section, was made of a carbon-Kevlar composite material flexible skin. This flexible skin was morphed by use of Shape Memory Alloy actuators for 35 test cases characterized by combinations of Mach numbers, Reynolds numbers and angles of attack. The Mach numbers varied from 0.2 to 0.3 and the angles of attack ranged between -1° and 2°. The optimized airfoils were determined by use of the CFD XFoil code. The purpose of this aeroelastic study was to determine the flutter conditions to be avoided during wind tunnel tests. These studies show that aeroelastic instabilities for the morphing configurations considered appeared at Mach number 0.55, which was higher than the wind tunnel Mach number limit speed of 0.3. The wind tunnel tests could thus be performed safely in the 6’×9’ wind tunnel at the Institute for Aerospace Research at the National Research Council Canada (IAR/NRC, where the new aeroelastic studies, applied on morphing wings, were validated.

  5. Structural Analysis of a Dragonfly Wing

    Jongerius, S.R.; Lentink, D.


    Dragonfly wings are highly corrugated, which increases the stiffness and strength of the wing significantly, and results in a lightweight structure with good aerodynamic performance. How insect wings carry aerodynamic and inertial loads, and how the resonant frequency of the flapping wings is tuned for carrying these loads, is however not fully understood. To study this we made a three-dimensional scan of a dragonfly (Sympetrum vulgatum) fore- and hindwing with a micro-CT scanner. The scans c...

  6. Morphometric Wing Characters as a Tool for Mosquito Identification

    Christe, Rafael de Oliveira; Multini, Laura Cristina; Vidal, Paloma Oliveira; Wilk-da-Silva, Ramon; de Carvalho, Gabriela Cristina; Marrelli, Mauro Toledo


    Mosquitoes are responsible for the transmission of important infectious diseases, causing millions of deaths every year and endangering approximately 3 billion people around the world. As such, precise identification of mosquito species is crucial for an understanding of epidemiological patterns of disease transmission. Currently, the most common method of mosquito identification relies on morphological taxonomic keys, which do not always distinguish cryptic species. However, wing geometric morphometrics is a promising tool for the identification of vector mosquitoes, sibling and cryptic species included. This study therefore sought to accurately identify mosquito species from the three most epidemiologically important mosquito genera using wing morphometrics. Twelve mosquito species from three epidemiologically important genera (Aedes, Anopheles and Culex) were collected and identified by taxonomic keys. Next, the right wing of each adult female mosquito was removed and photographed, and the coordinates of eighteen digitized landmarks at the intersections of wing veins were collected. The allometric influence was assessed, and canonical variate analysis and thin-plate splines were used for species identification. Cross-validated reclassification tests were performed for each individual, and a Neighbor Joining tree was constructed to illustrate species segregation patterns. The analyses were carried out and the graphs plotted with TpsUtil 1.29, TpsRelw 1.39, MorphoJ 1.02 and Past 2.17c. Canonical variate analysis for Aedes, Anopheles and Culex genera showed three clear clusters in morphospace, correctly distinguishing the three mosquito genera, and pairwise cross-validated reclassification resulted in at least 99% accuracy; subgenera were also identified correctly with a mean accuracy of 96%, and in 88 of the 132 possible comparisons, species were identified with 100% accuracy after the data was subjected to reclassification. Our results showed that Aedes, Culex

  7. Transonic Semispan Aerodynamic Testing of the Hybrid Wing Body with Over Wing Nacelles in the National Transonic Facility

    Chan, David T.; Hooker, John R.; Wick, Andrew; Plumley, Ryan W.; Zeune, Cale H.; Ol, Michael V.; DeMoss, Joshua A.


    A wind tunnel investigation of a 0.04-scale model of the Lockheed Martin Hybrid Wing Body (HWB) with Over Wing Nacelles (OWN) air mobility transport configuration was conducted in the National Transonic Facility at the NASA Langley Research Center under a collaborative partnership between NASA, the Air Force Research Laboratory, and Lockheed Martin Aeronautics Company. The wind tunnel test sought to validate the transonic aerodynamic performance of the HWB and to validate the efficiency benefits of the OWN installation as compared to the traditional under-wing installation. The semispan HWB model was tested in a clean wing configuration and also tested with two different nacelles representative of a modern turbofan engine and a future advanced high bypass ratio engine. The nacelles were installed in three different locations with two over-wing positions and one under-wing position. Five-component force and moment data, surface static pressure data, and aeroelastic deformation data were acquired. For the cruise configuration, the model was tested in an angle-of-attack range between -2 and 10 degrees at free-stream Mach numbers from 0.3 to 0.9 and at unit Reynolds numbers between 8 and 39 million per foot, achieving a maximum of 80% of flight Reynolds numbers across the Mach number range. The test results validated pretest computational fluid dynamic (CFD) simulations of the HWB performance including the OWN benefit and the results also exhibited excellent transonic drag data repeatability to within +/-1 drag count. This paper details the experimental setup and model overview, presents some sample data results, and describes the facility improvements that led to the success of the test.

  8. The Wings for Angels Project

    McMillan, Liberty; McMillan, Ellen; Ayers, Ann


    How can the spirits of critically ill children be raised? Alexis Weisel (co-president of the Monarch High School National Art Honor Society, 2010-2011) had this question in mind when she initiated and developed the Wings for Angels Project after hearing about the Believe in Tomorrow (BIT) organization through her art teacher, Ellen McMillan. The…

  9. Wings: Women Entrepreneurs Take Flight.

    Baldwin, Fred D.


    Women's Initiative Networking Groups (WINGS) provides low- and moderate-income women in Appalachian Kentucky with training in business skills, contacts, and other resources they need to succeed as entrepreneurs. The women form informal networks to share business know-how and support for small business startup and operations. The program plans to…


    The feasibility of the paraglider concept as a means of descent for individual airborne troops is presented. Full-scale 22-foot inflatable wings an effort to achieve system reliability. The feasibility of using the paraglider as a means of controlled delivery of airborne paratroopers was successfully demonstrated.

  11. [Winged scapula in lyme borreliosis].

    Rausch, V; Königshausen, M; Gessmann, J; Schildhauer, T A; Seybold, D


    Here we present the case of a young patient with one-sided winged scapula and lyme borreliosis. This disease can be very delimitating in daily life. If non-operative treatment fails, dynamic or static stabilization of the scapula can be a therapeutic option.

  12. Prediction of Wing Downwash Using CFD

    Mohammed MAHDI


    Full Text Available Wing downwash study and estimation of downwash effect on the tail plane is an important task during the aircraft design process, although a lot of papers and works has been done, but the experimental work is the most important, the progress in CFD simulation has reached to the point it is able to reduce the number of runs in the wind tunnel. In this work CFD has been utilized to calculate the downwash angle and downwash gradient with respect to the angle of attack over a high aspect ratio of a typical UAV. The results of the simulation shall be used in the estimation and calculation of the longitudinal static stability analysis of the UAV.

  13. Review Results on Wing-Body Interference

    Frolov Vladimir


    The paper presents an overview of results for wing-body interference, obtained by the author for varied wing-body combinations. The lift-curve slopes of the wing-body combinations are considered. In this paper a discrete vortices method (DVM) and 2D potential model for cross-flow around fuselage are used. The circular and elliptical cross-sections of the fuselage and flat wings of various forms are considered. Calculations showed that the value of the lift-curve slopes of the wing-body combin...

  14. Review Results on Wing-Body Interference

    Frolov Vladimir


    Full Text Available The paper presents an overview of results for wing-body interference, obtained by the author for varied wing-body combinations. The lift-curve slopes of the wing-body combinations are considered. In this paper a discrete vortices method (DVM and 2D potential model for cross-flow around fuselage are used. The circular and elliptical cross-sections of the fuselage and flat wings of various forms are considered. Calculations showed that the value of the lift-curve slopes of the wing-body combinations may exceed the same value for an isolated wing. This result confirms an experimental data obtained by other authors earlier. Within a framework of the used mathematical models the investigations to optimize the wing-body combination were carried. The present results of the optimization problem for the wing-body combination allowed to select the optimal geometric characteristics for configuration to maximize the values of the lift-curve slopes of the wing-body combination. It was revealed that maximums of the lift-curve slopes for the optimal mid-wing configuration with elliptical cross-section body had a sufficiently large relative width of the body (more than 30% of the span wing.

  15. AST Composite Wing Program: Executive Summary

    Karal, Michael


    The Boeing Company demonstrated the application of stitched/resin infused (S/RFI) composite materials on commercial transport aircraft primary wing structures under the Advanced Subsonic technology (AST) Composite Wing contract. This report describes a weight trade study utilizing a wing torque box design applicable to a 220-passenger commercial aircraft and was used to verify the weight savings a S/RFI structure would offer compared to an identical aluminum wing box design. This trade study was performed in the AST Composite Wing program, and the overall weight savings are reported. Previous program work involved the design of a S/RFI-base-line wing box structural test component and its associated testing hardware. This detail structural design effort which is known as the "semi-span" in this report, was completed under a previous NASA contract. The full-scale wing design was based on a configuration for a MD-90-40X airplane, and the objective of this structural test component was to demonstrate the maturity of the S/RFI technology through the evaluation of a full-scale wing box/fuselage section structural test. However, scope reductions of the AST Composite Wing Program pre-vented the fabrication and evaluation of this wing box structure. Results obtained from the weight trade study, the full-scale test component design effort, fabrication, design development testing, and full-scale testing of the semi-span wing box are reported.

  16. Design of a new tandem wings hybrid airship

    Li, Feng; Ye, ZhengYin; Gao, Chao


    It is scientifically important science value and engineering promising to develop the buoyancy-lift integrated hybrid airship for high attitude platform. Through the numerical method, a new tandem wings hybrid airship with both higher utility value and economy efficiency was obtained and its total performance and technical parameters were analyzed in detail. In order to further improve the lift-drag characteristics, we implemented the optimization design for aerodynamic configuration of tandem wings hybrid airship via the response surface method. The results indicate that the tandem wings hybrid airship has considerable volume efficiency and higher aerodynamic characteristics. After optimization, the lift-drag ratio of this hybrid airship was increased by 6.08%. In a given gross lift condition, tandem wings hybrid airship may provide more payload and specific productivity. Furthermore, the size of tandem airship is smaller so the demand for skin flexible materials can be reduced. Results of this study could serve as a new approach to designing buoyancy-lifting integrated hybrid airship.

  17. Periodic and Chaotic Flapping of Insectile Wings

    Huang, Yangyang


    Insects use flight muscles attached at the base of the wings to produce impressive wing flapping frequencies. The maximum power output of these flight muscles is insufficient to maintain such wing oscillations unless there is good elastic storage of energy in the insect flight system. Here, we explore the intrinsic self-oscillatory behavior of an insectile wing model, consisting of two rigid wings connected at their base by an elastic torsional spring. We study the wings behavior as a function of the total energy and spring stiffness. Three types of behavior are identified: end-over-end rotation, chaotic motion, and periodic flapping. Interestingly, the region of periodic flapping decreases as energy increases but is favored as stiffness increases. These findings are consistent with the fact that insect wings and flight muscles are stiff. They further imply that, by adjusting their muscle stiffness to the desired energy level, insects can maintain periodic flapping mechanically for a range of operating condit...

  18. Piezoelectrically actuated insect scale flapping wing

    Mukherjee, Sujoy; Ganguli, Ranjan


    An energy method is used in order to derive the non-linear equations of motion of a smart flapping wing. Flapping wing is actuated from the root by a PZT unimorph in the piezofan configuration. Dynamic characteristics of the wing, having the same size as dragonfly Aeshna Multicolor, are analyzed using numerical simulations. It is shown that flapping angle variations of the smart flapping wing are similar to the actual dragonfly wing for a specific feasible voltage. An unsteady aerodynamic model based on modified strip theory is used to obtain the aerodynamic forces. It is found that the smart wing generates sufficient lift to support its own weight and carry a small payload. It is therefore a potential candidate for flapping wing of micro air vehicles.

  19. A study on aerodynamics and mechanisms of elementary morphing models for flapping wing in bat forward flight

    Zi-Wu, Guan


    The large active wing deformation is a significant way to generate high aerodynamic forces required in bat flapping flight. Besides the twisting, the elementary morphing models of a bat wing are proposed, such as wing-bending in the spanwise direction, wing-cambering in the chordwise direction, and wing area-changing. A plate of aspect ratio 3 is used to model a bat wing and a three dimensional unsteady panel method is applied to predict the aerodynamic forces. It is found that the cambering model has a great positive influence on the lift, followed by area-changing model and then the bending model. The further study indicates that the vortex control is a main mechanism to produce high aerodynamic forces, and the mechanisms for the aerodynamic force enhancement are the asymmetry of the cambered wing and the amplifier effects of wing area-changing and wing bending. The lift and thrust are mainly generated during the downstroke and almost negligible forces during the upstroke by the integrated morphing model-wi...

  20. Hydrodynamic characteristics for flow around wavy wings with different wave lengths

    Mi Jeong Kim


    Full Text Available The present study numerically investigates the effect of the wavy leading edge on hydrodynamic characteristics for the flow of rectangular wings with the low aspect ratio of 1.5. Five different wave lengths at fixed wavy amplitude have been considered. Numerical simulations are performed at a wide range of the angle of attack (0° ≤α ≤ 40° at one Reynolds number of 106. The wavy wings considered in this study did not experience enough lift drop to be defined as the stall, comparing with the smooth wing. However, in the pre-stall region, the wavy wings reveal the considerable loss of the lift, compared to the smooth wing. In the post-stall, the lift coefficients of the smooth wing and the wavy wings are not much different. The pressure coefficient, limiting streamlines and the iso-surface of the spanwise vorticity are also highlighted to examine the effect of the wave length on the flow structures.

  1. Force and Power Measurements of a Functionally-Graded Chordwise-Flexible Flapping Wing

    Mudbhari, Durlav; Erdogan, Malcolm; Moored, Keith


    Flyers and swimmers flap their wings and fins to propel themselves efficiently over long distances. A key element to achieve their high performance is the flexibility of their appendages. While numerous studies have shown that homogeneously flexible wings can enhance force production and efficiency, animals actually have wings with varying flexural rigidity along their chord and span. The goal of this study is to understand and characterize the force production and energetics of functionally-graded, chordwise flexible wings. A flapping wing composed of a rigid and a flexible region, that define a chordwise gradient in flexural rigidity, is used to model functionally-graded materials. By varying the ratio of the lengths of the rigid to flexible regions, the flexural rigidity of the flexible region, and the flapping frequency, the thrust production of a functionally-graded wing is directly measured in a wind tunnel. A novel vacuum chamber apparatus is used in conjunction with the wind tunnel measurements to reliably measure the aerodynamic power input and the propulsive efficiency. Limited flow visualization is performed with particle image velocimetry in order to connect the force production and energetics of the partially-flexible wing with its generated flow structures. Supported by the Office of Naval Research under Program Director Dr. Bob Brizzolara, MURI Grant Number N00014-14-1-0533.

  2. Did Adult Diurnal Activity Influence the Evolution of Wing Morphology in Opoptera Butterflies?

    Penz, C M; Heine, K B


    The butterfly genus Opoptera includes eight species, three of which have diurnal habits while the others are crepuscular (the usual activity period for members of the tribe Brassolini). Although never measured in the field, it is presumed that diurnal Opoptera species potentially spend more time flying than their crepuscular relatives. If a shift to diurnal habits potentially leads to a higher level of activity and energy expenditure during flight, then selection should operate on increased aerodynamic and energetic efficiency, leading to changes in wing shape. Accordingly, we ask whether diurnal habits have influenced the evolution of wing morphology in Opoptera. Using phylogenetically independent contrasts and Wilcoxon rank sum tests, we confirmed our expectation that the wings of diurnal species have higher aspect ratios (ARs) and lower wing centroids (WCs) than crepuscular congeners. These wing shape characteristics are known to promote energy efficiency during flight. Three Opoptera wing morphotypes established a priori significantly differed in AR and WC values. The crepuscular, cloud forest dweller Opoptera staudingeri (Godman & Salvin) was exceptional in having an extended forewing tip and the highest AR and lowest WC within Opoptera, possibly to facilitate flight in a cooler environment. Our study is the first to investigate how butterfly wing morphology might evolve as a response to a behavioral shift in adult time of activity.

  3. Distribution of the characteristics of barbs and barbules on barn owl wing feathers.

    Weger, Matthias; Wagner, Hermann


    Owls are known for the development of a silent flight. One conspicuous specialization of owl wings that has been implied in noise reduction and that has been demonstrated to change the aerodynamic behavior of the wing is a soft dorsal wing surface. The soft surface is a result of changes in the shape of feather barbs and barbules in owls compared with other bird species. We hypothesized that as the aerodynamic characteristics of a wing change along its chordwise and spanwise direction, so may the shape of the barbs and barbules. Therefore, we examined in detail the shapes of the barbs and barbules in chordwise and spanwise directions. The results showed changes in the shapes of barbs and barbules at the anterior and distal parts of the wing, but not at more posterior parts. The increased density of hook radiates at the distalmost wing position could serve to stiffen that vane part that is subject to the highest forces. The change of pennulum length in the anterior part of the wing and the uniformity further back could mean that a soft surface may be especially important in regions where flow separation may occur.

  4. Wings as a new route of exposure to pesticides in the honey bee.

    Poquet, Yannick; Kairo, Guillaume; Tchamitchian, Sylvie; Brunet, Jean-Luc; Belzunces, Luc P


    In pesticide risk assessment, estimating the routes and levels of exposure is critical. For honey bees subjected to pesticide spray, toxicity is assessed by thorax contact to account for all possible contact exposures. In the present study, the authors tested 6 active substances with different hydrophobicity. For the first time, the authors demonstrated that it is possible to induce mortality by pesticide contact with only the wings of the honey bee. The toxicities induced by contact with the wings and thorax were similar, with the wing median lethal dose (LD50) being 0.99 to 2.23 times higher than that of the thorax. This finding demonstrates that the wings represent a relevant route of exposure in the honey bee. In a second approach, the authors estimated the air volume displaced by the wings during 1 beating cycle to be 0.51 ± 0.03 cm(3), which corresponds to a volume of 116.8 ± 5.8 cm(3)  s(-1) at a wing beat frequency of 230 Hz. The authors then tested realistic scenarios of exposure for bees flying through a pesticide cloud at different concentrations. In the worst-case scenario, the dose accumulated during the flight reached 525 ng bee(-1)  s(-1). These results show that the procedure used to assess the risk posed by contact with pesticides could be improved by accounting for wing exposure.

  5. The DelFly design, aerodynamics, and artificial intelligence of a flapping wing robot

    de Croon, G C H E; Remes, B D W; Ruijsink, R; De Wagter, C


    This book introduces the topics most relevant to autonomously flying flapping wing robots: flapping-wing design, aerodynamics, and artificial intelligence. Readers can explore these topics in the context of the "Delfly", a flapping wing robot designed at Delft University in The Netherlands. How are tiny fruit flies able to lift their weight, avoid obstacles and predators, and find food or shelter? The first step in emulating this is the creation of a micro flapping wing robot that flies by itself. The challenges are considerable: the design and aerodynamics of flapping wings are still active areas of scientific research, whilst artificial intelligence is subject to extreme limitations deriving from the few sensors and minimal processing onboard. This book conveys the essential insights that lie behind success such as the DelFly Micro and the DelFly Explorer. The DelFly Micro, with its 3.07 grams and 10 cm wing span, is still the smallest flapping wing MAV in the world carrying a camera, whilst the DelFly Expl...

  6. Effects of wing locations on wing rock induced by forebody vortices

    Ma Baofeng


    Full Text Available Previous studies have shown that asymmetric vortex wakes over slender bodies exhibit a multi-vortex structure with an alternate arrangement along a body axis at high angle of attack. In this investigation, the effects of wing locations along a body axis on wing rock induced by forebody vortices was studied experimentally at a subcritical Reynolds number based on a body diameter. An artificial perturbation was added onto the nose tip to fix the orientations of forebody vortices. Particle image velocimetry was used to identify flow patterns of forebody vortices in static situations, and time histories of wing rock were obtained using a free-to-roll rig. The results show that the wing locations can affect significantly the motion patterns of wing rock owing to the variation of multi-vortex patterns of forebody vortices. As the wing locations make the forebody vortices a two-vortex pattern, the wing body exhibits regularly divergence and fixed-point motion with azimuthal variations of the tip perturbation. If a three-vortex pattern exists over the wing, however, the wing-rock patterns depend on the impact of the highest vortex and newborn vortex. As the three vortices together influence the wing flow, wing-rock patterns exhibit regularly fixed-points and limit-cycled oscillations. With the wing moving backwards, the newborn vortex becomes stronger, and wing-rock patterns become fixed-points, chaotic oscillations, and limit-cycled oscillations. With further backward movement of wings, the vortices are far away from the upper surface of wings, and the motions exhibit divergence, limit-cycled oscillations and fixed-points. For the rearmost location of the wing, the wing body exhibits stochastic oscillations and fixed-points.

  7. Shape optimisation and performance analysis of flapping wings

    Ghommem, Mehdi


    In this paper, shape optimisation of flapping wings in forward flight is considered. This analysis is performed by combining a local gradient-based optimizer with the unsteady vortex lattice method (UVLM). Although the UVLM applies only to incompressible, inviscid flows where the separation lines are known a priori, Persson et al. [1] showed through a detailed comparison between UVLM and higher-fidelity computational fluid dynamics methods for flapping flight that the UVLM schemes produce accurate results for attached flow cases and even remain trend-relevant in the presence of flow separation. As such, they recommended the use of an aerodynamic model based on UVLM to perform preliminary design studies of flapping wing vehicles Unlike standard computational fluid dynamics schemes, this method requires meshing of the wing surface only and not of the whole flow domain [2]. From the design or optimisation perspective taken in our work, it is fairly common (and sometimes entirely necessary, as a result of the excessive computational cost of the highest fidelity tools such as Navier-Stokes solvers) to rely upon such a moderate level of modelling fidelity to traverse the design space in an economical manner. The objective of the work, described in this paper, is to identify a set of optimised shapes that maximise the propulsive efficiency, defined as the ratio of the propulsive power over the aerodynamic power, under lift, thrust, and area constraints. The shape of the wings is modelled using B-splines, a technology used in the computer-aided design (CAD) field for decades. This basis can be used to smoothly discretize wing shapes with few degrees of freedom, referred to as control points. The locations of the control points constitute the design variables. The results suggest that changing the shape yields significant improvement in the performance of the flapping wings. The optimisation pushes the design to "bird-like" shapes with substantial increase in the time

  8. Computational Analysis of a Wing Designed for the X-57 Distributed Electric Propulsion Aircraft

    Deere, Karen A.; Viken, Jeffrey K.; Viken, Sally A.; Carter, Melissa B.; Wiese, Michael R.; Farr, Norma L.


    A computational study of the wing for the distributed electric propulsion X-57 Maxwell airplane configuration at cruise and takeoff/landing conditions was completed. Two unstructured-mesh, Navier-Stokes computational fluid dynamics methods, FUN3D and USM3D, were used to predict the wing performance. The goal of the X-57 wing and distributed electric propulsion system design was to meet or exceed the required lift coefficient 3.95 for a stall speed of 58 knots, with a cruise speed of 150 knots at an altitude of 8,000 ft. The X-57 Maxwell airplane was designed with a small, high aspect ratio cruise wing that was designed for a high cruise lift coefficient (0.75) at angle of attack of 0deg. The cruise propulsors at the wingtip rotate counter to the wingtip vortex and reduce induced drag by 7.5 percent at an angle of attack of 0.6deg. The unblown maximum lift coefficient of the high-lift wing (with the 30deg flap setting) is 2.439. The stall speed goal performance metric was confirmed with a blown wing computed effective lift coefficient of 4.202. The lift augmentation from the high-lift, distributed electric propulsion system is 1.7. The predicted cruise wing drag coefficient of 0.02191 is 0.00076 above the drag allotted for the wing in the original estimate. However, the predicted drag overage for the wing would only use 10.1 percent of the original estimated drag margin, which is 0.00749.

  9. Supersonic Wing Optimization Using SpaRibs

    Locatelli, David; Mulani, Sameer B.; Liu, Qiang; Tamijani, Ali Y.; Kapania, Rakesh K.


    This research investigates the advantages of using curvilinear spars and ribs, termed SpaRibs, to design a supersonic aircraft wing-box in comparison to the use of classic design concepts that employ straight spars and ribs. The objective is to achieve a more efficient load-bearing mechanism and to passively control the deformation of the structure under the flight loads. Moreover, the use of SpaRibs broadens the design space and allows for natural frequencies and natural mode shape tailoring. The SpaRibs concept is implemented in a new optimization MATLAB-based framework referred to as EBF3SSWingOpt. This optimization scheme performs both the sizing and the shaping of the internal structural elements, connecting the optimizer with the analysis software. The shape of the SpaRibs is parametrically defined using the so called Linked Shape method. Each set of SpaRibs is placed in a one by one square domain of the natural space. The set of curves is subsequently transformed in the physical space for creating the wing structure geometry layout. The shape of each curve of each set is unique; however, mathematical relations link the curvature in an effort to reduce the number of design variables. The internal structure of a High Speed Commercial Transport aircraft concept developed by Boeing is optimized subjected to stress, subsonic flutter and supersonic flutter constraints. The results show that the use of the SpaRibs allows for the reduction of the aircraft's primary structure weight without violating the constraints. A weight reduction of about 15 percent is observed.

  10. Monostatic radar cross section of flying wing delta planforms

    Sevoor Meenakshisundaram Vaitheeswaran


    Full Text Available The design of the flying wing and its variants shapes continues to have a profound influence in the design of the current and future use of military aircraft. There is very little in the open literature available to the understanding and by way of comparison of the radar cross section of the different wing planforms, for obvious reasons of security and sensitivity. This paper aims to provide an insight about the radar cross section of the various flying wing planforms that would aid the need and amount of radar cross section suppression to escape detection from surveillance radars. Towards this, the shooting and bouncing ray method is used for analysis. In this, the geometric optics theory is first used for launching and tracing the electromagnetic rays to calculate the electromagnetic field values as the waves bounce around the target. The physical optics theory is next used to calculate the final scattered electric field using the far field integration along the observation direction. For the purpose of comparison, all the planform shapes are assumed to be having the same area, and only the aspect ratio and taper ratio are varied to feature representative airplanes.

  11. Active Flow Control on a Generic Trapezoidal Wing Planform

    Wygnanski, Israel; Little, Jesse; Roentsch, Bernhard; Endrikat, Sebastian


    Fluidic oscillators are employed to increase the lift and improve longitudinal stability of a generic trapezoidal wing having aspect ratio of 1.15 and taper ratio of 0.27. Actuation is applied along the flap hinge which spans the entire wing and is parallel to the trailing edge. Experiments are conducted at a Reynolds number of 1 . 7 ×106 for a wide range of incidence (-8° o to 24°) and flap deflection angles (0° to 75°). Baseline flow on the deflected flap is directed inboard prior to boundary layer separation, but changes to outboard with increasing incidence and flap deflection. The attached spanwise flow can be redirected using a sparse distribution of fluidic oscillators acting as a fluidic fence. However, the majority of lift enhancement and pitch break improvement is accomplished using a more dense distribution of actuators which attaches separated flow to the flap. Integral force and moment results are supported by surface flow visualization, pressure sensitive paint and PIV which reveal unique flow features such as a hinge vortex analogous to the leading edge vortex on a forward swept wing and the possible existence of an absolute instability in a plane parallel to the highly deflected flap. Supported by U.S. Office of Naval Research (N00014-14-1-0387).

  12. Role of wing morphing in thrust generation

    Mehdi Ghommem


    Full Text Available In this paper, we investigate the role of morphing on flight dynamics of two birds by simulating the flow over rigid and morphing wings that have the characteristics of two different birds, namely the Giant Petrel and Dove Prion. The simulation of a flapping rigid wing shows that the root of the wing should be placed at a specific angle of attack in order to generate enough lift to balance the weight of the bird. However, in this case the generated thrust is either very small, or even negative, depending on the wing shape. Further, results show that morphing of the wing enables a significant increase in the thrust and propulsive efficiency. This indicates that the birds actually utilize some sort of active wing twisting and bending to produce enough thrust. This study should facilitate better guidance for the design of flapping air vehicles.

  13. Rotor/Wing Interactions in Hover

    Young, Larry A.; Derby, Michael R.


    Hover predictions of tiltrotor aircraft are hampered by the lack of accurate and computationally efficient models for rotor/wing interactional aerodynamics. This paper summarizes the development of an approximate, potential flow solution for the rotor-on-rotor and wing-on-rotor interactions. This analysis is based on actuator disk and vortex theory and the method of images. The analysis is applicable for out-of-ground-effect predictions. The analysis is particularly suited for aircraft preliminary design studies. Flow field predictions from this simple analytical model are validated against experimental data from previous studies. The paper concludes with an analytical assessment of the influence of rotor-on-rotor and wing-on-rotor interactions. This assessment examines the effect of rotor-to-wing offset distance, wing sweep, wing span, and flaperon incidence angle on tiltrotor inflow and performance.

  14. Experimental Study on the Wing Formation of a Paraglider Canopy Cell (Inflatable Wing)

    Yamamori, Keitaro; Umemura, Akira; Hishida, Manabu

    This study focuses on the formation mechanism of para-foil canopy. Three types of model wing, which represent each cell of para-foil canopy (a rigid wing with air intake, an inflatable wing and a cassette model) were prepared to explore the effects of air intake on inflatable wing formation in wind tunnel experiments. The flow fields both outside and inside of the wings were investigated, together with the process that the flexible wing inflates to form a wing. It was found that the robust nature of canopy is derived from the concaving deformation of the leading edge at small angles of attack, and the enhanced outward suction pressure acting on the leading edge, which are caused by the flexibility of the wing as well as the pressure of air intake in sacrifice of increased drag coefficient.

  15. Experimental Investigation on Limit Cycle Wing Rock Effect on Wing Body Configuration Induced by Forebody Vortices

    Rong, Zhen; Deng, Xueying; Ma, Baofeng; Wang, Bing


    ...° swept wing configuration undergoing a limit cycle oscillation using a synchronous measurement and control technique of wing rock/particle image velocimetry/dynamic pressure associated with the time...

  16. Downwash in the plane of symmetry of an elliptically loaded wing

    Phillips, J. D.


    A closed-form solution for the downwash in the plane of symmetry of an elliptically loaded line is given. This theoretical result is derived from Prandtl's lifting-line theory and assumes that: (1) a three-dimensional wing can be replaced by a straight lifting line, (2) this line is elliptically loaded, and (3) the trailing wake is a flat-sheet which does not roll up. The first assumption is reasonable for distances greater than about 1 chord from the wing aerodynamic center. The second assumption is satisfied by any combination of wing twist, spanwise camber variation, or planform that approximates elliptic loading. The third assumption is justified only for high-aspect-ratio wings at low lift coefficients and downstream distances less than about 1 span from the aerodynamic center. It is shown, however, that assuming the wake to be fully rolled up gives downwash values reasonably close to those of the flat-sheet solution derived in this paper. The wing can therefore be modeled as a single horseshoe vortex with the same lift and total circulation as the equivalent ellipticity loaded line, and the predicted downwash will be a close approximation independent of aspect ratio and lift coefficient. The flat-sheet equation and the fully rolled up wake equation are both one-line formulas that predict the upwash field in front of the wing, as well as the downwash field behind it. These formulas are useful for preliminary estimates of the complex aerodynamic interaction between two wings (i.e., canard, tandem wing, and conventional aircraft) including the effects of gap and stagger.

  17. Experimental Aerodynamic Characteristics of an Oblique Wing for the F-8 OWRA

    Kennelly, Robert A., Jr.; Carmichael, Ralph L.; Smith, Stephen C.; Strong, James M.; Kroo, Ilan M.


    An experimental investigation was conducted during June-July 1987 in the NASA Ames 11-Foot Transonic Wind Tunnel to study the aerodynamic performance and stability and control characteristics of a 0.087-scale model of an F-8 airplane fitted with an oblique wing. This effort was part of the Oblique Wing Research Aircraft (OWRA) program performed in conjunction with Rockwell International. The Ames-designed, aspect ratio 10.47, tapered wing used specially designed supercritical airfoils with 0.14 thickness/chord ratio at the root and 0.12 at the 85% span location. The wing was tested at two different mounting heights above the fuselage. Performance and longitudinal stability data were obtained at sweep angles of 0deg, 30deg, 45deg, 60deg, and 65deg at Mach numbers ranging from 0.30 to 1.40. Reynolds number varied from 3.1 x 10(exp 6)to 5.2 x 10(exp 6), based on the reference chord length. Angle of attack was varied from -5deg to 18deg. The performance of this wing is compared with that of another oblique wing, designed by Rockwell International, which was tested as part of the same development program. Lateral-directional stability data were obtained for a limited combination of sweep angles and Mach numbers. Sideslip angle was varied from -5deg to +5deg. Landing flap performance was studied, as were the effects of cruise flap deflections to achieve roll trim and tailor wing camber for various flight conditions. Roll-control authority of the flaps and ailerons was measured. A novel, deflected wing tip was evaluated for roll-control authority at high sweep angles.

  18. Morphing fixed wing MAV modeling using VAM


    The design and implementation of a morphing Micro Air Vehicle (MAV) wing using a smart composite is attempted in this research work. Control surfaces actuated by traditional servos are difficult to instrument and fabricate on thin composite-wings of MAVs. Piezoelectric Fiber Reinforced Composites (PFRCs) are the chosen smart structural materials in the current work for incorporation onto fixed-wing MAVs to simultaneously perform the dual functions of structural load-bearing and actuatio...

  19. Improvement in Aerodynamic Characteristics of a Paraglider Wing Canopy

    Mashud, Mohammad; Umemura, Akira

    To determine the parameters which can improve the overall performance of a paraglider wing canopy, we have been investigating the fundamental aerodynamic characteristics of an inflatable cell model which is designed to represent the dynamic behaviors of each cell comprising the wing canopy. This paper describes the results of a series of wind tunnel experiments. It is shown that significant drag reduction can be achieved by adopting an appropriately designed shape for the soft cloth comprising the upper surface. A trade-off relationship between the aerodynamic quality (characterized by the lift-to-drag ratio) and structural strength (characterized by the internal air pressure coefficient) of the canopy is also examined in detail.

  20. Investigation potential flow about swept back wing using panel method

    WakkasAli Rasheed, NabeelAbdulhadiGhyadh, Sahib Shihab Ahmed


    Full Text Available In the present investigation Low order panel method with Dirichlet boundary condition conjugated with Kutta condition, was used to calculate pressure coefficients for potential flow about isolated swept back wings at different aspect ratios and different angles of attack. Also both local and total lift coefficients were calculated for the same wings, with detailed streamline behavior on both upper and lower surface. Constant strength quadrilateral doublet element and Constant strength quadrilateral source element were placed on each panel, except on wake sheet only constant strength quadrilateral doublets were placed to satisfy Kutta condition at trailing edge. A set of linear algebraic equations were established by setting inner potential equals to free stream potential. These equations were solved using Gauss-elimination to determine quadrilateral doublet singularity strength distribution. Finally finite difference formula was used to predict aerodynamic loads calculation.

  1. High performance forward swept wing aircraft

    Koenig, David G. (Inventor); Aoyagi, Kiyoshi (Inventor); Dudley, Michael R. (Inventor); Schmidt, Susan B. (Inventor)


    A high performance aircraft capable of subsonic, transonic and supersonic speeds employs a forward swept wing planform and at least one first and second solution ejector located on the inboard section of the wing. A high degree of flow control on the inboard sections of the wing is achieved along with improved maneuverability and control of pitch, roll and yaw. Lift loss is delayed to higher angles of attack than in conventional aircraft. In one embodiment the ejectors may be advantageously positioned spanwise on the wing while the ductwork is kept to a minimum.

  2. Subtractive Structural Modification of Morpho Butterfly Wings.

    Shen, Qingchen; He, Jiaqing; Ni, Mengtian; Song, Chengyi; Zhou, Lingye; Hu, Hang; Zhang, Ruoxi; Luo, Zhen; Wang, Ge; Tao, Peng; Deng, Tao; Shang, Wen


    Different from studies of butterfly wings through additive modification, this work for the first time studies the property change of butterfly wings through subtractive modification using oxygen plasma etching. The controlled modification of butterfly wings through such subtractive process results in gradual change of the optical properties, and helps the further understanding of structural optimization through natural evolution. The brilliant color of Morpho butterfly wings is originated from the hierarchical nanostructure on the wing scales. Such nanoarchitecture has attracted a lot of research effort, including the study of its optical properties, its potential use in sensing and infrared imaging, and also the use of such structure as template for the fabrication of high-performance photocatalytic materials. The controlled subtractive processes provide a new path to modify such nanoarchitecture and its optical property. Distinct from previous studies on the optical property of the Morpho wing structure, this study provides additional experimental evidence for the origination of the optical property of the natural butterfly wing scales. The study also offers a facile approach to generate new 3D nanostructures using butterfly wings as the templates and may lead to simpler structure models for large-scale man-made structures than those offered by original butterfly wings.

