WorldWideScience

Sample records for biplane wing planform

  1. Biplane wing planform and flight performance of the feathered dinosaur Microraptor gui

    OpenAIRE

    Chatterjee, Sankar; Templin, R. Jack

    2007-01-01

    Microraptor gui, a four-winged dromaeosaur from the Early Cretaceous of China, provides strong evidence for an arboreal-gliding origin of avian flight. It possessed asymmetric flight feathers not only on the manus but also on the pes. A previously published reconstruction shows that the hindwing of Microraptor supported by a laterally extended leg would have formed a second pair of wings in tetrapteryx fashion. However, this wing design conflicts with known theropod limb joints that entail a ...

  2. Potential flow about arbitrary biplane wing sections

    Science.gov (United States)

    Garrick, I E

    1937-01-01

    A rigorous treatment is given of the problem of determining the two-dimensional potential flow around arbitrary biplane cellules. The analysis involves the use of elliptic functions and is sufficiently general to include the effects of such elements as the section shapes, the chord ratio, gap, stagger, and decalage, which elements may be specified arbitrarily. The flow problem is resolved by making use of the methods of conformal representation. Thus the solution of the problem of transforming conformally two arbitrary contours into two circles is expressed by a pair of simultaneous integral equations, for which a method of numerical solution is outlined. As an example of the numerical process, the pressure distribution over certain arrangements of the NACA 4412 airfoil in biplane combinations is presented and compared with the monoplane pressure distribution.

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

    Science.gov (United States)

    Suárez-Tovar, C M; Sarmiento, C E

    2016-04-01

    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. PMID:26779975

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

    Science.gov (United States)

    Suárez-Tovar, C M; Sarmiento, C E

    2016-04-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

    Guoyu Luo; Mao Sun

    2005-01-01

    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.

  6. Exploratory investigation of the effectiveness of biplane wings with large-chord double slotted flaps in redirecting a propeller slipstream downward for vertical take-off

    Science.gov (United States)

    Kirby, Robert H

    1956-01-01

    Results are presented from static-force tests on biplane wings with large-chord double slotted flaps which turn the slipstream of a single counter rotating propeller downward for vertical take-off. The investigation provided information on the effect of chord length, flap deflection, propeller position, end plates, fuselage, and ground proximity on the efficiency of the wing system in turning the propeller slipstream.

  7. Bifurcation of hyperbolic planforms

    CERN Document Server

    Chossat, Pascal; Faugeras, Olivier

    2010-01-01

    Motivated by a model for the perception of textures by the visual cortex in primates, we analyse the bifurcation of periodic patterns for nonlinear equations describing the state of a system defined on the space of structure tensors, when these equations are further invariant with respect to the isometries of this space. We show that the problem reduces to a bifurcation problem in the hyperbolic plane D (Poincar\\'e disc). We make use of the concept of periodic lattice in D to further reduce the problem to one on a compact Riemann surface D/T, where T is a cocompact, torsion-free Fuchsian group. The knowledge of the symmetry group of this surface allows to carry out the machinery of equivariant bifurcation theory. Solutions which generically bifurcate are called "H-planforms", by analogy with the "planforms" introduced for pattern formation in Euclidean space. This concept is applied to the case of an octagonal periodic pattern, where we are able to classify all possible H-planforms satisfying the hypotheses o...

  8. Aeroelastic Analysis of Wings in the Transonic Regime: Planform’s Influence on the Dynamic Instability

    OpenAIRE

    Chiarelli, Mario Rosario; Bonomo, Salvatore

    2016-01-01

    This paper presents a study of transonic wings whose planform shape is curved. Using fluid structure interaction analyses, the dynamic instability conditions were investigated by including the effects of the transonic flow field around oscillating wings. To compare the dynamic aeroelastic characteristics of the curved wing configuration, numerical analyses were carried out on a conventional swept wing and on a curved planform wing. The results confirm that, for a curved planform wing, the dyn...

  9. Modelling planform changes of braided rivers

    NARCIS (Netherlands)

    Jagers, Hendrik Reinhard Albert

    2003-01-01

    This study has focused on modelling techniques to predict planform changes of braided rivers and their relation with state-of-the-art knowledge on the physical processes and the availability of model input data

  10. Controls on plan-form evolution of submarine channels

    Science.gov (United States)

    Imran, J.; Mohrig, D. C.

    2014-12-01

    Vertically aggrading sinuous channels constitute a basic building block of modern submarine fans and the greater continental slope. Interpretation of seismically imaged channels reveals a significant diversity in internal architecture, as well as important similarities and differences in the evolution of submarine channels relative to better studied rivers. Many submarine channel cross sections possess a 'gull wing' shape. Successive stacking of such channels demonstrates that systematic bank erosion is not required in order for lateral migration to occur. The lateral shift of such aggrading channels, however, is expected to be much less dynamic than in the case of terrestrial rivers. Recent high-resolution 3D seismic data from offshore Angola and an upstream segment of the Bengal Submarine Fan show intensely meandering channels that experience considerable lateral shifting during periods of active migration within submarine valleys. The cross sections of the actively migrating channels are similar to meandering river channels characterized by an outer cut-bank and inner-bank accretion. In submarine channels, the orientation of the secondary flow can be river-like or river-reverse depending on the channel gradient, cross sectional shape, and the adaptation length of the channel bend. In river channels, a single circulation cell commonly occupies the entire channel relief, redistributing the bed-load sediment across the channel, and influencing the thread of high velocity and thus the plan-form evolution of the channel. In submarine environments, the height of the circulation cell will be significantly smaller than channel relief, thus leading to development of lower relief point bars from bed-load transport. Nevertheless these "underfit" bars may play an important role in plan-form evolution of submarine channels. In rivers and submarine channels, the inclined surface accretion can be constructed via pure bed-load, suspended-load, or a combination of both transport

  11. Aeroelastic Analysis of Wings in the Transonic Regime: Planform’s Influence on the Dynamic Instability

    Directory of Open Access Journals (Sweden)

    Mario Rosario Chiarelli

    2016-01-01

    Full Text Available This paper presents a study of transonic wings whose planform shape is curved. Using fluid structure interaction analyses, the dynamic instability conditions were investigated by including the effects of the transonic flow field around oscillating wings. To compare the dynamic aeroelastic characteristics of the curved wing configuration, numerical analyses were carried out on a conventional swept wing and on a curved planform wing. The results confirm that, for a curved planform wing, the dynamic instability condition occurs at higher flight speed if compared to a traditional swept wing with similar profiles, aspect ratio, angle of sweep at root, similar structural layout, and similar mass. A curved wing lifting system could thus improve the performances of future aircrafts.

  12. The Effect of the Wings of Single Engine Airplanes on Propulsive Efficiency as Shown by Full Scale Wind Tunnel Tests

    Science.gov (United States)

    Weick, Fred E; Wood, Donald H

    1929-01-01

    An investigation was conducted to determine the effect of the wings on propulsive efficiency. The wings are shown to cause a reduction of 1 percent to 3 percent in propulsive efficiency, which is about the same for monoplane as well as biplane wings.

  13. Numerical study of a delta planform with multiple jets in ground effect

    Science.gov (United States)

    Chawla, K.; Van Dalsem, W. R.; Rao, K. V.

    1989-01-01

    The flow past a 60-deg delta wing equipped with two thrust-reverser jets near the inboard trailing edge has been analyzed by numerical solution of the 3D thin-layer Navier-Stokes equations. An implicit, partially flux-split, approximately-factored Navier-Stokes solver coupled with a multiple grid embedding scheme has been adapted to this problem. Studies of the impact of numerical parameters (e.g., grid refinement and dissipation levels), and flow-field parameters such as the height of the delta wing above the ground plane and the jet size on the solution, were performed. Results of these numerical studies indicate some challenges in the accurate resolution of complex 3D free shear layers and jets. Nevertheless, flow features such as jet deformation and ground vortex formation observed in experimental flow visualizations are captured. Further, comparisons with experimental data confirm the ability to simulate the loss of wing-borne lift, commonly referred to 'suckdown, as the delta planform flies at slow speeds in close proximity to the ground. Detailed analysis of the numerical results has also given additional insight into the structure of the ground vortex and the mechanisms of lift loss.

  14. Planform, aero-structural, and flight control optimization for tailless morphing aircraft

    Science.gov (United States)

    Molinari, Giulio; Arrieta, Andres F.; Ermanni, Paolo

    2015-04-01

    Tailless airplanes with swept wings rely on variations of the spanwise lift distribution to provide controllability in roll, pitch and yaw. Conventionally, this is achieved utilizing multiple control surfaces, such as elevons, on the wing trailing edge. As every flight condition requires different control moments (e.g. to provide pitching moment equilibrium), these surfaces are practically permanently displaced. Due to their nature, causing discontinuities, corners and gaps, they bear aerodynamic penalties, mostly in terms of shape drag. Shape adaptation, by means of chordwise morphing, has the potential of varying the lift of a wing section by deforming its profile in a way that minimizes the resulting drag. Furthermore, as the shape can be varied differently along the wingspan, the lift distribution can be tailored to each specific flight condition. For this reason, tailless aircraft appear as a prime choice to apply morphing techniques, as the attainable benefits are potentially significant. In this work, we present a methodology to determine the optimal planform, profile shape, and morphing structure for a tailless aircraft. The employed morphing concept is based on a distributed compliance structure, actuated by Macro Fiber Composite (MFC) piezoelectric elements. The multidisciplinary optimization is performed considering the static and dynamic aeroelastic behavior of the resulting structure. The goal is the maximization of the aerodynamic efficiency while guaranteeing the controllability of the plane, by means of morphing, in a set of flight conditions.

  15. Effect of canard position and wing leading-edge flap deflection on wing buffet at transonic speeds

    Science.gov (United States)

    Gloss, B. B.; Henderson, W. P.; Huffman, J. K.

    1974-01-01

    A generalized wind-tunnel model, with canard and wing planform typical of highly maneuverable aircraft, was tested. The addition of a canard above the wing chord plane, for the configuration with leading-edge flaps undeflected, produced substantially higher total configuration lift coefficients before buffet onset than the configuration with the canard off and leading-edge flaps undeflected. The wing buffet intensity was substantially lower for the canard-wing configuration than the wing-alone configuration. The low-canard configuration generally displayed the poorest buffet characteristics. Deflecting the wing leading-edge flaps substantially improved the wing buffet characteristics for canard-off configurations. The addition of the high canard did not appear to substantially improve the wing buffet characteristics of the wing with leading-edge flaps deflected.

  16. Aircraft wing structure detail design

    Science.gov (United States)

    Sager, Garrett L.; Roberts, Ron; Mallon, Bob; Alameri, Mohamed; Steinbach, Bill

    1993-01-01

    The provisions of this project call for the design of the structure of the wing and carry-through structure for the Viper primary trainer, which is to be certified as a utility category trainer under FAR part 23. The specific items to be designed in this statement of work were Front Spar, Rear Spar, Aileron Structure, Wing Skin, and Fuselage Carry-through Structure. In the design of these parts, provisions for the fuel system, electrical system, and control routing were required. Also, the total weight of the entire wing planform could not exceed 216 lbs. Since this aircraft is to be used as a primary trainer, and the SOW requires a useful life of 107 cycles, it was decided that all of the principle stresses in the structural members would be kept below 10 ksi. The only drawback to this approach is a weight penalty.