  3. Winglet effects on the flutter of twin-engine-transport type wing

    Bhatia, K. G.; Nagaraja, K. S.; Ruhlin, C. L.


    Flutter characteristics of a cantilevered high aspect ratio wing with winglet were investigated. The configuration represented a current technology, twin-engine airplane. A low-speed and a high-speed model were used to evaluate compressibility effects through transonic Mach numbers and a wide range of mass-density ratios. Four flutter mechanisms were obtained in test, as well as analysis from various combinations of configuration parameters. The coupling between wing tip vertical and chordwise motions was shown to have significant effect under some conditions. It is concluded that, for the flutter model configurations studied, the winglet related flutter was amenable to the conventional flutter analysis techniques.

  4. NASA Fixed Wing Project Propulsion Research and Technology Development Activities to Reduce Thrust Specific Energy Consumption

    Hathaway, Michael D.; DelRasario, Ruben; Madavan, Nateri K.


    This paper presents an overview of the propulsion research and technology portfolio of NASA Fundamental Aeronautics Program Fixed Wing Project. The research is aimed at significantly reducing the thrust specific fuel/energy consumption of notional advanced fixed wing aircraft (by 60 % relative to a baseline Boeing 737-800 aircraft with CFM56-7B engines) in the 2030-2035 time frame. The research investments described herein are aimed at improving propulsive efficiency through higher bypass ratio fans, improving thermal efficiency through compact high overall pressure ratio gas generators, and exploring the potential benefits of boundary layer ingestion propulsion and hybrid gas-electric propulsion concepts.

  5. NASA Fixed Wing Project Propulsion Research and Technology Development Activities to Reduce Thrust Specific Energy Consumption

    Hathaway, Michael D.; Rosario, Ruben Del; Madavan, Nateri K.


    This paper presents an overview of the propulsion research and technology portfolio of NASA Fundamental Aeronautics Program Fixed Wing Project. The research is aimed at significantly reducing the thrust specific fuel/energy consumption of notional advanced fixed wing aircraft (by 60 percent relative to a baseline Boeing 737-800 aircraft with CFM56-7B engines) in the 2030 to 2035 time frame. The research investments described herein are aimed at improving propulsive efficiency through higher bypass ratio fans, improving thermal efficiency through compact high overall pressure ratio gas generators, and exploring the potential benefits of boundary layer ingestion propulsion and hybrid gas-electric propulsion concepts.

  6. Projection moire interferometry measurements of micro air vehicle wings

    Fleming, Gary A.; Bartram, Scott M.; Waszak, Martin R.; Jenkins, Luther N.


    Projection Moire Interferometry (PMI) has been used to measure the structural deformation of micro air vehicle (MAV) wings during a series of wind tunnel tests. The MAV wings had a highly flexible wing structure, generically reminiscent of a bat's wing, which resulted in significant changes in wing shape as a function of MAV angle-of-attack and simulated flight speed. This flow-adaptable wing deformation is thought to provide enhanced vehicle stability and wind gust alleviation compared to rigid wing designs. Investigation of the potential aerodynamic benefits of a flexible MAV wing required measurement of the wing shape under aerodynamic loads. PMI was used to quantify the aerodynamically induced changes in wing shape for three MAV wings having different structural designs and stiffness characteristics. This paper describes the PMI technique, its application to MAV testing, and presents a portion of the PMI data acquired for the three different MAV wings tested.

  7. An Interactive Software for Conceptual Wing Flutter Analysis and Parametric Study

    Mukhopadhyay, Vivek


    An interactive computer program was developed for wing flutter analysis in the conceptual design stage. The objective was to estimate the flutter instability boundary of a flexible cantilever wing, when well-defined structural and aerodynamic data are not available, and then study the effect of change in Mach number, dynamic pressure, torsional frequency, sweep, mass ratio, aspect ratio, taper ratio, center of gravity, and pitch inertia, to guide the development of the concept. The software was developed for Macintosh or IBM compatible personal computers, on MathCad application software with integrated documentation, graphics, data base and symbolic mathematics. The analysis method was based on non-dimensional parametric plots of two primary flutter parameters, namely Regier number and Flutter number, with normalization factors based on torsional stiffness, sweep, mass ratio, taper ratio, aspect ratio, center of gravity location and pitch inertia radius of gyration. The parametric plots were compiled in a Vought Corporation report from a vast data base of past experiments and wind-tunnel tests. The computer program was utilized for flutter analysis of the outer wing of a Blended-Wing-Body concept, proposed by McDonnell Douglas Corp. Using a set of assumed data, preliminary flutter boundary and flutter dynamic pressure variation with altitude, Mach number and torsional stiffness were determined.

  8. Aerodynamic performance of two-dimensional, chordwise flexible flapping wings at fruit fly scale in hover flight.

    Sridhar, Madhu; Kang, Chang-kwon


    Fruit flies have flexible wings that deform during flight. To explore the fluid-structure interaction of flexible flapping wings at fruit fly scale, we use a well-validated Navier-Stokes equation solver, fully-coupled with a structural dynamics solver. Effects of chordwise flexibility on a two dimensional hovering wing is studied. Resulting wing rotation is purely passive, due to the dynamic balance between aerodynamic loading, elastic restoring force, and inertial force of the wing. Hover flight is considered at a Reynolds number of Re = 100, equivalent to that of fruit flies. The thickness and density of the wing also corresponds to a fruit fly wing. The wing stiffness and motion amplitude are varied to assess their influences on the resulting aerodynamic performance and structural response. Highest lift coefficient of 3.3 was obtained at the lowest-amplitude, highest-frequency motion (reduced frequency of 3.0) at the lowest stiffness (frequency ratio of 0.7) wing within the range of the current study, although the corresponding power required was also the highest. Optimal efficiency was achieved for a lower reduced frequency of 0.3 and frequency ratio 0.35. Compared to the water tunnel scale with water as the surrounding fluid instead of air, the resulting vortex dynamics and aerodynamic performance remained similar for the optimal efficiency motion, while the structural response varied significantly. Despite these differences, the time-averaged lift scaled with the dimensionless shape deformation parameter γ. Moreover, the wing kinematics that resulted in the optimal efficiency motion was closely aligned to the fruit fly measurements, suggesting that fruit fly flight aims to conserve energy, rather than to generate large forces.

  9. Effect of leading edge roundness on a delta wing in wing-rock motion

    Ng, T. Terry; Malcolm, Gerald N.


    The effect of wing leading-edge roundness on wing rock was investigated using flow visualization in a water tunnel. Eighty degree delta wing models were tested on free-to-roll and forced oscillation rigs. The onset of wing rock was delayed by increasing the roundness of the leading edges. The wing rock amplitude and frequency results suggested that damping was increased at lower angles of attack but reduced at higher angles of attack. Vortex lift-off and vortex breakdown, especially during dynamic situations, were strongly affected by the leading edge roundness. Different forms of wing rock motion could be sustained by combinations of vortex breakdown and vortex lift-off. Behaviors of the wing and vortex motions were explained by the influence of leading edge roundness on the separation location, vortex trajectory, and vortex breakdown.

  10. Biaxial mechanical characterization of bat wing skin.

    Skulborstad, A J; Swartz, S M; Goulbourne, N C


    The highly flexible and stretchable wing skin of bats, together with the skeletal structure and musculature, enables large changes in wing shape during flight. Such compliance distinguishes bat wings from those of all other flying animals. Although several studies have investigated the aerodynamics and kinematics of bats, few have examined the complex histology and mechanical response of the wing skin. This work presents the first biaxial characterization of the local deformation, mechanical properties, and fiber kinematics of bat wing skin. Analysis of these data has provided insight into the relationships among the structural morphology, mechanical properties, and functionality of wing skin. Large spatial variations in tissue deformation and non-negligible fiber strains in the cross-fiber direction for both chordwise and spanwise fibers indicate fibers should be modeled as two-dimensional elements. The macroscopic constitutive behavior was anisotropic and nonlinear, with very low spanwise and chordwise stiffness (hundreds of kilopascals) in the toe region of the stress-strain curve. The structural arrangement of the fibers and matrix facilitates a low energy mechanism for wing deployment and extension, and we fabricate examples of skins capturing this mechanism. We propose a comprehensive deformation map for the entire loading regime. The results of this work underscore the importance of biaxial field approaches for soft heterogeneous tissue, and provide a foundation for development of bio-inspired skins to probe the effects of the wing skin properties on aerodynamic performance.

  11. Numerical calculation of the transonic flow past a swept wing. [FLO 22

    Jameson, A; Caughey, D A


    A numerical method is presented for analyzing the transonic potential flow past a lifting, swept wing. A finite-difference approximation to the full potential equation is solved in a coordinate system which is nearly conformally mapped from the physical space in planes parallel to the symmetry plane, and reduces the wing surface to a portion of one boundary of the computational grid. A coordinate invariant, rotated difference scheme is used, and the difference equations are solved by relaxation. The method is capable of treating wings of arbitrary planform and dihedral, although approximations in treating the tips and vortex sheet make its accuracy suspect for wings of small aspect ratio. Comparisons of calculated results with experimental data are shown for examples of both conventional and supercritical transport wings. Agreement is quite good for both types, but it was found necessary to account for the displacement effect of the boundary layer for the supercritical wing, presumably because of its greater sensitivity to changes in effective geometry.

  12. A mechanical model of wing and theoretical estimate of taper factor for three gliding birds

    Moosarreza Shamsyeh Zahedi; Mir Yaseen Ali Khan


    We tested a mechanical model of wing, which was constructed using the measurements of wingspan and wing area taken from three species of gliding birds. In this model, we estimated the taper factors of the wings for jackdaw (Corrus monedula), Harris’ hawk (Parabuteo unicinctas) and Lagger falcon (Falco jugger) as 1.8, 1.5 and 1.8, respectively. Likewise, by using the data linear regression and curve estimation method, as well as estimating the taper factors and the angle between the humerus and the body, we calculated the relationship between wingspan, wing area and the speed necessary to meet the aerodynamic requirements of sustained flight. In addition, we calculated the relationship between the speed, wing area and wingspan for a specific angle between the humerus and the body over the range of stall speed to maximum speed of gliding flight. We then compared the results for these three species of gliding birds. These comparisons suggest that the aerodynamic characteristics of Harris’ hawk wings are similar to those of the falcon but different from those of the jackdaw. This paper also presents two simple equations to estimate the minimum angle between the humerus and the body as well as the minimum span ratio of a bird in gliding flight.

  13. Effects of unsteady deformation of flapping wing on its aerodynamic forces

    DU Gang; SUN Mao


    Effects of unsteady deformation of a flapping model insect wing on its aerodynamic force production are studied by solving the Navier-Stokes equations on a dynamically deforming grid.Aerodynamic forces on the flapping wing are not much affected by considerable twist,but affected by camber deformation.The effect of combined camber and twist deformation is similar to that of camber deformation.With a deformation of 6% camber and 20°twist(typical values observed for wings of many insects),lift is increased bv 10%~20%and lift-to-drag ratio by around 10%compared with the case of a rigid flat-plate wing.As a result.the deformation can increase the maximum lift coefficient of an insect.and reduce its power requirement for flight.For example,for a hovering bumblebee with dynamically deforming wings(6%camber and 20°twist),aerodynamic power required is reduced by about 16%compared with the case of rigid wings.

  14. A mechanical model of wing and theoretical estimate of taper factor for three gliding birds.

    Zahedi, Moosarreza Shamsyeh; Khan, Mir Yaseen Ali


    We tested a mechanical model of wing,which was constructed using the measurements of wingspan and wing area taken from three species of gliding birds.In this model,we estimated the taper factors of the wings for jackdaw (Corrus monedula), Harris' hawk (Parabuteo unicinctas) and Lagger falcon (Falco jugger) as 1.8, 1.5 and 1.8,respectively. Likewise, by using the data linear regression and curve estimation method,as well as estimating the taper factors and the angle between the humerus and the body, we calculated the relationship between wingspan,wing area and the speed necessary to meet the aerodynamic requirements of sustained flight.In addition,we calculated the relationship between the speed,wing area and wingspan for a specific angle between the humerus and the body over the range of stall speed to maximum speed of gliding flight.We then compared the results for these three species of gliding birds. These comparisons suggest that the aerodynamic characteristics of Harris' hawk wings are similar to those of the falcon but different from those of the jackdaw.This paper also presents two simple equations to estimate the minimum angle between the humerus and the body as well as the minimum span ratio of a bird in gliding flight.

  15. Performance study of winglets on tapered wing with curved trailing edge

    Ara, Ismat; Ali, Mohammad; Islam, Md. Quamrul; Haque, M. Nazmul


    Induced drag is the result of wingtip vortex produced from generating lift by finite wing. It is one of the main drags that an aircraft wing encounters during flight. It hampers aircraft performance by increasing fuel consumption and reducing endurance, range and speed. Winglets are used to reduce the induced drag. They weakens wingtip vortex and thus reduces induced drag. This paper represents the experimental investigation to reduce induced drag using winglet at the wingtip. A model of tapered wing with curved trailing edge (without winglet) as well as two similar wings with blended winglet and double blended winglet are prepared using NACA 4412 aerofoil in equal span and surface area. All the models are tested in a closed circuit subsonic wind tunnel at air speed of 108 km/h (0.09 Mach). Reynolds number of the flow is 2.28 × 105 on the basis of average chord length of the wings. The point surface static pressures at different angles of attack from -4° to 24° are measured for each of the wing and winglet combinations through different pressure tapings by using a multi-tube water manometer. From the static pressure distribution, lift coefficient, drag coefficient and lift to drag ratio of all models are calculated. From the analysis of calculated values, it is found that both winglets are able to minimize induced drag; however, the tapered curved trailing edge span with blended winglet provides better aerodynamic performance.

  16. Smart wing rotation and trailing-edge vortices enable high frequency mosquito flight

    Bomphrey, Richard J.; Nakata, Toshiyuki; Phillips, Nathan; Walker, Simon M.


    Mosquitoes exhibit unusual wing kinematics; their long, slender wings flap at remarkably high frequencies for their size (>800 Hz)and with lower stroke amplitudes than any other insect group. This shifts weight support away from the translation-dominated, aerodynamic mechanisms used by most insects, as well as by helicopters and aeroplanes, towards poorly understood rotational mechanisms that occur when pitching at the end of each half-stroke. Here we report free-flight mosquito wing kinematics, solve the full Navier-Stokes equations using computational fluid dynamics with overset grids, and validate our results with in vivo flow measurements. We show that, although mosquitoes use familiar separated flow patterns, much of the aerodynamic force that supports their weight is generated in a manner unlike any previously described for a flying animal. There are three key features: leading-edge vortices (a well-known mechanism that appears to be almost ubiquitous in insect flight), trailing-edge vortices caused by a form of wake capture at stroke reversal, and rotational drag. The two new elements are largely independent of the wing velocity, instead relying on rapid changes in the pitch angle (wing rotation) at the end of each half-stroke, and they are therefore relatively immune to the shallow flapping amplitude. Moreover, these mechanisms are particularly well suited to high aspect ratio mosquito wings.

  17. Effects of multiple vein microjoints on the mechanical behaviour of dragonfly wings: numerical modelling.

    Rajabi, H; Ghoroubi, N; Darvizeh, A; Appel, E; Gorb, S N


    Dragonfly wings are known as biological composites with high morphological complexity. They mainly consist of a network of rigid veins and flexible membranes, and enable insects to perform various flight manoeuvres. Although several studies have been done on the aerodynamic performance of Odonata wings and the mechanisms involved in their deformations, little is known about the influence of vein joints on the passive deformability of the wings in flight. In this article, we present the first three-dimensional finite-element models of five different vein joint combinations observed in Odonata wings. The results from the analysis of the models subjected to uniform pressures on their dorsal and ventral surfaces indicate the influence of spike-associated vein joints on the dorsoventral asymmetry of wing deformation. Our study also supports the idea that a single vein joint may result in different angular deformations when it is surrounded by different joint types. The developed numerical models also enabled us to simulate the camber formation and stress distribution in the models. The computational data further provide deeper insights into the functional role of resilin patches and spikes in vein joint structures. This study might help to more realistically model the complex structure of insect wings in order to design more efficient bioinspired micro-air vehicles in future.

  18. Three-dimensional canard-wing shape optimization in aircraft cruise and maneuver environments

    De Silva, B. M. E.; Carmichael, R. L.


    This paper demonstrates a numerical technique for canard-wing shape optimization at two operating conditions. For purposes of simplicity, a mean surface wing paneling code is employed for the aerodynamic calculations. The optimization procedures are based on the method of feasible directions. The shape functions for describing the thickness, camber, and twist are based on polynomial representations. The primary design requirements imposed restrictions on the canard and wing volumes and on the lift coefficients at the operating conditions. Results indicate that significant improvements in minimum drag and lift-to-drag ratio are possible with reasonable aircraft geometries. Calculations were done for supersonic speeds with Mach numbers ranging from 1 to 6. Planforms were mainly of a delta shape with aspect ratio of 1.

  19. Independently controlled wing stroke patterns in the fruit fly Drosophila melanogaster.

    Soma Chakraborty

    Full Text Available Flies achieve supreme flight maneuverability through a small set of miniscule steering muscles attached to the wing base. The fast flight maneuvers arise from precisely timed activation of the steering muscles and the resulting subtle modulation of the wing stroke. In addition, slower modulation of wing kinematics arises from changes in the activity of indirect flight muscles in the thorax. We investigated if these modulations can be described as a superposition of a limited number of elementary deformations of the wing stroke that are under independent physiological control. Using a high-speed computer vision system, we recorded the wing motion of tethered flying fruit flies for up to 12,000 consecutive wing strokes at a sampling rate of 6250 Hz. We then decomposed the joint motion pattern of both wings into components that had the minimal mutual information (a measure of statistical dependence. In 100 flight segments measured from 10 individual flies, we identified 7 distinct types of frequently occurring least-dependent components, each defining a kinematic pattern (a specific deformation of the wing stroke and the sequence of its activation from cycle to cycle. Two of these stroke deformations can be associated with the control of yaw torque and total flight force, respectively. A third deformation involves a change in the downstroke-to-upstroke duration ratio, which is expected to alter the pitch torque. A fourth kinematic pattern consists in the alteration of stroke amplitude with a period of 2 wingbeat cycles, extending for dozens of cycles. Our analysis indicates that these four elementary kinematic patterns can be activated mutually independently, and occur both in isolation and in linear superposition. The results strengthen the available evidence for independent control of yaw torque, pitch torque, and total flight force. Our computational method facilitates systematic identification of novel patterns in large kinematic datasets.

  20. Notch inhibits Yorkie activity in Drosophila wing discs.

    Alexandre Djiane

    Full Text Available During development, tissues and organs must coordinate growth and patterning so they reach the right size and shape. During larval stages, a dramatic increase in size and cell number of Drosophila wing imaginal discs is controlled by the action of several signaling pathways. Complex cross-talk between these pathways also pattern these discs to specify different regions with different fates and growth potentials. We show that the Notch signaling pathway is both required and sufficient to inhibit the activity of Yorkie (Yki, the Salvador/Warts/Hippo (SWH pathway terminal transcription activator, but only in the central regions of the wing disc, where the TEAD factor and Yki partner Scalloped (Sd is expressed. We show that this cross-talk between the Notch and SWH pathways is mediated, at least in part, by the Notch target and Sd partner Vestigial (Vg. We propose that, by altering the ratios between Yki, Sd and Vg, Notch pathway activation restricts the effects of Yki mediated transcription, therefore contributing to define a zone of low proliferation in the central wing discs.

  1. Distributed Turboelectric Propulsion for Hybrid Wing Body Aircraft

    Kim, Hyun Dae; Brown, Gerald V.; Felder, James L.


    Meeting future goals for aircraft and air traffic system performance will require new airframes with more highly integrated propulsion. Previous studies have evaluated hybrid wing body (HWB) configurations with various numbers of engines and with increasing degrees of propulsion-airframe integration. A recently published configuration with 12 small engines partially embedded in a HWB aircraft, reviewed herein, serves as the airframe baseline for the new concept aircraft that is the subject of this paper. To achieve high cruise efficiency, a high lift-to-drag ratio HWB was adopted as the baseline airframe along with boundary layer ingestion inlets and distributed thrust nozzles to fill in the wakes generated by the vehicle. The distributed powered-lift propulsion concept for the baseline vehicle used a simple, high-lift-capable internally blown flap or jet flap system with a number of small high bypass ratio turbofan engines in the airframe. In that concept, the engine flow path from the inlet to the nozzle is direct and does not involve complicated internal ducts through the airframe to redistribute the engine flow. In addition, partially embedded engines, distributed along the upper surface of the HWB airframe, provide noise reduction through airframe shielding and promote jet flow mixing with the ambient airflow. To improve performance and to reduce noise and environmental impact even further, a drastic change in the propulsion system is proposed in this paper. The new concept adopts the previous baseline cruise-efficient short take-off and landing (CESTOL) airframe but employs a number of superconducting motors to drive the distributed fans rather than using many small conventional engines. The power to drive these electric fans is generated by two remotely located gas-turbine-driven superconducting generators. This arrangement allows many small partially embedded fans while retaining the superior efficiency of large core engines, which are physically separated

  2. Use of a Digital Image Correlation Technique for Measuring the Material Properties of Beetle Wing

    Tailie Jin; Nam Seo Goo; Sung-Choong Woo; Hoon Cheol Park


    Beetle wings are very specialized flight organs consisting of the veins and membranes. Therefore it is necessary from a bionic view to investigate the material properties of a beetle wing experimentally. In the present study, we have used a Digital lmage Correlation (DIC) technique to measure the elastic modulus of a beetle wing membrane. Specimens were prepared by carefully cutting a beetle hind wing into 3.0 mm by 7.0 mm segments (the gage length was 5 mm). We used a scanning electron microscope for a precise measurement of the thickness of the beetle wing membrane. The specimen was attached to a designed fixture to induce a uniform displacement by means of a micromanipulator. We used an ARAMISTM system based on the digital image correlation technique to measure the corresponding displacement of a specimen. The thickness of the beetle wing varied at different points of the membrane. The elastic modulus differed in relation to the membrane arrangement showing a structural anisotropy; the elastic modulus in the chordwise direction is approximately 2.65 GPa, which is three times larger than the elastic modulus in the spanwise direction of 0.84 GPa. As a result, the digital image correlation-based ARAMIS system was suc-cessfully used to measure the elastic modulus of a beetle wing. In addition to membrane's elastic modulus, we considered the Poisson's ratio of the membrane and measured the elastic modulus of a vein using an Instron universal tensile machine. The result reveals the Poisson's ratio is nearly zero and the elastic modulus of a vein is about 11 GPa.

  3. A conformal mapping technique to correlate the rotating flow around a wing section of vertical axis wind turbine and an equivalent linear flow around a static wing

    Akimoto, Hiromichi; Hara, Yutaka; Kawamura, Takafumi; Nakamura, Takuju; Lee, Yeon-Seung


    In a vertical axis wind turbine (VAWT), turbine blades are subjected to the curved flow field caused by the revolution of turbine. However, performance prediction of VAWT is usually based on the fluid dynamic coefficients obtained in wind tunnel measurements of the two-dimensional static wing. The difference of fluid dynamic coefficients in the curved flow and straight flow deteriorates the accuracy of performance prediction. To find the correlation between the two conditions of curved and straight flow, the authors propose a conformal mapping method on complex plane. It provides bidirectional mapping between the two flow fields. For example, the flow around a symmetric wing in the curved flow is mapped to that around a curved (cambered) wing in the straight flow. Although the shape of mapped wing section is different from the original one, its aerodynamic coefficients show a good correlation to those of the original in the rotating condition. With the proposed method, we can reproduce the local flow field around a rotating blade from the flow data around the mapped static wing in the straight flow condition.

  4. Aerostructural Shape and Topology Optimization of Aircraft Wings

    James, Kai

    A series of novel algorithms for performing aerostructural shape and topology optimization are introduced and applied to the design of aircraft wings. An isoparametric level set method is developed for performing topology optimization of wings and other non-rectangular structures that must be modeled using a non-uniform, body-fitted mesh. The shape sensitivities are mapped to computational space using the transformation defined by the Jacobian of the isoparametric finite elements. The mapped sensitivities are then passed to the Hamilton-Jacobi equation, which is solved on a uniform Cartesian grid. The method is derived for several objective functions including mass, compliance, and global von Mises stress. The results are compared with SIMP results for several two-dimensional benchmark problems. The method is also demonstrated on a three-dimensional wingbox structure subject to fixed loading. It is shown that the isoparametric level set method is competitive with the SIMP method in terms of the final objective value as well as computation time. In a separate problem, the SIMP formulation is used to optimize the structural topology of a wingbox as part of a larger MDO framework. Here, topology optimization is combined with aerodynamic shape optimization, using a monolithic MDO architecture that includes aerostructural coupling. The aerodynamic loads are modeled using a three-dimensional panel method, and the structural analysis makes use of linear, isoparametric, hexahedral elements. The aerodynamic shape is parameterized via a set of twist variables representing the jig twist angle at equally spaced locations along the span of the wing. The sensitivities are determined analytically using a coupled adjoint method. The wing is optimized for minimum drag subject to a compliance constraint taken from a 2 g maneuver condition. The results from the MDO algorithm are compared with those of a sequential optimization procedure in order to quantify the benefits of the MDO

  5. Age determination of blue-winged teal

    Dane, C.W.


    Primary feather length, markings on the greater secondary coverts, and the degree of bill spotting were evaluated as characters for use in the spring to distinguish first-year, blue-winged teal (Anas discors) females from older ones. The length of the 10th primary feather did not prove suitable to separate different aged females. Extreme primary lengths might be used to determine the age of some males. In females that have been through a postnuptial molt the greater secondary coverts have a more symmetrical, and more acutely angled, white, inverted 'V'-marking. Any female with a 'V' subjectively classified as good has gone through at least one postnuptial molt, and a female with no sign of a 'V' on the coverts is a juvenile or yearling before her first postnuptial molt. By measuring the longest bill spot on the upper mandible of each known-age female, it was possible to determine the age of some female teal. Because the spots fade during the breeding season, no lower size limit could be set to delineate first-year females at that time of year, but any nest-trapped hen with a spot longer than 10 mm was considered to be older than 1 year. Upper and lower limits were also established to distinguish some yearlings and 2-year-olds in the fall.

  6. Habitat variation and wing coloration affect wing shape evolution in dragonflies.

    Outomuro, D; Dijkstra, K-D B; Johansson, F


    Habitats are spatially and temporally variable, and organisms must be able to track these changes. One potential mechanism for this is dispersal by flight. Therefore, we would expect flying animals to show adaptations in wing shape related to habitat variation. In this work, we explored variation in wing shape in relation to preferred water body (flowing water or standing water with tolerance for temporary conditions) and landscape (forested to open) using 32 species of dragonflies of the genus Trithemis (80% of the known species). We included a potential source of variation linked to sexual selection: the extent of wing coloration on hindwings. We used geometric morphometric methods for studying wing shape. We also explored the phenotypic correlation of wing shape between the sexes. We found that wing shape showed a phylogenetic structure and therefore also ran phylogenetic independent contrasts. After correcting for the phylogenetic effects, we found (i) no significant effect of water body on wing shape; (ii) male forewings and female hindwings differed with regard to landscape, being progressively broader from forested to open habitats; (iii) hindwings showed a wider base in wings with more coloration, especially in males; and (iv) evidence for phenotypic correlation of wing shape between the sexes across species. Hence, our results suggest that natural and sexual selection are acting partially independently on fore- and hindwings and with differences between the sexes, despite evidence for phenotypic correlation of wing shape between males and females.

  7. Pressure distributions and oil-flow patterns for a swept circulation-control wing

    Keener, Earl R.; Sanderfer, Dwight T.; Wood, Norman J.


    Pressure distributions and photographs of oil flow patterns are presented for a circulation control wing. The model was an aspect ratio four semispan wing mounted on the side wall of the NASA Ames Transonic Wind Tunnel. The airfoil was a 20 percent thick ellipse, modified with circular leading and trailing edges of 4 percent radius, and had a 25.4 cm constant chord. This configuration does not represent a specific wing design, but is generic. A full span, tangetial, rearward blowing, circulation control slot was incorporated ahead of the trailing edge on the upper surface. The wing was tested at Mach numbers from 0.3 to 0.75 at sweep angle of 0 to 45 deg with internal to external pressure ratios of 1.0 to 3.0. Lift and pitching momemt coefficients were obtained from measured pressure distributions at five span stations. When the conventional corrections resulting from sweep angle are applied to the lift and moment of circulation control sections, no additional corrections are necessary to account for changes in blowing efficiency. This is demonstrated for an aft sweep angle of 45 deg. An empirical technique for estimating the downwash distribution of a swept wing was validated.

  8. Sensitivity Analysis of Flutter Response of a Wing Incorporating Finite-Span Corrections

    Issac, Jason Cherian; Kapania, Rakesh K.; Barthelemy, Jean-Francois M.


    Flutter analysis of a wing is performed in compressible flow using state-space representation of the unsteady aerodynamic behavior. Three different expressions are used to incorporate corrections due to the finite-span effects of the wing in estimating the lift-curve slope. The structural formulation is based on a Rayleigh-Pitz technique with Chebyshev polynomials used for the wing deflections. The aeroelastic equations are solved as an eigen-value problem to determine the flutter speed of the wing. The flutter speeds are found to be higher in these cases, when compared to that obtained without accounting for the finite-span effects. The derivatives of the flutter speed with respect to the shape parameters, namely: aspect ratio, area, taper ratio and sweep angle, are calculated analytically. The shape sensitivity derivatives give a linear approximation to the flutter speed curves over a range of values of the shape parameter which is perturbed. Flutter and sensitivity calculations are performed on a wing using a lifting-surface unsteady aerodynamic theory using modules from a system of programs called FAST.

  9. Wind tunnel tests on a tail-less swept wing span-distributed cargo aircraft configuration

    Rao, D. M.; Huffman, J. K.


    The configuration consisted of a 30 deg -swept, untapered, untwisted wing utilizing a low-moment cambered airfoil of 20 percent streamwise thickness designed for low wave drag at M = 0.6, C sub L = 0.4. The tests covered a range of Mach numbers 0.3 to 0.725 and chord Reynolds number 1,100,000 to 2,040,000, angles of attack up to model buffet and sideslip angles + or - 4 deg. Configuration build up, wing pod filleting, airfoil modification and trailing edge control deflection effects were briefly investigated. Three wing tip vertical tail designs were also tested. Wing body filleting and a simple airfoil modification both produced increments to maximum lift/drag ratio. Addition of pods eliminated pitch instability of the basic wing. While the magnitude of these benefits probably was Reynolds number sensitive, they underline the potential for improving the aerodynamics of the present configuration. The cruise parameter (product of Mach number and lift/drag ratio) attained a maximum close to the airfoil design point. The configuration was found to be positively stable with normal control effectiveness about all three axes in the Mach number and C sub L range of interest.

  10. Design, fabrication, and characterization of multifunctional wings to harvest solar energy in flapping wing air vehicles

    Perez-Rosado, Ariel; Gehlhar, Rachel D.; Nolen, Savannah; Gupta, Satyandra K.; Bruck, Hugh A.


    Currently, flapping wing unmanned aerial vehicles (a.k.a., ornithopters or robotic birds) sustain very short duration flight due to limited on-board energy storage capacity. Therefore, energy harvesting elements, such as flexible solar cells, need to be used as materials in critical components, such as wing structures, to increase operational performance. In this paper, we describe a layered fabrication method that was developed for realizing multifunctional composite wings for a unique robotic bird we developed, known as Robo Raven, by creating compliant wing structure from flexible solar cells. The deformed wing shape and aerodynamic lift/thrust loads were characterized throughout the flapping cycle to understand wing mechanics. A multifunctional performance analysis was developed to understand how integration of solar cells into the wings influences flight performance under two different operating conditions: (1) directly powering wings to increase operation time, and (2) recharging batteries to eliminate need for external charging sources. The experimental data is then used in the analysis to identify a performance index for assessing benefits of multifunctional compliant wing structures. The resulting platform, Robo Raven III, was the first demonstration of a robotic bird that flew using energy harvested from solar cells. We developed three different versions of the wing design to validate the multifunctional performance analysis. It was also determined that residual thrust correlated to shear deformation of the wing induced by torsional twist, while biaxial strain related to change in aerodynamic shape correlated to lift. It was also found that shear deformation of the solar cells induced changes in power output directly correlating to thrust generation associated with torsional deformation. Thus, it was determined that multifunctional solar cell wings may be capable of three functions: (1) lightweight and flexible structure to generate aerodynamic forces, (2

  11. The Role of the Ratio of J-Point Elevation Magnitude and R-Wave Amplitude on the Same ECG Lead in the Risk Stratification of Subjects With Early Repolarization Pattern.

    Chen, Xu-Miao; Ji, Cheng-Cheng; Cheng, Yun-Jiu; Liu, Li-Juan; Zhu, Wei-Qi; Huang, Ying; Chen, Wei-Ying; Wu, Su-Hua


    Just as high-risk populations for cardiac arrest exist in patients with Brugada syndrome or long QT syndrome, high-risk and low-risk populations for cardiac arrest also exist in patients with early repolarization pattern (ERP). Electrocardiographic (ECG) characteristics can aid the risk stratification of patients with ERP. Electrocardiographic parameters such as magnitude of J-point elevation and J/R ratio were measured. The magnitude of J-point elevation, leads with J points elevated, J/R ratio, morphology of the ST segment, and QT/QTc interval were used in comparative analysis in 2 groups: 57 patients with ERP and cardiac arrest (cardiac arrest group) and 100 patients with ERP but without cardiac arrest (control group). There was no statistical difference in clinical characteristics of the 2 groups. The J/R ratio in the cardiac arrest group was significantly higher than in the control group (26.8% ± 18.1% vs 16.3% ± 10.3%, respectively; P J/R ratio and horizontal/descending ST segment were independently associated with increased risk of cardiac arrest in patients with ERP. In patients with ERP and cardiac arrest, J/R ratios were relatively higher and mostly with horizontal/descending ST segments, suggesting that J/R ratio and ST-segment morphology may be used as indicators for risk stratification in patients with ERP. © 2016 Wiley Periodicals, Inc.

  12. Interval Finite Element Analysis of Wing Flutter

    Wang Xiaojun; Qiu Zhiping


    The influences of uncertainties in structural parameters on the flutter speed of wing are studied. On the basis of the deterministic flutter analysis model of wing, the uncertainties in structural parameters are considered and described by interval numbers. By virtue of first-order Taylor series expansion, the lower and upper bound curves of the transient decay rate coefficient versus wind velocity are given. So the interval estimation of the flutter critical wind speed of wing can be obtained, which is more reasonable than the point esti- mation obtained by the deterministic flutter analysis and provides the basis for the further non-probabilistic interval reliability analysis of wing flutter. The flow chart for interval finite element model of flutter analysis of wing is given. The proposed interval finite element model and the stochastic finite element model for wing flutter analysis are compared by the examples of a three degrees of freedorn airfoil and fuselage and a 15° swepthack wing, and the results have shown the effectiveness and feasibility of the presented model. The prominent advantage of the proposed interval finite element model is that only the bounds of uncertain parameters axe required, and the probabilistic distribution densities or other statistical characteristics are not needed.

  13. In the wings of physics

    Jacob, Maurice René Michel


    In physics research, many activities occur backstage or to continue the theatrical metaphor, in the wings of physics. This book focuses on two such activities: the editing of physics journals and the operation of physical societies. The author was editor of Physics Letters B for particle physics and then of Physics Reports for a total of 18 years, as well as being president of the French Physical Society and later of the European Physical Society. This book puts together papers dealing with such activities which he has written at various times in his career. It takes the reader into the inner circles of scientific editing and of physical societies. Each introduced by a foreword, these papers can be read separately.

  14. Induce Drag Reduction of an Airplane Wing

    Md. Fazle Rabbi


    Full Text Available This work describes the aerodynamic characteristics for aircraft wing model with and without slotted winglet. When an aircraft moves forward with a high speed then a small circulatory motion of air is created at the wingtip due to the pressure difference between the upper and lower surface of the wing is called vortices. This circulatory fluid tends to leak from lower to upper surface of wing which causes downward motion is called “downwash” and generates a component of the local lift force in the direction of the free stream called induced drag. Downwash causes reduction of lift and contribute induced drag to the total drag. Drag reduction for aerial vehicles has a range of positive ramifications: reduced fuel consumption, larger operational range, greater endurance and higher achievable speeds. An experimental study is conducted to examine the potentiality of slotted winglet for the reduction of induced drag, and for the improvement of lift coefficient without increasing the span of aircraft wing. The model composed of a swept wing built from NACA 0012 airfoil. The test conducted in subsonic wind tunnel of 1m×1m rectangular test section at flow speed 25m/s placing the wing without winglet, wing with winglet at 30° inclination, wing with winglet at 60° inclination, and wing with winglet at 70° inclination at angle of attack ranging from 0 to 16 degree. The test result shows 20- 25% reduction in drag coefficient and 10-20% increase in lift coefficient by using slotted winglet.

  15. A Conceptual Design and Optimization Method for Blended-Wing-Body Aircraft

    Vos, R.; Van Dommelen, J.


    This paper details a new software tool to aid in the conceptual design of blended-wingbody aircraft. The tool consists of four main modules. In the preliminary sizing model a class I estimate of the maximum take-off weight, wing loading, and thrust-to-weight ratio is calculated. This information is

  16. Static aeroelastic analysis for generic configuration wing

    Lee, IN; Miura, Hirokazu; Chargin, Mladen K.


    A static aeroelastic analysis capability that calculates flexible air loads for generic configuration wings was developed. It was made possible by integrating a finite element structural analysis code (MSC/NASTRAN) and a panel code of aerodynamic analysis based on linear potential flow theory. The framework already built in MSC/NASTRAN was used, and the aerodynamic influence coefficient matrix was computed externally and inserted in the NASTRAN by means of a DMAP program. It was shown that deformation and flexible air loads of an oblique wing configuration including asymmetric wings can be calculated reliably by this code both in subsonic and supersonic speeds.

  17. CineVersum BlackWing Four


    从BlackWing One到现在最新推出的BlackWing Four,一直以来C1ndVersum所带来的投影机都受到了不少投影机爱好者的关注,其帅气的外形搭配独特的欧美系画面风格,让人印象深刻。BlackWingFour是Cine Versum最为强悍的家庭影院投影机之一,

  18. Generic Wing-Body Aerodynamics Data Base

    Holst, Terry L.; Olsen, Thomas H.; Kwak, Dochan (Technical Monitor)


    The wing-body aerodynamics data base consists of a series of CFD (Computational Fluid Dynamics) simulations about a generic wing body configuration consisting of a ogive-circular-cylinder fuselage and a simple symmetric wing mid-mounted on the fuselage. Solutions have been obtained for Nonlinear Potential (P), Euler (E) and Navier-Stokes (N) solvers over a range of subsonic and transonic Mach numbers and angles of attack. In addition, each solution has been computed on a series of grids, coarse, medium and fine to permit an assessment of grid refinement errors.

  19. Active Dihedral Control System for a Torisionally Flexible Wing

    Kendall, Greg T. (Inventor); Lisoski, Derek L. (Inventor); Morgan, Walter R. (Inventor); Griecci, John A. (Inventor)


    A span-loaded, highly flexible flying wing, having horizontal control surfaces mounted aft of the wing on extended beams to form local pitch-control devices. Each of five spanwise wing segments of the wing has one or more motors and photovoltaic arrays, and produces its own lift independent of the other wing segments, to minimize inter-segment loads. Wing dihedral is controlled by separately controlling the local pitch-control devices consisting of a control surface on a boom, such that inboard and outboard wing segment pitch changes relative to each other, and thus relative inboard and outboard lift is varied.

  20. AFM Study of Structure Influence on Butterfly Wings Coloration

    Dinara Sultanovna Dallaeva


    Full Text Available This study describes the structural coloration of the butterfly Vanessa Atalanta wings and shows how the atomic force microscopy (AFM can be applied to the study of wings morphology and wings surface behavior under the temperature. The role of the wings morphology in colors was investigated. Different colors of wings have different topology and can be identified by them. AFM in semi-contact mode was used to study the wings surface. The wing surface area, which is close to the butterfly body, has shiny brown color and the peak of surface roughness is about 600 nm. The changing of morphology at different temperatures is shown.

  1. DrawWing, a program for numerical description of insect wings

    Adam Tofilski


    Full Text Available There is usually a pattern of veins on an insect wing. This pattern is species-specific and is used taxonomically. For example, the coordinates of some characteristic points on the wing are used to compare vein patterns. The characteristic points are often vein junctions or vein ends. A tool is presented that enables automatic identification of vein junctions. An image of an insect wing is used to determine the wing outline and veins. The vein skeleton is obtained using a thinning algorithm. Bezier splines are fitted to both the wing outline and the vein skeleton. The splines are saved in an encapsulated postscript file. Another output file in text format contains the coordinates of vein junctions. Both the program and its source code are available under GNU General Public License at []. The program presented in this paper automatically provides a numerical description of an insect wing. It converts an image of an insect wing to a list of coordinates of vein junctions, and a wing diagram that can be used as an illustration. Coordinates of the vein junctions extracted by the program from wing images were used successfully to discriminate between males of Dolichovespula sylvestris and Dolichovespula saxonica.

  2. Fruit fly scale robots can hover longer with flapping wings than with spinning wings.

    Hawkes, Elliot W; Lentink, David


    Hovering flies generate exceptionally high lift, because their wings generate a stable leading edge vortex. Micro flying robots with a similar wing design can generate similar high lift by either flapping or spinning their wings. While it requires less power to spin a wing, the overall efficiency depends also on the actuator system driving the wing. Here, we present the first holistic analysis to calculate how long a fly-inspired micro robot can hover with flapping versus spinning wings across scales. We integrate aerodynamic data with data-driven scaling laws for actuator, electronics and mechanism performance from fruit fly to hummingbird scales. Our analysis finds that spinning wings driven by rotary actuators are superior for robots with wingspans similar to hummingbirds, yet flapping wings driven by oscillatory actuators are superior at fruit fly scale. This crossover is driven by the reduction in performance of rotary compared with oscillatory actuators at smaller scale. Our calculations emphasize that a systems-level analysis is essential for trading-off flapping versus spinning wings for micro flying robots.

  3. Resilin in dragonfly and damselfly wings and its implications for wing flexibility.

    Donoughe, Seth; Crall, James D; Merz, Rachel A; Combes, Stacey A


    Although there is mounting evidence that passive mechanical dynamics of insect wings play an integral role in insect flight, our understanding of the structural details underlying insect wing flexibility remains incomplete. Here, we use comparative morphological and mechanical techniques to illuminate the function and diversity of two mechanisms within Odonata wings presumed to affect dynamic wing deformations: flexible resilin vein-joints and cuticular spikes. Mechanical tests show that joints with more resilin have lower rotational stiffness and deform more in response to a load applied to an intact wing. Morphological studies of 12 species of Odonata reveal that resilin joints and cuticular spikes are widespread taxonomically, yet both traits display a striking degree of morphological and functional diversity that follows taxonomically distinct patterns. Interestingly, damselfly wings (suborder Zygoptera) are mainly characterized by vein-joints that are double-sided (containing resilin both dorsally and ventrally), whereas dragonfly wings (suborder Epiprocta) are largely characterized by single-sided vein-joints (containing resilin either ventrally or dorsally, but not both). The functional significance and diversity of resilin joints and cuticular spikes could yield insight into the evolutionary relationship between form and function of wings, as well as revealing basic principles of insect wing mechanical design.

  4. Effect of 3D stall-cells on the pressure distribution of a laminar NACA64-418 wing

    Ragni, Daniele; Ferreira, Carlos


    A 3D stall-cell flow-field has been studied in a 4.8 aspect-ratio wing obtained by linear extrusion of a laminar NACA64-418 airfoil profile. The span-wise change in the velocity and pressure distribution along the wing has been quantified with respect to the development of cellular structures from 8° to 20° angle of attack. Oil-flow visualizations help localizing the regular cellular pattern in function of the angle of attack. Multi-plane stereoscopic PIV measurements obtained by traversing the entire setup along the wing span show that the flow separation is not span-wise uniform. The combination of different stereoscopic fields into a 3D volume of velocity data allows studying the global effect of the stall-cell pattern on the wing flow. Integration of the experimentally computed pressure gradient from the Navier-Stokes equation is employed to compute the span-wise distribution of the mean surface pressure. Comparison of the results with the ones obtained from pressure taps installed in the wing evidences a span-wise periodic loading on the wing. The periodic loading has maxima confined in the stream-wise direction between the location of the highest airfoil curvature and the one of the airfoil flow separation. Estimation of the periodic loading is found within 2-6 % of the sectional wing lift.

  5. Transonic unsteady airloads on an energy efficient transport wing with oscillating control surfaces

    Sandford, M. C.; Ricketts, R. H.; Cazier, F. W., Jr.; Cunningham, H. J.


    An aspect ratio 10.8 supercritical wing with oscillating control surfaces is described. The wing is instrumental with 252 static orifices and 164 in situ dynamic pressure transducers for studying the effects of control surface deflection on steady and unsteady pressures at transonic speeds. Results from initial wind tunnel tests conducted in the Langley Transonic Dynamics Tunnel are discussed. Unsteady pressure results are presented for two trailing edge control surfaces oscillating separately at the design Mach number of 0.78. Some experimental results are compared with analytical results obtained by using linear lifting surface theory.

  6. Coriolis effects enhance lift on revolving wings.

    Jardin, T; David, L


    At high angles of attack, an aircraft wing stalls. This dreaded event is characterized by the development of a leading edge vortex on the upper surface of the wing, followed by its shedding which causes a drastic drop in the aerodynamic lift. At similar angles of attack, the leading edge vortex on an insect wing or an autorotating seed membrane remains robustly attached, ensuring high sustained lift. What are the mechanisms responsible for both leading edge vortex attachment and high lift generation on revolving wings? We review the three main hypotheses that attempt to explain this specificity and, using direct numerical simulations of the Navier-Stokes equations, we show that the latter originates in Coriolis effects.

  7. Left-Wing Extremism: The Current Threat

    Karl A. Seger


    Left-wing extremism is ''alive and well'' both in the US and internationally. Although the current domestic terrorist threat within the U. S. is focused on right-wing extremists, left-wing extremists are also active and have several objectives. Leftist extremists also pose an espionage threat to U.S. interests. While the threat to the U.S. government from leftist extremists has decreased in the past decade, it has not disappeared. There are individuals and organizations within the U.S. who maintain the same ideology that resulted in the growth of left-wing terrorism in this country in the 1970s and 1980s. Some of the leaders from that era are still communicating from Cuba with their followers in the U.S., and new leaders and groups are emerging.

  8. Mallard age and sex determination from wings

    Carney, S.M.; Geis, A.D.


    This paper describes characters on the wing plumage of the mallard that indicate age and sex. A key outlines a logical order in which to check age and sex characters on wings. This method was tested and found to be more than 95 percent reliable, although it was found that considerable practice and training with known-age specimens was required to achieve this level of accuracy....The implications of this technique and the sampling procedure it permits are discussed. Wing collections could provide information on production, and, if coupled with a banding program could permit seasonal population estimates to be calculated. In addition, representative samples of wings would provide data to check the reliability of several other waterfowl surveys.

  9. Trajectory Optimization Design for Morphing Wing Missile

    Ruisheng Sun; Chao Ming; Chuanjie Sun


    This paper presents a new particle swarm optimization ( PSO) algorithm to optimize the trajectory of morphing⁃wing missile so as to achieve the enlargement of the maximum range. Equations of motion for the two⁃dimensional dynamics are derived by treating the missile as an ideal controllable mass point. An investigation of aerodynamic characteristics of morphing⁃wing missile with varying geometries is performed. After deducing the optimizing trajectory model for maximizing range, a type of discrete method is put forward for taking optimization control problem into nonlinear dynamic programming problem. The optimal trajectory is solved by using PSO algorithm and penalty function method. The simulation results suggest that morphing⁃wing missile has the larger range than the fixed⁃shape missile when launched at supersonic speed, while morphing⁃wing missile has no obvious range increment than the fixed⁃shape missile at subsonic speed.

  10. Molecular determinants of bat wing development.

    Sears, K E


    The specialization of the forelimb into a wing allowed bats to become the only mammals to achieve powered flight. Recent studies in developmental biology have begun to elucidate the molecular mechanisms behind elements of this important morphological transformation. Specifically, researchers have identified molecular changes contributing to: the formation of the bat wing membrane, the elongation of skeletal elements of the bat wing and the reduction of the bat ulna. The general picture emerging from this research is that small changes in the expression of genes critical to many aspects of development have driven large changes in bat wing morphology. Thus, bats can be added to the growing list of groups in which expression changes in key developmental genes have been linked to the evolution of morphological innovations (e.g. early bilaterians, cetaceans, insects).

  11. Analysis of the Wing Tsun Punching Methods

    Jeff Webb


    Full Text Available The three punching techniques of Wing Tsun, while few in number, represent an effective approach to striking with the closed fist. At first glance, the rather short stroke of each punch would seem disproportionate to the amount of power it generates. Therefore, this article will discuss the structure and body mechanics of each punch, in addition to the various training methods employed for developing power. Two of the Wing Tsun punches, namely the lifting punch and the hooking punch, are often confused with similar punches found in Western boxing. The key differences between the Wing Tsun and boxing punches, both in form and function, will be discussed. Finally, the strategy for applying the Wing Tsun punches will serve as the greatest factor in differentiating them from the punches of other martial arts styles.

  12. Ultrastructure of dragonfly wing veins: composite structure of fibrous material supplemented by resilin.

    Appel, Esther; Heepe, Lars; Lin, Chung-Ping; Gorb, Stanislav N


    Dragonflies count among the most skilful of the flying insects. Their exceptional aerodynamic performance has been the subject of various studies. Morphological and kinematic investigations have showed that dragonfly wings, though being rather stiff, are able to undergo passive deformation during flight, thereby improving the aerodynamic performance. Resilin, a rubber-like protein, has been suggested to be a key component in insect wing flexibility and deformation in response to aerodynamic loads, and has been reported in various arthropod locomotor systems. It has already been found in wing vein joints, connecting longitudinal veins to cross veins, and was shown to endow the dragonfly wing with chordwise flexibility, thereby most likely influencing the dragonfly's flight performance. The present study revealed that resilin is not only present in wing vein joints, but also in the internal cuticle layers of veins in wings of Sympetrum vulgatum (SV) and Matrona basilaris basilaris (MBB). Combined with other structural features of wing veins, such as number and thickness of cuticle layers, material composition, and cross-sectional shape, resilin most probably has an effect on the vein's material properties and the degree of elastic deformations. In order to elucidate the wing vein ultrastructure and the exact localisation of resilin in the internal layers of the vein cuticle, the approaches of bright-field light microscopy, wide-field fluorescence microscopy, confocal laser-scanning microscopy, scanning electron microscopy and transmission electron microscopy were combined. Wing veins were shown to consist of up to six different cuticle layers and a single row of underlying epidermal cells. In wing veins of MBB, the latter are densely packed with light-scattering spheres, previously shown to produce structural colours in the form of quasiordered arrays. Longitudinal and cross veins differ significantly in relative thickness of exo- and endocuticle, with cross veins

  13. Cross Service Fixed-Wing Cost Estimation


    clarify the costing methods for O&S costs for fixed-wing delivery platforms with the intent of extending the research to other cross- service mission costs...proof-of-concept, this project will concentrate on equating equitable cross- service costs for fixed-wing munitions delivery platforms. The method of... delivery is an essential part of the AoA, especially when the project proposed is the replacement of current missile systems. The services have

  14. Kinematics and wing shape across flight speed in the bat, Leptonycteris yerbabuenae

    Von Busse, Rhea; Hedenström, Anders; Winter, York; Johansson, L. Christoffer


    Summary The morphology and kinematics of a flying animal determines the resulting aerodynamic lift through the regulation of the speed of the air moving across the wing, the wing area and the lift coefficient. We studied the detailed three-dimensional wingbeat kinematics of the bat, Leptonycteris yerbabuenae, flying in a wind tunnel over a range of flight speeds (0–7 m/s), to determine how factors affecting the lift production vary across flight speed and within wingbeats. We found that the wing area, the angle of attack and the camber, which are determinants of the lift production, decreased with increasing speed. The camber is controlled by multiple mechanisms along the span, including the deflection of the leg relative to the body, the bending of the fifth digit, the deflection of the leading edge flap and the upward bending of the wing tip. All these measures vary throughout the wing beat suggesting active or aeroelastic control. The downstroke Strouhal number, Std, is kept relatively constant, suggesting that favorable flow characteristics are maintained during the downstroke, across the range of speeds studied. The Std is kept constant through changes in the stroke plane, from a strongly inclined stroke plane at low speeds to a more vertical stroke plane at high speeds. The mean angular velocity of the wing correlates with the aerodynamic performance and shows a minimum at the speed of maximum lift to drag ratio, suggesting a simple way to determine the optimal speed from kinematics alone. Taken together our results show the high degree of adjustments that the bats employ to fine tune the aerodynamics of the wings and the correlation between kinematics and aerodynamic performance. PMID:23259057

  15. Kinematics and wing shape across flight speed in the bat, Leptonycteris yerbabuenae

    Rhea Von Busse


    The morphology and kinematics of a flying animal determines the resulting aerodynamic lift through the regulation of the speed of the air moving across the wing, the wing area and the lift coefficient. We studied the detailed three-dimensional wingbeat kinematics of the bat, Leptonycteris yerbabuenae, flying in a wind tunnel over a range of flight speeds (0–7 m/s, to determine how factors affecting the lift production vary across flight speed and within wingbeats. We found that the wing area, the angle of attack and the camber, which are determinants of the lift production, decreased with increasing speed. The camber is controlled by multiple mechanisms along the span, including the deflection of the leg relative to the body, the bending of the fifth digit, the deflection of the leading edge flap and the upward bending of the wing tip. All these measures vary throughout the wing beat suggesting active or aeroelastic control. The downstroke Strouhal number, Std, is kept relatively constant, suggesting that favorable flow characteristics are maintained during the downstroke, across the range of speeds studied. The Std is kept constant through changes in the stroke plane, from a strongly inclined stroke plane at low speeds to a more vertical stroke plane at high speeds. The mean angular velocity of the wing correlates with the aerodynamic performance and shows a minimum at the speed of maximum lift to drag ratio, suggesting a simple way to determine the optimal speed from kinematics alone. Taken together our results show the high degree of adjustments that the bats employ to fine tune the aerodynamics of the wings and the correlation between kinematics and aerodynamic performance.

  16. Kinematics and wing shape across flight speed in the bat, Leptonycteris yerbabuenae.

    Von Busse, Rhea; Hedenström, Anders; Winter, York; Johansson, L Christoffer


    The morphology and kinematics of a flying animal determines the resulting aerodynamic lift through the regulation of the speed of the air moving across the wing, the wing area and the lift coefficient. We studied the detailed three-dimensional wingbeat kinematics of the bat, Leptonycteris yerbabuenae, flying in a wind tunnel over a range of flight speeds (0-7 m/s), to determine how factors affecting the lift production vary across flight speed and within wingbeats. We found that the wing area, the angle of attack and the camber, which are determinants of the lift production, decreased with increasing speed. The camber is controlled by multiple mechanisms along the span, including the deflection of the leg relative to the body, the bending of the fifth digit, the deflection of the leading edge flap and the upward bending of the wing tip. All these measures vary throughout the wing beat suggesting active or aeroelastic control. The downstroke Strouhal number, St(d), is kept relatively constant, suggesting that favorable flow characteristics are maintained during the downstroke, across the range of speeds studied. The St(d) is kept constant through changes in the stroke plane, from a strongly inclined stroke plane at low speeds to a more vertical stroke plane at high speeds. The mean angular velocity of the wing correlates with the aerodynamic performance and shows a minimum at the speed of maximum lift to drag ratio, suggesting a simple way to determine the optimal speed from kinematics alone. Taken together our results show the high degree of adjustments that the bats employ to fine tune the aerodynamics of the wings and the correlation between kinematics and aerodynamic performance.

  17. Lift augmentation for highly swept wing aircraft

    Rao, Dhanvada M. (Inventor)


    A pair of spaced slots, disposed on each side of an aircraft centerline and spaced well inboard of the wing leading edges, are provided in the wing upper surfaces and directed tangentially spanwise toward thin sharp leading wing edges of a highly swept, delta wing aircraft. The slots are individually connected through separate plenum chambers to separate compressed air tanks and serve, collectively, as a system for providing aircraft lift augmentation. A compressed air supply is tapped from the aircraft turbojet power plant. Suitable valves, under the control of the aircraft pilot, serve to selective provide jet blowing from the individual slots to provide spanwise sheets of jet air closely adjacent to the upper surfaces and across the aircraft wing span to thereby create artificial vortices whose suction generate additional lift on the aircraft. When desired, or found necessary, unequal or one-side wing blowing is employed to generate rolling moments for augmented lateral control. Trailing flaps are provided that may be deflected differentially, individually, or in unison, as needed for assistance in take-off or landing of the aircraft.

  18. Analytical observations on the aerodynamics of a delta wing with leading edge flaps

    Oh, S.; Tavella, D.


    The effect of a leading edge flap on the aerodynamics of a low aspect ratio delta wing is studied analytically. The separated flow field about the wing is represented by a simple vortex model composed of a conical straight vortex sheet and a concentrated vortex. The analysis is carried out in the cross flow plane by mapping the wing trace, by means of the Schwarz-Christoffel transformation into the real axis of the transformed plane. Particular attention is given to the influence of the angle of attack and flap deflection angle on lift and drag forces. Both lift and drag decrease with flap deflection, while the lift-to-drag ratioe increases. A simple coordinate transformation is used to obtain a closed form expression for the lift-to-drag ratio as a function of flap deflection. The main effect of leading edge flap deflection is a partial suppression of the separated flow on the leeside of the wing. Qualitative comparison with experiments is presented, showing agreement in the general trends.

  19. The role of resonance in propulsion of an elastic pitching wing with or without inertia

    Zhang, Yang; Zhou, Chunhua; Luo, Haoxiang; Luo Team; Zhou Team


    Flapping wings of insects and undulating fins of fish both experience significant elastic deformations during propulsion, and it has been shown that in both cases, the deformations are beneficial to force enhancement and power efficiency. In fish swimming, the inertia of the fin structure is negligible and the hydrodynamic force is solely responsible for the deformation. However, in insect flight, both the wing inertia and aerodynamic force can be important factors leading to wing deformation. This difference raises the question about the role of the system (fluid-structure) resonance in the performance of propulsion. In this study, we use a 2D pitching foil as a model wing and vary its bending rigidity, pitching frequency, and mass ratio to investigate the fluid-structure interaction near resonance. The results show that at low mass ratios, i.e., a scenario of swimming, the system resonance greatly enhances thrust production and power efficiency, which is consistent with previous experimental results. However, at high mass ratios, i.e., a scenario of flying, the system resonance leads to overly large deformation that actually does not bring benefit any more. This conclusion thus suggests that resonance plays different roles in flying and in swimming. Supported by the NNSF of China and the NSF of US.

  20. The leading-edge vortex of swift wing-shaped delta wings.

    Muir, Rowan Eveline; Arredondo-Galeana, Abel; Viola, Ignazio Maria


    Recent investigations on the aerodynamics of natural fliers have illuminated the significance of the leading-edge vortex (LEV) for lift generation in a variety of flight conditions. A well-documented example of an LEV is that generated by aircraft with highly swept, delta-shaped wings. While the wing aerodynamics of a manoeuvring aircraft, a bird gliding and a bird in flapping flight vary significantly, it is believed that this existing knowledge can serve to add understanding to the complex aerodynamics of natural fliers. In this investigation, a model non-slender delta-shaped wing with a sharp leading edge is tested at low Reynolds number, along with a delta wing of the same design, but with a modified trailing edge inspired by the wing of a common swift Apus apus. The effect of the tapering swift wing on LEV development and stability is compared with the flow structure over the unmodified delta wing model through particle image velocimetry. For the first time, a leading-edge vortex system consisting of a dual or triple LEV is recorded on a swift wing-shaped delta wing, where such a system is found across all tested conditions. It is shown that the spanwise location of LEV breakdown is governed by the local chord rather than Reynolds number or angle of attack. These findings suggest that the trailing-edge geometry of the swift wing alone does not prevent the common swift from generating an LEV system comparable with that of a delta-shaped wing.

  1. Numerical study of the trailing vortex of a wing with wing-tip blowing

    Lim, Hock-Bin


    Trailing vortices generated by lifting surfaces such as helicopter rotor blades, ship propellers, fixed wings, and canard control surfaces are known to be the source of noise, vibration, cavitation, degradation of performance, and other hazardous problems. Controlling these vortices is, therefore, of practical interest. The formation and behavior of the trailing vortices are studied in the present research. In addition, wing-tip blowing concepts employing axial blowing and spanwise blowing are studied to determine their effectiveness in controlling these vortices and their effects on the performance of the wing. The 3D, unsteady, thin-layer compressible Navier-Stokes equations are solved using a time-accurate, implicit, finite difference scheme that employs LU-ADI factorization. The wing-tip blowing is simulated using the actuator plane concept, thereby, not requiring resolution of the jet slot geometry. Furthermore, the solution blanking feature of the chimera scheme is used to simplify the parametric study procedure for the wing-tip blowing. Computed results are shown to compare favorably with experimental measurements. It is found that axial wing-tip blowing, although delaying the rolling-up of the trailing vortices and the near-field behavior of the flowfield, does not dissipate the circulation strength of the trailing vortex farther downstream. Spanwise wing-tip blowing has the effect of displacing the trailing vortices outboard and upward. The increased 'wing-span' due to the spanwise wing-tip blowing has the effect of lift augmentation on the wing and the strengthening of the trailing vortices. Secondary trailing vortices are created at high spanwise wing-tip blowing intensities.

  2. Altitudinal Variability in Wing Patterns of Phyllonorycter salictella (Zeller, 1846 (Lepidoptera: Gracillariidae

    František Gregor


    Full Text Available Individual variability of wing patterns is not frequent in European species of the genus Phyllonorycter Hübner, 1822. It is unusually distinct in Phyllonorycter salictella (Zeller, 1846 which causes some taxonomic ambiguities and oversights. We found on numerous material of adults reared from overwintering pupae collected in the Czech and Slovak Republics since 1950 that this variability is related with altitude (temperature. Adults with the distinct generotypic (plesiomorphic wing patterns dominated in submountain populations while individuals with the strongly reduced (apomorphic wing drawings were represented quite negligibly. This ratio was reversed in lowland populations. The observed variability is continuous between extreme variants, it is regionally and trophic unaffected, and more pronounced in males than in females. The results support the view that the questionable taxa such as Phyllonorycter viminiella (Sircom, 1848 and P. heringiella (Grønlien, 1932 represent only individual (local or regional forms of the above species.

  3. Analytic State Space Model for an Unsteady Finite-Span Wing

    Izraelevitz, Jacob; Zhu, Qiang; Triantafyllou, Michael


    Real-time control of unsteady flows, such as force control in flapping wings, requires simple wake models that easily translate into robust control designs. We analytically derive a state-space model for the unsteady trailing vortex system behind a finite aspect-ratio flapping wing. Contrary to prior models, the downwash and lift distributions over the span can be arbitrary, including tip effects. The wake vorticity is assumed to be a fully unsteady distribution, with the exception of quasi-steady (no rollup) geometry. Each discretization along the span has one to four states to represent the local unsteady wake-induced downwash, lift, and circulation. The model supports independently time-varying velocity, heave, and twist along the span. We validate this state-space model through comparison with existing analytic solutions for elliptic wings and an unsteady inviscid panel method.

  4. An experimental study of the flow in a wing with a partial span drooped leading edge

    Winkelmann, A. E.; Tsao, C. P.


    The flow field produced by a low aspect ratio wing (AR = 3.0) with a partial span leading edge droop was investigated in a series of low speed wind tunnel tests (Reynolds number based on 17.8 cm chord = 560,000). Photographs were obtained of surface oil flow patterns over an angle of attack range of alpha = 0 to 29 deg. Flow field surveys of the partially stalled wing at alpha = 25 deg were completed using a hot-wire probe, a split-film probe and a Conrad probe. The flow field survey data was presented using a color video display. The data indicated regions of apparent reversed flow in the separation region behind the wing and indicated the general cross-sectional shape of the separated wake flow.

  5. Measurement on Camber Deformation of Wings of Free-flying Dragonflies and Beating-flying Dragonflies

    Deqiang Song; Lijiang Zeng


    The knowledge of wing orientation and deformation during flapping flight is necessary for a complete aerodynamic analysis, but to date those kinematic features have not been simultaneously quantified for free-flying insects. A projected comb-fringe (PCF) method has been developed for measuring spanwise camber changes on free-flying dragonflies and on beating-flying dragonflies through the course of a wingbeat, which bases on projecting a fringe pattern over the whole measurement area and then measuring the wing deformation from the distorted fringe pattern. Experimental results demonstrate substantial camber changes both along the wingspan and through the course of a wingbeat. The ratio of camber deformation to chord length for hind wing is up to 0.11 at 75% spanwise with a flapping angle of -0.66 degree for a free-flying dragonfly.

  6. Control of Flow Structure on Non-Slender Delta Wing: Bio-inspired Edge Modifications, Passive Bleeding, and Pulsed Blowing

    Yavuz, Mehmet Metin; Celik, Alper; Cetin, Cenk


    In the present study, different flow control approaches including bio-inspired edge modifications, passive bleeding, and pulsed blowing are introduced and applied for the flow over non-slender delta wing. Experiments are conducted in a low speed wind tunnel for a 45 degree swept delta wing using qualitative and quantitative measurement techniques including laser illuminated smoke visualization, particle image velocimety (PIV), and surface pressure measurements. For the bio-inspired edge modifications, the edges of the wing are modified to dolphin fluke geometry. In addition, the concept of flexion ratio, a ratio depending on the flexible length of animal propulsors such as wings, is introduced. For passive bleeding, directing the free stream air from the pressure side of the planform to the suction side of the wing is applied. For pulsed blowing, periodic air injection through the leading edge of the wing is performed in a square waveform with 25% duty cycle at different excitation frequencies and compared with the steady and no blowing cases. The results indicate that each control approach is quite effective in terms of altering the overall flow structure on the planform. However, the success level, considering the elimination of stall or delaying the vortex breakdown, depends on the parameters in each method.

  7. Comparison between lactulose/mannitol and [sup 51]Cr-ethylenediaminetetraacetic acid/[sup 14]C-mannitol methods for intestinal permeability; Frequency distribution pattern and variability of markers and marker ratios in healthy subjects

    Blomquist, L.; Bark, T.; Hedenborg, G.; Svenberg, T.; Norman, A. (Karolinska Hospital, Stockholm (Sweden))


    Urinary excretion of lactulose and mannitol, determined by gas-liquid chromatography, was compared with that of [sup 51]Cr-ethylenediaminetetraacetic acid (EDTA) and [sup 14]C-mannitol for measurement of intestinal permeability in 28 healthy humans. The 0- to 6-h excretion values for unlabelled and labelled mannitol (marker of transcellular permeability) were normally distributed, whereas excretion values for lactulose and [sup 51]Cr-EDTA (markers of paracellular permeability) were shewly distributed, as were the lactulose to mannitol and [sup 51]Cr-EDTA to [sup 14]C-mannitol ratios. Excretion of the transcellular markers, but not of the paracullular markers was significantly correlated to urinary volume; correction for urinary volume resulted in decreased test variability. Significant correlation was found between lactulose and [sup 51]Cr-EDTA excretion and between mannitol and [sup 14]C-mannitol excretion, but not between the lactulose to mannitol and [sup 51]Cr-EDTA to [sup 14]C-mannitol ratios. Inter- and intraindividual test variability was greater for each chemically determined marker than for the corresponding isotope-labelled marker. Similarly, variability was greater for each paracellular marker than for the corresponding transcellular marker and for each paracellular/transcellular marker ratio, than for the transcellular marker alone. Variability of mannitol excretion was increased by the frequent presence of food-derived mannitol in the urine. 23 refs., 5 figs., 2 tabs.

  8. Artificial evolution of the morphology and kinematics in a flapping-wing mini-UAV.

    de Margerie, E; Mouret, J B; Doncieux, S; Meyer, J-A


    Birds demonstrate that flapping-wing flight (FWF) is a versatile flight mode, compatible with hovering, forward flight and gliding to save energy. This extended flight domain would be especially useful on mini-UAVs. However, design is challenging because aerodynamic efficiency is conditioned by complex movements of the wings, and because many interactions exist between morphological (wing area, aspect ratio) and kinematic parameters (flapping frequency, stroke amplitude, wing unfolding). Here we used artificial evolution to optimize these morpho-kinematic features on a simulated 1 kg UAV, equipped with wings articulated at the shoulder and wrist. Flight tests were conducted in a dedicated steady aerodynamics simulator. Parameters generating horizontal flight for minimal mechanical power were retained. Results showed that flight at medium speed (10-12 m s(-1)) can be obtained for reasonable mechanical power (20 W kg(-1)), while flight at higher speed (16-20 m s(-1)) implied increased power (30-50 W kg(-1)). Flight at low speed (6-8 m s(-1)) necessitated unrealistic power levels (70-500 W kg(-1)), probably because our simulator neglected unsteady aerodynamics. The underlying adaptation of morphology and kinematics to varying flight speed were compared to available biological data on the flight of birds.

  9. Wing and body kinematics of forward flight in drone-flies.

    Meng, Xue Guang; Sun, Mao


    Here, we present a detailed analysis of the wing and body kinematics in drone-flies in free flight over a range of speeds from hovering to about 8.5 m s(-1). The kinematics was measured by high-speed video techniques. As the speed increased, the body angle decreased and the stroke plane angle increased; the wingbeat frequency changed little; the stroke amplitude first decreased and then increased; the ratio of the downstroke duration to the upstroke duration increased; the mean positional angle increased at lower speeds but changed little at speeds above 3 m s(-1). At a speed above about 1.5 m s(-1), wing rotation at supination was delayed and that at pronation was advanced, and consequently the wing rotations were mostly performed in the upstroke. In the downstroke, the relative velocity of the wing increased and the effective angle of attack decreased with speed; in the upstroke, they both decreased with speed at lower speeds, and at higher speeds, the relative velocity became larger but the effective angle of attack became very small. As speed increased, the increasing inclination of the stroke plane ensured that the effective angle of attack in the upstroke would not become negative, and that the wing was in suitable orientations for vertical-force and thrust production.

  10. Aerodynamic mechanism of forces generated by twisting model-wing in bat flapping flight

    管子武; 余永亮


    The aerodynamic mechanism of the bat wing membrane along the lateral border of its body is studied. The twist-morphing that alters the angle of attack (AOA) along the span-wise direction is observed widely during bat flapping flight. An assumption is made that the linearly distributed AOA is along the span-wise direction. The plate with the aspect ratio of 3 is used to model a bat wing. A three-dimensional (3D) unsteady panel method is used to predict the aerodynamic forces generated by the flapping plate with leading edge separation. It is found that, relative to the rigid wing flapping, twisting motion can increase the averaged lift by as much as 25% and produce thrust instead of drag. Furthermore, the aerodynamic forces (lift/drag) generated by a twisting plate-wing are similar to those of a pitching rigid-wing, meaning that the twisting in bat flight has the same function as the supination/pronation motion in insect flight.

  11. Aerodynamic Analysis of the Truss-Braced Wing Aircraft Using Vortex-Lattice Superposition Approach

    Ting, Eric Bi-Wen; Reynolds, Kevin Wayne; Nguyen, Nhan T.; Totah, Joseph J.


    The SUGAR Truss-BracedWing (TBW) aircraft concept is a Boeing-developed N+3 aircraft configuration funded by NASA ARMD FixedWing Project. This future generation transport aircraft concept is designed to be aerodynamically efficient by employing a high aspect ratio wing design. The aspect ratio of the TBW is on the order of 14 which is significantly greater than those of current generation transport aircraft. This paper presents a recent aerodynamic analysis of the TBW aircraft using a conceptual vortex-lattice aerodynamic tool VORLAX and an aerodynamic superposition approach. Based on the underlying linear potential flow theory, the principle of aerodynamic superposition is leveraged to deal with the complex aerodynamic configuration of the TBW. By decomposing the full configuration of the TBW into individual aerodynamic lifting components, the total aerodynamic characteristics of the full configuration can be estimated from the contributions of the individual components. The aerodynamic superposition approach shows excellent agreement with CFD results computed by FUN3D, USM3D, and STAR-CCM+. XXXXX Demand for green aviation is expected to increase with the need for reduced environmental impact. Most large transports today operate within the best cruise L/D range of 18-20 using the conventional tube-and-wing design. This configuration has led to marginal improvements in aerodynamic efficiency over this past century, as aerodynamic improvements tend to be incremental. A big opportunity has been shown in recent years to significantly reduce structural weight or trim drag, hence improved energy efficiency, with the use of lightweight materials such as composites. The Boeing 787 transport is an example of a modern airframe design that employs lightweight structures. High aspect ratio wing design can provide another opportunity for further improvements in energy efficiency. Historically, the study of high aspect ratio wings has been intimately tied to the study of

  12. A sequential, multi-complexity topology optimization process for aeroelastic wing structure design

    Guiles, Mark A.