  17. Application of Piezoelectrics to Flapping-Wing MAVs

    Science.gov (United States)

    Widstrand, Alex; Hubner, J. Paul

    2015-11-01

    Micro air vehicles (MAVs) are a class of unmanned aerial vehicles that are size-restricted and operate at low velocities and low Reynolds numbers. An ongoing challenge with MAVs is that their flight-related operations are highly constrained by their size and weight, which limits battery size and, therefore, available power. One type of MAV called an ornithopter flies using flapping wings to create both lift and thrust, much like birds and insects do. Further bio-inspiration from bats led to the design of membrane wings for these vehicles, which provide aerodynamic benefits through passive vibration. In an attempt to capitalize on this vibration, a piezoelectric film, which generates a voltage when stressed, was investigated as the wing surface. Two wing planforms with constant area were designed and fabricated. The goal was to measure the wings' flight characteristics and output energy in freestream conditions. Complications with the flapper arose which prevented wind tunnel tests from being performed; however, energy data was obtained from table-top shaker tests. Preliminary results indicate that wing shape affects the magnitude of the charge generated, with a quarter-elliptic planform outperforming a rectangular planform. Funding provided by NSF REU Site Award number 1358991.

  18. Piezoelectric energy harvester having planform-tapered interdigitated beams

    Science.gov (United States)

    Kellogg, Rick A.; Sumali, Hartono

    2011-05-24

    Embodiments of energy harvesters have a plurality of piezoelectric planform-tapered, interdigitated cantilevered beams anchored to a common frame. The plurality of beams can be arranged as two or more sets of beams with each set sharing a common sense mass affixed to their free ends. Each set thus defined being capable of motion independent of any other set of beams. Each beam can comprise a unimorph or bimorph piezoelectric configuration bonded to a conductive or non-conductive supporting layer and provided with electrical contacts to the active piezoelectric elements for collecting strain induced charge (i.e. energy). The beams are planform tapered along the entirety or a portion of their length thereby increasing the effective stress level and power output of each piezoelectric element, and are interdigitated by sets to increase the power output per unit volume of a harvester thus produced.

  19. Photogrammetric Method and Software for Stream Planform Identification

    Science.gov (United States)

    Stonedahl, S. H.; Stonedahl, F.; Lohberg, M. M.; Lusk, K.; Miller, D.

    2013-12-01

    Accurately characterizing the planform of a stream is important for many purposes, including recording measurement and sampling locations, monitoring change due to erosion or volumetric discharge, and spatial modeling of stream processes. While expensive surveying equipment or high resolution aerial photography can be used to obtain planform data, our research focused on developing a close-range photogrammetric method (and accompanying free/open-source software) to serve as a cost-effective alternative. This method involves securing and floating a wooden square frame on the stream surface at several locations, taking photographs from numerous angles at each location, and then post-processing and merging data from these photos using the corners of the square for reference points, unit scale, and perspective correction. For our test field site we chose a ~35m reach along Black Hawk Creek in Sunderbruch Park (Davenport, IA), a small, slow-moving stream with overhanging trees. To quantify error we measured 88 distances between 30 marked control points along the reach. We calculated error by comparing these 'ground truth' distances to the corresponding distances extracted from our photogrammetric method. We placed the square at three locations along our reach and photographed it from multiple angles. The square corners, visible control points, and visible stream outline were hand-marked in these photos using the GIMP (open-source image editor). We wrote an open-source GUI in Java (hosted on GitHub), which allows the user to load marked-up photos, designate square corners and label control points. The GUI also extracts the marked pixel coordinates from the images. We also wrote several scripts (currently in MATLAB) that correct the pixel coordinates for radial distortion using Brown's lens distortion model, correct for perspective by forcing the four square corner pixels to form a parallelogram in 3-space, and rotate the points in order to correctly orient all photos of

  20. Cardiac biplane strain imaging: initial in vivo experience

    Energy Technology Data Exchange (ETDEWEB)

    Lopata, R G P; Nillesen, M M; Thijssen, J M; De Korte, C L [Clinical Physics Laboratory, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Verrijp, C N; Lammens, M M Y; Van der Laak, J A W M [Department of Pathology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Singh, S K; Van Wetten, H B [Department of Cardiothoracic Surgery, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Kapusta, L [Pediatric Cardiology, Department of Pediatrics, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands)], E-mail: R.Lopata@cukz.umcn.nl

    2010-02-21

    In this study, first we propose a biplane strain imaging method using a commercial ultrasound system, yielding estimation of the strain in three orthogonal directions. Secondly, an animal model of a child's heart was introduced that is suitable to simulate congenital heart disease and was used to test the method in vivo. The proposed approach can serve as a framework to monitor the development of cardiac hypertrophy and fibrosis. A 2D strain estimation technique using radio frequency (RF) ultrasound data was applied. Biplane image acquisition was performed at a relatively low frame rate (<100 Hz) using a commercial platform with an RF interface. For testing the method in vivo, biplane image sequences of the heart were recorded during the cardiac cycle in four dogs with an aortic stenosis. Initial results reveal the feasibility of measuring large radial, circumferential and longitudinal cumulative strain (up to 70%) at a frame rate of 100 Hz. Mean radial strain curves of a manually segmented region-of-interest in the infero-lateral wall show excellent correlation between the measured strain curves acquired in two perpendicular planes. Furthermore, the results show the feasibility and reproducibility of assessing radial, circumferential and longitudinal strains simultaneously. In this preliminary study, three beagles developed an elevated pressure gradient over the aortic valve ({delta}p: 100-200 mmHg) and myocardial hypertrophy. One dog did not develop any sign of hypertrophy ({delta}p = 20 mmHg). Initial strain (rate) results showed that the maximum strain (rate) decreased with increasing valvular stenosis (-50%), which is in accordance with previous studies. Histological findings corroborated these results and showed an increase in fibrotic tissue for the hearts with larger pressure gradients (100, 200 mmHg), as well as lower strain and strain rate values.

  1. Geographic variation in Puget Sound tidal channel planform geometry

    Science.gov (United States)

    Hood, W. Gregory

    2015-02-01

    Tidal channels are central elements of salt marsh hydrodynamics, sediment dynamics, and habitat. To develop allometric models predicting the number and size of tidal channels that could develop following salt marsh restoration, channels were digitized from aerial photographs of Puget Sound river delta marshes. Salt marsh area was the independent variable for all dependent channel planform metrics. Tidal channel allometry showed similar scaling exponents for channel planform metrics throughout Puget Sound, simplifying comparisons between locations. Y-intercepts of allometric relationships showed geographic variation, which multiple-regression indicated was associated with tidal range and storm significant wave height. Channel size and complexity were positively related to tidal range and negatively related to wave height. Four case studies, each with paired regions of similar tidal range and contrasting wave environments, further indicated wave environment affected channel geometry. Wave-mediated sediment delivery may be the mechanism involved, with wave-sheltered areas experiencing relative sediment deficits, such that some salt marshes in Puget Sound are already suffering sea-level rise impacts that are reflected in their channel network geometry.

  2. Vibrations of cantilevered shallow cylindrical shells of rectangular planform

    Science.gov (United States)

    Leissa, A. W.; Lee, J. K.; Wang, A. J.

    1981-01-01

    A cantilevered, shallow shell of circular cylindrical curvature and rectangular planform exhibits free vibration behavior which differs considerably from that of a cantilevered beam or of a flat plate. Some numerical results can be found for the problem in the previously published literature, mainly obtained by using various finite element methods. The present paper is the first definitive study of the problem, presenting accurate non-dimensional frequency parameters for wide ranges of aspect ratio, shallowness ratio and thickness ratio. The analysis is based upon shallow shell theory. Numerical results are obtained by using the Ritz method, with algebraic polynomial trial functions for the displacements. Convergence is investigated, with attention being given both to the number of terms taken for each co-ordinate direction and for each of the three components of displacement. Accuracy of the results is also established by comparison with finite element results for shallow shells and with other accurate flat plate solutions.

  3. Cardiac biplane strain imaging: initial in vivo experience

    Science.gov (United States)

    Lopata, R. G. P.; Nillesen, M. M.; Verrijp, C. N.; Singh, S. K.; Lammens, M. M. Y.; van der Laak, J. A. W. M.; van Wetten, H. B.; Thijssen, J. M.; Kapusta, L.; de Korte, C. L.

    2010-02-01

    In this study, first we propose a biplane strain imaging method using a commercial ultrasound system, yielding estimation of the strain in three orthogonal directions. Secondly, an animal model of a child's heart was introduced that is suitable to simulate congenital heart disease and was used to test the method in vivo. The proposed approach can serve as a framework to monitor the development of cardiac hypertrophy and fibrosis. A 2D strain estimation technique using radio frequency (RF) ultrasound data was applied. Biplane image acquisition was performed at a relatively low frame rate (cardiac cycle in four dogs with an aortic stenosis. Initial results reveal the feasibility of measuring large radial, circumferential and longitudinal cumulative strain (up to 70%) at a frame rate of 100 Hz. Mean radial strain curves of a manually segmented region-of-interest in the infero-lateral wall show excellent correlation between the measured strain curves acquired in two perpendicular planes. Furthermore, the results show the feasibility and reproducibility of assessing radial, circumferential and longitudinal strains simultaneously. In this preliminary study, three beagles developed an elevated pressure gradient over the aortic valve (Δp: 100-200 mmHg) and myocardial hypertrophy. One dog did not develop any sign of hypertrophy (Δp = 20 mmHg). Initial strain (rate) results showed that the maximum strain (rate) decreased with increasing valvular stenosis (-50%), which is in accordance with previous studies. Histological findings corroborated these results and showed an increase in fibrotic tissue for the hearts with larger pressure gradients (100, 200 mmHg), as well as lower strain and strain rate values.

  4. Theoretical stability and control characteristics of wings with various amounts of taper and twist

    Science.gov (United States)

    Pearson, H. A.; Jones, R. T.

    1976-01-01

    Stability derivatives have been computed for twisted wings of different planforms that include variations in both the wing taper and the aspect ratio. Taper ratios of 1.0, 0.50, and 0.25 are considered for each of three aspect ratios: 6, 10, and 16. The specific derivatives for which results are given are the rolling moment and the yawing moment derivatives with respect to rolling velocity, yawing velocity, and angle of sideslip. In addition to the stability derivatives, results are included for determining the theoretical rolling moment due to aileron deflection and a series of influence lines is given by which the loading across the span may be determined for any angle-of-attack distribution that may occur on the wing planforms considered.