    The design of structures is motivated by the requirement that performance goals must be met at the lowest possible cost. In the realm of aircraft design, the least-weight structure typically leads to the lowest cost vehicle. Therefore, the goal becomes that of supporting all flight loads at the minimum achievable weight. This study outlines a method to identify the optimal layout or topology of a wing structure that minimizes the wing's weight under multiple loads, subject to strength and aeroelastic constraints. The procedure was developed with the goal of using available, well-defined tools for structural sizing optimization to simplify the layout selection process. This approach uses a sequence of sizing optimization problems to identify and remove non-essential elements from an overpopulated structure. The optimization and deletion processes produce a series of improving feasible topologies for the set of flight loads imposed on the wing. These candidate structures are compared and the least-weight design is chosen as the optimum. The procedure was first applied to a plane truss problem and was able to reproduce the well-established Michell truss solution, providing validation of the approach. Then, the process was applied to wing models representing several different types of aircraft to illustrate its applicability across a wide range of wing design problems.

  13. A Comparison of Metallic, Composite and Nanocomposite Optimal Transonic Transport Wings

    Kennedy, Graeme J.; Kenway, Gaetan K. W.; Martins, Joaquim R. R.


    Current and future composite material technologies have the potential to greatly improve the performance of large transport aircraft. However, the coupling between aerodynamics and structures makes it challenging to design optimal flexible wings, and the transonic flight regime requires high fidelity computational models. We address these challenges by solving a series of high-fidelity aerostructural optimization problems that explore the design space for the wing of a large transport aircraft. We consider three different materials: aluminum, carbon-fiber reinforced composites and an hypothetical composite based on carbon nanotubes. The design variables consist of both aerodynamic shape (including span), structural sizing, and ply angle fractions in the case of composites. Pareto fronts with respect to structural weight and fuel burn are generated. The wing performance in each case is optimized subject to stress and buckling constraints. We found that composite wings consistently resulted in lower fuel burn and lower structural weight, and that the carbon nanotube composite did not yield the increase in performance one would expect from a material with such outstanding properties. This indicates that there might be diminishing returns when it comes to the application of advanced materials to wing design, requiring further investigation.

  14. Aerodynamic study on wing and tail small UAV without runways

    Soetanto, Maria F.; R., Randy; Alfan M., R.; Dzaldi


    This paper consists of the design and analysis of the aerodynamics of the profiles of wing and tail of a Small Unmanned Aerial Vehicle (UAV). UAV is a remote-controlled aircraft that can carry cameras, sensors and even weapons on an area that needed aerial photography or aerial video [1]. The aim of this small UAV is for used in situations where manned flight is considered too risky or difficult, such as fire fighting or surveillance, while the term 'small means the design of this UAV has to be relatively small and portable so that peoples are able to carry it during their operations [CASR Part 101.240: it is a UAV which is has a launch mass greater than 100 grams but less than 100 kilograms] [2]. Computational Fluid Dynamic (CFD) method was used to analyze the fluid flow characteristics around the aerofoil's profiles, such as the lift generation for each angle of attack and longitudinal stability caused by vortex generation on trailing edge. Based on the analysis and calculation process, Clark-Y MOD with aspect ratio, AR = 4.28 and taper ratio, λ = 0.65 was chosen as the wing aerofoil and SD 8020 with AR = 4.8 and λ = 0.5 was chosen as the horizontal tail, while SD 8020 with AR = 1.58 and λ = 0.5 was chosen as the vertical tail. The lift and drag forces generated for wing and tail surfaces can be determined from the Fluent 6.3 simulation. Results showed that until angle of attack of 6 degrees, the formation of flow separation is still going on behind the trailing edge, and the stall condition occurs at 14 degrees angle of attack which is characterized by the occurrence of flow separation at leading edge, with a maximum lift coefficient (Cl) obtained = 1.56. The results of flight tests show that this small UAV has successfully maneuvered to fly, such as take off, some acrobatics when cruising and landing smoothly, which means that the calculation and analysis of aerodynamic aerofoil's profile used on the wing and tail of the Small UAV were able to be validated.

  15. Populists in Parliament : Comparing Left-Wing and Right-Wing Populism in the Netherlands

    Otjes, Simon; Louwerse, Tom


    In parliament, populist parties express their positions almost every day through voting. There is great diversity among them, for instance between left-wing and right-wing populist parties. This gives rise to the question: is the parliamentary behaviour of populists motivated by their populism or by

  16. Aerodynamics of two-dimensional flapping wings in tandem configuration

    Lua, K. B.; Lu, H.; Zhang, X. H.; Lim, T. T.; Yeo, K. S.


    This paper reports a fundamental investigation on the aerodynamics of two-dimensional flapping wings in tandem configuration in forward flight. Of particular interest are the effects of phase angle (φ) and center-to-center distance (L) between the front wing and the rear wing on the aerodynamic force generation at a Reynolds number of 5000. Both experimental and numerical methods were employed. A force sensor was used to measure the time-history aerodynamic forces experienced by the two wings and digital particle image velocimetry was utilized to obtain the corresponding flow structures. Both the front wing and the rear wing executed the same simple harmonic motions with φ ranging from -180° to 180° and four values of L, i.e., 1.5c, 2c, 3c, and 4c (c is the wing chord length). Results show that at fixed L = 2c, tandem wings perform better than the sum of two single wings that flap independently in terms of thrust for phase angle approximately from -90° to 90°. The maximum thrust on the rear wing occurs during in-phase flapping (φ = 0°). Correlation of transient thrust and flow structure indicates that there are generally two types of wing-wake interactions, depending on whether the rear wing crosses the shear layer shed from the front wing. Finally, increasing wing spacing has similar effect as reducing the phase angle, and an approximate mathematical model is derived to describe the relationship between these two parameters.

  17. Survey of research on unsteady aerodynamic loading of delta wings

    Ashley, H.; Vaneck, T.; Katz, J.; Jarrah, M. A.


    For aeronautical applications, there has been recent interest in accurately determining the aerodynamic forces and moments experienced by low-aspect-ratio wings performing transient maneuvers which go to angles of attack as high as 90 deg. Focusing on the delta planform with sharp leading edges, the paper surveys experimental and theoretical investigations dealing with the associated unsteady flow phenomena. For maximum angles above a value between 30 and 40 deg, flow details and airloads are dominated by hysteresis in the 'bursting' instability of intense vortices which emanate from the leading edge. As examples of relevant test results, force and moment histories are presented for a model series with aspect ratios 1, 1.5 and 2. Influences of key parameters are discussed, notably those which measure unsteadiness. Comparisons are given with two theories: a paneling approximation that cannot capture bursting but clarifies other unsteady influences, and a simplified estimation scheme which uses measured bursting data.

  18. Survey of research on unsteady aerodynamic loading of delta wings

    Ashley, H.; Vaneck, T.; Katz, J.; Jarrah, M. A.


    For aeronautical applications, there has been recent interest in accurately determining the aerodynamic forces and moments experienced by low-aspect-ratio wings performing transient maneuvers which go to angles of attack as high as 90 deg. Focusing on the delta planform with sharp leading edges, the paper surveys experimental and theoretical investigations dealing with the associated unsteady flow phenomena. For maximum angles above a value between 30 and 40 deg, flow details and airloads are dominated by hysteresis in the 'bursting' instability of intense vortices which emanate from the leading edge. As examples of relevant test results, force and moment histories are presented for a model series with aspect ratios 1, 1.5 and 2. Influences of key parameters are discussed, notably those which measure unsteadiness. Comparisons are given with two theories: a paneling approximation that cannot capture bursting but clarifies other unsteady influences, and a simplified estimation scheme which uses measured bursting data.

  19. Adaptation to different climates results in divergent phenotypic plasticity of wing size and shape in an invasive drosophilid

    Roberta Loh; Jean R. David; Vincent Debat; Blanche Christine Bitner-Mathé


    The phenotypic plasticity of wing size and wing shape of Zaprionus indianus was investigated in relation to growth temperature (17°C to 31°C) in two natural populations living under different climates, equatorial and subtropical. The two populations were clearly distinguished not only by their wing size (the populations from the colder climate being bigger in size), but also by the shape of the response curves to growth temperature i.e., their reaction norms. In this respect, the temperature at which the size of the wing was maximum was about 3°C higher in the equatorial population. Such a difference in size plasticity is already found in two other nonclosely related species, might be a general evolutionary pattern in drosophilids. Wing shape was investigated by calculating an ellipse included into the wing blade, then by considering the ratio of the two axes, and also by analysing the angular position of 10 wing-vein landmarks. For an overall shape index (ratio of the two axes of the ellipse), a regular and almost linear increase was observed with increasing temperature i.e., a more round shape at high temperatures. Wing shape was also analysed by considering the variations of the various angles according to temperature. A diversity of response curves was observed, revealing either a monotonous increase or decrease with increasing temperature, and sometimes a bell shape curve. An interesting conclusion is that, in most cases, a significant difference was observed between the two populations, and the difference was more pronounced at low temperatures. These angular variations are difficult to interpret in an evolutionary context. More comparative studies should be undertaken before reaching some general conclusions.

  20. High Bypass Ratio Jet Noise Reduction and Installation Effects Including Shielding Effectiveness

    Thomas, Russell H.; Czech, Michael J.; Doty, Michael J.


    overall nozzle configuration design was selected for application to the N2A Hybrid Wing Body concept that will be the subject of the NASA Langley 14 by 22 Foot Subsonic Tunnel high fidelity aeroacoustic characterization experiment. The best overall nozzle selected includes T-fan type chevrons, uniform chevrons on the core nozzle, and no additional pylon of the type that created a strong acoustic effect at lower bypass ratios. The T-fan chevrons are oriented azimuthally away from the ground observer locations. This best overall nozzle compared to the baseline nozzle was assessed, at equal thrust, to produce sufficient installed noise reduction of the jet noise component to enable the N2A HWB to meet NASA s noise goal of 42 dB cumulative below Stage 4.

  1. Expanding subjectivities

    Lundgaard Andersen, Linda; Soldz, Stephen


    A major theme in recent psychoanalytic thinking concerns the use of therapist subjectivity, especially “countertransference,” in understanding patients. This thinking converges with and expands developments in qualitative research regarding the use of researcher subjectivity as a tool to understa...

  2. Rapid State Space Modeling Tool for Rectangular Wing Aeroservoelastic Studies

    Suh, Peter M.; Conyers, Howard Jason; Mavris, Dimitri N.


    This report introduces a modeling and simulation tool for aeroservoelastic analysis of rectangular wings with trailing-edge control surfaces. The inputs to the code are planform design parameters such as wing span, aspect ratio, and number of control surfaces. Using this information, the generalized forces are computed using the doublet-lattice method. Using Roger's approximation, a rational function approximation is computed. The output, computed in a few seconds, is a state space aeroservoelastic model which can be used for analysis and control design. The tool is fully parameterized with default information so there is little required interaction with the model developer. All parameters can be easily modified if desired. The focus of this report is on tool presentation, verification, and validation. These processes are carried out in stages throughout the report. The rational function approximation is verified against computed generalized forces for a plate model. A model composed of finite element plates is compared to a modal analysis from commercial software and an independently conducted experimental ground vibration test analysis. Aeroservoelastic analysis is the ultimate goal of this tool, therefore, the flutter speed and frequency for a clamped plate are computed using damping-versus-velocity and frequency-versus-velocity analysis. The computational results are compared to a previously published computational analysis and wind-tunnel results for the same structure. A case study of a generic wing model with a single control surface is presented. Verification of the state space model is presented in comparison to damping-versus-velocity and frequency-versus-velocity analysis, including the analysis of the model in response to a 1-cos gust.

  3. Flow field of flexible flapping wings

    Sallstrom, Erik

    The agility and maneuverability of natural fliers would be desirable to incorporate into engineered micro air vehicles (MAVs). However, there is still much for engineers to learn about flapping flight in order to understand how such vehicles can be built for efficient flying. The goal of this study is to develop a methodology for capturing high quality flow field data around flexible flapping wings in a hover environment and to interpret it to gain a better understanding of how aerodynamic forces are generated. The flow field data was captured using particle image velocimetry (PIV) and required that measurements be taken around a repeatable flapping motion to obtain phase-averaged data that could be studied throughout the flapping cycle. Therefore, the study includes the development of flapping devices with a simple repeatable single degree of freedom flapping motion. The acquired flow field data has been examined qualitatively and quantitatively to investigate the mechanisms behind force production in hovering flight and to relate it to observations in previous research. Specifically, the flow fields have been investigated around a rigid wing and several carbon fiber reinforced flexible membrane wings. Throughout the whole study the wings were actuated with either a sinusoidal or a semi-linear flapping motion. The semi-linear flapping motion holds the commanded angular velocity nearly constant through half of each half-stroke while the sinusoidal motion is always either accelerating or decelerating. The flow fields were investigated by examining vorticity and vortex structures, using the Q criterion as the definition for the latter, in two and three dimensions. The measurements were combined with wing deflection measurements to demonstrate some of the key links in how the fluid-structure interactions generated aerodynamic forces. The flow fields were also used to calculate the forces generated by the flapping wings using momentum balance methods which yielded

  4. Antifatigue properties of dragonfly Pantala flavescens wings.

    Li, Xiu-Juan; Zhang, Zhi-Hui; Liang, Yun-Hong; Ren, Lu-Quan; Jie, Meng; Yang, Zhi-Gang


    The wing of a dragonfly is thin and light, but can bear high frequent alternating stress and present excellent antifatigue properties. The surface morphology and microstructure of the wings of dragonfly Pantala flavescens were observed using SEM in this study. Based on the biological analysis method, the configuration, morphology, and structure of the vein were studied, and the antifatigue properties of the wings were investigated. The analytical results indicated that the longitudinal veins, cross veins, and membrane of dragonfly wing form a optimized network morphology and spacially truss-like structure which can restrain the formation and propagation of the fatigue cracks. The veins with multilayer structure present high strength, flexibility, and toughness, which are beneficial to bear alternating load during the flight of dragonfly. Through tensile-tensile fatigue failure tests, the results were verified and indicate that the wings of dragonfly P. flavescens have excellent antifatigue properties which are the results of the biological coupling and synergistic effect of morphological and structural factors.

  5. Elastic deformation and energy loss of flapping fly wings.

    Lehmann, Fritz-Olaf; Gorb, Stanislav; Nasir, Nazri; Schützner, Peter


    During flight, the wings of many insects undergo considerable shape changes in spanwise and chordwise directions. We determined the origin of spanwise wing deformation by combining measurements on segmental wing stiffness of the blowfly Calliphora vicina in the ventral and dorsal directions with numerical modelling of instantaneous aerodynamic and inertial forces within the stroke cycle using a two-dimensional unsteady blade elementary approach. We completed this approach by an experimental study on the wing's rotational axis during stroke reversal. The wing's local flexural stiffness ranges from 30 to 40 nN m(2) near the root, whereas the distal wing parts are highly compliant (0.6 to 2.2 nN m(2)). Local bending moments during wing flapping peak near the wing root at the beginning of each half stroke due to both aerodynamic and inertial forces, producing a maximum wing tip deflection of up to 46 deg. Blowfly wings store up to 2.30 μJ elastic potential energy that converts into a mean wing deformation power of 27.3 μW. This value equates to approximately 5.9 and 2.3% of the inertial and aerodynamic power requirements for flight in this animal, respectively. Wing elasticity measurements suggest that approximately 20% or 0.46 μJ of elastic potential energy cannot be recovered within each half stroke. Local strain energy increases from tip to root, matching the distribution of the wing's elastic protein resilin, whereas local strain energy density varies little in the spanwise direction. This study demonstrates a source of mechanical energy loss in fly flight owing to spanwise wing bending at the stroke reversals, even in cases in which aerodynamic power exceeds inertial power. Despite lower stiffness estimates, our findings are widely consistent with previous stiffness measurements on insect wings but highlight the relationship between local flexural stiffness, wing deformation power and energy expenditure in flapping insect wings.

  6. Principle of bio-inspired insect wing rotational hinge design

    Fei, Fan

    A principle for designing and fabricating bio-inspired miniature artificial insect flapping wing using flexure rotational hinge design is presented. A systematic approach of selecting rotational hinge stiffness value is proposed. Based on the understanding of flapping wing aerodynamics, a dynamic simulation is constructed using the established quasi-steady model and the wing design. Simulations were performed to gain insight on how different parameters affect the wing rotational response. Based on system resonance a model to predict the optimal rotational hinge stiffness based on given wing parameter and flapping wing kinematic is proposed. By varying different wing parameters, the proposed method is shown to be applicable to a wide range of wing designs with different sizes and shapes. With the selected hinge stiffness value, aspects of the rotational joint design is discussed and an integrated wing-hinge structure design using laminated carbon fiber and polymer film is presented. Manufacturing process of such composite structure is developed to achieve high accuracy and repeatability. The yielded hinge stiffness is verified by measurements. To validate the proposed model, flapping wing experiments were conducted. A flapping actuation set up is built using DC motor and a controller is implemented on a microcontroller to track desired wing stroke kinematic. Wing stroke and rotation kinematic were extracted using a high speed camera and the lift generation is evaluated. A total of 49 flapping experiments were presented, experimental data shows good correlation with the model's prediction. With the wing rotational hinge stiffness designed so that the rotational resonant frequency is twice as the stroke frequency, the resulting wing rotation generates near optimal lift. With further simulation, the proposed model shows low sensitivity to wing parameter variation. As a result, giving a design parameter of a flapping wing robot platform, the proposed principle can

  7. Wake development behind paired wings with tip and root trailing vortices: consequences for animal flight force estimates.

    Jan T Horstmann

    Full Text Available Recent experiments on flapping flight in animals have shown that a variety of unrelated species shed a wake behind left and right wings consisting of both tip and root vortices. Here we present an investigation using Particle Image Velocimetry (PIV of the behaviour and interaction of trailing vortices shed by paired, fixed wings that simplify and mimic the wake of a flying animal with a non-lifting body. We measured flow velocities at five positions downstream of two adjacent NACA 0012 aerofoils and systematically varied aspect ratio, the gap between the wings (corresponding to the width of a non-lifting body, angle of attack, and the Reynolds number. The range of aspect ratios and Reynolds number where chosen to be relevant to natural fliers and swimmers, and insect flight in particular. We show that the wake behind the paired wings deformed as a consequence of the induced flow distribution such that the wingtip vortices convected downwards while the root vortices twist around each other. Vortex interaction and wake deformation became more pronounced further downstream of the wing, so the positioning of PIV measurement planes in experiments on flying animals has an important effect on subsequent force estimates due to rotating induced flow vectors. Wake deformation was most severe behind wings with lower aspect ratios and when the distance between the wings was small, suggesting that animals that match this description constitute high-risk groups in terms of measurement error. Our results, therefore, have significant implications for experimental design where wake measurements are used to estimate forces generated in animal flight. In particular, the downstream distance of the measurement plane should be minimised, notwithstanding the animal welfare constraints when measuring the wake behind flying animals.

  8. Developing an Accurate CFD Based Gust Model for the Truss Braced Wing Aircraft

    Bartels, Robert E.


    The increased flexibility of long endurance aircraft having high aspect ratio wings necessitates attention to gust response and perhaps the incorporation of gust load alleviation. The design of civil transport aircraft with a strut or truss-braced high aspect ratio wing furthermore requires gust response analysis in the transonic cruise range. This requirement motivates the use of high fidelity nonlinear computational fluid dynamics (CFD) for gust response analysis. This paper presents the development of a CFD based gust model for the truss braced wing aircraft. A sharp-edged gust provides the gust system identification. The result of the system identification is several thousand time steps of instantaneous pressure coefficients over the entire vehicle. This data is filtered and downsampled to provide the snapshot data set from which a reduced order model is developed. A stochastic singular value decomposition algorithm is used to obtain a proper orthogonal decomposition (POD). The POD model is combined with a convolution integral to predict the time varying pressure coefficient distribution due to a novel gust profile. Finally the unsteady surface pressure response of the truss braced wing vehicle to a one-minus-cosine gust, simulated using the reduced order model, is compared with the full CFD.

  9. Structural Design Exploration of an Electric Powered Multi-Propulsor Wing Configuration

    Moore, James B.; Cutright, Steve


    Advancements in aircraft electric propulsion may enable an expanded operational envelope for electrically powered vehicles compared to their internal combustion engine counterparts. High aspect ratio wings provide additional lift and drag reduction for a proposed multi-propulsor design, however, the challenge is to reduce the weight of wing structures while maintaining adequate structural and aeroelastic margins. Design exploration using a conventional design-and-build philosophy coupled with a finite element method (FEM)-based design of experiments (DOE) strategy are presented to examine high aspect ratio wing structures that have spanwise distributed electric motors. Multiple leading-edge-mounted engine masses presented a challenge to design a wing within acceptable limits for dynamic and aeroelastic stability. Because the first four primary bending eigenmodes of the proposed wing structure are very sensitive to outboard motor placement, safety-of-flight requirements drove the need for multiple spars, rib attachments, and outboard structural reinforcements in the design. Global aeroelasticity became an increasingly important design constraint during the on-going design process, with outboard motor pod flutter ultimately becoming a primary design constraint. Designers successively generated models to examine stress, dynamics, and aeroelasticity concurrently. This research specifically addressed satisfying multi-disciplinary design criteria to generate fluid-structure interaction solution sets, and produced high aspect ratio primary structure designs for the NASA Scalable Convergent Electric Propulsion Technology and Operations Research (SCEPTOR) project in the Aeronautic Research Mission Directorate at NASA. In this paper, a dynamics-driven, quasi-inverse design methodology is presented to address aerodynamic performance goals and structural challenges encountered for the SCEPTOR demonstrator vehicle. These results are compared with a traditional computer aided

  10. A Ratio Scale Measurement of Conformity.

    Beins, Bernard C.; Porter, J. William

    A sensitive technique for assessing conformity on a ratio scale was designed and tested in one group of 18 naive subjects and one group of 20 volunteer subjects, 10 of whom were naive and 10 of whom were informed. All subjects were undergraduates from Thomas More College (New York). The experiment required subjects to observe a line briefly…

  11. Aerodynamics of wings at low Reynolds numbers: Boundary layer separation and reattachment

    McArthur, John

    Due to advances in electronics technology, it is now possible to build small scale flying and swimming vehicles. These vehicles will have size and velocity scales similar to small birds and fish, and their characteristic Reynolds number will be between 104 and 105. Currently, these flying and swimming vehicles do not perform well, and very little research has been done to characterize them, or to explain why they perform so poorly. This dissertation documents three basic investigations into the performance of small scale lifting surfaces, with Reynolds numbers near 104. Part I. Low Reynolds number aerodynamics. Three airfoil shapes were studied at Reynolds numbers of 1 and 2x104: a flat plate airfoil, a circular arc cambered airfoil, and the Eppler 387 airfoil. Lift and drag force measurements were made on both 2D and 3D conditions, with the 3D wings having an aspect ratio of 6, and the 2D condition being approximated by placing end plates at the wing tips. Comparisons to the limited number of previous measurements show adequate agreement. Previous studies have been inconclusive on whether lifting line theory can be applied to this range of Re, but this study shows that lifting line theory can be applied when there are no sudden changes in the slope of the force curves. This is highly dependent on the airfoil shape of the wing, and explains why previous studies have been inconclusive. Part II. The laminar separation bubble. The Eppler 387 airfoil was studied at two higher Reynolds numbers: 3 and 6x10 4. Previous studies at a Reynolds number of 6x104 had shown this airfoil experiences a drag increase at moderate lift, and a subsequent drag decrease at high lift. Previous studies suggested that the drag increase is caused by a laminar separation bubble, but the experiments used to show this were conducted at higher Reynolds numbers and extrapolated down. Force measurements were combined with flow field measurements at Reynolds numbers 3 and 6x104 to determine whether

  12. Aeroelastic Analysis of Modern Complex Wings

    Kapania, Rakesh K.; Bhardwaj, Manoj K.; Reichenbach, Eric; Guruswamy, Guru P.


    A process is presented by which aeroelastic analysis is performed by using an advanced computational fluid dynamics (CFD) code coupled with an advanced computational structural dynamics (CSD) code. The process is demonstrated on an F/A-18 Stabilator using NASTD (an in-house McDonnell Douglas Aerospace East CFD code) coupled with NASTRAN. The process is also demonstrated on an aeroelastic research wing (ARW-2) using ENSAERO (an in-house NASA Ames Research Center CFD code) coupled with a finite element wing-box structures code. Good results have been obtained for the F/A-18 Stabilator while results for the ARW-2 supercritical wing are still being obtained.

  13. Transonic flow theory of airfoils and wings

    Garabedian, P R


    Supercritical wing technology is expected to have a significant influence on the next generation of commercial aircraft. Computational fluid dynamics is playing a central role in the development of new supercritical wing sections. One of the principal tools is a fast and reliable code that simulates two-dimensional wind tunnel data for transonic flow at high Reynolds numbers. This is used widely by industry to assess drag creep and drag rise. Codes for the design of shockless airfoils by the hodograph method have not been so well received because they usually require a lot of trial and error. However, a more advanced mathematical approach makes it possible to assign the pressure as a function of the arc length and then obtain a shockless airfoil that nearly achieves the given distribution of pressure. This tool should enable engineers to design families of transonic airfoils more easily both for airplane wings and for compressor blades in cascade.

  14. Emission line galaxies and active galactic nuclei in WINGS clusters

    Marziani, P.; D'Onofrio, M.; Bettoni, D.; Poggianti, B. M.; Moretti, A.; Fasano, G.; Fritz, J.; Cava, A.; Varela, J.; Omizzolo, A.


    We present the analysis of the emission line galaxies members of 46 low-redshift (0.04 environment is indicated by both a lower frequency, and a systematically lower Balmer emission line equivalent width and luminosity with respect to control samples; this implies a lower amount of ionized gas per unit mass and a lower star formation rate if the source is classified as Hii region. A sizable population of transition objects and of low-luminosity LINERs (≈ 10-20% of all emission line galaxies) are detected among WINGS cluster galaxies. These sources are a factor of ≈1.5 more frequent, or at least as frequent, as in control samples with respect to Hii sources. Transition objects and LINERs in clusters are most affected in terms ofline equivalent width by the environment and appear predominantly consistent with so-called retired galaxies. Shock heating can be a possible gas excitation mechanism that is able to account for observed line ratios. Specific to the cluster environment, we suggest interaction between atomic and molecular gas and the intracluster medium as a possible physical cause of line-emitting shocks. The data whose description is provided in Table B.1, and emission line catalog of the WINGS database are only available at the CDS via anonymous ftp to ( or via

  15. Identification of Nonlinearities in Joints of a Wing Structure

    Sani M.S.M.


    Full Text Available Nonlinear structural identification is essential in engineering. As new materials are being used andstructures become slender and lighter, nonlinear behaviour of structures becomes more important. There have been many studies into the development and application of system identification methods for structural nonlinearity based on changes in natural frequencies, mode shapes and damping ratios. A great challenge is to identify nonlinearity in large structural systems. Much work has been undertaken in the development of nonlinear system identification methods (e.g. Hilbert Transform, NARMAX, and Proper Orthogonal Decomposition, however, it is arguable that most of these methods are cumbersome when applied to realistic large structures that contain mostly linear modes with some local nonlinearity (e.g. aircraft engine pylon attachment to a wing. In this paper, a multi-shaker force appropriation method is developed to determine the underlying linear and nonlinear structural properties through the use of the measurement and generation of restoring force surfaces. One undamped mode is excited in each multi-shaker test. Essentially, this technique is a derivative of the restoring surface method and involves a non-linear curve fitting performed in modal space. A reduced finite element model is established and its effectiveness in revealing the nonlinear characteristics of the system is discussed. The method is demonstrated through both numerical simulations and experiments on a simple jointed laboratory structure with seeded faults, which represents an engine pylon structure that consists of a rectangular wing with two stores suspended underneath.

  16. Wind-induced vibration experiment on solar wing

    Tamura Yukio


    Full Text Available This paper describes wind tunnel experimental results of wind-induced responses of a solar wing system, and investigates its aeroelastic instability using a scaled model. The model comprised 12 solar wing units, each supported by 2 cables. The gaps between units were set constant. Two sag ratios (i.e. sag/span length were adopted. The wind speed was varied from 0 to 16m/s, and 18 different wind speeds were used. From the experiment, when the sag was 2%, a sudden increase in fluctuating displacement was found near a mean wind speed of 10m/s at a wind direction of 40° A sudden increase in fluctuating displacements was also found near a mean wind speed of 1m/s when the wind direction was larger than 60° When the sag increased to 5%, some differences among units in mean displacements were found and complicate vibration in fluctuating displacement at low wind speed was observed.

  17. Decoupler pylon: wing/store flutter suppressor

    Reed, W. H., III (Inventor)


    A device for suspending a store from a support such as an aircraft wing and more specifically for increasing the flutter speed of an aircraft flying with attached store and reducing the sensitivity of flutter to changes in the pitch inertia and center of gravity location of the store is described. It comprises softspring where the store pitch mode is decoupled from support modes and a low frequency active control mechanism which maintains store alignment. A pneumatic suspension system both isolates the store in pitch and, under conditions of changing mean load, aligns the store with the wing to which it is attached.

  18. Spanwise transition section for blended wing-body aircraft

    Hawley, Arthur V. (Inventor)


    A blended wing-body aircraft includes a central body, a wing, and a transition section which interconnects the body and the wing on each side of the aircraft. The two transition sections are identical, and each has a variable chord length and thickness which varies in proportion to the chord length. This enables the transition section to connect the thin wing to the thicker body. Each transition section has a negative sweep angle.

  19. Nonlinear, unsteady aerodynamic loads on rectangular and delta wings

    Atta, E. H.; Kandil, O. A.; Mook, D. T.; Nayfeh, A. H.


    Nonlinear unsteady aerodynamic loads on rectangular and delta wings in an incompressible flow are calculated by using an unsteady vortex-lattice model. Examples include flows past fixed wings in unsteady uniform streams and flows past wings undergoing unsteady motions. The unsteadiness may be due to gusty winds or pitching oscillations. The present technique establishes a reliable approach which can be utilized in the analysis of problems associated with the dynamics and aeroelasticity of wings within a wide range of angles of attack.

  20. Ornithopter type flapping wings for autonomous micro air vehicles


    In this paper, an ornithopter prototype that mimics the flapping motion of bird flight is developed, and the lift and thrust generation characteristics of different wing designs are evaluated. This project focused on the spar arrangement and material used for the wings that could achieves improved performance. Various lift and thrust measurement techniques are explored and evaluated. Various wings of insects and birds were evaluated to understand how these natural flyers with flapping wings a...

  1. Sonic boom focusing prediction and delta wing shape optimization for boom mitigation studies

    Khasdeo, Nitin

    Supersonic travel over land would be a reality if new aircraft are designed such that they produce quieter ground sonic booms, no louder than 0.3 psf according to the FAA requirement. An attempt is made to address the challenging goal of predicting the sonic boom focusing effects and mitigate the sonic boom ground overpressure for delta wing geometry. Sonic boom focusing is fundamentally a nonlinear phenomenon and can be predicted by numerically solving the nonlinear Tricomi equation. The conservative time domain scheme is developed to carry out the sonic boom focusing or super boom studies. The computational scheme is a type differencing scheme and is solved using a time-domain scheme, which is called a conservative type difference solution. The finite volume method is used on a structured grid topology. A number of input signals Concorde wave, symmetric and ax symmetric ramp, flat top and typical N wave type are simulated for sonic boom focusing prediction. A parametric study is launched in order to investigate the effects of several key parameters that affect the magnitude of shock wave amplification and location of surface of amplification or "caustics surface." A parametric studies includes the effects of longitudinal and lateral boundaries, footprint and initial shock strength of incoming wave and type of input signal on sonic boom focusing. Another very important aspect to be looked at is the mitigation strategies of sonic boom ground signature. It has been decided that aerodynamic reshaping and geometrical optimization are the main goals for mitigating the ground signal up to the acceptance level of FAA. Biconvex delta wing geometry with a chord length of 60 ft and maximum thickness ratio of 5% of the chord is used as a base line model to carry out the fundamental research focus. The wing is flying at an altitude 40,000 ft with a Mach number of 2.0. Boom mitigation work is focused on investigating the effects of wing thickness ratio, wing camber ratio, wing

  2. Titanium honeycomb structure. [for supersonic aircraft wing structure

    Davis, R. A.; Elrod, S. D.; Lovell, D. T.


    A brazed titanium honeycomb sandwich system for supersonic transport wing cover panels provides the most efficient structure spanwise, chordwise, and loadwise. Flutter testing shows that high wing stiffness is most efficient in a sandwich structure. This structure also provides good thermal insulation if liquid fuel is carried in direct contact with the wing structure in integral fuel tanks.

  3. How swifts control their glide performance with morphing wings

    Lentink, D.; Muller, U. K.; Stamhuis, E. J.; de Kat, R.; van Gestel, W.; Veldhuis, L. L. M.; Henningsson, P.; Hedenstrom, A.; Videler, J. J.


    Gliding birds continually change the shape and size of their wings(1-6), presumably to exploit the profound effect of wing morphology on aerodynamic performance(7-9). That birds should adjust wing sweep to suit glide speed has been predicted qualitatively by analytical glide models(2,10), which extr

  4. A Wind Tunnel Investigation of Joined Wing Scissor Morphing


    wing stalls when the rear wing stalls [23]. While this improves efficiency it also decreases the wetted area while maintaining the same lifting...Analysis and Optimization on Joined-Wing Configurations. Dir. Dong-Hwan Lee and P. C. Chen. Slide Program. Zona Technology. 2. Bagwill, Tracy L., and

  5. How swifts control their glide performance with morphing wings

    Lentink, D.; Müller, U.K.; Stamhuis, E.J.; Kat, de R.; Gestel, van W.J.H.; Veldhuis, L.L.M.; Henningsson, P.; Hedenström, A.; Videler, J.J.; Leeuwen, van J.L.


    Gliding birds continually change the shape and size of their wings1, 2, 3, 4, 5, 6, presumably to exploit the profound effect of wing morphology on aerodynamic performance7, 8, 9. That birds should adjust wing sweep to suit glide speed has been predicted qualitatively by analytical glide models2, 10

  6. Nacelle/pylon interference study on a 1/17th-scale, twin-engine, low-wing transport model

    Pendergraft, Odis C., Jr.; Ingraldi, Anthony M.; Re, Richard J.; Kariya, Timmy T.


    NASA-Langley has conducted wind tunnel tests of a twin-engine, low-wing transport aircraft configuration with 10.8-aspect ratio supercritical wing, in order to ascertain and compare the wing/nacelle interference effects of through-flow nacelled simulating 'superfan' very high bypass ratio (BPR=20) turbofans and current-technology (BPR=6) turbofans. Measurements of model forces and moments have been obtained, together with extensive external static pressure measurement on the model's wings, nacelles, and pylons in the Mach 0.5-0.8 range, at angles of attack in the -4 to +8 deg range. The superfan nacelles exhibit a significant advantage over current-technology turbofan nacelles, when the superfan's SFC gains are taken into account.

  7. The costae presenting in high-temperature-induced vestigial wings of Drosophila: implications for anterior wing margin formation

    Daxiang Yang


    It has long been noted that high temperature produces great variation in wing forms of the vestigial mutant of Drosophila. Most of the wings have defects in the wing blade and partially formed wing margin, which are the result of autonomous cell death in the presumptive wing blade or costal region of the wing disc. The vestigial gene ($vg$) and the interaction of Vg protein with other gene products are well understood. With this biochemical knowledge, reinvestigations of the high-temperature-induced vestigial wings and the elucidation of the molecular mechanism underlying the large-scale variation of the wing forms may provide insight into further understanding of development of the wing of Drosophila. As a first step of such explorations, I examined high-temperature-induced (29°C) vestigial wings. In the first part of this paper, I provide evidences to show that the proximal and distal costae in these wings exhibit regular and continuous variation, which suggests different developmental processes for the proximal and distal costal sections. Judging by the costae presenting in the anterior wing margin, I propose that the proximal and distal costal sections are independent growth units. The genes that regulate formation of the distal costal section also strongly affect proliferation of cells nearby; however, the same phenomenon has not been found in the proximal costal section. The distal costal section seems to be an extension of the radius vein. vestigial, one of the most intensely researched temperature-sensitive mutations, is a good candidate for the study of marginal vein formation. In the second part of the paper, I regroup the wing forms of these wings, chiefly by comparison of venation among these wings, and try to elucidate the variation of the wing forms according to the results of previous work and the conclusions reached in the first part of this paper, and provide clues for further researches.

  8. Wind tunnel tests for a flapping wing model with a changeable camber using macro-fiber composite actuators

    Kim, Dae-Kwan; Han, Jae-Hung; Kwon, Ki-Jung


    In the present study, a biomimetic flexible flapping wing was developed on a real ornithopter scale by using macro-fiber composite (MFC) actuators. With the actuators, the maximum camber of the wing can be linearly changed from -2.6% to +4.4% of the maximum chord length. Aerodynamic tests were carried out in a low-speed wind tunnel to investigate the aerodynamic characteristics, particularly the camber effect, the chordwise flexibility effect and the unsteady effect. Although the chordwise wing flexibility reduces the effective angle of attack, the maximum lift coefficient can be increased by the MFC actuators up to 24.4% in a static condition. Note also that the mean values of the perpendicular force coefficient rise to a value of considerably more than 3 in an unsteady aerodynamic flow region. Additionally, particle image velocimetry (PIV) tests were performed in static and dynamic test conditions to validate the flexibility and unsteady effects. The static PIV results confirm that the effective angle of attack is reduced by the coupling of the chordwise flexibility and the aerodynamic force, resulting in a delay in the stall phenomena. In contrast to the quasi-steady flow condition of a relatively high advance ratio, the unsteady aerodynamic effect due to a leading edge vortex can be found along the wing span in a low advance ratio region. The overall results show that the chordwise wing flexibility can produce a positive effect on flapping aerodynamic characteristics in quasi-steady and unsteady flow regions; thus, wing flexibility should be considered in the design of efficient flapping wings.

  9. Aerodynamic Interactions Between Contralateral Wings and Between Wings and Body of a Model Insect at Hovering and Small Speed Motions

    LIANG Bin; SUN Mao


    In this paper,we study the aerodynamic interactions between the contralateral wings and between the body and wings of a model insect,when the insect is hovering and has various translational and rotational motions,using the method numerically solving the Navier-Stokes equations over moving overset grids.The aerodynamic interactional effects are identified by comparing the results of a complete model insect,the corresponding wing pair,single wing and body without the wings.Horizontal,vertical and lateral translations and roll,pitch and yaw rotations at small speeds are considered.The results indicate that for the motions considered,both the interaction between the contralateral wings and the interaction between the body and wings are weak.The changes in the forces and moments of a wing due to the contralateral wing interaction,of the wings due to the presence of the body,and of the body due to the presence of the wings are generally less than 4.5%.Results show that aerodynamic forces of wings and body can be measured or computed separately in the analysis of flight stability and control of hovering insects.

  10. Aerodynamic comparison of a butterfly-like flapping wing-body model and a revolving-wing model

    Suzuki, Kosuke; Yoshino, Masato


    The aerodynamic performance of flapping- and revolving-wing models is investigated by numerical simulations based on an immersed boundary-lattice Boltzmann method. As wing models, we use (i) a butterfly-like model with a body and flapping-rectangular wings and (ii) a revolving-wing model with the same wings as the flapping case. Firstly, we calculate aerodynamic performance factors such as the lift force, the power, and the power loading of the two models for Reynolds numbers in the range of 50-1000. For the flapping-wing model, the power loading is maximal for the maximum angle of attack of 90°, a flapping amplitude of roughly 45°, and a phase shift between the flapping angle and the angle of attack of roughly 90°. For the revolving-wing model, the power loading peaks for an angle of attack of roughly 45°. In addition, we examine the ground effect on the aerodynamic performance of the revolving-wing model. Secondly, we compare the aerodynamic performance of the flapping- and revolving-wing models at their respective maximal power loadings. It is found that the revolving-wing model is more efficient than the flapping-wing model both when the body of the latter is fixed and where it can move freely. Finally, we discuss the relative agilities of the flapping- and revolving-wing models.

  11. Fiber-optically sensorized composite wing

    Costa, Joannes M.; Black, Richard J.; Moslehi, Behzad; Oblea, Levy; Patel, Rona; Sotoudeh, Vahid; Abouzeida, Essam; Quinones, Vladimir; Gowayed, Yasser; Soobramaney, Paul; Flowers, George


    Electromagnetic interference (EMI) immune and light-weight, fiber-optic sensor based Structural Health Monitoring (SHM) will find increasing application in aerospace structures ranging from aircraft wings to jet engine vanes. Intelligent Fiber Optic Systems Corporation (IFOS) has been developing multi-functional fiber Bragg grating (FBG) sensor systems including parallel processing FBG interrogators combined with advanced signal processing for SHM, structural state sensing and load monitoring applications. This paper reports work with Auburn University on embedding and testing FBG sensor arrays in a quarter scale model of a T38 composite wing. The wing was designed and manufactured using fabric reinforced polymer matrix composites. FBG sensors were embedded under the top layer of the composite. Their positions were chosen based on strain maps determined by finite element analysis. Static and dynamic testing confirmed expected response from the FBGs. The demonstrated technology has the potential to be further developed into an autonomous onboard system to perform load monitoring, SHM and Non-Destructive Evaluation (NDE) of composite aerospace structures (wings and rotorcraft blades). This platform technology could also be applied to flight testing of morphing and aero-elastic control surfaces.

  12. Applications of a transonic wing design method

    Campbell, Richard L.; Smith, Leigh A.


    A method for designing wings and airfoils at transonic speeds using a predictor/corrector approach was developed. The procedure iterates between an aerodynamic code, which predicts the flow about a given geometry, and the design module, which compares the calculated and target pressure distributions and modifies the geometry using an algorithm that relates differences in pressure to a change in surface curvature. The modular nature of the design method makes it relatively simple to couple it to any analysis method. The iterative approach allows the design process and aerodynamic analysis to converge in parallel, significantly reducing the time required to reach a final design. Viscous and static aeroelastic effects can also be accounted for during the design or as a post-design correction. Results from several pilot design codes indicated that the method accurately reproduced pressure distributions as well as the coordinates of a given airfoil or wing by modifying an initial contour. The codes were applied to supercritical as well as conventional airfoils, forward- and aft-swept transport wings, and moderate-to-highly swept fighter wings. The design method was found to be robust and efficient, even for cases having fairly strong shocks.

  13. Conceptual Study of Rotary-Wing Microrobotics


    xx  I.  Introduction ...Edge TPV Thermo-Photovoltaic CONCEPTUAL STUDY OF ROTARY-WING MICROROBOTICS I. Introduction Flying micro-robots offer unimaginable military...Tweezers 1989 1 cm3 inch robot 1991 Magnetostrictive mover in pipe 1992 Insect-based robot 1993 Ciliary-motion conveyor 1994 Pipe inspection robot

  14. Mother Nature inspires new wind turbine wing

    Sønderberg Petersen, L.


    The sight of a bird of prey hanging immobile in the air while its wings continuously adjust themselves slightly in relation to the wind in order to keep the bird in the same position in the air, is a sight that most of us have admired, including the windenergy scientists at Risø DTU. They have st...

  15. Can Wing Tip Vortices Be Accurately Simulated?


    additional tail buffeting.2 In commercial applications, winglets have been installed on passenger aircraft to minimize vortex formation and reduce lift...air. In military applications, wing tip In commercial applications, winglets have been installed on passenger aircraft to minimize increases with downstream distances.

  16. Hybrid Wing Body Configuration Scaling Study

    Nickol, Craig L.


    The Hybrid Wing Body (HWB) configuration is a subsonic transport aircraft concept with the potential to simultaneously reduce fuel burn, noise and emissions compared to conventional concepts. Initial studies focused on very large applications with capacities for up to 800 passengers. More recent studies have focused on the large, twin-aisle class with passenger capacities in the 300-450 range. Efficiently scaling this concept down to the single aisle or smaller size is challenging due to geometric constraints, potentially reducing the desirability of this concept for applications in the 100-200 passenger capacity range or less. In order to quantify this scaling challenge, five advanced conventional (tube-and-wing layout) concepts were developed, along with equivalent (payload/range/technology) HWB concepts, and their fuel burn performance compared. The comparison showed that the HWB concepts have fuel burn advantages over advanced tube-and-wing concepts in the larger payload/range classes (roughly 767-sized and larger). Although noise performance was not quantified in this study, the HWB concept has distinct noise advantages over the conventional tube-and-wing configuration due to the inherent noise shielding features of the HWB. NASA s Environmentally Responsible Aviation (ERA) project will continue to investigate advanced configurations, such as the HWB, due to their potential to simultaneously reduce fuel burn, noise and emissions.

  17. Migration on Wings Aerodynamics and Energetics

    Kantha, Lakshmi


    This book is an effort to explore the technical aspects associated with bird flight and migration on wings. After a short introduction on the birds migration, the book reviews the aerodynamics and Energetics of Flight and presents the calculation of the Migration Range. In addition, the authors explains aerodynamics of the formation flight and finally introduces great flight diagrams.

  18. Topology Optimization of an Aircraft Wing


    baseline products were built in Solidworks prior to the optimization process. Loading on the wing was applied for multiple aerodynamic profiles generating...redesign and placement of the fuel tank was desired. A simple model of the baseline tank was built in Solidworks to estimate the total volume. Overall

  19. Prevention of wing rock motion for lightly damped aircraft in lateral-directional dynamics

    Emad N.Abdulwahab; CHEN Hong-quan


    Based on the Ricatti technique,the methodology for preventing the limit cycle accomplished by adding a control function to the original equation of wing rock motion is presented in this paper.To analyze the state variables of the system,the complete set of nonlinear equations of motion including an effective linear control function was solved for A-4D and Mig-21 Aircraft.The roll angle responding to the linear control function for both models was estimated when the systems were tested under different damping ratios.The numerical results show that a linear control function including both the roll attitude and the roll rate is sufficient to suppress the wing rock motion with an acceptable error in desired time.A good agreement between the numerical results and the published work is obtained for the limit cycle oscillation existence at different damping ratios.

  20. On the shape optimization of flapping wings and their performance analysis

    Ghommem, Mehdi


    The present work is concerned with the shape optimization of flapping wings in forward flight. The analysis is performed by combining a gradient-based optimizer with the unsteady vortex lattice method (UVLM). We describe the UVLM simulation procedure and provide the first methodology to select properly the mesh and time-step sizes to achieve invariant UVLM simulation results under mesh refinement. Our objective is to identify a set of optimized shapes that maximize the propulsive efficiency, defined as the ratio of the propulsive power over the aerodynamic power, under lift, thrust, and area constraints. Several parameters affecting flight performance are investigated and their impact is described. These include the wingÊ1/4s aspect ratio, camber line, and curvature of the leading and trailing edges. This study provides guidance for shape design of engineered flying systems. © 2013 Elsevier Masson SAS.

  1. First `Winged' and `X'-shaped Radio Source Candidates

    Cheung, C.C.


    A small number of double-lobed radio galaxies (17 from our own census of the literature) show an additional pair of low surface brightness ''wings'', thus forming an overall ''X''-shaped appearance. The origin of the wings in these radio sources is unclear. They may be the result of back-flowing plasma from the currently active radio lobes into an asymmetric medium surrounding the active nucleus, which would make these ideal systems in which to study thermal/non-thermal plasma interactions in extragalactic radio sources. Another possibility is that the wings are the aging radio lobes left over after a (rapid) realignment of the central supermassive black-hole/accretion disk system due perhaps to a merger. Generally, these models are not well tested; with the small number of known examples, previous works focused on detailed case studies of selected sources with little attempt at a systematic study of a large sample. Using the VLA-FIRST survey database, we are compiling a large sample of winged and X-shaped radio sources for such studies. As a first step toward this goal, an initial sample of 100 new candidate objects of this type are presented in this paper. The search process is described, optical identifications from available literature data, and basic radio data are presented. From the limited resolution FIRST images ({approx} 5''), we can already confidently classify a sufficient number of these objects as having the characteristic wing lengths >80% of the active lobes to more than double the number of known X-shaped radio sources. We have also included as candidates, radio sources with shorter wings (<80% wing to lobe length ratios), or simply ''winged'' sources, as it is probable that projection effects are important. Finally, among the candidates are four quasars (z=0.37 to 0.84), and several have morphologies suggestive of Fanaroff-Riley type-I (low-power) radio galaxies. While followup

  2. Design of a high altitude long endurance flying-wing solar-powered unmanned air vehicle

    Alsahlani, A. A.; Johnston, L. J.; Atcliffe, P. A.


    The low-Reynolds number environment of high-altitude §ight places severe demands on the aerodynamic design and stability and control of a high altitude, long endurance (HALE) unmanned air vehicle (UAV). The aerodynamic efficiency of a §ying-wing configuration makes it an attractive design option for such an application and is investigated in the present work. The proposed configuration has a high-aspect ratio, swept-wing planform, the wing sweep being necessary to provide an adequate moment arm for outboard longitudinal and lateral control surfaces. A design optimization framework is developed under a MATLAB environment, combining aerodynamic, structural, and stability analysis. Low-order analysis tools are employed to facilitate efficient computations, which is important when there are multiple optimization loops for the various engineering analyses. In particular, a vortex-lattice method is used to compute the wing planform aerodynamics, coupled to a twodimensional (2D) panel method to derive aerofoil sectional characteristics. Integral boundary-layer methods are coupled to the panel method in order to predict §ow separation boundaries during the design iterations. A quasi-analytical method is adapted for application to flyingwing con¦gurations to predict the wing weight and a linear finite-beam element approach is used for structural analysis of the wing-box. Stability is a particular concern in the low-density environment of high-altitude flight for flying-wing aircraft and so provision of adequate directional stability and control power forms part of the optimization process. At present, a modified Genetic Algorithm is used in all of the optimization loops. Each of the low-order engineering analysis tools is validated using higher-order methods to provide con¦dence in the use of these computationally-efficient tools in the present design-optimization framework. This paper includes the results of employing the present optimization tools in the design of a

  3. Constructal Theory and Aeroelastic Design of Flexible Flying Wing Aircraft

    Pezhman Mardanpour


    Full Text Available The aeroelastic behavior of high-aspect-ratio very flexible flying wing is highly affected by the geometric nonlinearities of the aircraft structure. This paper reviews the findings on how these nonlinearities influence the structural and flight dynamics, and it shows that the aeroelastic flight envelope could significantly be extended with proper choices of design parameters such as engine placement. Moreover, in order to investigate the physics behind the effects of design parameters, constructal theory of design is reviewed. The constructal theory advances the philosophy of design as science, it states that the better structural design emerges when stress flow strangulation is avoided. Furthermore, it shows that airplanes, through their evolution, have obeyed theoretical allometric rules that unite their designs.

  4. Aeroelastic Tailoring of a Plate Wing with Functionally Graded Materials

    Dunning, Peter D.; Stanford, Bret K.; Kim, H. Alicia; Jutte, Christine V.


    This work explores the use of functionally graded materials for the aeroelastic tailoring of a metallic cantilevered plate-like wing. Pareto trade-off curves between dynamic stability (flutter) and static aeroelastic stresses are obtained for a variety of grading strategies. A key comparison is between the effectiveness of material grading, geometric grading (i.e., plate thickness variations), and using both simultaneously. The introduction of material grading does, in some cases, improve the aeroelastic performance. This improvement, and the physical mechanism upon which it is based, depends on numerous factors: the two sets of metallic material parameters used for grading, the sweep of the plate, the aspect ratio of the plate, and whether the material is graded continuously or discretely.

  5. Aircraft energy efficiency laminar flow control wing design study

    Bonner, T. F., Jr.; Pride, J. D., Jr.; Fernald, W. W.


    An engineering design study was performed in which laminar flow control (LFC) was integrated into the wing of a commercial passenger transport aircraft. A baseline aircraft configuration was selected and the wing geometry was defined. The LFC system, with suction slots, ducting, and suction pumps was integrated with the wing structure. The use of standard aluminum technology and advanced superplastic formed diffusion bonded titanium technology was evaluated. The results of the design study show that the LFC system can be integrated with the wing structure to provide a structurally and aerodynamically efficient wing for a commercial transport aircraft.

  6. Diagnosis of Wing Icing Through Lift and Drag Coefficient Change Detection for Small Unmanned Aircraft

    Sørensen, Kim Lynge; Blanke, Mogens; Johansen, Tor Arne


    This paper address the issue of structural change, caused by ice accretion, on UAVs by utilising a Neyman Pearson (NP) based statistical change detection approach, for the identification of structural changes of fixed wing UAV airfoils. A structural analysis is performed on the nonlinear aircraft...... system and residuals are generated, where a generalised likelihood ratio test is applied to detect faults. Numerical simulations demonstrate a robust detection with adequate balance between false alarm rate and sensitivity....

  7. Large capacity oblique all-wing transport aircraft

    Galloway, Thomas L.; Phillips, James A.; Kennelly, Robert A., Jr.; Waters, Mark H.


    Dr. R. T. Jones first developed the theory for oblique wing aircraft in 1952, and in subsequent years numerous analytical and experimental projects conducted at NASA Ames and elsewhere have established that the Jones' oblique wing theory is correct. Until the late 1980's all proposed oblique wing configurations were wing/body aircraft with the wing mounted on a pivot. With the emerging requirement for commercial transports with very large payloads, 450-800 passengers, Jones proposed a supersonic oblique flying wing in 1988. For such an aircraft all payload, fuel, and systems are carried within the wing, and the wing is designed with a variable sweep to maintain a fixed subsonic normal Mach number. Engines and vertical tails are mounted on pivots supported from the primary structure of the wing. The oblique flying wing transport has come to be known as the Oblique All-Wing (OAW) transport. This presentation gives the highlights of the OAW project that was to study the total concept of the OAW as a commercial transport.

  8. Multiple cues for winged morph production in an aphid metacommunity.

    Mohsen Mehrparvar

    Full Text Available Environmental factors can lead individuals down different developmental pathways giving rise to distinct phenotypes (phenotypic plasticity. The production of winged or unwinged morphs in aphids is an example of two alternative developmental pathways. Dispersal is paramount in aphids that often have a metapopulation structure, where local subpopulations frequently go extinct, such as the specialized aphids on tansy (Tanacetum vulgare. We conducted various experiments to further understand the cues involved in the production of winged dispersal morphs by the two dominant species of the tansy aphid metacommunity, Metopeurum fuscoviride and Macrosiphoniella tanacetaria. We found that the ant-tended M. fuscoviride produced winged individuals predominantly at the beginning of the season while the untended M. tanacetaria produced winged individuals throughout the season. Winged mothers of both species produced winged offspring, although in both species winged offspring were mainly produced by unwinged females. Crowding and the presence of predators, effects already known to influence wing production in other aphid species, increased the percentage of winged offspring in M. tanacetaria, but not in M. fuscoviride. We find there are also other factors (i.e. temporal effects inducing the production of winged offspring for natural aphid populations. Our results show that the responses of each aphid species are due to multiple wing induction cues.

  9. Numerical study of aerodynamic characteristics of FSW aircraft with dierent wing positions under supersonic condition

    Lei Juanmian; Zhao Shuai; Wang Suozhu


    This paper investigates the influence of forward-swept wing (FSW) positions on the aero-dynamic characteristics of aircraft under supersonic condition (Ma=1.5). The numerical method based on Reynolds-averaged Navier–Stokes (RANS) equations, Spalart–Allmaras (S–A) turbu-lence model and implicit algorithm is utilized to simulate the flow field of the aircraft. The aerody-namic parameters and flow field structures of the horizontal tail and the whole aircraft are presented. The results demonstrate that the spanwise flow of FSW flows from the wingtip to the wing root, generating an upper wing surface vortex and a trailing edge vortex nearby the wing root. The vortexes generated by FSW have a strong downwash effect on the tail. The lower the vertical position of FSW, the stronger the downwash effect on tail. Therefore, the effective angle of attack of tail becomes smaller. In addition, the lift coefficient, drag coefficient and lift–drag ratio of tail decrease, and the center of pressure of tail moves backward gradually. For the whole aircraft, the lower the vertical position of FSW, the smaller lift, drag and center of pressure coefficients of aircraft. The closer the FSW moves towards tail, the bigger pitching moment and center of pres-sure coefficients of the whole aircraft, but the lift and drag characteristics of the horizontal tail and the whole aircraft are basically unchanged. The results have potential application for the design of new concept aircraft.

  10. A Wing-Shaped Captive Balloon for Observation in Urban Area

    Nakamura, M.; Ono, K.; Sakai, S.


    Many meteorological observations in urban area are made in recent years in order to investigate the mechanism of heat island. For this purpose, high density observations in both space and time are required. Generally vertical meteorological observations can be made by towers, radars, balloons. Among these methods, Captive balloons are the easiest way to make observations especially in urban area. Conventional balloons are, however, influenced by the wind and difficult to keep the specified position. Moreover, it can be dangerous to conduct such observations in the highly build-up area. To overcome these difficulties, we are developing a new type of captive balloon. It has a wing form to gain lift and keep its position. It is also designed small to be kept in a carport. The wing form NACA4424 is adopted to minimize the drag force. This wing form is, however, rather thin and does not have enough volume to hold helium gas for floatation. To boost up the floatation, two gasbags with an airship form are installed at the ends of the wing.To check the aerodynamical properties of the balloon, we made wind tunnel test with 1/10 model of it. It shows that maximum lift/drag ratio is 5, which is enough large to keep balloon height, even when the large gasbags are installed. These results are enough to gain the lift and certify to achieve our aims.

  11. Vorticity Confinement Applied to Turbulent Wing Tip Vortices for Wake-Integral Drag Prediction

    Pierson, Kristopher; Povitsky, Alex


    In the current study the vorticity confinement (VC) approach was applied to tip vortices shed by edges of stationary wings in order to predict induced drag by far-field integration in Trefftz plane. The VC parameter was evaluated first by application to convection of vortices in 2-D uniform flow and then to tip vortices shed in 3-D simulation of finite-aspect ratio rectangular wing in subsonic flight. Dependence of VC parameter on the flight Mach number and the angle of attack was evaluated. The aerodynamic drag results with application of VC to prevent numerical diffusion are much closer to analytic lifting line theory compared to integration over surface of wing while the viscous profile drag is more accurately evaluated by surface integration. To apply VC to viscous and turbulent flows, it is shown that VC does not affect the physical rate of dissipation of vortices in viscous/turbulent flows at time scales corresponding to convection of vortices from the wing to Trefftz plane of integration. To account for turbulent effects on tip vortices, VC was applied in combination with Spalart-Allmaras, k- ɛ, and six Reynolds stresses models of turbulence. The results are compared to experiments to validate the physical dissipation of tip vortex. This research was supported by The Dayton Area Graduate Studies Institute (DAGSI) and US Air Force Research Laboratory (AFRL) grants in 2009-2013, US Army Research Office (ARO) in 2012-2013 and ASEE/AFRL summer faculty grant.

  12. Polymer based flapping-wing robotic insect: Progress in design, fabrication, and characterization

    Bontemps, A.; Vanneste, T.; Soyer, C.; Paquet, J. B.; Grondel, S.; Cattan, E.


    In the last decade, many researchers pursued the development of tiny flying robots inspired by natural flyers destined for the exploration of confined spaces, for example. Within this context, our main objective is to devise a flying robot bioinspired from insect in terms of size and wing kinematics using MEMS technologies. For this purpose, an original design has been developed around resonant thorax and wings by the way of an indirect actuation and a concise transmission whereas the all-polymer prototypes are obtained using a micromachining SU-8 photoresist process. This paper reports our recent progress on the design of a flapping-wing robotic insect as well as on the characterization of its performance. Prototypes with a wingspan of 3 cm and a mass of 22 mg are achieved. Due to the introduction of an innovative compliant link, large and symmetrical bending angles of 70° are obtained at a flapping frequency of 30 Hz along with passive wing torsion while minimizing its energy expenditure. Furthermore, it leads to a mean lift force representing up to 75 % of the prototype weight as measured by an in-house force sensor. Different improvements are currently underway to increase the power-to-weight ratio of the prototype and to obtain an airborne prototype.

  13. REML estimates of genetic parameters of sexual dimorphism for wing and thorax length in Drosophila melanogaster

    Sandrine Mignon-Grasteau; Jean David; Patricia Gibert; Hélène Legout; Georges Pétavy; Brigitte Moreteau; Catherine Beaumont


    Restricted maximum likelihood was used to estimate genetic parameters of male and female wing and thorax length in isofemale lines of Drosophila melanogaster, and results compared to estimates obtained earlier with the classical analysis of variance approach. As parents within an isofemale line were unknown, a total of 500 parental pedigrees were simulated and mean estimates computed. Full and half sibs were distinguished, in contrast to usual isofemale studies in which animals were all treated as half sibs and hence heritability was overestimated. Heritability was thus estimated at 0.33, 0.38, 0.30 and 0.33 for male and female wing length and male and female thorax length, respectively, whereas corresponding estimates obtained using analysis of variance were 0.46, 0.54, 0.35 and 0.38. Genetic correlations between male and female traits were 0.85 and 0.62 for wing and thorax length, respectively. Sexual dimorphism and the ratio of female to male traits were moderately heritable (0.30 and 0.23 for wing length, 0.38 and 0.23 for thorax length). Both were moderately and positively correlated with female traits, and weakly and negatively correlated with male traits. Such heritabilities confirmed that sexual dimorphism might be a fast evolving trait in Drosophila.

  14. Fixed membrane wings for micro air vehicles: Experimental characterization, numerical modeling, and tailoring

    Stanford, Bret; Ifju, Peter; Albertani, Roberto; Shyy, Wei


    Fixed wing micro air vehicles (wingspan between 10 and 15 cm) are aerodynamically challenging due to the low Reynolds number regime (10 4-10 5) they operate in. The low aspect ratio wings (typically used to maximize area under a size constraint) promote strong tip vortices, and are susceptible to rolling instabilities. Wind gusts can be of the same order of magnitude as the flight speed (10-15 m/s). Standard control surfaces on an empennage must be eliminated for size considerations and drag reduction, and the range of stable center of gravity locations is only a few millimeters long. Membrane aeroelasticity has been identified as a tenable method to alleviate these issues: flexible wing structures with geometric twist (adaptive washout for gust rejection, delayed stall) and aerodynamic twist (adaptive inflation for high lift, larger stability margins) are both considered here. Recent investigations in static aeroelastic characterization, including flight loads, wing deformation, flow structures, aeroelastic-tailoring studies through laminate orientation, as well as unconventional techniques based on membrane pre-tension, are reviewed. Multi-objective optimization aimed at improving lift, drag, and pitching moment considerations is also discussed.

  15. Mimicking unfolding motion of a beetle hind wing

    MUHAMMAD Azhar; PARK Hoon C; HWANG Do Y; BYUN Doyoung; GOO Nam S


    This paper presents an experimental research aiming to realize an artificial hind wing that can mimic the wing unfolding motion of Allomyrina dichotoma, an insect in coleopteran order. Based on the understanding of working principles of beetle wing folding/unfolding mechanisms, the hind wing unfolding motion is mimicked by a combination of creative ideas and state-of-art artificial muscle actuator. In this work, we devise two types of artificial wings and the successfully demonstrate that they can be unfolded by actuation of shape memory alloy wires to provide actuation force at the wing base and along the leading edge vein. The folding/unfolding mechanisms may provide an insight for portable nano/micro air vehicles with morphing wings.

  16. Preliminary study of effects of winglets on wing flutter

    Doggett, R. V., Jr.; Farmer, M. G.


    Some experimental flutter results are presented over a Mach number range from about 0.70 to 0.95 for a simple, swept, tapered, flat-plate wing model having a planform representative of subsonic transport airplanes and for the same wing model equipped with two different upper surface winglets. Both winglets had the same planform and area (about 2 percent of the basic-wing area); however, one weighed about 0.3 percent of the basic-wing weight, and the other weighed about 1.8 percent of the wing weight. The addition of the lighter winglet reduced the wing-flutter dynamic pressure by about 3 percent; the heavier winglet reduced the wing-flutter dynamic pressure by about 12 percent. The experimental flutter results are compared at a Mach number of 0.80 with analytical flutter results obtained by using doublet-lattice and lifting-surface (kernel-function) unsteady aerodynamic theories.

  17. Exploratory flight investigation of aircraft response to the wing vortex wake generated by the augmentor wing jet STOL research aircraft

    Jacobsen, R. A.; Drinkwater, F. J., III


    A brief exploratory flight program was conducted at Ames Research Center to investigate the vortex wake hazard of a powered-lift STOL aircraft. The study was made by flying an instrumented Cessna 210 aircraft into the wake of the augmentor wing jet STOL research aircraft at separation distances from 1 to 4 n.mi. Characteristics of the wake were evaluated in terms of the magnitude of the upset of the probing aircraft. Results indicated that within 1 n.mi. separation the wake could cause rolling moments in excess of roll control power and yawing moments equivalent to rudder control power of the probe aircraft. Subjective evaluations by the pilots of the Cessna 210 aircraft, supported by response measurements, indicated that the upset caused by the wake of the STOL aircraft was comparable to that of a DC-9 in the landing configuration.

  18. Preliminary study of a large span-distributed-load flying-wing cargo airplane concept

    Jernell, L. S.


    An aircraft capable of transporting containerized cargo over intercontinental distances is analyzed. The specifications for payload weight, density, and dimensions in essence configure the wing and establish unusually low values of wing loading and aspect ratio. The structural weight comprises only about 18 percent of the design maximum gross weight. Although the geometric aspect ratio is 4.53, the winglet effect of the wing-tip-mounted vertical tails, increase the effective aspect ratio to approximately 7.9. Sufficient control power to handle the large rolling moment of inertia dictates a relatively high minimum approach velocity of 315 km/hr (170 knots). The airplane has acceptable spiral, Dutch roll, and roll-damping modes. A hardened stability augmentation system is required. The most significant noise source is that of the airframe. However, for both take-off and approach, the levels are below the FAR-36 limit of 108 db. The design mission fuel efficiency is approximately 50 percent greater than that of the most advanced, currently operational, large freighter aircraft. The direct operating cost is significantly lower than that of current freighters, the advantage increasing as fuel price increases.

  19. Leading-edge vortex burst on a low-aspect-ratio rotating flat plate

    Medina, Albert; Jones, Anya R.


    This study experimentally investigates the phenomenon of leading-edge-vortex burst on rotating flat plate wings. An aspect-ratio-2 wing was driven in pure rotation at a Reynolds number of Re=2500 . Of primary interest is the evolution of the leading-edge vortex along the wing span over a single-revolution wing stroke. Direct force measurements of the lift produced by the wing revealed a single global lift maximum relatively early in the wing stroke. Stereoscopic particle image velocimetry was applied to several chordwise planes to quantify the structure and strength of the leading-edge vortex and its effect on lift production. This analysis revealed opposite-sign vorticity entrainment into the core of the leading-edge vortex, originating from a layer of secondary vorticity along the wing surface. Coincident with the lift peak, there emerged both a concentration of opposite vorticity in the leading-edge-vortex core, as well as axial flow stagnation within the leading-edge-vortex core. Planar control volume analysis was performed at the midspan to quantify the contributions of vorticity transport mechanisms to the leading-edge-vortex circulation. The rate of circulation annihilation by opposite-signed vorticity entrainment was found to be minimal during peak lift production, where convection balanced the flux of vorticity resulting in stagnation and eventually reversal of axial flow. Finally, vortex burst was found to be correlated with swirl number, where bursting occurs at a swirl threshold of Sw<0.6 .

  20. Core and Wing Densities of Asymmetric Coronal Spectral Profiles: Implications for the Mass Supply of the Solar Corona

    Patsourakos, S.; Klimchuk, J. A.; Young, P. R.


    Recent solar spectroscopic observations have shown that coronal spectral lines can exhibit asymmetric profiles, with enhanced emissions at their blue wings. These asymmetries correspond to rapidly upflowing plasmas at speeds exceeding approximately equal to 50 km per sec. Here, we perform a study of the density of the rapidly upflowing material and compare it with that of the line core that corresponds to the bulk of the plasma. For this task, we use spectroscopic observations of several active regions taken by the Extreme Ultraviolet Imaging Spectrometer of the Hinode mission. The density sensitive ratio of the Fe(sub XIV) lines at 264.78 and 274.20 Angstroms is used to determine wing and core densities.We compute the ratio of the blue wing density to the core density and find that most values are of order unity. This is consistent with the predictions for coronal nanoflares if most of the observed coronal mass is supplied by chromospheric evaporation driven by the nanoflares. However, much larger blue wing-to-core density ratios are predicted if most of the coronal mass is supplied by heated material ejected with type II spicules. Our measurements do not rule out a spicule origin for the blue wing emission, but they argue against spicules being a primary source of the hot plasma in the corona. We note that only about 40% of the pixels where line blends could be safely ignored have blue wing asymmetries in both Fe(sub XIV) lines. Anticipated sub-arcsecond spatial resolution spectroscopic observations in future missions could shed more light on the origin of blue, red, and mixed asymmetries.

  1. Use of wing morphometrics to identify populations of the Old World screwworm fly, Chrysomya bezziana (Diptera: Calliphoridae): a preliminary study of the utility of museum specimens.

    Hall, M J R; MacLeod, N; Wardhana, A H


    The Old World screwworm (OWS) fly, Chrysomya bezziana (Diptera: Calliphoridae), is a major economic and welfare problem for humans and animals in the Old World tropics. Using a bootstrapped log likelihood ratio test of the output of Procrustes principal components and canonical variates analyses for a small sample of museum specimens from which 19 2D wing landmarks had been collected: (1) a consistent and statistically significant difference exists between landmark configurations derived from wings of pinned specimens and those removed from the body and mounted on slides; (2) a highly statistically significant sexual dimorphism in wing morphometry was identified; and (3) a highly statistically significant difference in wing morphometry between populations of the OWS fly from Africa (Tanzania, South Africa Sudan, Zaire, Zimbabwe,) and Asia (Sumba, Indonesia) exists. These results show that wing orientation and gender must be considered when conducting morphometric investigations of OWS fly wings. The latter result is also consistent with results from previous molecular and morphological studies, which indicate there are two distinct genetic lineages within this species. Wing morphometry holds great promise as a practical tool to aid in identification of the geographical origin of introductions of this important pest species, by providing diagnostic markers to distinguish geographical populations and complement molecular diagnostics.

  2. Application of a finite difference method to the analysis of transonic flow over oscillating airfoils and wings

    Weatherill, W. H.; Sebastian, J. D.; Ehlers, F. E.


    A finite difference method for solving the unsteady flow about harmonically oscillating wings is investigated. The procedure is based on separating the velocity potential into steady and unsteady parts and linearing the resulting unsteady differential equation for small disturbances. Solutions are obtained using relaxation procedures. The means for improving the solution stability characteristics of the relaxation process are explored. A direct procedure is formulated which permits obtaining solutions for combinations of Mach number and reduced frequency for which the relaxation process has proved unstable. The pressure distribution for an aspect ratio 5 rectangular wing oscillating in pitch is presented.

  3. Boundary layer and separation control on wings at low Reynolds numbers

    Yang, Shanling

    Results on boundary layer and separation control through acoustic excitation at low Re numbers are reported. The Eppler 387 profile is specifically chosen because of its pre-stall hysteresis and bi-stable state behavior in the transitional Re regime, which is a result of flow separation and reattachment. External acoustic forcing on the wing yields large improvements (more than 70%) in lift-to-drag ratio and flow reattachment at forcing frequencies that correlate with the measured anti-resonances in the wind tunnel. The optimum St/Re1/2 range for Re = 60,000 matches the proposed optimum range in the literature, but there is less agreement for Re = 40,000, which suggests that correct St scaling has not been determined. The correlation of aerodynamic improvements to wind tunnel resonances implies that external acoustic forcing is facility-dependent, which inhibits practical application. Therefore, internal acoustic excitation for the same wing profile is also pursued. Internal acoustic forcing is designed to be accomplished by embedding small speakers inside a custom-designed wing that contains many internal cavities and small holes in the suction surface. However, initial testing of this semi-porous wing model shows that the presence of the small holes in the suction surface completely transforms the aerodynamic performance by changing the mean chordwise separation location and causing an originally separated, low-lift state flow to reattach into a high-lift state. The aerodynamic improvements are not caused by the geometry of the small holes themselves, but rather by Helmholtz resonance that occurs in the cavities, which generate tones that closely match the intrinsic flow instabilities. Essentially, opening and closing holes in the suction surface of a wing, perhaps by digital control, can be used as a means of passive separation control. Given the similarity of wing-embedded pressure tap systems to Helmholtz resonators, particular attention must be given to the

  4. Aeroelastic Analysis of a Flexible Wing Wind Tunnel Model with Variable Camber Continuous Trailing Edge Flap Design

    Nguyen, Nhan; Ting, Eric; Lebofsky, Sonia


    This paper presents data analysis of a flexible wing wind tunnel model with a variable camber continuous trailing edge flap (VCCTEF) design for drag minimization tested at the University of Washington Aeronautical Laboratory (UWAL). The wind tunnel test was designed to explore the relative merit of the VCCTEF concept for improved cruise efficiency through the use of low-cost aeroelastic model test techniques. The flexible wing model is a 10%-scale model of a typical transport wing and is constructed of woven fabric composites and foam core. The wing structural stiffness in bending is tailored to be half of the stiffness of a Boeing 757-era transport wing while the torsional stiffness is about the same. This stiffness reduction results in a wing tip deflection of about 10% of the wing semi-span. The VCCTEF is a multi-segment flap design having three chordwise camber segments and five spanwise flap sections for a total of 15 individual flap elements. The three chordwise camber segments can be positioned appropriately to create a desired trailing edge camber. Elastomeric material is used to cover the gaps in between the spanwise flap sections, thereby creating a continuous trailing edge. Wind tunnel data analysis conducted previously shows that the VCCTEF can achieve a drag reduction of up to 6.31% and an improvement in the lift-to-drag ratio (L=D) of up to 4.85%. A method for estimating the bending and torsional stiffnesses of the flexible wingUWAL wind tunnel model from static load test data is presented. The resulting estimation indicates that the stiffness of the flexible wing is significantly stiffer in torsion than in bending by as much as 9 to 1. The lift prediction for the flexible wing is computed by a coupled aerodynamic-structural model. The coupled model is developed by coupling a conceptual aerodynamic tool Vorlax with a finite-element model of the flexible wing via an automated geometry deformation tool. Based on the comparison of the lift curve slope

  5. Effects of Dragonfly Wing Structure on the Dynamic Performances

    Huaihui Ren; Xishu Wang; Xudong Li; Yinglong Chen


    The configurations of dragonfly wings,including the corrugations of the chordwise cross-section,the microstructure of the longitudinal veins and membrane,were comprehensively investigated using the Environmental Scanning Electron Microscopy (ESEM).Based on the experimental results reported previously,the multi-scale and multi-dimensional models with different structural features of dragonfly wing were created,and the biological dynamic behaviors of wing models were discussed through the Finite Element Method (FEM).The results demonstrate that the effects of different structural features on dynamic behaviors of dragonfly wing such as natural frequency/modal,bending/torsional deformation,reaction force/torque are very significant.The corrugations of dragonfly wing along the chordwise can observably improve the flapping frequency because of the greater structural stiffness of wings.In updated model,the novel sandwich microstructure of the longitudinal veins remarkably improves the torsional deformation of dragonfly wing while it has a little effect on the flapping frequency and bending deformation.These integrated structural features can adjust the deformation of wing oneself,therefore the flow field around the wings can be controlled adaptively.The fact is that the flights of dragonfly wing with sandwich microstructure of longitudinal veins are more efficient and intelligent.