  5. 3D/3D registration of coronary CTA and biplane XA reconstructions for improved image guidance

    Energy Technology Data Exchange (ETDEWEB)

    Dibildox, Gerardo, E-mail: g.dibildox@erasmusmc.nl; Baka, Nora; Walsum, Theo van [Biomedical Imaging Group Rotterdam, Departments of Radiology and Medical Informatics, Erasmus Medical Center, 3015 GE Rotterdam (Netherlands); Punt, Mark; Aben, Jean-Paul [Pie Medical Imaging, 6227 AJ Maastricht (Netherlands); Schultz, Carl [Department of Cardiology, Erasmus Medical Center, 3015 GE Rotterdam (Netherlands); Niessen, Wiro [Quantitative Imaging Group, Faculty of Applied Sciences, Delft University of Technology, 2628 CJ Delft, The Netherlands and Biomedical Imaging Group Rotterdam, Departments of Radiology and Medical Informatics, Erasmus Medical Center, 3015 GE Rotterdam (Netherlands)

    2014-09-15

    Purpose: The authors aim to improve image guidance during percutaneous coronary interventions of chronic total occlusions (CTO) by providing information obtained from computed tomography angiography (CTA) to the cardiac interventionist. To this end, the authors investigate a method to register a 3D CTA model to biplane reconstructions. Methods: The authors developed a method for registering preoperative coronary CTA with intraoperative biplane x-ray angiography (XA) images via 3D models of the coronary arteries. The models are extracted from the CTA and biplane XA images, and are temporally aligned based on CTA reconstruction phase and XA ECG signals. Rigid spatial alignment is achieved with a robust probabilistic point set registration approach using Gaussian mixture models (GMMs). This approach is extended by including orientation in the Gaussian mixtures and by weighting bifurcation points. The method is evaluated on retrospectively acquired coronary CTA datasets of 23 CTO patients for which biplane XA images are available. Results: The Gaussian mixture model approach achieved a median registration accuracy of 1.7 mm. The extended GMM approach including orientation was not significantly different (P > 0.1) but did improve robustness with regards to the initialization of the 3D models. Conclusions: The authors demonstrated that the GMM approach can effectively be applied to register CTA to biplane XA images for the purpose of improving image guidance in percutaneous coronary interventions.

  6. Angel's Wings

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ 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.

  7. Optimization of an Active Twist Rotor Blade Planform for Improved Active Response and Forward Flight Performance

    Science.gov (United States)

    Sekula, Martin K; Wilbur, Matthew L.

    2014-01-01

    A study was conducted to identify the optimum blade tip planform for a model-scale active twist rotor. The analysis identified blade tip design traits which simultaneously reduce rotor power of an unactuated rotor while leveraging aeromechanical couplings to tailor the active response of the blade. Optimizing the blade tip planform for minimum rotor power in forward flight provided a 5 percent improvement in performance compared to a rectangular blade tip, but reduced the vibration control authority of active twist actuation by 75 percent. Optimizing for maximum blade twist response increased the vibration control authority by 50 percent compared to the rectangular blade tip, with little effect on performance. Combined response and power optimization resulted in a blade tip design which provided similar vibration control authority to the rectangular blade tip, but with a 3.4 percent improvement in rotor performance in forward flight.

  8. Comparison of planform multi-channel network characteristics of alluvial and bedrock constrained large rivers

    Science.gov (United States)

    Carling, P. A.; Meshkova, L.; Robinson, R. A.

    2011-12-01

    The Mekong River in northern Cambodia is an multi-channel mixed bedrock-alluvial river but it was poorly researched until present. Preliminary study of the Mekong geomorphology was conducted by gathering existing knowledge of its geological and tectonic settings, specific riparian vegetation and ancient alluvial terraces in which the river has incised since the Holocene. Altogether this process has allowed a geomorphological portrait of the river to be composed within the Quaternary context. Following this outline, the planform characteristics of the Mekong River network are compared, using analysis of channel network and islands configurations, with the fluvial patterns of the Orange River (South Africa), Upper Columbia River (Canada) and the Ganga River (India, Bangladesh). These rivers are selected as examples of multi-channel mixed bedrock alluvial, anastomosed alluvial and braided alluvial rivers respectively. Network parameters such as channel bifurcation angles asymmetry, sinuosity, braid intensity and island morphometric shape metrics are compared and contrasted between bedrock and alluvial systems. In addition, regional and local topographic trend surfaces produced for each river planform help explain the local changes in river direction and the degree of anastomosis, and distinguish the bedrock-alluvial rivers from the alluvial rivers. Variations between planform characteristics are to be explained by channel forming processes and in the case of mixed bedrock-alluvial rivers mediated by structural control. Channel metrics (derived at the reach-scale) provide some discrimination between different multi-channel patterns but are not always robust when considered singly. In contrast, island shape metrics (obtained at subreach-scale) allow robust discrimination between alluvial and bedrock systems.

  9. Predicting the planform configuration of the braided Toklat River, AK with a suite of rule-based models

    Science.gov (United States)

    Podolak, Charles J.

    2013-01-01

    An ensemble of rule-based models was constructed to assess possible future braided river planform configurations for the Toklat River in Denali National Park and Preserve, Alaska. This approach combined an analysis of large-scale influences on stability with several reduced-complexity models to produce the predictions at a practical level for managers concerned about the persistence of bank erosion while acknowledging the great uncertainty in any landscape prediction. First, a model of confluence angles reproduced observed angles of a major confluence, but showed limited susceptibility to a major rearrangement of the channel planform downstream. Second, a probabilistic map of channel locations was created with a two-parameter channel avulsion model. The predicted channel belt location was concentrated in the same area as the current channel belt. Finally, a suite of valley-scale channel and braid plain characteristics were extracted from a light detection and ranging (LiDAR)-derived surface. The characteristics demonstrated large-scale stabilizing topographic influences on channel planform. The combination of independent analyses increased confidence in the conclusion that the Toklat River braided planform is a dynamically stable system due to large and persistent valley-scale influences, and that a range of avulsive perturbations are likely to result in a relatively unchanged planform configuration in the short term.

  10. AC1 Wing

    Directory of Open Access Journals (Sweden)

    Adrian DOBRE

    2010-03-01

    Full Text Available The AC1 wing replaces the old wing of the wind tunnel model AEROTAXI, which has been made at scale 1:9. The new wing is part of CESAR program and improves the aerodynamic characteristics of the old one. The geometry of the whole wing was given by FOI Sweden and position of AC1 wing must coincide with the structure of the AEROTAXI model.

  11. AC1 Wing

    OpenAIRE

    Adrian DOBRE

    2010-01-01

    The AC1 wing replaces the old wing of the wind tunnel model AEROTAXI, which has been made at scale 1:9. The new wing is part of CESAR program and improves the aerodynamic characteristics of the old one. The geometry of the whole wing was given by FOI Sweden and position of AC1 wing must coincide with the structure of the AEROTAXI model.

  12. Monoplane 3D Overlay Roadmap versus Conventional Biplane 2D Roadmap Technique for Neurointervenional Procedures

    Science.gov (United States)

    Jang, Dong-Kyu; Stidd, David A.; Schafer, Sebastian; Chen, Michael; Moftakhar, Roham

    2016-01-01

    Purpose We investigated whether a 3D overlay roadmap using monoplane fluoroscopy offers advantages over a conventional 2D roadmap using biplane fluoroscopy during endovascular aneurysm treatment. Materials and Methods A retrospective chart review was conducted for 131 consecutive cerebral aneurysm embolizations by three neurointerventionalists at a single institution. Allowing for a transition period, the periods from January 2012 to August 2012 (Time Period 1) and February 2013 to July 2013 (Time Period 2) were analyzed for radiation exposure, contrast administration, fluoroscopy time, procedure time, angiographic results, and perioperative complications. Two neurointerventionalists (Group 1) used a conventional 2D roadmap for both Time Periods, and one neurointerventionalist (Group 2) transitioned from a 2D roadmap during Time Period 1 to a 3D overlay roadmap during Time Period 2. Results During Time Period 2, Group 2 demonstrated reduced fluoroscopy time (paneurysms with similar angiographic occlusions and complications rate relative to biplane 2D roadmap, which implies possible compensation of limitations of monoplane fluoroscopy by 3D overlay technique. PMID:27621947

  13. Moments About Body Centered Coordinate Axes At Limb Joints From Force Plate And Biplane Photography Measurements

    Science.gov (United States)

    Balakrishnan, S.; Thornton-Trump, A. B.; Brodland, G. W.

    1983-07-01

    Traditional locomotion analysis considers motion in a translating coordinate frame and the analysis is performed primarily in the sagittal plane. The results of several studies in the present work have shown that the aspect of symmetry is rarely present in pathological gait. Loss of function in one plane of movement gives rise to larger motions in other planes. This brings into focus the necessity for three dimensional measurement for adequately representing pathological gait. Description of quantities associated with gait in the appropriate moving frame of each segment would be closer to joint angulation of limb segments. Although this description has been attempted by a few researchers, the assumption of small angle theory and vectorial addition of rotation angles commonly employed for defining the rotation matrices is not applicable to pathological gait. The present work illustrates the use of biplane photography for displacement measurement in human movement. Transformations based on Eulerian angle rotations are derived based on biplane measurements. From the three dimensional ground reaction forces measured by a force plate, moments about the moving upper body coordinate axes are computed through a three dimensional mathematical model.

  14. Insight on the Peruvian Amazon River: A Planform Metric Characterization of its Morphodynamics

    Science.gov (United States)

    Garcia, A. M. P.; Ortals, C.; Frias, C. E.; Abad, J. D.; Vizcarra, J.

    2014-12-01

    Starting in Peru, the Amazon River flows through Colombia and Brazil; additionally, tributaries from Bolivia, Venezuela, and Ecuador contribute to the massive river and its unique geomorphic features. Accordingly, the Amazon Basin has become an important aspect of South America; it is an area of extraordinary biodiversity, rich resources, and unique cultures. However, due to the sheer magnitude and exceptionality of the Amazon River, research regarding the morphodynamic processes that shape and define the river has been difficult. Consequently, current research has not completely understood the planform dynamics of some portions of this river that present a main channel and secondary channels known as "anabranching structures". The purpose of this research was to gain an understanding of the geomorphology of the upper Amazon, the Peruvian section, by obtaining migration rates and planform metrics, including channel count, length, width, and sinuosity, as well as island count, area, and shape. With this data, the morphodynamics of the Peruvian Amazon, especially the relationship between the main channel and its secondary channels in each "anabranching structure" along the river, could be analyzed according to correlations found between various metrics. This analysis was carried out for 5-year time spans over a period of 25 years. Preliminary results showed that the average migration rate versus channel bend radius envelope peak is lower for the secondary channels than for the main channel. However, the maximum migration rate was not always found in the main channel; for several structures, the most dynamic channels were the secondary ones. This implies a certain periodicity to the river's migratory patterns that could be related to the valley boundaries, the local channel sinuosity or geological formations in the study area.

  15. Cardiac dimensional analysis by use of biplane cineradiography: description and validation of method.

    Science.gov (United States)

    Lipscomb, K

    1980-01-01

    Biplane cineradiography is a potentially powerful tool for precise measurement of intracardiac dimensions. The most systematic approach to these measurements is the creation of a three-dimensional coordinate system within the x-ray field. Using this system, interpoint distances, such as between radiopaque clips or coronary artery bifurcations, can be calculated by use of the Pythagoras theorem. Alternatively, calibration factors can be calculated in order to determine the absolute dimensions of a structure, such as a ventricle or coronary artery. However, cineradiography has two problems that have precluded widespread use of the system. These problems are pincushion distortion and variable image magnification. In this paper, methodology to quantitate and compensate for these variables is presented. The method uses radiopaque beads permanently mounted in the x-ray field. The position of the bead images on the x-ray film determine the compensation factors. Using this system, measurements are made with a standard deviation of approximately 1% of the true value.