  6. Interceptive management of winged maxillary central incisors

    Mamta Dali


    Full Text Available Introduction: Winged maxillary incisors are a well-recognized clinical finding, which can result in psychological trauma to children at growing age. Interceptive treatment is usually carried out in mixed dentition period in order to reduce the severity of a developing malocclusion in future. Case Report: This paper reports a case of 6-years-old female patient with winged maxillary central incisor being treated with derotation technique using the beggs brackets along with nance palatal arch space maintainer. Discussion: The major advantages in carrying out this treatment with fixed brackets are the ease with which the force magnitude and vector can be controlled much more precisely than with a removable appliance, minimal discomfort to the patient and reduces the need for patient co-operation.

  7. The Crest Wing Wave Energy Device

    Kofoed, Jens Peter; Antonishen, Michael Patrick

    This report presents the results of a continuation of an experimental study of the wave energy converting abilities of the Crest Wing wave energy converter (WEC), in the following referred to as ‘Phase 2'. The Crest Wing is a WEC that uses its movement in matching the shape of an oncoming wave...... to generate power. Model tests have been performed using scale models (length scale 1:30), provided by WaveEnergyFyn, in regular and irregular wave states that can be found in Assessment of Wave Energy Devices. Best Practice as used in Denmark (Frigaard et al., 2008). The tests were carried out at Dept....... of Civil Engineering, Aalborg University (AAU) in the 3D deep water wave tank. The displacement and force applied to a power take off system, provided by WaveEnergyFyn, were measured and used to calculate mechanical power available to the power take off....

  8. Charge Capacity of Piezoelectric Membrane Wings

    Grybas, Matthew; Hubner, J. Paul


    Micro air vehicles (MAVs) have small wings often fabricated with flexible frames and membranes. These membranes flex and vibrate. Piezoelectric films have the ability to convert induced stress or strain into electrical energy. Thus, it is of interest to investigate if piezoelectric films can be used as a structural member of an MAV wing and generate both lift and energy through passive vibrations. Both a shaker test and a wind tunnel test have been conducted to characterize and assess energy production and aerodynamic characteristics including lift, drag and efficiency. The piezoelectric film has been successful as a lifting surface and produces a measurable charge. This work was supported by NSF REU Site Award 1358991.


    Muhammet ARSLAN


    Full Text Available Woodworking which is in the most important Turk art branches have been used especially in Anatolia land readily. Wooden material that is seen on architectural units such as mimbar, ambo, wings of door and window, lectern has an important particularly with its ornamental figures. Wooden composition on the north and east doors of Adıyaman Great Mosque was built by Dulkadir Principality but regulated again in the last period of Ottoman Empire, is a theme which is exemined detailedly in Turk art. In this article, it is tried to determined ornamentel and tecnical characteristics of wooden door wings of Adıyaman Great Mosque belongs to early XX. century and the place of them in Turk art.

  10. Origin and diversification of wings: Insights from a neopteran insect.

    Medved, Victor; Marden, James H; Fescemyer, Howard W; Der, Joshua P; Liu, Jin; Mahfooz, Najmus; Popadić, Aleksandar


    Winged insects underwent an unparalleled evolutionary radiation, but mechanisms underlying the origin and diversification of wings in basal insects are sparsely known compared with more derived holometabolous insects. In the neopteran species Oncopeltus fasciatus, we manipulated wing specification genes and used RNA-seq to obtain both functional and genomic perspectives. Combined with previous studies, our results suggest the following key steps in wing origin and diversification. First, a set of dorsally derived outgrowths evolved along a number of body segments including the first thoracic segment (T1). Homeotic genes were subsequently co-opted to suppress growth of some dorsal flaps in the thorax and abdomen. In T1 this suppression was accomplished by Sex combs reduced, that when experimentally removed, results in an ectopic T1 flap similar to prothoracic winglets present in fossil hemipteroids and other early insects. Global gene-expression differences in ectopic T1 vs. T2/T3 wings suggest that the transition from flaps to wings required ventrally originating cells, homologous with those in ancestral arthropod gill flaps/epipods, to migrate dorsally and fuse with the dorsal flap tissue thereby bringing new functional gene networks; these presumably enabled the T2/T3 wing's increased size and functionality. Third, "fused" wings became both the wing blade and surrounding regions of the dorsal thorax cuticle, providing tissue for subsequent modifications including wing folding and the fit of folded wings. Finally, Ultrabithorax was co-opted to uncouple the morphology of T2 and T3 wings and to act as a general modifier of hindwings, which in turn governed the subsequent diversification of lineage-specific wing forms.

  11. About Subjects


    正During my high school years,I found physics,chemistry and maths specially interesting.Actually,I was interested in many subjects,such as biology,history,geography and English.But somehow I simply couldn't remember the events of history or the facts about geography.I couldn't remember the some of the English idioms well either.On the other hand,physics,chemistry and maths were easy for me to learn.After considering carefully my interests and talents,I felt that science might be the best choice for me.So I was determined to study natural science at college.After graduating from college,I would like to return to school to teach.

  12. CFD Analysis of UAV Flying Wing



    Full Text Available Numerical methods for solving equations describing the evolution of 3D fluid experienced a significant development closely related to the progress of information systems. Today, especially in the field of fluid mechanics, numerical simulations allow the study of gas-thermodynamic confirmed by experimental techniques in wind tunnel conditions and actual flight tests for modeling complex aircraft. The article shows a case of numerical analysis of the lifting surface on the UAV type flying wing.

  13. X-38 on B-52 Wing Pylon


    A unique, close-up view of the X-38 (Crew Return Vehicle) under the wing of NASA's B-52 mothership prior to launch of the lifting-body research vehicle. The photo was taken from the observation window of the B-52 bomber as it banked in flight. The X-38 Crew Return Vehicle (CRV) research project is designed to develop the technology for a prototype emergency crew return vehicle or lifeboat for the International Space Station.

  14. Maintenance cost study of rotary wing aircraft


    The feasibility was studied of predicting rotary wing operation maintenance costs by using several aircraft design factors for the aircraft dynamic systems. The dynamic systems considered were engines, drives and transmissions, rotors, and flight controls. Multiple regression analysis was used to correlate aircraft design and operational factors with manhours per flight hour, and equations for each dynamic system were developed. Results of labor predictions using the equations compare favorably with actual values.

  15. Autonomous Deicing System For Airplane Wing

    Hickman, G. A.; Gerardi, J. J.


    Prototype autonomous deicing system for airplane includes network of electronic and electromechanical modules at various locations in wings and connected to central data-processing unit. Small, integrated solid-state device, using long coils installed under leading edge, exciting small vibrations to detect ice and larger vibrations to knock ice off. In extension of concept, outputs of vibration sensors and other sensors used to detect rivet-line fractures, fatigue cracks, and other potentially dangerous defects.

  16. Mother Nature inspires new wind turbine wing

    Sønderberg Petersen, L.


    The sight of a bird of prey hanging immobile in the air while its wings continuously adjust themselves slightly in relation to the wind in order to keep the bird in the same position in the air, is a sight that most of us have admired, including the windenergy scientists at Risø DTU. They have st...... started transferring the principle to wind turbine blades to make them adaptive...

  17. Effect of multiple engine placement on aeroelastic trim and stability of flying wing aircraft

    Mardanpour, Pezhman; Richards, Phillip W.; Nabipour, Omid; Hodges, Dewey H.


    Effects of multiple engine placement on flutter characteristics of a backswept flying wing resembling the HORTEN IV are investigated using the code NATASHA (Nonlinear Aeroelastic Trim And Stability of HALE Aircraft). Four identical engines with defined mass, inertia, and angular momentum are placed in different locations along the span with different offsets from the elastic axis while fixing the location of the aircraft c.g. The aircraft experiences body freedom flutter along with non-oscillatory instabilities that originate from flight dynamics. Multiple engine placement increases flutter speed particularly when the engines are placed in the outboard portion of the wing (60-70% span), forward of the elastic axis, while the lift to drag ratio is affected negligibly. The behavior of the sub- and supercritical eigenvalues is studied for two cases of engine placement. NATASHA captures a hump body-freedom flutter with low frequency for the clean wing case, which disappears as the engines are placed on the wings. In neither case is there any apparent coalescence between the unstable modes. NATASHA captures other non-oscillatory unstable roots with very small amplitude, apparently originating with flight dynamics. For the clean-wing case, in the absence of aerodynamic and gravitational forces, the regions of minimum kinetic energy density for the first and third bending modes are located around 60% span. For the second mode, this kinetic energy density has local minima around the 20% and 80% span. The regions of minimum kinetic energy of these modes are in agreement with calculations that show a noticeable increase in flutter speed if engines are placed forward of the elastic axis at these regions.

  18. Role of Soft Matter in the Sandwich Vein of Dragonfly Wing in Its Configuration and Aerodynamic Behaviors

    Xishu Wang; Zhihao Zhang; Huaihui Ren; Yinglong Chen; Bisheng Wu


    The microstructure of the main longitudinal veins of the dragonfly wing and the aerodynamic behaviors of the wing were investigated in this paper.The microstructure of longitudinal vein presents two circumferential chitin layers and a protein-fiber soft layer.The dragonfly wing is corrugated due to the spatial arrangement of longitudinal veins.It was found that the corrugation angle could significantly influence the lift/drag ratio across a range of attack angles by the wind tunnel experiments.The results of the finite element analysis indicate that the protein soft layer of vein facilitates the change of the corrugation angle by allowing substantial relative twisting deformation between two neighboring veins,which is not possible in veins without a soft sandwich layer.

  19. Noise characteristics of an electromagnetic sea-ice thickness sounder on a fixed wing aircraft

    Rabenstein, Lasse; Hendricks, Stefan; Lobach, John; Haas, Christian


    In this paper, the noise sources of an airborne electromagnetic frequency domain instrument used to measure sea-ice thickness are studied. The antennas are mounted on the wings of an aircraft. The paper presents real data examples showing that strong noise limited the accuracy of the thickness measurement to ± 0.5 m in the best case. Even drift cor­rection and frequency filtering did not reduce the noise to a level necessary for sea ice thickness measurements with an accuracy of 0.1 m. We show results of 3D finite element modeling of the coupling between transmitter and receiver coils and the aircraft, which indicate that wing flexure is the primary cause of the strong noise. Wing deflection angles below 5° relative to the fuselage are large enough to cause changes higher than the wanted signal from the seawater under the ice. Wing flexure noise can be divided into an inductive and geometric contribution, both of the same order. Most of the wing flexure signal appears on the inphase component only, hence the quadrature component should be taken for sea ice thickness retrievals when wing flexure is present even when the inphase produces a larger ocean sig­nal. Results also show that pitch and roll movements of the aircraft and electromagnetic coupling between seawater and aircraft can contribute significantly to the total noise. For flight heights of 30 m over the ocean these effects can change the sig­nal by about 10% or more. For highly quantitative measurements like sea-ice thickness all these effects must be taken into account. We conclude that a fixed wing electromagnetic instrument for the purpose of measure­ments in a centimeter scale must include instrumentation to measure the relative position of the antenna coils with an accuracy of 1/10 mm. Furthermore the antenna separation distance should be as large as possible in order to increase the measured ratio of secondary to primary magnetic field strength.

  20. Performance Comparison between Optimised Camber and Span for a Morphing Wing

    Christopher Simon Beaverstock


    Full Text Available Morphing technology offers a strategy to modify the wing geometry, and the wing planform and cross-sectional parameters can be optimised to the flight conditions. This paper presents an investigation into the effect of span and camber morphing on the mission performance of a 25-kg UAV, with a straight, rectangular, unswept wing. The wing is optimised over two velocities for various fixed wing and morphing wing strategies, where the objective is to maximise aerodynamic efficiency or range. The investigation analyses the effect of the low and high speed velocity selected, the weighting of the low and high velocity on the computation of the mission parameter, the maximum allowable span retraction and the weight penalty on the mission performance. Models that represent the adaptive aspect ratio (AdAR span morphing concept and the fish bone active camber (FishBAC camber morphing concept are used to investigate the effect on the wing parameters. The results indicate that generally morphing for both span and camber, the aerodynamic efficiency is maximised for a 30%–70% to 40%–60% weighting between the low and high speed flight conditions, respectively. The span morphing strategy with optimised fixed camber at the root can deliver up to 25% improvement in the aerodynamic efficiency over a fixed camber and span, for an allowable 50% retraction with a velocity range of 50–115 kph. Reducing the allowable retraction to 25% reduces the improvement to 8%–10% for a 50%–50% mission weighting. Camber morphing offers a maximum of 4.5% improvement approximately for a velocity range of 50–90 kph. Improvements in the efficiency achieved through camber morphing are more sensitive to the velocity range in the mission, generally decreasing rapidly by reducing or increasing the velocity range, where span morphing appears more robust for an increase in velocity range beyond the optimum. However, where span morphing requires considerable modification to the

  1. Functional analysis of genes differentially expressed in the Drosophila wing disc: role of transcripts enriched in the wing region.

    Jacobsen, Thomas L; Cain, Donna; Paul, Litty; Justiniano, Steven; Alli, Anwar; Mullins, Jeremi S; Wang, Chun Ping; Butchar, Jon P; Simcox, Amanda


    Differential gene expression is the major mechanism underlying the development of specific body regions. Here we assessed the role of genes differentially expressed in the Drosophila wing imaginal disc, which gives rise to two distinct adult structures: the body wall and the wing. Reverse genetics was used to test the function of uncharacterized genes first identified in a microarray screen as having high levels of expression in the presumptive wing. Such genes could participate in elaborating the specific morphological characteristics of the wing. The activity of the genes was modulated using misexpression and RNAi-mediated silencing. Misexpression of eight of nine genes tested caused phenotypes. Of 12 genes tested, 10 showed effective silencing with RNAi transgenes, but only 3 of these had resulting phenotypes. The wing phenotypes resulting from RNAi suggest that CG8780 is involved in patterning the veins in the proximal region of the wing blade and that CG17278 and CG30069 are required for adhesion of wing surfaces. Venation and apposition of the wing surfaces are processes specific to wing development providing a correlation between the expression and function of these genes. The results show that a combination of expression profiling and tissue-specific gene silencing has the potential to identify new genes involved in wing development and hence to contribute to our understanding of this process. However, there are both technical and biological limitations to this approach, including the efficacy of RNAi and the role that gene redundancy may play in masking phenotypes.

  2. Addition of antioxidant from bamboo leaves as an effective way to reduce the formation of acrylamide in fried chicken wings.

    Zhang, Yu; Xu, Weizhong; Wu, Xiaoqin; Zhang, Xiaoling; Zhang, Ying


    The efficiency of antioxidant from bamboo leaves on the reduction of acrylamide during thermal processing and optimization of levels of addition of antioxidant from bamboo leaves applied to fried chicken wings are reported. The authors optimized the method of the addition of antioxidant from bamboo leaves to fried chicken wings and the frying processing parameters, and also compared the relationship between the content of total flavonoids in three extracts (EBL(971), EBL(972) and antioxidant from bamboo leaves) and the extent of the reduction of acrylamide. The acrylamide levels were quantified by a validated liquid chromatography coupled with tandem mass spectrometry detection method and the sensory evaluation was performed in a double-blind manner. The results showed that nearly 57.8 and 59.0% of acrylamide in fried chicken wings were reduced when the antioxidant from bamboo leaves addition ratios were 0.1 and 0.5% (w/w), respectively. The maximum inhibitory rate was achieved when antioxidant from bamboo leaves was chosen as the additive with a total flavonoid content of 32% compared with other two extracts and antioxidant from bamboo leaves mixed with flour was selected as the method of addition. Sensory evaluation results showed that the odour and flavour of fried chicken wings with antioxidant from bamboo leaves treatments had no significant difference compared with normal food matrixes (p > 0.05) when the antioxidant from bamboo leaves addition ratio was Colour acceptability in the study of sensory evaluation was in good correspondence with colour formation of fried chicken wings in each test group. These results suggest that antioxidant from bamboo leaves could significantly reduce acrylamide formation in fried chicken wings and yet still retain the original flavour and odour of the fried products. This study could be regarded as a pioneer contribution to the reduction of acrylamide in various foods by natural antioxidants.

  3. Analysis and Flexible Structural Modeling for Oscillating Wing Utilizing Aeroelasticity

    Shao Ke; Wu Zhigang; Yang Chao


    Making use of modal characteristics of the natural vibration of flexible structure to design the oscillating wing aircraft is proposed.A series of equations concerning the oscillating wing of flexible structures are derived. The kinetic equation for aerodynamic force coupled with elastic movement is set up, and relevant formulae are derived. The unsteady aerodynamic one in that formulae is revised. The design principle, design process and range of application of such oscillating wing analytical method are elaborated. A flexible structural oscillating wing model is set up, and relevant time response analysis and frequency response analysis are conducted. The analytical results indicate that adopting the new-type driving way for the oscillating wing will not have flutter problems and will be able to produce propulsive force. Furthermore, it will consume much less power than the fixed wing for generating the same lift.

  4. Fiber Optic Wing Shape Sensing on NASA's Ikhana UAV

    Richards, Lance; Parker, Allen R.; Ko, William L.; Piazza, Anthony


    This document discusses the development of fiber optic wing shape sensing on NASA's Ikhana vehicle. The Dryden Flight Research Center's Aerostructures Branch initiated fiber-optic instrumentation development efforts in the mid-1990s. Motivated by a failure to control wing dihedral resulting in a mishap with the Helios aircraft, new wing displacement techniques were developed. Research objectives for Ikhana included validating fiber optic sensor measurements and real-time wing shape sensing predictions; the validation of fiber optic mathematical models and design tools; assessing technical viability and, if applicable, developing methodology and approaches to incorporate wing shape measurements within the vehicle flight control system; and, developing and flight validating approaches to perform active wing shape control using conventional control surfaces and active material concepts.

  5. Compound Wing Vertical Takeoff and Landing Small Unmanned Aircraft System

    Logan, Michael J. (Inventor); Motter, Mark A. (Inventor); Deloach, Richard (Inventor); Vranas, Thomas L. (Inventor); Prendergast, Joseph M. (Inventor); Lipp, Brittney N. (Inventor)


    Systems, methods, and devices are provided that enable robust operations of a small unmanned aircraft system (sUAS) using a compound wing. The various embodiments may provide a sUAS with vertical takeoff and landing capability, long endurance, and the capability to operate in adverse environmental conditions. In the various embodiments a sUAS may include a fuselage and a compound wing comprising a fixed portion coupled to the fuselage, a wing lifting portion outboard of the fixed portion comprising a rigid cross member and a controllable articulating portion configured to rotate controllable through a range of motion from a horizontal position to a vertical position, and a freely rotating wing portion outboard of the wing lifting portion and configured to rotate freely based on wind forces incident on the freely rotating wing portion.

  6. Video measurements of instantaneous forces of flapping wing vehicles

    Jennings, Alan; Mayhew, Michael; Black, Jonathan


    Flapping wings for small aerial vehicles have revolutionary potential for maneuverability and endurance. Ornithopters fail to achieve the performance of their biological equivalents, despite extensive research on how animals fly. Flapping wings produce peak forces due to the stroke reversal of the wing. This research demonstrates in-flight measurements of an ornithopter through the use of image processing, specifically measuring instantaneous forces. Results show that the oscillation about the flight path is significant, being about 20% of the mean velocity and up to 10 g's. Results match forces with deformations of the wing to contrast the timing and wing shape of the upstroke and the downstroke. Holding the vehicle fixed (e.g. wind tunnel testing or simulations) structural resonance is affected along with peak forces, also affecting lift. Non-contact, in-flight measurements are proposed as the best method for matching the flight conditions of flapping wing vehicles.

  7. Simplifying a wing: diversity and functional consequences of digital joint reduction in bat wings.

    Bahlman, Joseph W; Price-Waldman, Rosalyn M; Lippe, Hannah W; Breuer, Kenneth S; Swartz, Sharon M


    Bat wings, like other mammalian forelimbs, contain many joints within the digits. These joints collectively affect dynamic three-dimensional (3D) wing shape, thereby affecting the amount of aerodynamic force a wing can generate. Bats are a speciose group, and show substantial variation in the number of wing joints. Additionally, some bat species have joints with extensor but no flexor muscles. While several studies have examined the diversity in number of joints and presence of muscles, musculoskeletal variation in the digits has not been interpreted in phylogenetic, functional or ecological contexts. To provide this context, the number of joints and the presence/absence of muscles are quantified for 44 bat species, and are mapped phylogenetically. It is shown that, relative to the ancestral state, joints and muscles were lost multiple times from different digits and in many lineages. It is also shown that joints lacking flexors undergo cyclical flexion and extension, in a manner similar to that observed in joints with both flexors and extensors. Comparison of species with contrasting feeding ecologies demonstrates that species that feed primarily on non-mobile food (e.g. fruit) have fewer fully active joints than species that catch mobile prey (e.g. insects). It is hypothesized that there is a functional trade-off between energetic savings and maneuverability. Having fewer joints and muscles reduces the mass of the wing, thereby reducing the energetic requirements of flapping flight, and having more joints increases the assortment of possible 3D wing shapes, thereby enhancing the range and fine control of aerodynamic force production and thus maneuverability.

  8. Flow structure and vorticity transport on a plunging wing

    Eslam Panah, Azar

    circulation, in magnitude, as the leading-edge shear layer flux. A small but non-negligible vorticity source was also attributed to spanwise flow toward the end of the downstroke. Preliminary measurements of the structure and dynamics of the leading-edge vortex (LEV) are also investigated for plunging finite-aspect-ratio wings at a chord Reynolds number of 10,000 while varying aspect ratio and root boundary condition. Stereoscopic particle image velocimetry (SPIV) measurements are used to characterize LEV dynamics and interactions with the plate in multiple chordwise planes. The relationship between the vorticity field and the spanwise flow field over the wing, and the influence of root boundary conditions on these quantities has been investigated. The viscous symmetry plane is found to influence this flow field, in comparison to other studies YiRo:2010,Vi:2011b,CaWaGuVi:2012, by influencing tilting of the LEV near the symmetry wall, and introducing a corewise root-to-tip flow near the symmetry plane. Modifications in the root boundary conditions are found to significantly affect this. LEV circulations for the different aspect ratio plates are also compared. At the bottom of the downstroke, the maximum circulation is found at the middle of the semi-span in each case. The circulation of the sAR=2 wing is found to significantly exceed that of the sAR=1 wing and, surprisingly, the maximum circulation value is found to be independent of root boundary conditions for thesAR=2 case and also closely matched that of the quasi-2D case. Furthermore, the 3-D flow field of a finite wing ofsAR=2 was characterized using three-dimensional reconstructions of planar PIV data after minimizing the gap between the plunging plate and the top stationary wall. The LEV on the finite wing rapidly evolved into an arch structure centered at approximately the 50% spanwise position, similar to previous observations by Calderon et al., and Yilmaz and Rockwell. At that location, the circulation contribution

  9. Winging of scapula due to serratus anterior tear

    Varun Kumar Singh; Gauresh Shantaram Vargaonkar


    Winging of scapula occurs most commonly due to injury to long thoracic nerve supplying serratus anterior muscle.Traumatic injury to serratus anterior muscle itself is very rare.We reported a case of traumatic winging of scapula due to tear of serratus anterior muscle in a 19-year-old male.Winging was present in neutral position and in extension of right shoulder joint but not on "push on wall" test.Patient was managed conservatively and achieved satisfactory result.

  10. The aerodynamic and structural study of flapping wing vehicles


    This thesis reports on the aerodynamic and structural study carried out on flapping wings and flapping vehicles. Theoretical and experimental investigation of aerodynamic forces acting on flapping wings in simple harmonic oscillations is undertaken in order to help conduct and optimize the aerodynamic and structural design of flapping wing vehicles. The research is focused on the large scale ornithopter design of similar size and configuration to a hang glider. By means of Theodorsen’s th...

  11. Wing shape of dengue vectors from around the world

    Henry, A; Thongsripong, P.; Fonseca-Gonzalez, I.; Jaramillo-Ocampo, N.; Dujardin, Jean-Pierre


    Wing shape is increasingly utilized in species identification and characterization. For dengue vectors Aedes aegypti and Aedes albopictus, it could be used as a complement for ensuring accurate diagnostic of damaged specimens. However, the impact of world migration on wing shape is unknown. Has the spread of these invasive species increased shape variation to the extent of producing interspecific overlapping? To answer this question, the geometric patterns of wing venation in Ae. aegypti and ...

  12. Noniterative grid generation using parabolic difference equations for fuselage-wing flow calculations

    Nakamura, S.


    A fast method for generating three-dimensional grids for fuselage-wing transonic flow calculations using parabolic difference equations is described. No iterative scheme is used in the three-dimensional sense; grids are generated from one grid surface to the next starting from the fuselage surface. The computational procedure is similar to the iterative solution of the two-dimensional heat conduction equation. The proposed method is at least 10 times faster than the elliptic grid generation method and has much smaller memory requirements. Results are presented for a fuselage and wing of NACA-0012 section and thickness ratio of 10 percent. Although only H-grids are demonstrated, the present technique should be applicable to C-grids and O-grids in three dimensions.

  13. Wind-tunnel experiments on divergence of forward-swept wings

    Ricketts, R. H.; Doggett, R. V., Jr.


    An experimental study to investigate the aeroelastic behavior of forward-swept wings was conducted in the Langley Transonic Dynamics Tunnel. Seven flat-plate models with varying aspect ratios and wing sweep angles were tested at low speeds in air. Three models having the same planform but different airfoil sections (i.e., flat-plate, conventional, and supercritical) were tested at transonic speeds in Freon 12. Linear analyses were performed to provide predictions to compare with the measured aeroelastic instabilities which include both static divergence and flutter. Six subcritical response testing techniques were formulated and evaluated at transonic speeds for accuracy in predicting static divergence. Two "divergence stoppers" were developed and evaluated for use in protecting the model from structural damage during tests.

  14. Technicians prepare the inflatable wing on Paresev 1-C


    This photo shows the Paresev (Paraglider Research Vehicle) space frame receiving a new wing. Frank Fedor and a technician helper are attaching a half-scale version of an inflatable wing in a hangar at NASA Flight Research Center at Edwards, California. The Paresev in this configuration was called the 1-C and was expected to closely approximate the aerodynamic characteristics that would be encountered with the Gemini space capsule with a parawing extended. The whole wing was not inflatable; the three chambers that acted as spars and supported the wing inflated.

  15. Aeroelastic Deformation and Buckling of Inflatable Wings under Dynamic Loads

    Simpson, Andrew; Smith, Suzanne; Jacob, Jamey


    Inflatable wings have recently been used to control a vehicle in flight via wing warping. Internal pressure is required to maintain wing shape and externally mounted mechanical actuators are used to asynchronously deform the wing semi-spans for control. Since the rigidity of the inflatable wing varies as a function of inflation pressure, there is a need to relate the wing shape with aerodynamic loads. Via wind tunnel tests, span-wise deformations, twist and flutter have been observed under certain dynamic loading conditions. Photogrammetry techniques are used to measure the static aeroelastic deformation of the wings and videogrammetry is used to examine the dynamic shape changes (flutter). The resulting shapes can be used to determine corresponding aerodynamic characteristics. For particular inflation pressures, buckling can be induced at sufficiently high dynamic loads either through high dynamic pressure or large angle of attack. This results in a set of critical loading parameters. An inflatable winged vehicle would require operation within these limits. The focus of the presentation will be on defining and exploring the unsuitable operating conditions and the effects these conditions have on the operation of the wing.

  16. Embedded Fiber Optic Shape Sensing for Aeroelastic Wing Components Project

    National Aeronautics and Space Administration — As the aerospace industry continues to push for greater vehicle efficiency, performance, and longevity, properties of wing aeroelasticity and flight dynamics have...

  17. Design, Fabrication and Testing Of Flapping Wing Micro Air Vehicle

    K. P. Preethi Manohari Sai


    Full Text Available Flapping flight has the potential to revolutionize micro air vehicles (MAVs due to increased aerodynamic performance, improved maneuverability and hover capabilities. The purpose of this project is to design and fabrication of flapping wing micro air vehicle. The designed MAV will have a wing span of 40cm. The drive mechanism will be a gear mechanism to drive the flapping wing MAV, along with one actuator. Initially, a preliminary design of flapping wing MAV is drawn and necessary calculation for the lift calculation has been done. Later a CAD model is drawn in CATIA V5 software. Finally we tested by Flying.

  18. MEMS wing technology for a battery-powered ornithopter


    The objective of this project is to develop a battery-powered ornithopter (flapping-wing) Micro Aerial Vehicle (MAV) with MEMS wings. In this paper, we present a novel MEMS-based wing technology that we developed using titanium-alloy metal as wingframe and parylene C as wing membrane. MEMS technology enables systematic research in terms of repeatablility, size control, and weight minimization. We constructed a high quality low-speed wind tunnel with velocity uniformity of 0.5% and speeds from...

  19. Feedback Linearization Controller Of The Delta WingRock Phenomena

    Mohammed Alkandari


    Full Text Available This project deals with the control of the wing rock phenomena of a delta wing aircraft. a control schemeis proposed to stabilize the system. The controlleris a feedback linearization controller. It is shown that the proposed control scheme guarantee the asymptotic convergence to zero of all the states of the system. To illustrate the performance of the proposed controller, simulation results are presented and discussed. It is found that the proposed control scheme work well for the wing rock phenomena of a delta wing aircraft.

  20. Complexity analyses of multi-wing chaotic systems

    He Shao-Bo; Sun Ke-Hui; Zhu Cong-Xu


    The complexities of multi-wing chaotic systems based on the modified Chen system and a multi-segment quadratic function are investigated by employing the statistical complexity measure (SCM) and the spectral entropy (SE) algorithm.How to choose the parameters of the SCM and SE algorithms is discussed.The results show that the complexity of the multi-wing chaotic system does not increase as the number of wings increases,and it is consistent with the results of the Grassberger-Procaccia (GP) algorithm and the largest Lyapunov exponent (LLE) of the multi-wing chaotic system.

  1. Complexity analyses of multi-wing chaotic systems

    He, Shao-Bo; Sun, Ke-Hui; Zhu, Cong-Xu


    The complexities of multi-wing chaotic systems based on the modified Chen system and a multi-segment quadratic function are investigated by employing the statistical complexity measure (SCM) and the spectral entropy (SE) algorithm. How to choose the parameters of the SCM and SE algorithms is discussed. The results show that the complexity of the multi-wing chaotic system does not increase as the number of wings increases, and it is consistent with the results of the Grassberger—Procaccia (GP) algorithm and the largest Lyapunov exponent (LLE) of the multi-wing chaotic system.

  2. Aerodynamic Design Methodology for Blended Wing Body Transport

    LI Peifeng; ZHANG Binqian; CHEN Yingchun; YUAN Changsheng; LIN Yu


    This paper puts forward a design idea for blended wing body (BWB).The idea is described as that cruise point,maximum lift to drag point and pitch trim point are in the same flight attitude.According to this design idea,design objectives and constraints are defined.By applying low and high fidelity aerodynamic analysis tools,BWB aerodynamic design methodology is established by the combination of optimization design and inverse design methods.High lift to drag ratio,pitch trim and acceptable buffet margin can be achieved by this design methodology.For 300-passenger BWB configuration based on static stability design,as compared with initial configuration,the maximum lift to drag ratio and pitch trim are achieved at cruise condition,zero lift pitching moment is positive,and buffet characteristics is well.Fuel burn of 300-passenger BWB configuration is also significantly reduced as compared with conventional civil transports.Because aerodynamic design is carried out under the constraints of BWB design requirements,the design configuration fulfills the demands for interior layout and provides a solid foundation for continuous work.

  3. Anisotropy and non-homogeneity of an Allomyrina Dichotoma beetle hind wing membrane

    Ha, N S; Jin, T L; Goo, N S; Park, H C, E-mail: [Biomimetics and Intelligent Microsystem Laboratory, Department of Advanced Technology Fusion, Konkuk University, Seoul 143-701 (Korea, Republic of)


    Biomimetics is one of the most important paradigms as researchers seek to invent better engineering designs over human history. However, the observation of insect flight is a relatively recent work. Several researchers have tried to address the aerodynamic performance of flapping creatures and other natural properties of insects, although there are still many unsolved questions. In this study, we try to answer the questions related to the mechanical properties of a beetle's hind wing, which consists of a stiff vein structure and a flexible membrane. The membrane of a beetle's hind wing is small and flexible to the point that conventional methods cannot adequately quantify the material properties. The digital image correlation method, a non-contact displacement measurement method, is used along with a specially designed mini-tensile testing system. To reduce the end effects, we developed an experimental method that can deal with specimens with as high an aspect ratio as possible. Young's modulus varies over the area in the wing and ranges from 2.97 to 4.5 GPa in the chordwise direction and from 1.63 to 2.24 GPa in the spanwise direction. Furthermore, Poisson's ratio in the chordwise direction is 0.63-0.73 and approximately twice as large as that in the spanwise direction (0.33-0.39). From these results, we can conclude that the membrane of a beetle's hind wing is an anisotropic and non-homogeneous material. Our results will provide a better understanding of the flapping mechanism through the formulation of a fluid-structure interaction analysis or aero-elasticity analysis and meritorious data for biomaterial properties database as well as a creative design concept for a micro aerial flapper that mimics an insect.

  4. Folding wings like a cockroach: a review of transverse wing folding ensign wasps (Hymenoptera: Evaniidae: Afrevania and Trissevania.

    István Mikó

    Full Text Available We revise two relatively rare ensign wasp genera, whose species are restricted to Sub-Saharan Africa: Afrevania and Trissevania. Afrevania longipetiolata sp. nov., Trissevania heatherae sp. nov., T. hugoi sp. nov., T. mrimaensis sp. nov. and T. slideri sp. nov. are described, males and females of T. anemotis and Afrevania leroyi are redescribed, and an identification key for Trissevaniini is provided. We argue that Trissevania mrimaensis sp. nov. and T. heatherae sp. nov. populations are vulnerable, given their limited distributions and threats from mining activities in Kenya. We hypothesize that these taxa together comprise a monophyletic lineage, Trissevaniini, tr. nov., the members of which share the ability to fold their fore wings along two intersecting fold lines. Although wing folding of this type has been described for the hind wing of some insects four-plane wing folding of the fore wing has never been documented. The wing folding mechanism and the pattern of wing folds of Trissevaniini is shared only with some cockroach species (Blattodea. It is an interesting coincidence that all evaniids are predators of cockroach eggs. The major wing fold lines of Trissevaniini likely are not homologous to any known longitudinal anatomical structures on the wings of other Evaniidae. Members of the new tribe share the presence of a coupling mechanism between the fore wing and the mesosoma that is composed of a setal patch on the mesosoma and the retinaculum of the fore wing. While the setal patch is an evolutionary novelty, the retinaculum, which originally evolved to facilitate fore and hind wing coupling in Hymenoptera, exemplifies morphological exaptation. We also refine and clarify the Semantic Phenotype approach used in previous taxonomic revisions and explore the consequences of merging new with existing data. The way that semantic statements are formulated can evolve in parallel, alongside improvements to the ontologies themselves.