  16. The examination of the side scatter in the simultaneous bi-plane system of cerebral angiography

    International Nuclear Information System (INIS)

    In the simultaneous bi-plane system, one of the most important problems is the deterioration of radiographic image quality by the scattered X-rays from many direction. We met with good results by using the rare earth substance for the sake of deteriorating the side scattered X-rays. Then we compared the effects of elimination of the side scattered X-rays by using aluminum with that by using some rare earth substance and studied by X-ray spectrum theoretically. From the above-mentioned things, we got the best effect when the absorption edge of rare earth substance agreed with the region of energy of the side scattered X-rays. (author)

  17. Evaluation of automated statistical shape model based knee kinematics from biplane fluoroscopy

    DEFF Research Database (Denmark)

    Baka, Nora; Kaptein, Bart L.; Giphart, J. Erik;

    2014-01-01

    State-of-the-art fluoroscopic knee kinematic analysis methods require the patient-specific bone shapes segmented from CT or MRI. Substituting the patient-specific bone shapes with personalizable models, such as statistical shape models (SSM), could eliminate the CT/MRI acquisitions, and thereby...... decrease costs and radiation dose (when eliminating CT). SSM based kinematics, however, have not yet been evaluated on clinically relevant joint motion parameters. Therefore, in this work the applicability of SSMs for computing knee kinematics from biplane fluoroscopic sequences was explored. Kinematic......-posterior tibial drawer, joint distraction-contraction, flexion, tibial rotation and adduction. The relationship between kinematic precision and bone shape accuracy was also investigated. The SSM based kinematics resulted in sub-millimeter (0.48-0.81mm) and approximately 1° (0.69-0.99°) median precision...

  18. Fractures of the thoracic spine in patients with minor trauma: Comparison of diagnostic accuracy and dose of biplane radiography and MDCT

    International Nuclear Information System (INIS)

    Objectives: To investigate the accuracy of biplane radiography in the detection of fractures of the thoracic spine in patients with minor trauma using multidetector computed tomography (MDCT) as the reference and to compare the dose of both techniques. Methods: 107 consecutive trauma patients with suspected fractures of the thoracic spine on physical examination were included. All had undergone biplane radiography first, followed by a MDCT scan between October 2008 and October 2012. A fourfold table was used for the classification of the screening test results. Both the Chi-square test (χ2) and the mean dose-length product (DLP) were used to compare the diagnostic methods. Results: MDCT revealed 77 fractures in 65/107 patients (60.7%). Biplane radiography was true positive in 32/107 patients (29.9%), false positive in 19/107 patients (17.8%), true negative in 23/107 (21.5%) and false negative in 33/107 patients (30.8%), showing a sensitivity of 49.2%, a specificity of 54.7%, a positive predictive value (PPV) of 62.7%, a negative predictive value (NPV) of 41.1%, and an accuracy of 51.4%. The presence of a fracture on biplane radiography was highly statistical significant, if this was simultaneously proven by MDCT (χ2 = 7.6; p = 0.01). None of the fractures missed on biplane radiography was unstable. The mean DLP on biplane radiography was 14.5 mGy cm (range 1.9–97.8) and on MDCT 374.6 mGy cm (range 80.2–871). Conclusions: The sensitivity and the specificity of biplane radiography in the diagnosis of fractures of the thoracic spine in patients with minor trauma are low. Considering the wide availability of MDCT that is usually necessary for taking significant therapeutic steps, the indication for biplane radiography should be very restrictive

  19. Monoplane 3D Overlay Roadmap versus Conventional Biplane 2D Roadmap Technique for Neurointervenional Procedures

    Science.gov (United States)

    Jang, Dong-Kyu; Stidd, David A.; Schafer, Sebastian; Chen, Michael; Moftakhar, Roham

    2016-01-01

    Purpose We investigated whether a 3D overlay roadmap using monoplane fluoroscopy offers advantages over a conventional 2D roadmap using biplane fluoroscopy during endovascular aneurysm treatment. Materials and Methods A retrospective chart review was conducted for 131 consecutive cerebral aneurysm embolizations by three neurointerventionalists at a single institution. Allowing for a transition period, the periods from January 2012 to August 2012 (Time Period 1) and February 2013 to July 2013 (Time Period 2) were analyzed for radiation exposure, contrast administration, fluoroscopy time, procedure time, angiographic results, and perioperative complications. Two neurointerventionalists (Group 1) used a conventional 2D roadmap for both Time Periods, and one neurointerventionalist (Group 2) transitioned from a 2D roadmap during Time Period 1 to a 3D overlay roadmap during Time Period 2. Results During Time Period 2, Group 2 demonstrated reduced fluoroscopy time (p<0.001), procedure time (P=0.023), total radiation dose (p=0.001), and fluoroscopy dose (P=0.017) relative to Group 1. During Time Period 2, there was no difference of immediate angiographic results and procedure complications between the two groups. Through the transition from Time Period 1 to Time Period 2, Group 2 demonstrated decreased fluoroscopy time (p< 0.001), procedure time (p=0.022), and procedure complication rate (p=0.041) in Time Period 2 relative to Time Period 1. Conclusion The monoplane 3D overlay roadmap technique reduced fluoroscopy dose and fluoroscopy time during neurointervention of cerebral aneurysms with similar angiographic occlusions and complications rate relative to biplane 2D roadmap, which implies possible compensation of limitations of monoplane fluoroscopy by 3D overlay technique. PMID:27621947

  20. Flapping of Insectile Wings

    Science.gov (United States)

    Huang, Yangyang; Kanso, Eva

    2015-11-01

    Insects use flight muscles attached at the base of the wings to produce impressive wing flapping frequencies. Yet the effects of muscle stiffness on the performance of insect wings remain unclear. Here, we construct an insectile wing model, consisting of two rigid wings connected at their base by an elastic torsional spring and submerged in an oscillatory flow. The wing system is free to rotate and flap. We first explore the extent to which the flyer can withstand roll perturbations, then study its flapping behavior and performance as a function of spring stiffness. We find an optimal range of spring stiffness that results in large flapping amplitudes, high force generation and good storage of elastic energy. We conclude by conjecturing that insects may select and adjust the muscle spring stiffness to achieve desired movement. These findings may have significant implications on the design principles of wings in micro air-vehicles.

  1. Revisiting nonlinearity in meandering river planform dynamics using Gradual Wavelet Reconstruc­­tion

    Science.gov (United States)

    Schwenk, J.; Foufoula-Georgiou, E.; Lanzoni, S.

    2014-12-01

    Characterizing the intrinsic nonlinearity in meandering river dynamics is important because it dictates river evolution response to perturbations such as bank armoring or channel straightening. Meandering river dynamics have been described in terms of chaos or self-organized criticality—characterizations predicated on the presence of nonlinearity—yet recent studies have found only limited evidence for its existence. Standard nonlinearity tests are performed by generating a number of linearized surrogate series from a signal of interest. Inherent nonlinearities in the original signal are destroyed in the surrogates via phase randomization in the Fourier domain. Nonlinearity is inferred if a significant difference exists between the original and the surrogates in an appropriately determined phase space. These tests detect the presence or absence of nonlinearity but cannot identify which scales and locations are contributing most to the signal's nonlinearity. A new surrogate generation method called Gradual Wavelet Reconstruction (GWR) has two key advantages over the standard methodology. First, GWR quantifies the degree of nonlinearity rather than simply detecting its presence or absence, providing a basis for comparisons between river planforms and models of meander migration. Second, because the GWR methodology relies on localized transformations, it can determine the scales and locations primarily contributing to the observed complexity. As a result of those advantages too, GWR has been shown to detect the presence of nonlinearity in signals where standard tests have failed. We apply GWR methodology to time series of channel sinuosity predicted by two established models of long-time meander migration: a HIPS-type model and that of Zolezzi and Seminara (2001). Although the former model has been shown to capture first-order meander dynamics, it fails to fully couple sediment and flow dynamics; nor does it account for the resonance phenomenon. Using GWR, we show

  2. Numerical investigation of long-term planform dynamics and stability of river meandering on fluvial floodplains

    Science.gov (United States)

    Xu, Dong; Bai, Yuchuan; Ma, Jianmin; Tan, Yan

    2011-09-01

    A mathematical model for river meandering and floodplain development is presented under the assumption of constant channel width, which combined Johanneson and Parker (1989) linear theory for flows in river bends and a conceptual depositional model from Howard (1992). A new bank erosion model is also developed, which takes into consideration of the nonlinearity in near-bank velocity and the outer bank height. Simulations reproduce the long-term behavior of river meandering and floodplain evolution in a way very similar to their natural processes. Based on the simulation results, stability of river meandering dynamics is discussed and the concept of filtration effect is introduced to highlight meandering rivers' capability to filter out arbitrarily applied planform disturbance. Simulations are also carried out to investigate the influence of the velocity nonlinearity and the outer bank height in bank erosion model, as well as their combinations. Results show that the consideration of velocity nonlinearity in bank erosion model leads to highly upstream-skewing geometry of fully developed river meanders, as well as a slower downstream migration of meander trains. The influence of nonlinearity in bank erosion model is much smaller than the influence of bank height, which reduces the bank migration rate exponentially in the newly introduced bank erosion model. The outer bank height consideration tends to decelerate the downstream migration rate of river meanders and accelerate lateral expansion of the floodplain as well. Consequently, a broader floodplain is generated compared with simulations without bank height considerations.

  3. Investigation of the Role of Planform Shape and Swimming Gait in Cetacean Propulsion

    Science.gov (United States)

    Ayancik, Fatma; Fish, Frank E.; Moored, Keith W.

    2015-11-01

    Dolphins and whales, known as cetaceans, have morphological characteristics associated with enhanced thrust production, high propulsive efficiency and reduced drag. These animals oscillate their moderate aspect ratio flukes in a heaving and pitching motion to propel themselves through the water. Surprisingly, these animals display a large variation in their fluke shape and swimming gait. The present study aims to probe the connection between the fluke shape and swimming gait in high performance swimming. The planform shape of cetacean flukes is parameterized with a NACA-inspired function where the coefficients are fit to several species. An unsteady three-dimensional boundary element method is used to identify the thrust production, energetics and wake structure of free-swimming flukes with an added virtual body drag. The shape and gait parameters of the different species are exchanged to gain a broader understanding of the connection between shape and gait. The numerical results are compared with lunate tail theory to assess the limitations of the theory and its predictions of force and energetic scalings. Supported by the Office of Naval Research under Program Director Dr. Bob Brizzolara, MURI grant number N00014-14-1-0533.

  4. Quantifying downstream impacts of impoundment on flow regime and channel planform, lower Trinity River, Texas

    Science.gov (United States)

    Wellmeyer, Jessica L.; Slattery, Michael C.; Phillips, Jonathan D.

    2005-07-01

    As human population worldwide has grown, so has interest in harnessing and manipulating the flow of water for the benefit of humans. The Trinity River of eastern Texas is one such watershed greatly impacted by engineering and urbanization. Draining the Dallas-Fort Worth metroplex, just under 30 reservoirs are in operation in the basin, regulating flow while containing public supplies, supporting recreation, and providing flood control. Lake Livingston is the lowest, as well as largest, reservoir in the basin, a mere 95 km above the Trinity's outlet near Galveston Bay. This study seeks to describe and quantify channel activity and flow regime, identifying effects of the 1968 closure of Livingston dam. Using historic daily and peak discharge data from USGS gauging stations, flow duration curves are constructed, identifying pre- and post-dam flow conditions. A digital historic photo archive was also constructed using six sets of aerial photographs spanning from 1938 to 1995, and three measures of channel activity applied using a GIS. Results show no changes in high flow conditions following impoundment, while low flows are elevated. However, the entire post-dam period is characterized by significantly higher rainfall, which may be obscuring the full impact of flow regulation. Channel activity rates do not indicate a more stabilized planform following dam closure; rather they suggest that the Trinity River is adjusting itself to the stress of Livingston dam in a slow, gradual process that may not be apparent in a modern time scale.

  5. Wind-tunnel experiments on divergence of forward-swept wings

    Science.gov (United States)

    Ricketts, R. H.; Doggett, R. V., Jr.

    1980-01-01

    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.

  6. Vortices around Dragonfly Wings

    CERN Document Server

    Kweon, Jihoon

    2009-01-01

    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 Aeschna juncea (Norberg, 1972), and the Reynolds number is 1,000 based on the maximum translational velocity and mean chord length. The numerical method is based on an immersed boundary method (Kim et al., 2001). In counter-stroke (phi=180 degree), the wing-tip vortices from both wings are connected in the wake, generating an entangled wing-tip vortex (e-WTV). A strong downward motion induced by this vortex decreases the lift force in the following downstroke (Kweon and Choi, 2008). When the fore-wing leads the hind-wing (phi=...

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

    Science.gov (United States)

    Phillips, J. D.

    1985-01-01

    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.

  8. An intelligent three dimensional reconstruction system for cerebral arteries from biplane cineangiograms

    International Nuclear Information System (INIS)

    In this study, an intelligent system is developed for the three dimensional reconstruction of cerebral arteries from biplane cineangiograms. The system is composed of two blocks, i.e., an inferencing-control-block and a processing-block. The inferencing-control block controls the flow of the image-processing by inferencing with the knowledge stored in the block and is a production system based on 'IF, THEN' rule. The processing-block is a collection of image processing procedures activated by a call from the inferencing-control-block. On the other hand, the flow of the image-processing is outlined as follows: After the extraction of vessel center lines from the angiograms, the blood flow directions and connectivity states of vessels are determined and the vessel graph is translated to a vessel connectivity tree. Then, by utilizing the knowledge about anatomic structure of cerebral arteries and characteristics of angiograms, important arteries are distinguished and vessel groups classified. Finally, by using a shape-oriented matching method, the vessels on the two projected planes are matched and the three dimensional structure of vessels constructed. An example is presented to demonstrate the effectiveness of the use of the knowledge which enables the system to improve the efficiency and precision of the processing, such as vessel analysis and matching. (author)

  9. Knee-joint configuration analysis by bi-plane x-ray photogrammetry, 1

    International Nuclear Information System (INIS)

    This paper investigates the three dimensional rotation between the tibia and femur, which constitute the femorotibial joint, using the bi-plane photogrammetric system developed by the authors. Calculation method of rotational angles is presented based on the corrective rotation of tibial coordinates (r, a, s) to the femoral coordinates (R, A, S). Experiments are performed on two fresh human normal left joints (died at 53 years and 57 years). Internal and external torques of 2.5 N · m are applied to intact and anterior cruciate ligament (ACL) cut joints at flexions ranging from 0 deg to 80 deg and their 3-D rotational angles are measured. Known clinical facts relating to the present experiment of ACL cut from normal knee are : (1) By the application of the internal torgue, it causes the increase of the internal rotation at flexions ranging from 0 deg to 40 deg. (2) It has no effect on the adduction-abduction of the knee. Comparing the present results with the clinical ones, it is concluded that the proposed calculation method is adequate. (author)

  10. Femoral shape analysis by bi-plane x-ray photogrammetry

    International Nuclear Information System (INIS)

    Hip joints are the joints of ilia and femurs, and their imperfect jointing becomes arthropathy. As one of the causes of imperfect jointing, the irregular form is conceivable. Therefore, the neck shaft angle and anteversion angle have been measured, but these methods are two-dimensional, the photographing is difficult, and the accuracy of measurement is problematic. Especially recently, advanced operations such as the total replacement of a joint have been carried out, and accurate diagnosis and treatment by full scale three-dimensional measurement are required. The bi-plane x-ray photogrammetry reported by the authors before can sufficiently meet this requirement, and the analyzer of femoral shape which can measure and calculate the accurate three-dimensional arrangement of a shaft axis, a neck axis and a head center of a femur, and enables the graphic display of the results was developed. This analyzer comprises a personal computer (NEC PC8800), a base frame and a measuring table. The measurement of femurs, the form analysis and graphic display, the construction of the analyzer and the examples of output, and the results of measurement are reported. (Kako, I.)

  11. Femoral shape analysis by Bi-plane x-ray photogrammetry

    International Nuclear Information System (INIS)

    For the osteotomy on hip joint diseases caused by abnormality of the shape of bones, an accurate 3-dimensional femoral shape must be recognized before operation. It has been reported by the present authors that spinal shape is sufficiently analyzed by a developed system based on bi-plane photogrammetry. This paper describes an application of the system to the femoral shape analysis. The shaft axis, the neck axis, the head center of femur and the radius of the head are reconstructed 3-dimensionally using the vector analysis of plane and line, and the least square approximation method. The obtained axes and head are graphically displayed on the screen of a personal computer through the perspective transformation. The shape parameters usually used in clinic, such as the anteversion angle and the neck-shaft angle, are also calculated by the present method. Result obtained by this system is compared with that by photographical measurement of exposed femurs, then the present method is reduced to have higher accuracy than Kai's method currently used. (author)

  12. Butterfly wing colours : scale beads make white pierid wings brighter

    NARCIS (Netherlands)

    Stavenga, DG; Stowe, S; Siebke, K; Zeil, J; Arikawa, K

    2004-01-01

    The wing-scale morphologies of the pierid butterflies Pieris rapae (small white) and Delias nigrina (common jezabel), and the heliconine Heliconius melpomene are compared and related to the wing-reflectance spectra. Light scattering at the wing scales determines the wing reflectance, but when the sc

  13. Wing-Wake Interactions between Ipsilateral Wings in Dragonfly Flight

    Science.gov (United States)

    Dong, Haibo; Liang, Zongxian

    2009-11-01

    Bilateral and ipsilateral wing-wing interactions can be commonly observed in insect flights. As a representative example of ipsilateral wing-wing interaction, dragonflies in flight have been widely studied. An important fact is that the flow over their hindwings is affected by the presence of the forewings. Wake capture and phase-change play very important role on aerodynamic performance of the hindwings We present a direct numerical simulation of a modeled dragonfly (Aeshna juncea) in slow flight as studied in Azuma et al (JEB 1985). Realistic morphologies of wing, body, and kinematics are used for maximum including wing and body features of a dragonfly. This work aims to study the relations between wake-topology and aerodynamic performance due to wing-wing and wing-wake interactions of dragonfly ipsilateral wings. DNS results are also compared with Local Momentum Theory (Azuma et al).

  14. Vegetative impacts upon bedload transport capacity and channel stability for differing alluvial planforms in the Yellow River source zone

    Science.gov (United States)

    Li, Zhi Wei; Yu, Guo An; Brierley, Gary; Wang, Zhao Yin

    2016-07-01

    The influence of vegetation upon bedload transport and channel morphodynamics is examined along a channel stability gradient ranging from meandering to anabranching to anabranching-braided to fully braided planform conditions along trunk and tributary reaches of the Upper Yellow River in western China. Although the regional geology and climate are relatively consistent across the study area, there is a distinct gradient in the presence and abundance of riparian vegetation for these reaches atop the Qinghai-Tibet Plateau (elevations in the study area range from 2800 to 3400 m a.s.l.). To date, the influence of vegetative impacts upon channel planform and bedload transport capacity of alluvial reaches of the Upper Yellow River remains unclear because of a lack of hydrological and field data. In this region, the types and pattern of riparian vegetation vary with planform type as follows: trees exert the strongest influence in the anabranching reach, the meandering reach flows through meadow vegetation, the anabranching-braided reach has a grass, herb, and sparse shrub cover, and the braided reach has no riparian vegetation. A non-linear relation between vegetative cover on the valley floor and bedload transport capacity is evident, wherein bedload transport capacity is the highest for the anabranching reach, roughly followed by the anabranching-braided, braided, and meandering reaches. The relationship between the bedload transport capacity of a reach and sediment supply from upstream exerts a significant influence upon channel stability. Bedload transport capacity during the flood season (June-September) in the braided reach is much less than the rate of sediment supply, inducing bed aggradation and dynamic channel adjustments. Rates of channel adjustment are less pronounced for the anabranching-braided and anabranching reaches, while the meandering reach is relatively stable (i.e., this is a passive meandering reach).

  15. Historical changes in channel network extent and channel planform in an intensively managed landscape: Natural versus human-induced effects

    Science.gov (United States)

    Rhoads, Bruce L.; Lewis, Quinn W.; Andresen, William

    2016-01-01

    Humans have become major geomorphological agents, effecting substantial change in the characteristics of Earth's physical landscapes. The agricultural Midwest of the United States is a region marked by pronounced human influence at the landscape scale. Humans undoubtedly have strongly influenced critical zone processes, including fluvial processes, in intensively managed agricultural landscapes, yet the exact nature of human alteration of these processes is unknown. This study documents historical changes in the extent of the stream channel network and in channel planform within the upper Sangamon River basin - an intensively managed agricultural watershed in Illinois. Results indicate that the modern channel network is nearly three times more extensive than the channel network in the 1820s. Most change in drainage density has occurred in headwater portions of the basin where numerous drainage ditches have been added to the network to drain flat uplands. No detectable change in channel position is evident between 1940 and 2012 along about 60% of the total length of the Sangamon River and its major tributaries. Nearly 30% of the total length exhibits change related to meander dynamics (cutoffs and lateral migration), whereas about 8% has changed as a result of channelization. Channelized sections typically remain straight for decades following human modification, supporting the notion that humans produce long-lasting catastrophic change in channel planform in this region. The findings confirm that humans are effective agents of morphological change in fluvial systems in this intensively managed watershed. Documenting human-induced versus natural changes in fluvial systems is important for evaluating how other critical zone processes in intensively managed landscapes have been affected by these changes. Human-induced changes in channel extent and planform most likely have altered this landscape from one dominated by biogeochemical transformations and storage of water

  16. The characterization of tandem and corrugated wings

    Science.gov (United States)

    Lian, Yongsheng; Broering, Timothy; Hord, Kyle; Prater, Russell

    2014-02-01

    Dragonfly wings have two distinct features: a tandem configuration and wing corrugation. Both features have been extensively studied with the aim to understand the superior flight performance of dragonflies. In this paper we review recent development of tandem and corrugated wing aerodynamics. With regards to the tandem configuration, this review will focus on wing/wing and wing/vortex interactions at different flapping modes and wing spacing. In addition, the aerodynamics of tandem wings under gusty conditions will be reviewed and compared with isolated wings to demonstrate the gust resistance characteristics of flapping wings. Regarding corrugated wings, we review their structural and aerodynamic characteristics.