  5. Folding wings like a cockroach: a review of transverse wing folding ensign wasps (Hymenoptera: Evaniidae: Afrevania and Trissevania).

    Mikó, István; Copeland, Robert S; Balhoff, James P; Yoder, Matthew J; Deans, Andrew R


    We revise two relatively rare ensign wasp genera, whose species are restricted to Sub-Saharan Africa: Afrevania and Trissevania. Afrevania longipetiolata sp. nov., Trissevania heatherae sp. nov., T. hugoi sp. nov., T. mrimaensis sp. nov. and T. slideri sp. nov. are described, males and females of T. anemotis and Afrevania leroyi are redescribed, and an identification key for Trissevaniini is provided. We argue that Trissevania mrimaensis sp. nov. and T. heatherae sp. nov. populations are vulnerable, given their limited distributions and threats from mining activities in Kenya. We hypothesize that these taxa together comprise a monophyletic lineage, Trissevaniini, tr. nov., the members of which share the ability to fold their fore wings along two intersecting fold lines. Although wing folding of this type has been described for the hind wing of some insects four-plane wing folding of the fore wing has never been documented. The wing folding mechanism and the pattern of wing folds of Trissevaniini is shared only with some cockroach species (Blattodea). It is an interesting coincidence that all evaniids are predators of cockroach eggs. The major wing fold lines of Trissevaniini likely are not homologous to any known longitudinal anatomical structures on the wings of other Evaniidae. Members of the new tribe share the presence of a coupling mechanism between the fore wing and the mesosoma that is composed of a setal patch on the mesosoma and the retinaculum of the fore wing. While the setal patch is an evolutionary novelty, the retinaculum, which originally evolved to facilitate fore and hind wing coupling in Hymenoptera, exemplifies morphological exaptation. We also refine and clarify the Semantic Phenotype approach used in previous taxonomic revisions and explore the consequences of merging new with existing data. The way that semantic statements are formulated can evolve in parallel, alongside improvements to the ontologies themselves.

  6. Basal Complex and Basal Venation of Odonata Wings: Structural Diversity and Potential Role in the Wing Deformation

    Rajabi, H.; Ghoroubi, N.; Malaki, M.; Darvizeh, A.; Gorb, S. N.


    Dragonflies and damselflies, belonging to the order Odonata, are known to be excellent fliers with versatile flight capabilities. The ability to fly over a wide range of speeds, high manoeuvrability and great agility are a few characteristics of their flight. The architecture of the wings and their structural elements have been found to play a major role in this regard. However, the precise influence of individual wing components on the flight performance of these insects remains unknown. The design of the wing basis (so called basal complex) and the venation of this part are responsible for particular deformability and specific shape of the wing blade. However, the wing bases are rather different in representatives of different odonate groups. This presumably reflects the dimensions of the wings on one hand, and different flight characteristics on the other hand. In this article, we develop the first three-dimensional (3D) finite element (FE) models of the proximal part of the wings of typical representatives of five dragonflies and damselflies families. Using a combination of the basic material properties of insect cuticle, a linear elastic material model and a nonlinear geometric analysis, we simulate the mechanical behaviour of the wing bases. The results reveal that although both the basal venation and the basal complex influence the structural stiffness of the wings, it is only the latter which significantly affects their deformation patterns. The use of numerical simulations enabled us to address the role of various wing components such as the arculus, discoidal cell and triangle on the camber formation in flight. Our study further provides a detailed representation of the stress concentration in the models. The numerical analysis presented in this study is not only of importance for understanding structure-function relationship of insect wings, but also might help to improve the design of the wings for biomimetic micro-air vehicles (MAVs). PMID:27513753

  7. Flutter parametric studies of cantilevered twin-engine-transport type wing with and without winglet. Volume 1: Low-speed investigations

    Bhatia, K. G.; Nagaraja, K. S.


    Flutter characteristics of a cantilevered high aspect ratio wing with winglet were investigated. The configuration represented a current technology, twin-engine airplane. A low-speed and high-speed model were used to evaluate compressibility effects through transonic Mach numbers and a wide range of mass-density ratios. Four flutter mechanisms were obtained in test, as well as analysis from various combinations of configuration parameters. The coupling between wing tip vertical and chordwise motions was shown to have significant effect under some conditions. It is concluded that for the flutter model configurations studied, the winglet related flutter was amenable to the conventional flutter analysis techniques.

  8. The energetic cost of variations in wing span and wing asymmetry in the zebra finch Taeniopygia guttata.

    Hambly, C; Harper, E J; Speakman, J R


    Asymmetry is a difference in the sizes of bilaterally paired structures. Wing asymmetry may have an effect on the kinematics of flight, with knock-on effects for the energetic cost of flying. In this study the 13C-labelled bicarbonate technique was used to measure the energy expended during the flight of zebra finches Taeniopygia guttata, prior to and after experimental manipulation to generate asymmetry and a change in wing span by trimming the primary feathers. In addition, simultaneous high-speed video footage enabled differences in flight kinematics such as flight speed, wing amplitude, up- and downstroke duration and wing beat frequency to be examined. In 10 individuals, the primary feathers on the right wing were trimmed first, by 0.5 cm, and then by an additional 0.5 cm in six of these individuals. In a separate 'control' group (N=7), approximately 0.25 cm was trimmed off the primary feathers of both wings, to produce the same reduction in wing span as 0.5 cm trimmed from one wing, while maintaining symmetry. When birds were manipulated to become asymmetric they maintained flight speed. They also increased the left wing amplitude and decreased the right up- and downstroke durations to counteract the changes in wing shape, which meant that they had an increase in wing beat frequency. When the wing area was reduced while maintaining symmetry, birds flew with slower flight speed. In this case wing amplitude did not change and wing upstroke slightly decreased, causing an increased wing beat frequency. The mean flight cost in the pre-manipulated birds was 1.90+/-0.1 W. There was a slight increase in flight cost with both of the asymmetry manipulations (0.5 cm, increase of 0.04 W; 1.0 cm, increase of 0.12 W), neither of which reached statistical significance. There was, however, a significantly increased flight cost when the wing span was reduced without causing asymmetry (increase of 0.45 W; paired t-test T=2.3, P=0.03).

  9. Wing Force & Moment Characterization of Flapping Wings for Micro Air Vehicle Application


    is that position of the wing where φ = Φ0 as shown in Fig. 3(B). When Φ0 6= 0, the motion is called asymetric flapping. When Φ0 = 0, the motion is...For symmetric rotation, Ψ0 = 0, otherwise the motion is refered to as asymetric rotation. Angle of attack The angle of attack is the angle between

  10. Unsteady surface pressure measurements on a slender delta wing undergoing limit cycle wing rock

    Arena, Andrew S., Jr.; Nelson, Robert C.


    An experimental investigation of slender wing limit cycle motion known as wing rock was investigated using two unique experimental systems. Dynamic roll moment measurements and visualization data on the leading edge vortices were obtained using a free to roll apparatus that incorporates an airbearing spindle. In addition, both static and unsteady surface pressure data was measured on the top and bottom surfaces of the model. To obtain the unsteady surface pressure data a new computer controller drive system was developed to accurately reproduce the free to roll time history motions. The data from these experiments include, roll angle time histories, vortex trajectory data on the position of the vortices relative to the model's surface, and surface pressure measurements as a function of roll angle when the model is stationary or undergoing a wing rock motion. The roll time history data was numerically differentiated to determine the dynamic roll moment coefficient. An analysis of these data revealed that the primary mechanism for the limit cycle behavior was a time lag in the position of the vortices normal to the wing surface.

  11. Repeatable Manufacture of Wings for Flapping Wing Micro Air Vehicles Using Microelectromechanical System (MEMS) Fabrication Techniques


    104 A1.5 Dragonfly ......................................................................................................... 106 the size range being investigated include bats, swallows, hummingbirds, butterflies, beetles, dragonflies , and moths. A short synopsis of the...a MAV wing. Dragonflies are precise and controlled flyers, with the ability to hover and accelerate quickly, both from a dead stop as well as

  12. Three-dimensional winged nanocone optical antennas.

    Huttunen, Mikko J; Lindfors, Klas; Andriano, Domenico; Mäkitalo, Jouni; Bautista, Godofredo; Lippitz, Markus; Kauranen, Martti


    We introduce 3D optical antennas based on winged nanocones. The antennas support particle plasmon oscillations with current distributions that facilitate transformation of transverse far-field radiation to strong longitudinal local fields near the cone apices. We characterize the optical responses of the antennas by their extinction spectra and by second-harmonic generation microscopy with cylindrical vector beams. The results demonstrate a new 3D polarization-controllable optical antenna for applications in apertureless near-field microscopy, spectroscopy, and plasmonic sensing.

  13. Variable Geometry Aircraft Wing Supported by Struts And/Or Trusses

    Melton, John E. (Inventor); Dudley, Michael R. (Inventor)


    The present invention provides an aircraft having variable airframe geometry for accommodating efficient flight. The aircraft includes an elongated fuselage, an oblique wing pivotally connected with said fuselage, a wing pivoting mechanism connected with said oblique wing and said fuselage, and a brace operably connected between said oblique wing and said fuselage. The present invention also provides an aircraft having an elongated fuselage, an oblique wing pivotally connected with said fuselage, a wing pivoting mechanism connected with said oblique wing and said fuselage, a propulsion system pivotally connected with said oblique wing, and a brace operably connected between said propulsion system and said fuselage.

  14. Morphing Wing Design with an Innovative Three-Dimensional Warping Actuation Project

    National Aeronautics and Space Administration — Advanced wing configurations where traditional control surfaces are replaced by dynamically controlled distribution of wing twist and/or camber can provide...

  15. Global Local Structural Optimization of Transportation Aircraft Wings

    Ciampa, P.D.; Nagel, B.; Van Tooren, M.J.L.


    The study presents a multilevel optimization methodology for the preliminary structural design of transportation aircraft wings. A global level is defined by taking into account the primary wing structural components (i.e., ribs, spars and skin) which are explicitly modeled by shell layered finite e

  16. Inertial Force Coupling to Nonlinear Aeroelasticity of Flexible Wing Aircraft

    Nguyen, Nhan T.; Ting, Eric


    This paper investigates the inertial force effect on nonlinear aeroelasticity of flexible wing aircraft. The geometric are nonlinearity due to rotational and tension stiffening. The effect of large bending deflection will also be investigated. Flutter analysis will be conducted for a truss-braced wing aircraft concept with tension stiffening and inertial force coupling.

  17. Ray analysis of a class of hybrid cylindrical aircraft wings

    Jha, RM; Bokhari, SA; Sudhakan, V; Mahapatra, PR


    A new approach to the modelling of aircraft wings, based on the combination of hybrid quadric (parabolic and circular) cylinders, has been presented for electromagnetic applications. Closed-form expressions have been obtained for ray parameters required in the high-frequency mutual coupling computation of antenna pairs located arbitrarily on an aircraft wing.

  18. Influence of anisotropic piezoelectric actuators on wing aerodynamic forces


    Changing the shape of an airfoil to enhance overall aircraft performance has always been a goal of aircraft designers. Using smart material to reshape the wing can improve aerodynamic performance. The influence of anisotropic effects of piezoelectric actuators on the aerodynamic characteristics of a simplified HALE wing model was investigated. Test verification was conducted.

  19. Energy-based Aeroelastic Analysis and Optimisation of Morphing Wings

    De Breuker, R.


    Morphing aircraft can change their shape radically when confronted with a variety of conflicting flight conditions throughout their mission. For instance the F-14 Tomcat fighter aircraft, known from the movie Top Gun, was able to sweep its wings from a straight wing configuration to a highly swept v

  20. Influence of anisotropic piezoelectric actuators on wing aerodynamic forces

    GUAN De; LI Min; LI Wei; WANG MingChun


    Changing the shape of an airfoil to enhance overall aircraft performance has always been s goal of aircraft designers.Using smart material to reshape the wing can improve aerodynamic performance.The influence of anisotropic effects of piezo-electric actuators on the aerodynamic characteristics of a simplified HALE wing model was investigated.Test verification was conducted.

  1. Significance of wing morphometry in distinguishing some of the ...



    Jul 20, 2009 ... the photos, Scale factor values were shown on the ruler. Wing pho- tos were ... Analysis of wing Landmark data (in TPS format). At the end of the .... not clearly separated, and most groups were mixed. (Figure 9, Table 7).

  2. Wing flexibility effects in clap-and-fling

    Percin, M.; Hu, Y.; Van Oudheusden, B.W.; Remes, B.; Scarano, F.


    The work explores the use of time-resolved tomographic PIV measurements to study a flapping-wing model, the related vortex generation mechanisms and the effect of wing flexibility on the clap-and-fling movement in particular. An experimental setup is designed and realized in a water t

  3. The function of PS integrins in Drosophila wing morphogenesis.

    Wilcox, M; DiAntonio, A; Leptin, M


    Integrins are found on many cell types during the development of most organisms. In Drosophila their functions can be analysed genetically. An analysis of lethal mutations in a PS integrin gene showed that the integrins were required for muscle attachment and for certain cell sheet migrations during embryogenesis. In this paper we use viable mutations in integrin component genes to look at integrin function in the later stages of development of one adult structure, the wing. We show that two known viable mutations, one which has its primary effect on the fly's escape response, the other on wing morphogenesis, are mutations in the beta and PS2alpha subunits, respectively, of the PS integrins. The mutation non-jumper (mys(mj42)) in the beta subunit leads to wasting of the thoracic jump muscles. Flies in which the dosage of this allele is reduced (and no wildtype copy is present) show defects also in wing morphogenesis. The two surfaces of the wing fail to connect properly, resulting in 'blistering' of the wing and the formation of extra crossveins. The mutation in the gene for the PS2alpha integrin subunit, inflated, also leads to a failure in wing surface apposition and consequent wing blistering. When the two mutations are combined, the mutant phenotype is greatly enhanced. Thus, one of the roles of the PS integrins in late Drosophila development is to ensure the correct apposition and patterning of the wing epithelia.

  4. Anisotropism of the Non-Smooth Surface of Butterfly Wing

    Gang Sun; Yan Fang; Qian Cong; Lu-quan Ren


    Twenty-nine species of butterflies were collected for observation and determination of the wing surfaces using a Scanning Electron Microscope (SEM). Butterfly wing surface displays structural anisotropism in micro-, submicro- and nano-scales. The scales on butterfly wing surface arrange like overlapping roof tiles. There are submicrometric vertical gibbosities, horizontal links, and nano-protuberances on the scales. First-incline-then-drip method and first-drip-then-incline method were used to measure the Sliding Angle (SA) of droplet on butterfly wing surface by an optical Contact Angle (CA) measuring system.Relatively smaller sliding angles indicate that the butterfly wing surface has fine self-cleaning property. Significantly different SAs in various directions indicate the anisotropic self-cleaning property of butterfly wing surface. The SAs on the butterfly wing surface without scales are remarkably larger than those with scales, which proves the crucial role of scales in determining the self-cleaning property. Butterfly wing surface is a template for design and fabrication of biomimetic materials and self-cleaning substrates. This work may offer insights into how to design directional self-cleaning coatings and anisotropic wetting surface.

  5. Stable structural color patterns displayed on transparent insect wings.

    Shevtsova, Ekaterina; Hansson, Christer; Janzen, Daniel H; Kjærandsen, Jostein


    Color patterns play central roles in the behavior of insects, and are important traits for taxonomic studies. Here we report striking and stable structural color patterns--wing interference patterns (WIPs)--in the transparent wings of small Hymenoptera and Diptera, patterns that have been largely overlooked by biologists. These extremely thin wings reflect vivid color patterns caused by thin film interference. The visibility of these patterns is affected by the way the insects display their wings against various backgrounds with different light properties. The specific color sequence displayed lacks pure red and matches the color vision of most insects, strongly suggesting that the biological significance of WIPs lies in visual signaling. Taxon-specific color patterns are formed by uneven membrane thickness, pigmentation, venation, and hair placement. The optically refracted pattern is also stabilized by microstructures of the wing such as membrane corrugations and spherical cell structures that reinforce the pattern and make it essentially noniridescent over a large range of light incidences. WIPs can be applied to map the micromorphology of wings through direct observation and are useful in several fields of biology. We demonstrate their usefulness as identification patterns to solve cases of cryptic species complexes in tiny parasitic wasps, and indicate their potentials for research on the genetic control of wing development through direct links between the transregulatory wing landscape and interference patterns we observe in Drosophila model species. Some species display sexually dimorphic WIPs, suggesting sexual selection as one of the driving forces for their evolution.

  6. Closed-type wing for drones: positive and negative characteristics

    Leonid I. Gretchihin


    Full Text Available The paper presents the aerodynamics of a wing of a closed oval ellipsoidal shape, designed with the use of the molecular-kinetic theory. The positive and negative characteristics of aircraft - drones with an oval wing are described. The theoretical calculations have been experimentally checked.

  7. Jet reorientation in active galactic nuclei : two winged radio galaxies

    Dennett-Thorpe, J; Scheuer, PAG; Laing, RA; Bridle, AH; Pooley, GG; Reich, W


    Winged, or X-shaped, radio sources form a small class of morphologically peculiar extragalactic sources. We present multifrequency radio observations of two such sources. We derive maximum ages since any re-injection of fresh particles of 34 and 17 Myr for the wings of 3C 223.1 and 3C 403 respective

  8. Flapping-wing mechanical butterfly on a wheel

    Godoy-Diana, Ramiro; Thiria, Benjamin; Pradal, Daniel


    We examine the propulsive performance of a flapping-wing device turning on a ``merry-go-round'' type base. The two-wing flapper is attached to a mast that is ball-bearing mounted to a central shaft in such a way that the thrust force produced by the wings makes the flapper turn around this shaft. The oscillating lift force produced by the flapping wings is aligned with the mast to avoid vibration of the system. A turning contact allows to power the motor that drives the wings. We measure power consumption and cruising speed as a function of flapping frequency and amplitude as well as wing flexibility. The design of the wings permits to change independently their flexibility in the span-wise and chord-wise directions and PIV measurements in various planes let us examine the vorticity field around the device. A complete study of the effect of wing flexibility on the propulsive performance of the system will be presented at the conference.

  9. Vortex interactions with flapping wings and fins can be unpredictable

    Lentink, D.; Heijst, van G.J.F.; Muijres, F.T.; Leeuwen, van J.L.


    As they fly or swim, many animals generate a wake of vortices with their flapping fins and wings that reveals the dynamics of their locomotion. Previous studies have shown that the dynamic interaction of vortices in the wake with fins and wings can increase propulsive force. Here, we explore whether

  10. Comparison of wing-span averaging effects on lift, rolling moment, and bending moment for two span load distributions and for two turbulence representations

    Lichtenstein, J. H.


    An analytical method of computing the averaging effect of wing-span size on the loading of a wing induced by random turbulence was adapted for use on a digital electronic computer. The turbulence input was assumed to have a Dryden power spectral density. The computations were made for lift, rolling moment, and bending moment for two span load distributions, rectangular and elliptic. Data are presented to show the wing-span averaging effect for wing-span ratios encompassing current airplane sizes. The rectangular wing-span loading showed a slightly greater averaging effect than did the elliptic loading. In the frequency range most bothersome to airplane passengers, the wing-span averaging effect can reduce the normal lift load, and thus the acceleration, by about 7 percent for a typical medium-sized transport. Some calculations were made to evaluate the effect of using a Von Karman turbulence representation. These results showed that using the Von Karman representation generally resulted in a span averaging effect about 3 percent larger.

  11. Experimental fine-structure branching ratios for Na-rare-gas optical collisions

    Havey, M.D.; Delahanty, F.T.; Vahala, L.L.; Copeland, G.E.


    Experimental ratios for branching into the fine-structure levels of the Na 3p multiplet, as a consequence of an optical collision with He, Ne, Ar, Kr, or Xe, are reported. The process studied is Na(3s /sup 2/S/sub 1/2/) -->..Na(3p /sup 2/P/sub j/)+scrR+(n-1), where scrR represents a rare-gas atom and where the laser frequency is tuned in the wings of the Na resonance transitions. The branching ratios are defined as I(D1)/I(D2) where I(D1) and I(D2) are measured intensities of the atomic Na D1 and D2 lines. The ratios are determined for detunings ranging from about 650 cm/sup -1/ in the blue wing to 170 cm/sup -1/ in the red wing of the Na 3p multiplet. The branching is found to be strongly detuning dependent in the vicinity of the NaAr, NaKr, and NaXe near-red-wing satellites. The blue-wing branching ratios show a detuning-dependent approach to a recoil, or sudden statistical, limit of 0.5, irrespective of the rare gas. Fine-structure changing cross sections have also been measured for resonant excitation of the Na 3p /sup 2/P/sub j/ state; the results are consistent with cross sections obtained from wing excitation.

  12. On the Minimum Induced Drag of Wings

    Bowers, Albion H.


    Of all the types of drag, induced drag is associated with the creation and generation of lift over wings. Induced drag is directly driven by the span load that the aircraft is flying at. The tools by which to calculate and predict induced drag we use were created by Ludwig Prandtl in 1903. Within a decade after Prandtl created a tool for calculating induced drag, Prandtl and his students had optimized the problem to solve the minimum induced drag for a wing of a given span, formalized and written about in 1920. This solution is quoted in textbooks extensively today. Prandtl did not stop with this first solution, and came to a dramatically different solution in 1932. Subsequent development of this 1932 solution solves several aeronautics design difficulties simultaneously, including maximum performance, minimum structure, minimum drag loss due to control input, and solution to adverse yaw without a vertical tail. This presentation lists that solution by Prandtl, and the refinements by Horten, Jones, Kline, Viswanathan, and Whitcomb.



    The calculation of wing shielding effect starts from solving Ffowcs Williams and Hawkings equation without quadrupole source in time domain. The sound scattering of the wing and fuselage which are surrounded by a multi-propeller sound field is modeled as a second sound source. A program is developed to calculate the acoustical effects of the rigid fuselage as well as wings with arbitrary shape in motion at low Mach number. As an example, the numerical calculation of the wing shielding of Y12 aircraft with an approximate shape is presented. The result manifests clearly the shielding effect of the wing on the fuselage and the approach is more efficient than that published before.

  14. Four-winged flapping flyer in forward flight

    Godoy-Diana, Ramiro; Centeno, Mariana; Weinreb, Alexis; Thiria, Benjamin


    We study experimentally a four-winged flapping flyer with chord-wise flexible wings in a self-propelled setup. For a given physical configuration of the flyer (i.e. fixed distance between the forewing and hindwing pairs and fixed wing flexibility), we explore the kinematic parameter space constituted by the flapping frequency and the forewing-hindwing phase lag. Cruising speed and consumed electric power measurements are performed for each point in the $(f,\\varphi)$ parameter space and allow us to discuss the problem of performance and efficiency in four-winged flapping flight. We show that different phase-lags are needed for the system to be optimised for fastest flight or lowest energy consumption. A conjecture of the underlying mechanism is proposed in terms of the coupled dynamics of the forewing-hindwing phase lag and the deformation kinematics of the flexible wings.

  15. Optimization of Kinematics of a Flapping Wing Mechanism

    George, Ryan; Thomson, Scott; Mattson, Christopher; Colton, Mark; Tree, Mike


    Flapping flight offers several potential advantages over conventional fixed wing flight, such as agility and maneuverability in confined spaces, potentially decreased noise and detectability, and hovering capability. In this presentation, a water tunnel-based flapping wing apparatus is introduced that allows for arbitrary wing trajectories in three rotational degrees of freedom and simultaneous measurements of lift and thrust production. An optimal flapping trajectory for takeoff is found using hardware-in-the-loop optimization methodology. Wing motion derived from high-speed imaging of a ladybug during takeoff is used as a first iteration of the hardware-in-the-loop optimization. Using real-time force measurements and a gradient-based optimization approach, the algorithm searches for the optimal trajectory for a variety of parameters such as lift or efficiency. Hardware performance is assessed. Results from the optimization routine, including the final flapping trajectory are reported for both rigid and compliant wings.

  16. Design and Construction of Passively Articulated Ornithopter Wings

    Mastro, Alexander Timothy

    Birds, bats, and insects are able to fly efficiently and execute impressive in-flight, landing, and takeoff maneuvers with apparent ease through actuation of their highly articulated wings. This contrasts the approach used to enable the flight of comparatively simple man-made rotary and fixed wing aircraft. The complex aerodynamics underlying flapping-based flight pose an everpresent challenge to scientists hoping to reveal the secrets of animal flight. Despite this, interest in engineering aircraft on the bird and insect scale is higher than ever. Herein, I present my attempt to design and construct bioinspired passively articulated ornithopter wings. Two different hinge-based joint design concepts are investigated across several design iterations. The advantages and disadvantages of each implementation are discussed. Finally, the necessary instrumentation to analyze the performance of the wings is designed and fabricated, followed by testing of the wings.

  17. Physical properties of the benchmark models program supercritical wing

    Dansberry, Bryan E.; Durham, Michael H.; Bennett, Robert M.; Turnock, David L.; Silva, Walter A.; Rivera, Jose A., Jr.


    The goal of the Benchmark Models Program is to provide data useful in the development and evaluation of aeroelastic computational fluid dynamics (CFD) codes. To that end, a series of three similar wing models are being flutter tested in the Langley Transonic Dynamics Tunnel. These models are designed to simultaneously acquire model response data and unsteady surface pressure data during wing flutter conditions. The supercritical wing is the second model of this series. It is a rigid semispan model with a rectangular planform and a NASA SC(2)-0414 supercritical airfoil shape. The supercritical wing model was flutter tested on a flexible mount, called the Pitch and Plunge Apparatus, that provides a well-defined, two-degree-of-freedom dynamic system. The supercritical wing model and associated flutter test apparatus is described and experimentally determined wind-off structural dynamic characteristics of the combined rigid model and flexible mount system are included.

  18. Ontogeny of aerial righting and wing flapping in juvenile birds

    Evangelista, Dennis; Huynh, Tony; Krivitskiy, Igor; Dudley, Robert


    Mechanisms of aerial righting in juvenile Chukar Partridge (Alectoris chukar) were studied from hatching through 14 days post hatching (dph). Asymmetric movements of the wings were used from 1 to 8 dph to effect progressively more successful righting behaviour via body roll. Following 8 dph, wing motions transitioned to bilaterally symmetric flapping that yielded aerial righting via nose down pitch, along with substantial increases in vertical force production during descent. Ontogenetically, the use of such wing motions to effect aerial righting precedes both symmetric flapping and a previously documented behaviour in chukar (i.e., wing assisted incline running) hypothesized to be relevant to incipient flight evolution in birds. These findings highlight the importance of asymmetric wing activation and controlled aerial manoeuvres during bird development, and are potentially relevant to understanding the origins of avian flight.

  19. Wind-Tunnel Investigation of Subsonic Longitudinal Aerodynamic Characteristics of a Tiltable-Wing Vertical-Take-Off-and-Landing Supersonic Bomber Configuration Including Turbojet Power Effects

    Thompson, Robert F.; Vogler, Raymond D.; Moseley, William C., Jr.


    Jet-powered model tests were made to determine the low-speed longitudinal aerodynamic characteristics of a vertical-take-off and-landing supersonic bomber configuration. The configuration has an unique engine-wing arrangement wherein six large turbojet engines (three on each side of the fuselage) are buried in a low-aspect-ratio wing which is tilted into the vertical plane for take-off. An essentially two-dimensional variable inlet, spanning the leading edge of each wing semispan, provides air for the engines. Jet flow conditions were simulated for a range of military (nonafterburner) and afterburner turbojet-powered flight at subsonic speeds. Three horizontal tails were tested at a station down-stream of the jet exit and at three heights above the jet axes. A semi-span model was used and test parameters covered wing-fuselage incidence angles from 0 deg to 15 deg, wing angles of attack from -4 deg to 36 deg, a variable range of horizontal-tail incidence angles, and some variations in power simulation conditions. Results show that, with all horizontal tails tested, there were large variations in static stability throughout the lift range. When the wing and fuselage were alined, the model was statically stable throughout the test range only with the largest tail tested (tail span of 1.25 wing span) and only when the tail was located in the low test position which placed the tail nearest to the undeflected jet. For transition flight conditions, none of the tail configurations provided satisfactory longitudinal stability or trim throughout the lift range. Jet flow was destabilizing for most of the test conditions, and varying the jet-exit flow conditions at a constant thrust coefficient had little effect on the stability of this model. Wing leading-edge simulation had some important effects on the longitudinal aerodynamic characteristics.

  20. On the Importance of Nonlinear Aeroelasticity and Energy Efficiency in Design of Flying Wing Aircraft

    Pezhman Mardanpour


    Full Text Available Energy efficiency plays important role in aeroelastic design of flying wing aircraft and may be attained by use of lightweight structures as well as solar energy. NATASHA (Nonlinear Aeroelastic Trim And Stability of HALE Aircraft is a newly developed computer program which uses a nonlinear composite beam theory that eliminates the difficulties in aeroelastic simulations of flexible high-aspect-ratio wings which undergoes large deformation, as well as the singularities due to finite rotations. NATASHA has shown that proper engine placement could significantly increase the aeroelastic flight envelope which typically leads to more flexible and lighter aircraft. The areas of minimum kinetic energy for the lower frequency modes are in accordance with the zones with maximum flutter speed and have the potential to save computational effort. Another aspect of energy efficiency for High Altitude, Long Endurance (HALE drones stems from needing to minimize energy consumption because of limitations on the source of energy, that is, solar power. NATASHA is capable of simulating the aeroelastic passive morphing maneuver (i.e., morphing without relying on actuators and at as near zero energy cost as possible of the aircraft so as the solar panels installed on the wing are in maximum exposure to sun during different time of the day.

  1. Aircraft wing structural design optimization based on automated finite element modelling and ground structure approach

    Yang, Weizhu; Yue, Zhufeng; Li, Lei; Wang, Peiyan


    An optimization procedure combining an automated finite element modelling (AFEM) technique with a ground structure approach (GSA) is proposed for structural layout and sizing design of aircraft wings. The AFEM technique, based on CATIA VBA scripting and PCL programming, is used to generate models automatically considering the arrangement of inner systems. GSA is used for local structural topology optimization. The design procedure is applied to a high-aspect-ratio wing. The arrangement of the integral fuel tank, landing gear and control surfaces is considered. For the landing gear region, a non-conventional initial structural layout is adopted. The positions of components, the number of ribs and local topology in the wing box and landing gear region are optimized to obtain a minimum structural weight. Constraints include tank volume, strength, buckling and aeroelastic parameters. The results show that the combined approach leads to a greater weight saving, i.e. 26.5%, compared with three additional optimizations based on individual design approaches.

  2. The interference aerodynamics caused by the wing elasticity during store separation

    Lei, Yang; Zheng-yin, Ye


    Air-launch-to-orbit is the technology that has stores carried aloft and launched the store from the plane to the orbit. The separation between the aircraft and store is one of the most important and difficult phases in air-launch-to-orbit technology. There exists strong aerodynamic interference between the aircraft and the store in store separation. When the aspect ratio of the aircraft is large, the elastic deformations of the wing must be considered. The main purpose of this article is to study the influence of the interference aerodynamics caused by the elastic deformations of the wing to the unsteady aerodynamics of the store. By solving the coupled functions of unsteady Navier-Stokes equations, six degrees of freedom dynamic equations and structural dynamic equations simultaneously, the store separation with the elastic deformation of the aircraft considered is simulated numerically. And the interactive aerodynamic forces are analyzed. The study shows that the interference aerodynamics is obvious at earlier time during the separation, and the dominant frequency of the elastic wing determines the aerodynamic forces frequencies of the store. Because of the effect of the interference aerodynamics, the roll angle response and pitch angle response increase. When the store is mounted under the wingtip, the additional aerodynamics caused by the wingtip vortex is obvious, which accelerate the divergence of the lateral force and the lateral-directional attitude angle of the store. This study supports some beneficial conclusions to the engineering application of the air-launch-to-orbit.

  3. Nonlinear analysis and enhancement of wing-based piezoaeroelastic energy harvesters

    Abdelkefi, Abdessattar


    We investigate the level of harvested power from aeroelastic vibrations for an elastically mounted wing supported by nonlinear springs. The energy is harvested by attaching a piezoelectric transducer to the plunge degree of freedom. The considered wing has a low-aspect ratio and hence three dimensional aerodynamic effects cannot be neglected. To this end, the three dimensional unsteady vortex lattice method for the prediction of the unsteady aerodynamic loads is developed. A strong coupling scheme that is based on Hamming\\'s fourth-order predictor-corrector method and accounts for the interaction between the aerodynamic loads and the motion of the wing is employed. The effects of the electrical load resistance, nonlinear torsional spring and eccentricity between the elastic axis and the gravity axis on the level of the harvested power, pitch and plunge amplitudes are investigated for a range of operating wind speeds. The results show that there is a specific wind speed beyond which the pitch motion does not pick any further energy from the incident flow. As such, the displacement in the plunge direction grows significantly and causes enhanced energy harvesting. The results also show that the nonlinear torsional spring plays an important role in enhancing the level of the harvested power. Furthermore, the harvested power can be increased by an order of magnitude by properly choosing the eccentricity and the load resistance. This analysis is helpful in designing piezoaeroelastic energy harvesters that can operate optimally at specific wind speeds. © 2013 Elsevier Ltd.

  4. A Chandra Study of the Radio Galaxy NGC 326: Wings, Outburst History, and AGN Feedback

    Hodges-Kluck, Edmund


    NGC 326 is one of the most prominent X- or Z-shaped radio galaxies (XRGs/ZRGs) and has been the subject of several studies attempting to explain its morphology through either fluid motions or reorientation of the jet axis. We examine a 100 ks archival Chandra exposure and find several features associated with the radio galaxy: a high-temperature front that may indicate a shock, high-temperature knots around the rim of the radio emission, and a cavity associated with the eastern wing of the radio galaxy. A reasonable interpretation of these features in light of the radio data allows us to reconstruct the history of the AGN outbursts. The active outburst was likely once a powerful radio source which has since decayed, and circumstantial evidence favors reorientation as the means to produce the wings. Because of the obvious interaction between the radio galaxy and the ICM and the wide separation between the active lobes and wings, we conclude that XRGs are excellent sources in which to study AGN feedback in gala...

  5. Factors Affecting the Incidence of Angel Wing in White Roman Geese: Stocking Density and Genetic Selection.

    Lin, M J; Chang, S C; Lin, T Y; Cheng, Y S; Lee, Y P; Fan, Y K


    The present study investigated stocking density and genetic lines, factors that may alter the severity and incidence of angel wing (AW), in White Roman geese. Geese (n = 384) from two genetically selected lines (normal- winged line, NL, and angel-winged line, AL, respectively) and one commercial line (CL) were raised in four pens. Following common commercial practice, low-stocking-density (LD), medium-stocking-density, and high-stocking-density treatments were respectively administered to 24, 32, and 40 geese per pen at 0 to 3 weeks (1.92 m(2)/pen) and 4 to 6 weeks (13.2 m(2)/pen) of age and to 24, 30, and 36 geese at 7 to 14 weeks (20.0 m(2)/pen) of age. The results revealed that stocking density mainly affected body weight gain in geese younger than 4 weeks, and that geese subjected to LD had a high body weight at 2 weeks of age. However, the effect of stocking density on the severity score of AW (SSAW) and incidence of AW (IAW) did not differ significantly among the treatments. Differences were observed among the genetic stocks; that is, SSAW and IAW were significantly higher in AL than in NL and CL. Genetic selection generally aggravates AW, complicating its elimination. To effectively reduce IAW, stocking density, a suspected causal factor, should be lower than that presently applied commercially.

  6. Comparison of data correction methods for blockage effects in semispan wing model testing

    Haque Anwar U


    Full Text Available Wing alone models are usually tested in wind tunnels for aerospace applications like aircraft and hybrid buoyant aircraft. Raw data obtained from such testing is subject to different corrections such as wall interference, blockage, offset in angle of attack, dynamic pressure and free stream velocity etc. Since the flow is constrained by wind tunnel walls, therefore special emphasis is required to deliberate the limitation of correction methods for blockage correction. In the present research work, different aspects of existing correction methods are explored with the help of an example of a straight semi-span wing. Based on the results of analytical relationships of standard methods, it was found that although multiple variables are involved in the standard methods for the estimation of blockage, they are based on linearized flow theory such as source sink method and potential flow assumption etc, which have intrinsic limitations. Based on the computed and estimated experimental results, it is recommended to obtain the corrections by adding the difference in results of solid walls and far-field condition in the wind tunnel data. Computational Fluid Dynamics technique is found to be useful to determine the correction factors for a wing installed at zero spacer height/gap, with and without the tunnel wall.