  17. AERODYNAMICS OF WING TIP SAILS

    OpenAIRE

    MUSHTAK AL-ATABI

    2006-01-01

    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 fact...

  18. Parametric geometric model and shape optimization of an underwater glider with blended-wing-body

    Science.gov (United States)

    Sun, Chunya; Song, Baowei; Wang, Peng

    2015-11-01

    Underwater glider, as a new kind of autonomous underwater vehicles, has many merits such as long-range, extended-duration and low costs. The shape of underwater glider is an important factor in determining the hydrodynamic efficiency. In this paper, a high lift to drag ratio configuration, the Blended-Wing-Body (BWB), is used to design a small civilian under water glider. In the parametric geometric model of the BWB underwater glider, the planform is defined with Bezier curve and linear line, and the section is defined with symmetrical airfoil NACA 0012. Computational investigations are carried out to study the hydrodynamic performance of the glider using the commercial Computational Fluid Dynamics (CFD) code Fluent. The Kriging-based genetic algorithm, called Efficient Global Optimization (EGO), is applied to hydrodynamic design optimization. The result demonstrates that the BWB underwater glider has excellent hydrodynamic performance, and the lift to drag ratio of initial design is increased by 7% in the EGO process.

  19. Twin Flavor Chicken Wings

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    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

  20. Aerodynamic characteristics of wings designed with a combined-theory method to cruise at a Mach number of 4.5

    Science.gov (United States)

    Mack, Robert J.

    1988-01-01

    A wind-tunnel study was conducted to determine the capability of a method combining linear theory and shock-expansion theory to design optimum camber surfaces for wings that will fly at high-supersonic/low-hypersonic speeds. Three force models (a flat-plate reference wing and two cambered and twisted wings) were used to obtain aerodynamic lift, drag, and pitching-moment data. A fourth pressure-orifice model was used to obtain surface-pressure data. All four wing models had the same planform, airfoil section, and centerbody area distribution. The design Mach number was 4.5, but data were also obtained at Mach numbers of 3.5 and 4.0. Results of these tests indicated that the use of airfoil thickness as a theoretical optimum, camber-surface design constraint did not improve the aerodynamic efficiency or performance of a wing as compared with a wing that was designed with a zero-thickness airfoil (linear-theory) constraint.

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

    Science.gov (United States)

    Lehmann, Fritz-Olaf

    2008-01-01

    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.

  2. A biplane roentgen videometry system for dynamic /60 per second/ studies of the shape and size of circulatory structures, particularly the left ventricle.

    Science.gov (United States)

    Ritman, E. L.; Sturm, E.; Wood, E. H.; Heintzen, P. H.

    1971-01-01

    A roentgen-television digital-computer technique and a display system developed for dynamic circulatory structure studies are described. Details are given for a videoroentgenographic setup which is used for obtaining biplane roentgen silhouettes of a left ventricle. A 60 per sec measurement of the shape and volume of angiographically outlined cardiac chambers can be made by this technique along with simultaneous ECG, pressure, and flow measurements accessible for real-time digital computer processing and analysis.

  3. Radiofrequency Ablation Combined with Chemoembolization for Intermediate-Sized (3-5 cm) Hepatocellular Carcinomas Under Dual Guidance of Biplane Fluoroscopy and Ultrasonography

    Energy Technology Data Exchange (ETDEWEB)

    Min, Ji Hye; Lee, Min Woo; Cha, Dong Ik [Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710 (Korea, Republic of); Jeon, Yong Hwan [Department of Radiology, Kangwon National University College of Medicine, Chuncheon 200-722 (Korea, Republic of); Shin, Sung Wook; Cho, Sung Ki; Rhim, Hyunchul; Lim, Hyo K. [Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710 (Korea, Republic of)

    2013-07-01

    To assess the technical feasibility and local efficacy of percutaneous radiofrequency ablation (RFA) combined with transcatheter arterial chemoembolization (TACE) for an intermediate-sized (3-5 cm in diameter) hepatocellular carcinoma (HCC) under the dual guidance of biplane fluoroscopy and ultrasonography (US). Patients with intermediate-sized HCCs were treated with percutaneous RFA combined with TACE. RFA was performed under the dual guidance of biplane fluoroscopy and US within 14 days after TACE. We evaluated the rate of major complications on immediate post-RFA CT images. Primary technique effectiveness rate was determined on one month follow-up CT images. The cumulative rate of local tumor progression was estimated with the use of Kaplan-Meier method. Twenty-one consecutive patients with 21 HCCs (mean size: 3.6 cm; range: 3-4.5 cm) were included. After TACE (mean: 6.7 d; range: 1-14 d), 20 (95.2%) of 21 HCCs were visible on fluoroscopy and were ablated under dual guidance of biplane fluoroscopy and US. The other HCC that was poorly visible by fluoroscopy was ablated under US guidance alone. Major complications were observed in only one patient (pneumothorax). Primary technique effectiveness was achieved for all 21 HCCs in a single RFA session. Cumulative rates of local tumor progression were estimated as 9.5% and 19.0% at one and three years, respectively. RFA combined with TACE under dual guidance of biplane fluoroscopy and US is technically feasible and effective for intermediate-sized HCC treatment.

  4. Low Aspect-Ratio Wings for Wing-Ships

    DEFF Research Database (Denmark)

    Filippone, Antonino; Selig, M.

    1998-01-01

    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...... of ground, is presented. It is shownthat the performance of such wings is generally inferior to that of slender wings, although in ground placement can yield substantial improvements in the aerodynamic efficiency....

  5. Remote sensing, planform, and facies analysis of the Plain of Tineh, Egypt for the remains of the defunct Pelusiac River

    Science.gov (United States)

    Quintanar, Jessica; Khan, Shuhab D.; Fathy, Mohamed S.; Zalat, Abdel-Fattah A.

    2013-11-01

    The Pelusiac Branch was a distributary river in the Nile Delta that splits off from the main trunk of the Nile River as it flowed toward the Mediterranean. At approximately 25 A.D., it was chocked by sand and silt deposits from prograding beach accretion processes. The lower course of the river and its bifurcation point from the trunk of the Nile have been hypothesized based on ancient texts and maps, as well as previous research, but results have been inconsistent. Previous studies partly mapped the lower course of the Pelusiac River in the Plain of Tineh, east of the Suez Canal, but rapid urbanization related to the inauguration of the Peace Canal mega-irrigation project has covered any trace of the linear feature reported by these previous studies. The present study used multispectral remote sensing data of GeoEYE-1 and Landsat-TM to locate and accurately map the course of the defunct Pelusiac River within the Plain of Tineh. Remote sensing analysis identified a linear feature that is 135 m wide at its maximum and approximately 13 km long. It extends from the Pelusium ruins to the Suez Canal, just north of the Peace Canal. This remotely located linear feature corresponds to the path of the Pelusiac River during Roman times. Planform geomorphology was applied to determine the hydrological regime and paleodischarge of the river prior to becoming defunct. Planform analysis derived a bankfull paleodischarge value of ~ 5700 m3 s- 1 and an average discharge of 650 m3 s- 1, using the reach average for the interpreted Pelusiac River. The derived values show a river distributary similar in discharge to the modern dammed Damietta river. Field work completed in April of 2012 derived four sedimentary lithofacies of the upper formation on the plain that included pro-delta, delta-front and delta-plain depositional environments. Diatom and fossil mollusk samples were also identified that support coastal beach and lagoonal environments of deposition. Measured section columns

  6. Fog spontaneously folds mosquito wings

    Science.gov (United States)

    Dickerson, Andrew K.; Liu, Xing; Zhu, Ting; Hu, David L.

    2015-02-01

    The flexibility of insect wings confers aerodynamic benefits, but can also present a hazard if exposed to fog or dew. Fog can cause water to accumulate on wings, bending them into tight taco shapes and rendering them useless for flight. In this combined experimental and theoretical study, we use high-speed video to film the spontaneous folding of isolated mosquito wings due to the evaporation of a water drop. We predict shapes of the deformed wing using two-dimensional elastica theory, considering both surface tension and Laplace pressure. We also recommend fold-resistant geometries for the wings of flapping micro-aerial vehicles. Our work reveals the mechanism of insect wing folding and provides a framework for further study of capillarity-driven folding in both natural and biomimetic systems at small scales.

  7. Improved determination of biplane imaging geometry from two projection images and its application to three-dimensional reconstruction of coronary arterial trees.

    Science.gov (United States)

    Chen, S Y; Metz, C E

    1997-05-01

    A technique has been developed for accurate estimation of three-dimensional (3D) biplane imaging geometry and reconstruction of 3D objects based on two perspective projections acquired at arbitrary orientations, without the need of calibration. The required prior information (i.e., the intrinsic parameters of each single-plane imaging system) for determination of biplane imaging geometry includes (a) the distance between each focal spot and its image plane, SID (the focal-spot to imaging-plane distance); (b) the pixel size, psize (e.g., 0.3 mm/pixel); (c) the distance between the two focal spots ff' or the known 3D distance between two points in the projection images; and (d) for each view, an approximation of the magnification factor, MF (e.g., 1.2), which is the ratio of the SID and the approximate distance of the object to the focal spot. Item (d) is optional but may provide a more accurate estimation if it is available. Given five or more corresponding object points in both views, a constrained nonlinear optimization algorithm is applied to obtain an optimal estimate of the biplane imaging geometry in the form of a rotation matrix R and a translation vector t that characterize the position and orientation of one imaging system relative to the other. With the calculated biplane imaging geometry, 3D spatial information concerning the object can then be reconstructed. The accuracy of this method was evaluated by using a computer-simulated coronary arterial tree and a cube phantom object. Our simulation study showed that a computer-simulated coronary tree can be reconstructed from two views with less than 2 and 8.4 mm root-mean-square (rms) configuration (or relative-position) error and absolute-position error, respectively, even if the input errors in the corresponding 2D points are fairly large (more than two pixels = 0.6 mm). In contrast, input image error of more than one pixel (= 0.3 mm) can yield 3D position errors of 10 cm or more when other existing methods

  8. Wind Tunnel Application of a Pressure-Sensitive Paint Technique to a Double Delta Wing Model at Subsonic and Transonic Speeds

    Science.gov (United States)

    Erickson, Gary E.; Gonzalez, Hugo A.

    2006-01-01

    A pressure-sensitive paint (PSP) technique was applied in a wind tunnel experiment in the NASA Langley Research Center 8-Foot Transonic Pressure Tunnel to study the effect of wing fillets on the global vortex induced surface static pressure field about a sharp leading-edge 76 deg./40 deg. double delta wing, or strake-wing, model at subsonic and transonic speeds. Global calibrations of the PSP were obtained at M(sub infinity) = 0.50, 0.70, 0.85, 0.95, and 1.20, a Reynolds number per unit length of 2.0 million, and angles of attack from 10 degrees to 20 degrees using an insitu method featuring the simultaneous acquisition of electronically scanned pressures (ESP) at discrete locations on the model. The mean error in the PSP measurements relative to the ESP data was approximately 2 percent or less at M(sub infinity) = 0.50 to 0.85 but increased to several percent at M(sub infinity) =0.95 and 1.20. The PSP pressure distributions and pseudo-colored, planform-view pressure maps clearly revealed the vortex-induced pressure signatures at all Mach numbers and angles of attack. Small fillets having parabolic or diamond planforms situated at the strake-wing intersection were respectively designed to manipulate the vortical flows by removing the leading-edge discontinuity or introducing additional discontinuities. The fillets caused global changes in the vortex-dominated surface pressure field that were effectively captured in the PSP measurements. The vortex surface pressure signatures were compared to available off-surface vortex cross-flow structures obtained using a laser vapor screen (LVS) flow visualization technique. The fillet effects on the PSP pressure distributions and the observed leading-edge vortex flow characteristics were consistent with the trends in the measured lift, drag, and pitching moment coefficients.

  9. Freight Wing Trailer Aerodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Graham, Sean (Primary Investigator); Bigatel, Patrick

    2004-10-17

    Freight Wing Incorporated utilized the opportunity presented by this DOE category one Inventions and Innovations grant to successfully research, develop, test, patent, market, and sell innovative fuel and emissions saving aerodynamic attachments for the trucking industry. A great deal of past scientific research has demonstrated that streamlining box shaped semi-trailers can significantly reduce a truck's fuel consumption. However, significant design challenges have prevented past concepts from meeting industry needs. Market research early in this project revealed the demands of truck fleet operators regarding aerodynamic attachments. Products must not only save fuel, but cannot interfere with the operation of the truck, require significant maintenance, add significant weight, and must be extremely durable. Furthermore, SAE/TMC J1321 tests performed by a respected independent laboratory are necessary for large fleets to even consider purchase. Freight Wing used this information to create a system of three practical aerodynamic attachments for the front, rear and undercarriage of standard semi trailers. SAE/TMC J1321 Type II tests preformed by the Transportation Research Center (TRC) demonstrated a 7% improvement to fuel economy with all three products. If Freight Wing is successful in its continued efforts to gain market penetration, the energy and environmental savings would be considerable. Each truck outfitted saves approximately 1,100 gallons of fuel every 100,000 miles, which prevents over 12 tons of CO2 from entering the atmosphere. If all applicable trailers used the technology, the country could save approximately 1.8 billion gallons of diesel fuel, 18 million tons of emissions and 3.6 billion dollars annually.

  10. Automated measurement of Drosophila wings

    Directory of Open Access Journals (Sweden)

    Mezey Jason

    2003-12-01

    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.

  11. Control of a swept wing tailless aircraft through wing morphing

    Science.gov (United States)

    Guiler, Richard W.

    Inspired by flight in nature, work done by Lippisch, the Hortens, and Northrop offered insight to achieving the efficiency of bird flight with swept-wing tailless aircraft. Tailless designs must incorporate aerodynamic compromises for control, which have inhibited potential advantages. A morphing mechanism, capable of changing the twist of wing and that can also provide pitch, roll and yaw control for a tailless swept wing aircraft is the first step to a series of morphing techniques, which will lead to more fluid, bird-like flight. This research focuses on investigating the design of a morphing wing to improve the flight characteristics of swept wing Horten type tailless aircraft. Free flight demonstrators, wind tunnel flow visualization, wind-tunnel force and moment data along with CFD studies have been used to evaluate the stability, control and efficiency of a morphing swept wing tailless aircraft. A wing morphing mechanism for the control of a swept wing tailless aircraft has been developed. This new control technique was experimentally and numerically compared to an existing elevon equipped tailless aircraft and has shown the potential for significant improvement in efficiency. The feasibility of this mechanism was also validated through flight testing of a flight weight version. In the process of comparing the Horten type elevon equipped aircraft and the morphing model, formal wind tunnel verification of wingtip induced thrust, found in Horten (Bell Shaped Lift distribution) type swept wing tailless aircraft was documented. A more complete physical understanding of the highly complex flow generated in the control region of the morphing tailless aircraft has been developed. CFD models indicate the possibility of the presence of a Leading Edge Vortex (LEV) on the control section morphing wing when the tip is twisted between +3.5 degrees and +7 degrees. The presence of this LEV causes a reduction of drag while lift is increased. Similar LEVs have been

  12. Narrative review of the in vivo mechanics of the cervical spine after anterior arthrodesis as revealed by dynamic biplane radiography.

    Science.gov (United States)

    Anderst, William

    2016-01-01

    Arthrodesis is the standard of care for numerous pathologic conditions of the cervical spine and is performed over 150,000 times annually in the United States. The primary long-term concern after this surgery is adjacent segment disease (ASD), defined as new clinical symptoms adjacent to a previous fusion. The incidence of adjacent segment disease is approximately 3% per year, meaning that within 10 years of the initial surgery, approximately 25% of cervical arthrodesis patients require a second procedure to address symptomatic adjacent segment degeneration. Despite the high incidence of ASD, until recently, there was little data available to characterize in vivo adjacent segment mechanics during dynamic motion. This manuscript reviews recent advances in our knowledge of adjacent segment mechanics after cervical arthrodesis that have been facilitated by the use of dynamic biplane radiography. The primary observations from these studies are that current in vitro test paradigms often fail to replicate in vivo spine mechanics before and after arthrodesis, that intervertebral mechanics vary among cervical motion segments, and that joint arthrokinematics (i.e., the interactions between adjacent vertebrae) are superior to traditional kinematics measurements for identifying altered adjacent segment mechanics after arthrodesis. Future research challenges are identified, including improving the biofidelity of in vitro tests, determining the natural history of in vivo spine mechanics, conducting prospective longitudinal studies on adjacent segment kinematics and arthrokinematics after single and multiple-level arthrodesis, and creating subject-specific computational models to accurately estimate muscle forces and tissue loading in the spine during dynamic activities.

  13. High knee valgus in female subjects does not yield higher knee translations during drop landings: a biplane fluoroscopic study.

    Science.gov (United States)

    Torry, Michael R; Shelburne, Kevin B; Myers, Casey; Giphart, J Erik; Pennington, W Wesley; Krong, Jacob P; Peterson, Daniel S; Steadman, J Richard; Woo, Savio L-Y

    2013-02-01

    The goal of this study was to determine the effects of peak knee valgus angle and peak knee abductor moment on the anterior, medial, and lateral tibial translations (ATT, MTT, LTT) in the "at risk" female knee during drop landing. Fifteen female subjects performed drop landings from 40 cm. Three-dimension knee motion was simultaneously recorded using a high speed, biplane fluoroscopy system, and a video-based motion analysis system. Valgus knee angles and knee abduction moments were stratified into low, intermediate, and high groups and peak ATT, MTT, and LTT were compared between these groups with ANOVA (α = 0.05). Significant differences were observed between stratified groups in peak knee valgus angle (p < 0.0001) and peak knee abduction moment (p < 0.0001). However, no corresponding differences in peak ATT, LTT, and MTT between groups exhibiting low to high-peak knee valgus angles (ATT: p = 0.80; LTT: p = 0.25; MTT: p = 0.72); or, in peak ATT (p = 0.61), LTT (p = 0.26) and MTT (p = 0.96) translations when stratified according to low to high knee abduction moments, were found. We conclude that the healthy female knee is tightly regulated with regard to translations even when motion analysis derived knee valgus angles and abduction moments are high.

  14. Beetle wings are inflatable origami

    Science.gov (United States)

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

    2015-11-01

    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.

  15. AERODYNAMICS OF WING TIP SAILS

    Directory of Open Access Journals (Sweden)

    MUSHTAK AL-ATABI

    2006-06-01

    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.

  16. Gravel extraction and planform change in a wandering gravel-bed river: The River Wear, Northern England

    Science.gov (United States)

    Wishart, Duncan; Warburton, Jeff; Bracken, Louise

    2008-02-01

    Within-channel alluvial gravel extraction is one of the most important forms of anthropogenically induced morphological change in river channels. In British rivers commercial gravel extraction was widespread between the 1930s and 1960s, and limited gravel extraction operations to reduce flood risk or maintain navigation continue to the present day. Despite this, gravel extraction has received little attention in UK river studies. This paper examines the significance of within-channel gravel extraction, during the period 1945-1960, on the planform of the River Wear in northern England. The study focuses on two 3 km piedmont reaches at Wolsingham and Harperley Park, located at the margin of the upland zone. Examination of detailed archival accounts of the gravel extraction operations, supplemented by the analysis of aerial photographs has enabled the impact of gravel extraction on the channel of the River Wear to be determined. Sediment budget calculations suggest large sediment deficits in both study reaches, however, assessing potential impacts simply in terms of a sediment deficit may be misleading as channel adjustments depend on local factors and a detailed consideration of the reach-scale sediment budget. Differences in the nature of channel adjustments of both reaches were found to be primarily a function of the method of gravel extraction employed. Overall patterns of channel change along the extraction reaches, over the past 150 years, were similar to reaches where gravel extraction was not practiced. This highlights the difficulty of trying to establish the significance of different processes where both local (gravel extraction) and catchment-scale factors (climate and land use) are operating.

  17. Structural Analysis of a Dragonfly Wing

    NARCIS (Netherlands)

    Jongerius, S.R.; Lentink, D.

    2010-01-01

    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

  18. Radiofrequency Ablation for Viable Hepatocellular Carcinoma around Retained Iodized Oil after Transcatheter Arterial Chemoembolization: Usefulness of Biplane Fluoroscopy Plus Ultrasound Guidance

    Energy Technology Data Exchange (ETDEWEB)

    Min, Ji Hye; Lee, Min Woo; Rhim, Hyun Chul; Choi, Dong Gil; KIm, Young Son; Cha, Dong Ik; Lim, Hyo K. [Dept. of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Kim, Young Jun [Dept. of Radiology and Research Institute of Biomedical Science, Konkuk University School of Medicine, Seoul (Korea, Republic of)

    2012-11-15

    To assess the technical feasibility and local efficacy of biplane fluoroscopy plus US-guided percutaneous radiofrequency ablation (RFA) for viable hepatocellular carcinoma (HCC) around retained iodized oil after transcatheter arterial chemoembolization (TACE). Our prospective study was approved by our institutional review board and informed consent was obtained from all participating patients. For patients with viable HCC around retained iodized oil after TACE, biplane fluoroscopy plus US-guided RFA was performed. We evaluated the rate of technical success and major complications on a post-RFA CT examination and local tumor progression with a follow-up CT. Among 40 consecutive patients, 19 were excluded due to one of the following reasons: poorly visible HCC on fluoroscopy (n = 13), high risk location (n 2), RFA performed under monoplane fluoroscopy and US guidance (n = 2), and poorly identifiable new HCCs on US (n = 2). The remaining 21 patients with 21 viable HCCs were included. The size of total tumors ranged from 1.4 to 5.0 cm (mean: 3.2 cm) in the longest diameter. Technical success was achieved for all 21 HCCs, and major complications were observed in none of the patients. During the follow-up period (mean, 20.3 months; range, 6.5-29.9 months), local tumor progression was found in two patients (2/21, 9.5%). Distant intrahepatic metastasis developed in 76.2% (16/21) of patients. When retained iodized oil around the tumor after TACE hampers the targeting of the viable tumor for RFA, biplane fluoroscopy plus US-guided RFA may be performed owing to its technical feasibility and effective treatment for viable HCCs.