  7. Comparison of data correction methods for blockage effects in semispan wing model testing

    Haque, Anwar U.; Asrar, Waqar; Omar, Ashraf A.; Sulaeman, Erwin; J. S Ali, Mohamed


    Wing alone models are usually tested in wind tunnels for aerospace applications like aircraft and hybrid buoyant aircraft. Raw data obtained from such testing is subject to different corrections such as wall interference, blockage, offset in angle of attack, dynamic pressure and free stream velocity etc. Since the flow is constrained by wind tunnel walls, therefore special emphasis is required to deliberate the limitation of correction methods for blockage correction. In the present research work, different aspects of existing correction methods are explored with the help of an example of a straight semi-span wing. Based on the results of analytical relationships of standard methods, it was found that although multiple variables are involved in the standard methods for the estimation of blockage, they are based on linearized flow theory such as source sink method and potential flow assumption etc, which have intrinsic limitations. Based on the computed and estimated experimental results, it is recommended to obtain the corrections by adding the difference in results of solid walls and far-field condition in the wind tunnel data. Computational Fluid Dynamics technique is found to be useful to determine the correction factors for a wing installed at zero spacer height/gap, with and without the tunnel wall.

  8. Dynamic Pattern Formation for Wings of Pterygota in an Eclosion ---Pattern Analysis for Wings with the Imago---

    Seino, M.; Kakazu, Y.

    The vein and cell patterns for the fore and hind wing of Lepidoptera, Hemiptera, Orthoptera and Odonata are analyzed and discussed. For vein patterns of them, the fractal properties are shown and the inequality between four orders is obtained. The nature of wings observed by mass distributions for fractal dimensions of the vein pattern is presented.

  9. Is there a right-wing alternative to the left-wing Bohemianism in Israel?

    Cyril Aslanov


    Full Text Available Cet article s’efforce de comprendre les raisons de l’absence d’une bohème littéraire de droite en Israël. Au-delà des facteurs structurels liés à l’association naturelle de la bohème avec la gauche, soit comme un choix par défaut soit comme un terme marqué, le conservatisme inhérent à la littérature droitière est incompatible avec la renonciation au passé qui caractérise souvent les lettres israéliennes. En outre, la bohème de gauche en Israël ne tarit pas de critiques vis-à-vis de son propre pays. Cette préoccupation brille par son absence dans les écrits souvent partisans émanant de la droite. Enfin, la réception de la littérature israélienne hors d’Israël favorise nettement la bohème littéraire de gauche au point qu’on voit se dessiner une répartition complémentaire entre la droite aux commandes du pays et la gauche, maîtresse presque exclusive du Parnasse israélien.This article tries to understand why a right-wing literary Bohemianism failed to emerge in Israel. Besides the structural reasons connected with the natural association of Bohemianism with the Left, either as a default choice or as a marked option, the conservatism inherent to right-wing oriented literature is incompatible with modern Israeli attempt to get rid of the tradition. Moreover, what makes left-wing Israeli Bohemianism more credible is its constant need of self-criticism, a concern that blatantly lacks in the partisan writing emanating from the Right. Lastly, the reception abroad obviously favors left-wing Israeli Bohemianism to the extent that there might be a complementary distribution of functions between right-wing politics and left-wing literature in contemporary Israel.

  10. Transonic Aerodynamic Characteristics of a 45 deg Swept Wing Fuselage Model with a Finned and Unfinned Body Pylon Mounted Beneath the Fuselage or Wing, Including Measurements of Body Loads

    Wornom, Dewey E.


    An investigation of a model of a standard size body in combination with a representative 45 deg swept-wing-fuselage model has been conducted in the Langley 8-foot transonic pressure tunnel over a Mach number range from 0.80 to 1.43. The body, with a fineness ratio of 8.5, was tested with and without fins, and was pylon-mounted beneath the fuselage or wing. Force measurements were obtained on the wing-fuselage model with and without the body, for an angle-of-attack range from -2 deg to approximately 12 deg and an angle-of-sideslip range from -8 deg to 8 deg. In addition, body loads were measured over the same angle-of-attack and angle-of-sideslip range. The Reynolds number for the investigation, based on the wing mean aerodynamic chord, varied from 1.85 x 10(exp 6) to 2.85 x 10(exp 6). The addition of the body beneath the fuselage or the wing increased the drag coefficient of the complete model over the Mach number range tested. On the basis of the drag increase per body, the under-fuselage position was the more favorable. Furthermore, the bodies tended to increase the lateral stability of the complete model. The variation of body loads with angle of attack for the unfinned bodies was generally small and linear over the Mach number range tested with the addition of fins causing large increases in the rates of change of normal-force coefficient and nose-down pitching-moment coefficient. The variation of body side-force coefficient with sideslip for the unfinned body beneath the fuselage was at least twice as large as the variation of this load for the unfinned body beneath the wing. The addition of fins to the body beneath either the fuselage or the wing approximately doubled the rate of change of body side-force coefficient with sideslip. Furthermore, the variation of body side-force coefficient with sideslip for the body beneath the wing was at least twice as large as the variation of this load with angle of attack.

  11. Effect of a wing-tip mounted pusher turboprop on the aerodynamic characteristics of a semi-span wing

    Patterson, J. C., Jr.; Bartlett, G. R.


    An exploratory investigation has been conducted at the NASA Langley Research Center to determine the installed performance of a wing tip-mounted pusher turboprop. Tests were conducted using a semispan model having an unswept, untapered wing with a air-driven motor located on the tip of the wing, with an SR-2 design high speed propeller installed on the rear shaft of the motor. All tests were conducted at a Mach number of 0.70, at angles of attack of approximately -2 to +4 deg, and at a Reynolds number of 3.82 million based on the wing chord of 13 inches. The data indicate that, as a result of locating the propeller behind the wing trailing edge, at the wingtip, in the cross flow of the tip vortex, it is possible to recover part of the vortex energy as an increase in propeller thrust and, therefore, a reduction in the lift-induced drag as well.

  12. Transition from leg to wing forces during take-off in birds.

    Provini, Pauline; Tobalske, Bret W; Crandell, Kristen E; Abourachid, Anick


    Take-off mechanics are fundamental to the ecology and evolution of flying animals. Recent research has revealed that initial take-off velocity in birds is driven mostly by hindlimb forces. However, the contribution of the wings during the transition to air is unknown. To investigate this transition, we integrated measurements of both leg and wing forces during take-off and the first three wingbeats in zebra finch (Taeniopygia guttata, body mass 15 g, N=7) and diamond dove (Geopelia cuneata, body mass 50 g, N=3). We measured ground reaction forces produced by the hindlimbs using a perch mounted on a force plate, whole-body and wing kinematics using high-speed video, and aerodynamic forces using particle image velocimetry (PIV). Take-off performance was generally similar between species. When birds were perched, an acceleration peak produced by the legs contributed to 85±1% of the whole-body resultant acceleration in finch and 77±6% in dove. At lift-off, coincident with the start of the first downstroke, the percentage of hindlimb contribution to initial flight velocity was 93.6±0.6% in finch and 95.2±0.4% in dove. In finch, the first wingbeat produced 57.9±3.4% of the lift created during subsequent wingbeats compared with 62.5±2.2% in dove. Advance ratios were aerodynamics during wingbeats 2 and 3. These results underscore the relatively low contribution of the wings to initial take-off, and reveal a novel transitional role for the first wingbeat in terms of force production.

  13. Reproductive success and habitat characteristics of Golden-winged Warblers in high-elevation pasturelands

    Wood, Petra; Aldinger, Kyle R.


    The Golden-winged Warbler (Vermivora chrysoptera) is one of the most rapidly declining vertebrate species in the Appalachian Mountains. It is the subject of extensive range-wide research and conservation action. However, little is known about this species' breeding ecology in high-elevation pasturelands, a breeding habitat with conservation potential considering the U.S. Natural Resource Conservation Service's Working Lands for Wildlife program targeting private lands in the Appalachian Mountains. We located 100 nests of Golden-winged Warblers in pastures in and around the Monongahela National Forest in West Virginia during 2008–2012. Daily nest survival rate (mean ± SE  =  0.962 ± 0.006), clutch size (4.5 ± 0.1), and number of young fledged per nest attempt (2.0 ± 0.2) and successful nest (4.0 ± 0.1) fell within the range of values reported in other parts of the species' range and were not significantly affected by year or the presence/absence of cattle grazing. Classification tree analysis revealed that nests were in denser vegetation (≥52%) and closer to forest edges (<36.0 m) and shrubs (<7.0 cm) than random locations within the male's territory. Successful nests had significantly more woody cover (≥9%) within 1 m than failed nests. Our results suggest that cattle grazing at 1.2–2.4 ha of forage/animal unit with periodic mowing can create and maintain these characteristics without interfering with the nesting of Golden-winged Warblers. High-elevation pasturelands may provide a refuge for remaining populations of Golden-winged Warblers in this region.

  14. Multidisciplinary design optimization of adaptive wing leading edge

    SUN; RuJie; CHEN; GuoPing; ZHOU; Chen; ZHOU; LanWei; JIANG; JinHui


    Adaptive wing can significantly enhance aircraft aerodynamic performance, which refers to aerodynamic and structural opti-mization designs. This paper introduces a two-step approach to solve the interrelated problems of the adaptive leading edge. In the first step, the procedure of airfoil optimization is carried out with an initial configuration of NACA 0006. On the basis of the combination of design of experiment (DOE), response surface method (RSM) and genetic algorithm (GA), an adaptive air-foil can be obtained whose lift-to-drag ratio is larger than the baseline airfoil’s at the given angle of attack and subsonic speed.The next step is to design a compliant structure to achieve the target airfoil shape, which is the optimization result of the previous step. In order to minimize the deviation of the deformed shape from the target shape, the load path representation topology method is presented. This method is developed by way of GA, with size and shape optimization incorporated in it simul-taneously. Finally, a comparison study with the Solid Isotropic Material with Penalization (SIMP) method in Altair OptiStruct is conducted, and the results demonstrate the validity and effectiveness of the proposed approach.

  15. An experimental study of tip shape effects on the flutter of aft-swept, flat-plate wings

    Dansberry, Bryan E.; Rivera, Jose A., Jr.; Farmer, Moses G.


    The effects of tip chord orientation on wing flutter are investigated experimentally using six cantilever-mounted, flat-plate wing models. Experimentally determined flutter characteristics of the six models are presented covering both the subsonic and transonic Mach number ranges. While all models have a 60 degree leading edge sweep, a 40.97 degree trailing edge sweep, and a root chord of 34.75 inches, they are subdivided into two series characterized by a higher aspect ratio and a lower aspect ratio. Each series is made up of three models with tip chord orientations which are parallel to the free-stream flow, perpendicular to the model mid-chord line, and perpendicular to the free-stream flow. Although planform characteristics within each series of models are held constant, structural characteristics such as mode shapes and natural frequencies are allowed to vary.

  16. Variable-complexity aerodynamic optimization of an HSCT wing using structural wing-weight equations

    Hutchison, M. G.; Unger, E. R.; Mason, W. H.; Grossman, B.; Haftka, R. T.


    A new approach for combining conceptual and preliminary design techniques for wing optimization is presented for the high-speed civil transport (HSCT). A wing-shape parametrization procedure is developed which allows the linking of planform and airfoil design variables. Variable-complexity design strategies are used to combine conceptual and preliminary-design approaches, both to preserve interdisciplinary design influences and to reduce computational expense. In the study, conceptual-design-level algebraic equations are used to estimate aircraft weight, supersonic wave drag, friction drag and drag due to lift. The drag due to lift and wave drag are also evaluated using more detailed, preliminary-design-level techniques. The methodology is applied to the minimization of the gross weight of an HSCT that flies at Mach 3.0 with a range of 6500 miles.

  17. Jet noise of high aspect-ratio rectangular nozzles with application to pneumatic high-lift devices

    Munro, Scott Edward

    Circulation control wings are a type of pneumatic high-lift device that have been extensively researched as to their aerodynamic benefits. However, there has been little research into the possible airframe noise reduction benefits. The key element of noise is the jet noise associated with the jet sheet emitted from the blowing slot. This jet sheet is essentially a high aspect-ratio rectangular jet. This study directly compared far-field noise emissions from a state-of-the-art circulation control wing high lift configuration, and a conventional wing also configured for high lift. Results indicated that a circulation control wing had a significant acoustic advantage over a conventional wing for identical lift performance. A high aspect-ratio nozzle was fabricated to study the general characteristics of high aspect-ratio jets with aspect ratios from 100 to 3000. The results of this study provided the basic elements in understanding how to reduce the noise from a circulation control wing. High aspect-ratio nozzle results showed that the jet noise of this type of jet was proportional to the 8th power of the jet velocity. It was also found that the jet noise was proportional to the slot height to the 3/2 power and slot width to the 1/2 power. Fluid dynamic experiments were also performed on the high aspect-ratio nozzle. Single hot-wire experiments indicated that the jet exhaust from the high aspect-ratio nozzle was similar to a 2-d turbulent jet. Two-wire space-correlation experiments were performed to attempt to find a relationship between the slot height of the jet and the length-scale of the flow noise generating turbulence structure. The turbulent eddy convection velocity was also calculated, and was found to vary with the local centerline velocity, and also as a function of the frequency of the eddy.

  18. Numerical Wing/Store Interaction Analysis of a Parametric F16 Wing

    Cattarius, Jens


    A new numerical methodology to examine fluid-structure interaction of a wing/pylon/store system has been developed. The aeroelastic equation of motion of the complete system is solved iteratively in the time domain using a two-entity numerical code comprised of ABAQUS/Standard and the Unsteady-Vortex-Lattice Method. Both codes communicate through an iterative handshake procedure during which displacements and air loads are updated. For each increment in time the force/displacement equilibriu...

  19. Digital Morphing Wing: Active Wing Shaping Concept Using Composite Lattice-Based Cellular Structures

    Jenett, Benjamin; Calisch, Sam; Cellucci, Daniel; Cramer, Nick; Gershenfeld, Neil; Swei, Sean


    Abstract We describe an approach for the discrete and reversible assembly of tunable and actively deformable structures using modular building block parts for robotic applications. The primary technical challenge addressed by this work is the use of this method to design and fabricate low density, highly compliant robotic structures with spatially tuned stiffness. This approach offers a number of potential advantages over more conventional methods for constructing compliant robots. The discrete assembly reduces manufacturing complexity, as relatively simple parts can be batch-produced and joined to make complex structures. Global mechanical properties can be tuned based on sub-part ordering and geometry, because local stiffness and density can be independently set to a wide range of values and varied spatially. The structure's intrinsic modularity can significantly simplify analysis and simulation. Simple analytical models for the behavior of each building block type can be calibrated with empirical testing and synthesized into a highly accurate and computationally efficient model of the full compliant system. As a case study, we describe a modular and reversibly assembled wing that performs continuous span-wise twist deformation. It exhibits high performance aerodynamic characteristics, is lightweight and simple to fabricate and repair. The wing is constructed from discrete lattice elements, wherein the geometric and mechanical attributes of the building blocks determine the global mechanical properties of the wing. We describe the mechanical design and structural performance of the digital morphing wing, including their relationship to wind tunnel tests that suggest the ability to increase roll efficiency compared to a conventional rigid aileron system. We focus here on describing the approach to design, modeling, and construction as a generalizable approach for robotics that require very lightweight, tunable, and actively deformable structures. PMID:28289574

  20. Noise of model target type thrust reversers for engine-over-the-wing applications

    Stone, J. R.; Gutierrez, O. A.


    The present work reports on experiments concerning the noise generated by V-gutter and semicylindrical target reversers with circular and short-aspect-ratio slot nozzles having equivalent diameters of about 5 cm. At subsonic jet velocities of interest for engine-over-the-wing (OTW) powered-lift aircraft, the reversers were noisier than the nozzles alone and had a more uniform directional distribution and more high-frequency noise. Reverser shape was more important than nozzle shape in determining the reverser noise characteristics. An estimate is made of perceived noise level along the 152-m sideline for a hypothetical OTW powered-lift airplane.

  1. Ornithopter Type Flapping Wings for Autonomous Micro Air Vehicles

    Sutthiphong Srigrarom


    Full Text Available In this paper, an ornithopter prototype that mimics the flapping motion of bird flight is developed, and the lift and thrust generation characteristics of different wing designs are evaluated. This project focused on the spar arrangement and material used for the wings that could achieves improved performance. Various lift and thrust measurement techniques are explored and evaluated. Various wings of insects and birds were evaluated to understand how these natural flyers with flapping wings are able to produce sufficient lift to fly. The differences in the flapping aerodynamics were also detailed. Experiments on different wing designs and materials were conducted and a paramount wing was built for a test flight. The first prototype has a length of 46.5 cm, wing span of 88 cm, and weighs 161 g. A mechanism which produced a flapping motion was fabricated and designed to create flapping flight. The flapping flight was produced by using a single motor and a flexible and light wing structure. A force balance made of load cell was then designed to measure the thrust and lift force of the ornithopter. Three sets of wings varying flexibility were fabricated, therefore lift and thrust measurements were acquired from each different set of wings. The lift will be measured in ten cycles computing the average lift and frequency in three different speeds or frequencies (slow, medium and fast. The thrust measurement was measure likewise but in two cycles only. Several observations were made regarding the behavior of flexible flapping wings that should aid in the design of future flexible flapping wing vehicles. The wings angle or phase characteristic were analyze too and studied. The final ornithopter prototype weighs only 160 g, has a wing span of 88.5 cm, that could flap at a maximum flapping frequency of 3.869 Hz, and produce a maximum thrust and lift of about 0.719 and 0.264 N respectively. Next, we proposed resonance type flapping wing utilizes the near

  2. Turbulent Flow Over a Low-Camber Pitching Arc Wing

    Molki, Majid


    Aerodynamics of pitching airfoils and wings are of great importance to the design of air vehicles. This investigation presents the effect of camber on flow field and force coefficient for a pitching circular-arc airfoil. The wing considered in this study is a cambered plate of zero thickness which executes a linear pitch ramp, hold and return of 45° amplitude. The momentum equation is solved on a mesh that is attached to the wing and executes a pitching motion with the wing about a pivot point located at 0.25-chord or 0.50-chord distance from the leading edge. Turbulence is modeled by the k - ω SST model. Using the open-source software OpenFOAM, the conservation equations are solved on a dynamic mesh and the flow is resolved all the way to the wall (y+ ~ 1). The computations are performed for Re = 40,000 with the reduced pitch rate equal to K = cθ˙ / 2U∞ = 0 . 2 . The results are presented for three wings, namely, a flat plate (zero camber) and wings of 4% and 10% camber. It is found that the flow has complex features such as leading-edge vortex, near-wake vortex pairs, clockwise and counter-clockwise vortices, and trailing-edge vortex. While vortices are formed over the flat plate, they are formed both over and under the cambered wing.

  3. Aerodynamics and flight performance of flapping wing micro air vehicles

    Silin, Dmytro

    Research efforts in this dissertation address aerodynamics and flight performance of flapping wing aircraft (ornithopters). Flapping wing aerodynamics was studied for various wing sizes, flapping frequencies, airspeeds, and angles of attack. Tested wings possessed both camber and dihedral. Experimental results were analyzed in the framework of momentum theory. Aerodynamic coefficients and Reynolds number are defined using a reference velocity as a vector sum of a freestream velocity and a strokeaveraged wingtip velocity. No abrupt stall was observed in flapping wings for the angle of attack up to vertical. If was found that in the presence of a freestream lift of a flapping wing in vertical position is higher than the propulsive thrust. Camber and dihedral increased both lift and thrust. Lift-curve slope, and maximum lift coefficient increased with Reynolds number. Performance model of an ornithopter was developed. Parametric studies of steady level flight of ornithopters with, and without a tail were performed. A model was proposed to account for wing-sizing effects during hover. Three micro ornithopter designs were presented. Ornithopter flight testing and data-logging was performed using a telemetry acquisition system, as well as motion capture technology. The ability of ornithopter for a sustained flight and a presence of passive aerodynamic stability were shown. Flight data were compared with performance simulations. Close agreement in terms of airspeed and flapping frequency was observed.

  4. The design and testing of subscale smart aircraft wing bolts

    Vugampore, J. M. V.; Bemont, C.


    Presently costly periodic inspection is vital in guaranteeing the structural integrity of aircraft. This investigation assesses the potential for significantly reducing aircraft maintenance costs without modification of aircraft structures by implementing smart wing bolts, manufactured from TRIP steel, which can be monitored for damage in situ. TRIP steels undergo a transformation from paramagnetic austenite to ferromagnetic martensite during deformation. Subscale smart aircraft wing bolts were manufactured from hot rolled TRIP steel. These wing bolts were used to demonstrate that washers incorporating embedded inductance coils can be utilized to measure the martensitic transformation occurring in the TRIP steel during bolt deformation. Early in situ warning of a critical bolt stress level was thereby facilitated, potentially reducing the costly requirement for periodic wing bolt removal and inspection. The hot rolled TRIP steels that were utilized in these subscale bolts do not however exhibit the mechanical properties required of wing bolt material. Thus warm rolled TRIP steel alloys were also investigated. The mechanical properties of the best warm rolled TRIP steel alloy tested almost matched those of AISI 4340. The warm rolled alloys were also shown to exhibit transformation before yield, allowing for earlier warning when overload occurs. Further work will be required relating to fatigue crack detection, environmental temperature fluctuation and more thorough material characterization. However, present results show that in situ early detection of wing bolt overload is feasible via the use of high alloy warm rolled TRIP steel wing bolts in combination with inductive sensor embedded washers.

  5. Static Aeroelastic Effects of Formation Flight for Slender Unswept Wings

    Hanson, Curtis E.


    The static aeroelastic equilibrium equations for slender, straight wings are modified to incorporate the effects of aerodynamically-coupled formation flight. A system of equations is developed by applying trim constraints and is solved for component lift distribution, trim angle-of-attack, and trim aileron deflection. The trim values are then used to calculate the elastic twist distribution of the wing box. This system of equations is applied to a formation of two gliders in trimmed flight. Structural and aerodynamic properties are assumed for the gliders, and solutions are calculated for flexible and rigid wings in solo and formation flight. It is shown for a sample application of two gliders in formation flight, that formation disturbances produce greater twist in the wingtip immersed in the vortex than for either the opposing wingtip or the wings of a similar airplane in solo flight. Changes in the lift distribution, resulting from wing twist, increase the performance benefits of formation flight. A flexible wing in formation flight will require greater aileron deflection to achieve roll trim than a rigid wing.

  6. Rib for blended wing-body aircraft

    Hawley, Arthur V. (Inventor)


    Structural ribs for providing structural support for a structure, such as the pressure cabin of a blended-wing body aircraft. In a first embodiment, the ribs are generally Y-shaped, being comprised of a vertical web and a pair of inclined webs attached to the vertical web to extend upwardly and outwardly from the vertical web in different directions, with only the upper edges of the inclined webs being attached to a structural element. In a second embodiment, the ribs are generally trident-shaped, whereby the vertical web extends upwardly beyond the intersection of the inclined webs with the vertical web, with the upper edge of the vertical web as well as the upper edges of the inclined webs being attached to the same structural element.

  7. Effects of pioglitazone on urine albumin/creatine ratio in non-diabetic subjects with hypertriglyceridemia%吡格列酮对非糖尿病高甘油三酯血症患者尿微量白蛋白/尿肌酐比值的影响

    阮丹杰; 杨正强; 王伟; 王雪琴; 魏靖; 卜石; 杨文英


    目的 观察吡格列酮干预后非糖尿病高甘油三酯血症患者尿微量白蛋白/尿肌酐比值变化,探讨其对该人群心血管疾病发生风险的影响.方法 采用前瞻性随机安慰剂对照方法,从2005年2月至11月在北京市怀柔区第一医院体检中心及卫生部中日友好医院内分泌科门诊就诊的患者中,选取无或仅有轻度糖代谢受损的非糖尿病高甘油三酯血症者88例,采用随机数字表法分为安慰剂对照组(n=35)、生活方式宣传教育加安慰剂组(n=27)、生活方式宣传教育加吡格列酮干预组(15 ms/d,n=26),随访2年,每年进行口服匍萄糖耐量试验,测定血糖、血胰岛素、游离脂肪酸、甘油三酯、尿微量白蛋白/尿肌酐比值.应用方差分析进行数据统计.结果 共有67例患者完成2年随访,其中安慰剂对照组23例,生活方式宣传教育加安慰剂组22例,生活方式宣传教育加吡格列酮干预组22例.基线时,安慰剂对照组、生活方式宣传教育加安慰剂组、生活方式宣传教育加吡格列酮干预组游离脂肪酸、甘油三酯、空腹血糖差异无统计学意义.第二年末时,三组空腹血糖差异仍无统计学意义,生活方式宣传教育加吡格列酮干预组游离脂肪酸显著低于安慰剂对照组(分别为0.30、0.43 mmol/L,t=-0.18,P<0.05),游离脂肪酸降幅显著大于安慰剂对照组(分别为-0.246、-0.003,t=-0.24,P≤0.01).基线时,三组尿微量白蛋白/尿肌酐比值差异无统计学意义.第二年末时,生活方式宣传教育加吡格列酮干预组尿微量白蛋白/尿肌酐比值低于安慰剂对照组(分别为0.31、2.28g/mol,P<0.01).结论 非糖尿病高甘油三酯血症患者尿微量白蛋白/尿肌酐比值逐年升高,应用吡格列酮可使该比值显著下降,并可能降低心血管疾病发生风险.%Objective To study the effects of pioglitazone intervention on urine albumin/creatine ratio in non-diabetic subjects with

  8. Butterfly wing coloration studied with a novel imaging scatterometer

    Stavenga, Doekele


    Animal coloration functions for display or camouflage. Notably insects provide numerous examples of a rich variety of the applied optical mechanisms. For instance, many butterflies feature a distinct dichromatism, that is, the wing coloration of the male and the female differ substantially. The male Brimstone, Gonepteryx rhamni, has yellow wings that are strongly UV iridescent, but the female has white wings with low reflectance in the UV and a high reflectance in the visible wavelength range. In the Small White cabbage butterfly, Pieris rapae crucivora, the wing reflectance of the male is low in the UV and high at visible wavelengths, whereas the wing reflectance of the female is higher in the UV and lower in the visible. Pierid butterflies apply nanosized, strongly scattering beads to achieve their bright coloration. The male Pipevine Swallowtail butterfly, Battus philenor, has dorsal wings with scales functioning as thin film gratings that exhibit polarized iridescence; the dorsal wings of the female are matte black. The polarized iridescence probably functions in intraspecific, sexual signaling, as has been demonstrated in Heliconius butterflies. An example of camouflage is the Green Hairstreak butterfly, Callophrys rubi, where photonic crystal domains exist in the ventral wing scales, resulting in a matte green color that well matches the color of plant leaves. The spectral reflection and polarization characteristics of biological tissues can be rapidly and with unprecedented detail assessed with a novel imaging scatterometer-spectrophotometer, built around an elliptical mirror [1]. Examples of butterfly and damselfly wings, bird feathers, and beetle cuticle will be presented. [4pt] [1] D.G. Stavenga, H.L. Leertouwer, P. Pirih, M.F. Wehling, Optics Express 17, 193-202 (2009)

  9. The morphological basis of the arm-to-wing transition.

    Poore, Samuel O


    Human-powered flight has fascinated scientists, artists, and physicians for centuries. This history includes Abbas Ibn Firnas, a Spanish inventor who attempted the first well-documented human flight; Leonardo da Vinci and his flying machines; the Turkish inventor Hezarfen Ahmed Celebi; and the modern aeronautical pioneer Otto Lilienthal. These historic figures held in common their attempts to construct wings from man-made materials, and though their human-powered attempts at flight never came to fruition, the ideas and creative elements contained within their flying machines were essential to modern aeronautics. Since the time of these early pioneers, flight has continued to captivate humans, and recently, in a departure from creating wings from artificial elements, there has been discussion of using reconstructive surgery to fabricate human wings from human arms. This article is a descriptive study of how one might attempt such a reconstruction and in doing so calls upon essential evidence in the evolution of flight, an understanding of which is paramount to constructing human wings from arms. This includes a brief analysis and exploration of the anatomy of the 150-million-year-old fossil Archaeopteryx lithographica, with particular emphasis on the skeletal organization of this primitive bird's wing and wrist. Additionally, certain elements of the reconstruction must be drawn from an analysis of modern birds including a description of the specialized shoulder of the European starling, Sturnus vulgaris. With this anatomic description in tow, basic calculations regarding wing loading and allometry suggest that human wings would likely be nonfunctional. However, with the proper reconstructive balance between primitive (Archaeopteryx) and modern (Sturnus), and in attempting to integrate a careful analysis of bird anatomy with modern surgical techniques, the newly constructed human wings could function as cosmetic features simulating, for example, the nonfunctional

  10. Quiet Clean Short-haul Experimental Engine (QCSEE). The aerodynamic and mechanical design of the QCSEE over-the-wing fan


    The aerodynamic and mechanical design of a fixed-pitch 1.36 pressure ratio fan for the over-the-wing (OTW) engine is presented. The fan has 28 blades. Aerodynamically, the fan blades were designed for a composite blade, but titanium blades were used in the experimental fan as a cost savings measure.

  11. Review Essay: Extremist Right-Wing Orientation and Youth Violence in the Context of Psychologically based Biography Research

    Silke Baer


    Full Text Available Michaela KÖTTIG's book closes two gaps in research on right-wing political extremism. First, she deals with young women in the right-wing scene. This is a group that has been subject to little research, having generally been taken to be on the fringe of activity and with little political activity of its own. Second, KÖTTIG works exclusively with qualitative research methods, using narrative biographical interviews and reconstructive case studies which include three-generational family histories. KÖTTIG also draws on studies of clinical psychological trauma studies and attempts to reconstruct early childhood experiences. The comparison of case studies shows numerous correspondences and variations in the biographical experience of the interviewees as well as in the consequences for individual coping mechanisms. Recurrent issues include experiences of alienation from parents, the eminent importance of one grandparent, and the effects of unconscious trans-generational transmission of affect and thought patterns caused by parents' and grandparents' suppression of the family's history during the Third Reich. These and other factors can contribute to the build-up of extreme right-wing patterns of thought and behavior. KÖTTIG's insightful study shows the importance of this kind of qualitative biographical research in examining the complexity of the biographical conditions for right-wing extremism in girls and young women. URN: urn:nbn:de:0114-fqs080281

  12. Winging of scapula due to serratus anterior tear

    Varun Singh Kumar


    Full Text Available 【Abstract】Winging of scapula occurs most commonly due to injury to long thoracic nerve supplying serratus anterior muscle. Traumatic injury to serratus anterior muscle itself is very rare. We reported a case of traumatic winging of scapula due to tear of serratus anterior muscle in a 19-year-old male. Winging was present in neutral position and in extension of right shoulder joint but not on "push on wall" test. Patient was managed conservatively and achieved satisfactory result. Key words: Serratus anterior tear; Scapula; Wounds and injuries

  13. Laminar-turbulent transition on the flying wing model

    Pavlenko, A. M.; Zanin, B. Yu.; Katasonov, M. M.


    Results of an experimental study of a subsonic flow past aircraft model having "flying wing" form and belonging to the category of small-unmanned aerial vehicles are reported. Quantitative data about the structure of the flow near the model surface were obtained by hot-wire measurements. It was shown, that with the wing sweep angle 34 °the laminar-turbulent transition scenario is identical to the one on a straight wing. The transition occurs through the development of a package of unstable oscillations in the boundary layer separation.

  14. Static measurements of slender delta wing rolling moment hysteresis

    Katz, Joseph; Levin, Daniel


    Slender delta wing planforms are susceptible to self-induced roll oscillations due to aerodynamic hysteresis during the limit cycle roll oscillation. Test results are presented which clearly establish that the static rolling moment hysteresis has a damping character; hysteresis tends to be greater when, due to either wing roll or side slip, the vortex burst moves back and forth over the wing trailing edge. These data are an indirect indication of the damping role of the vortex burst during limit cycle roll oscillations.

  15. Structural Health Monitoring Analysis for the Orbiter Wing Leading Edge

    Yap, Keng C.


    This viewgraph presentation reviews Structural Health Monitoring Analysis for the Orbiter Wing Leading Edge. The Wing Leading Edge Impact Detection System (WLE IDS) and the Impact Analysis Process are also described to monitor WLE debris threats. The contents include: 1) Risk Management via SHM; 2) Hardware Overview; 3) Instrumentation; 4) Sensor Configuration; 5) Debris Hazard Monitoring; 6) Ascent Response Summary; 7) Response Signal; 8) Distribution of Flight Indications; 9) Probabilistic Risk Analysis (PRA); 10) Model Correlation; 11) Impact Tests; 12) Wing Leading Edge Modeling; 13) Ascent Debris PRA Results; and 14) MM/OD PRA Results.

  16. Aeroelastic Tailoring of Transport Wings Including Transonic Flutter Constraints

    Stanford, Bret K.; Wieseman, Carol D.; Jutte, Christine V.


    Several minimum-mass optimization problems are solved to evaluate the effectiveness of a variety of novel tailoring schemes for subsonic transport wings. Aeroelastic stress and panel buckling constraints are imposed across several trimmed static maneuver loads, in addition to a transonic flutter margin constraint, captured with aerodynamic influence coefficient-based tools. Tailoring with metallic thickness variations, functionally graded materials, balanced or unbalanced composite laminates, curvilinear tow steering, and distributed trailing edge control effectors are all found to provide reductions in structural wing mass with varying degrees of success. The question as to whether this wing mass reduction will offset the increased manufacturing cost is left unresolved for each case.

  17. Bioinspired ultraviolet reflective photonic structures derived from butterfly wings (Euploea)

    Song, Fang; Su, Huilan; Chen, Jianjun; Zhang, Di; Moon, Won-Jin


    Butterfly wings have been demonstrated to have potential applications in various optical devices. For complementarily, we extend them to ultraviolet (UV) reflectors, inspired by the UV reflective photonic structures that have been evolved to satisfy UV communication systems of butterflies. UV reflective photonic structures of butterfly wings were replicated in multiscale, and thus endowed the resultant SnO2 materials with enhanced UV reflection. This biomimetic strategy provides us a universal way towards UV reflectors without changing the chemical compositions. Furthermore, the UV reflection could be potentially tuned by choosing different photonic structures of butterfly wings and other bio-species.

  18. Fruit flies modulate passive wing pitching to generate in-flight turns

    Bergou, Attila J; Guckenheimer, John; Cohen, Itai; Wang, Z Jane


    Flying insects execute aerial maneuvers through subtle manipulations of their wing motions. Here, we measure the free flight kinematics of fruit flies and determine how they modulate their wing pitching to induce sharp turns. By analyzing the torques these insects exert to pitch their wings, we infer that the wing hinge acts as a torsional spring that passively resists the wing's tendency to flip in response to aerodynamic and inertial forces. To turn, the insects asymmetrically change the spring rest angles to generate rowing motions of their wings. Thus, insects can generate these maneuvers using only a slight active actuation that biases their wing motion.

  19. Nutritional physiology of life-history trade-offs: how food protein-carbohydrate content influences life-history traits in the wing-polymorphic cricket Gryllus firmus.

    Clark, Rebecca M; Zera, Anthony J; Behmer, Spencer T


    Although life-history trade-offs result from the differential acquisition and allocation of nutritional resources to competing physiological functions, many aspects of this topic remain poorly understood. Wing-polymorphic insects, which possess alternative morphs that trade off allocation to flight capability versus early reproduction, provide a good model system for exploring this topic. In this study, we used the wing-polymorphic cricket Gryllus firmus to test how expression of the flight capability versus reproduction trade-off was modified across a heterogeneous protein-carbohydrate nutritional landscape. Newly molted adult female long- and short-winged crickets were given one of 13 diets with different concentrations and ratios of protein and digestible carbohydrate; for each cricket, we measured consumption patterns, growth and allocation to reproduction (ovary mass) versus flight muscle maintenance (flight muscle mass and somatic lipid stores). Feeding responses in both morphs were influenced more by total macronutrient concentration than by protein-carbohydrate ratio, except at high-macronutrient concentration, where protein-carbohydrate balance was important. Mass gain tended to be greatest on protein-biased diets for both morphs, but was consistently lower across all diets for long-winged females. When long-winged females were fed high-carbohydrate foods, they accumulated greater somatic lipid stores; on high-protein foods, they accumulated greater somatic protein stores. Food protein-carbohydrate content also affected short-winged females (selected for early reproductive onset), which showed dramatic increases in ovary size, including ovarian stores of lipid and protein, on protein-biased foods. This is the first study to show how the concentration and ratio of dietary protein and carbohydrate affects consumption and allocation to key physiological features associated with the reproduction-dispersal life-history trade-off. © 2015. Published by The

  20. Financial Key Ratios

    Tănase Alin-Eliodor


    Full Text Available This article focuses on computing techniques starting from trial balance data regarding financial key ratios. There are presented activity, liquidity, solvency and profitability financial key ratios. It is presented a computing methodology in three steps based on a trial balance.