  19. Accuracy of biplane x-ray imaging combined with model-based tracking for measuring in-vivo patellofemoral joint motion

    Directory of Open Access Journals (Sweden)

    Zauel Roger

    2008-09-01

    Full Text Available Abstract Background Accurately measuring in-vivo motion of the knee's patellofemoral (PF joint is challenging. Conventional measurement techniques have largely been unable to accurately measure three-dimensional, in-vivo motion of the patella during dynamic activities. The purpose of this study was to assess the accuracy of a new model-based technique for measuring PF joint motion. Methods To assess the accuracy of this technique, we implanted tantalum beads into the femur and patella of three cadaveric knee specimens and then recorded dynamic biplane radiographic images while manually flexing and extending the specimen. The position of the femur and patella were measured from the biplane images using both the model-based tracking system and a validated dynamic radiostereometric analysis (RSA technique. Model-based tracking was compared to dynamic RSA by computing measures of bias, precision, and overall dynamic accuracy of four clinically-relevant kinematic parameters (patellar shift, flexion, tilt, and rotation. Results The model-based tracking technique results were in excellent agreement with the RSA technique. Overall dynamic accuracy indicated errors of less than 0.395 mm for patellar shift, 0.875° for flexion, 0.863° for tilt, and 0.877° for rotation. Conclusion This model-based tracking technique is a non-invasive method for accurately measuring dynamic PF joint motion under in-vivo conditions. The technique is sufficiently accurate in measuring clinically relevant changes in PF joint motion following conservative or surgical treatment.

  20. Static aeroelastic analysis of composite wing

    Science.gov (United States)

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

    1990-01-01

    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.

  1. Investigation into the Role of Dragonfly Wing Flexibility During Passive Wing Pitch Reversal

    Science.gov (United States)

    Bajwa, Yousaf; Williams, Ventress; Ren, Yan; Dong, Haibo; Flow Simulation Research Group Team

    2013-11-01

    Wing deformation is a characteristic part of flapping wing flight. In dragonflies, a torsion wave can be observed propagating from the tip to the root during stroke reversal. In this paper, we utilize high-speed photogrammetry and 3d surface reconstruction techniques to quantify wing deformation and kinematics of a dragonfly. We then use finite elements in the absolute nodal coordinate formulation to estimate strain energy in the wing during wing pitch reversal. We use this data to analyze the role of wing structure in facilitating wing rotation and bringing about the characteristic torsion wave. The influence of the elastic force in facilitating wing rotation is then compared with inertial and aerodynamic forces as well. A quantitative look into the variation of strain energy within the insect wing during wing rotation could lead to more efficient design of dynamic wing pitching mechanisms. Supported by NSF CBET-1343154.

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

    Science.gov (United States)

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

    1993-01-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

    Xin Yu; Mao Sun

    2009-01-01

    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.

  4. Aerodynamic control with passively pitching wings

    Science.gov (United States)

    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.

  5. [Winged scapula in lyme borreliosis].

    Science.gov (United States)

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

    2016-06-01

    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.

  6. The Wings for Angels Project

    Science.gov (United States)

    McMillan, Liberty; McMillan, Ellen; Ayers, Ann

    2012-01-01

    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…

  7. Biplane roentgen videometric system for dynamic, 60/sec, studies of the shape and size of circulatory structures, particularly the left ventricle.

    Science.gov (United States)

    Ritman, E. L.; Sturm, R. E.; Wood, E. H.

    1973-01-01

    An operator interactive video system for the measurement of roentgen angiographically outlined structures is described. Left ventricular volume and three-dimensional shapes are calculated from up to 200 pairs of diameters measured from ventriculograms at the rate of 60 pairs of biplane images per second. The accuracy and reproducibility of volumes calculated by the system were established by analysis of roentgenograms of inanimate objects of known volume and by comparison of left ventricular stroke volumes calculated by the system with the stroke volumes calculated by an indicator-dilution technique and an aortic root electromagnetic flowmeter. Computer-generated display of the large amounts of data obtained by the videometry system is described.

  8. Numerical evaluation of the effects of planform geometry and inflow conditions on flow, turbulence structure, and bed shear velocity at a stream confluence with a concordant bed

    Science.gov (United States)

    Constantinescu, George; Miyawaki, Shinjiro; Rhoads, Bruce; Sukhodolov, Alexander

    2014-10-01

    This study numerically investigates the effects of variations in inflow conditions and planform geometry on large-scale coherent flow structures and bed friction velocities at a stream confluence with natural bathymetry and concordant bed morphology. Several numerical experiments are conducted in which either the Kelvin-Helmholtz mode or the wake mode dominates within the mixing interface (MI) between the two confluent streams as the junction angle and alignments of the tributaries are altered. In the Kelvin-Helmholtz mode, the MI contains mostly corotating vortices driven by the mean transverse shear across the MI, while in the wake mode the MI contains counterrotating vortices forming by the interaction of the separated shear layers on the two sides of a zone of stagnant fluid near the junction corner. A large angle between the two incoming streams is not necessary for the development of strongly coherent streamwise-oriented vortical (SOV) cells in the immediate vicinity of the MI. Results show that such SOV cells can develop and produce high bed friction velocities even for cases with a low angle between the two tributaries and for cases where the downstream channel is approximately aligned with the axes of the two tributaries (low-curvature cases). SOV cells tend not to develop only when the incoming streams are parallel and aligned with the downstream channel (junction angle of zero), and the incoming flows produce a strong Kelvin-Helmholtz mode. Under such conditions, quasi 2-D MI vortices play the primary role in mixing and the production of high bed shear velocities. Simulations with and without natural bed morphology/local bank line irregularities indicate that planform geometry and inflow conditions primarily govern the development of coherent flow structures, but that bathymetric and bank line effects can locally modify details of these structures.

  9. Review Results on Wing-Body Interference

    Directory of Open Access Journals (Sweden)

    Frolov Vladimir

    2016-01-01

    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.

  10. Periodic and Chaotic Flapping of Insectile Wings

    CERN Document Server

    Huang, Yangyang

    2015-01-01

    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...

  11. Piezoelectrically actuated insect scale flapping wing

    Science.gov (United States)

    Mukherjee, Sujoy; Ganguli, Ranjan

    2010-04-01

    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.

  12. Locomotion by Tandem and Parallel Wings

    Science.gov (United States)

    Tanida, Yoshimichi

    A two-dimensional analysis was carried out on the locomotion by tandem and parallel wings in relation to the free flight of dragonflies and beetles, remarking the mutual interference between fore and hind wings. The results obtained are summarized as follows: In the case of tandem wings, (1)High thrust and propulsive efficiency can be achieved when the forewing oscillates with a definite phase lag behind the hindwing, as in the case of real dragonflies, (2)Somewhat smaller amplitude of hindwing leads to optimum condition for work sharing of two wings, (3)The hard forewing does not serve for the thrust and propulsive efficiency, whereas the hard hindwing does for the augmentation of them; In the case of parallel wings, (4)The hard wing placed near the soft wing acts nearly as an infinite plate, as for the ground effect, increasing both thrust and propulsive efficiency.

  13. Parametric geometric model and shape optimization of an underwater glider with blended-wing-body

    Directory of Open Access Journals (Sweden)

    Sun Chunya

    2015-11-01

    Full Text Available Underwater glider, as a new kind of autonomous underwater vehicles, has many merits such as long-range, extended-duration and low costs. The shape of underwater glider is an important factor in determining the hydrodynamic efficiency. In this paper, a high lift to drag ratio configuration, the Blended-Wing-Body (BWB, is used to design a small civilian under water glider. In the parametric geometric model of the BWB underwater glider, the planform is defined with Bezier curve and linear line, and the section is defined with symmetrical airfoil NACA 0012. Computational investigations are carried out to study the hydrodynamic performance of the glider using the commercial Computational Fluid Dynamics (CFD code Fluent. The Kriging-based genetic algorithm, called Efficient Global Optimization (EGO, is applied to hydrodynamic design optimization. The result demonstrates that the BWB underwater glider has excellent hydrodynamic performance, and the lift to drag ratio of initial design is increased by 7% in the EGO process.

  14. Surgical Treatment of Winged Scapula

    OpenAIRE

    Galano, Gregory J.; Bigliani, Louis U.; Ahmad, Christopher S.; Levine, William N.

    2008-01-01

    Injuries to the long thoracic and spinal accessory nerves present challenges in diagnosis and treatment. Palsies of the serratus anterior and trapezius muscles lead to destabilization of the scapula with medial and lateral scapular winging, respectively. Although nonoperative treatment is successful in some patients, failures have led to the evolution of surgical techniques involving various combinations of fascial graft and/or transfer of adjacent muscles. Our preferred method of reconstruct...

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

    Directory of Open Access Journals (Sweden)

    Ma Baofeng

    2016-10-01

    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.

  16. Wing-wake interaction reduces power consumption in insect tandem wings

    Science.gov (United States)

    Lehmann, Fritz-Olaf

    Insects are capable of a remarkable diversity of flight techniques. Dragonflies, in particular, are notable for their powerful aerial manoeuvres and endurance during prey catching or territory flights. While most insects such as flies, bees and wasps either reduced their hinds wings or mechanically coupled fore and hind wings, dragonflies have maintained two independent-controlled pairs of wings throughout their evolution. An extraordinary feature of dragonfly wing kinematics is wing phasing, the shift in flapping phase between the fore and hind wing periods. Wing phasing has previously been associated with an increase in thrust production, readiness for manoeuvrability and hunting performance. Recent studies have shown that wing phasing in tandem wings produces a twofold modulation in hind wing lift, but slightly reduces the maximum combined lift of fore and hind wings, compared to two wings flapping in isolation. Despite this disadvantage, however, wing phasing is effective in improving aerodynamic efficiency during flight by the removal of kinetic energy from the wake. Computational analyses demonstrate that this increase in flight efficiency may save up to 22% aerodynamic power expenditure compared to insects flapping only two wings. In terms of engineering, energetic benefits in four-wing flapping are of substantial interest in the field of biomimetic aircraft design, because the performance of man-made air vehicles is often limited by high-power expenditure rather than by lift production. This manuscript provides a summary on power expenditures and aerodynamic efficiency in flapping tandem wings by investigating wing phasing in a dynamically scaled robotic model of a hovering dragonfly.

  17. Optimal design of a flying-wing aircraft inner wing structure configuration

    OpenAIRE

    HUANG, HAIDONG

    2012-01-01

    Flying-wing aircraft are considered to have great advantages and potentials in aerodynamic performance and weight saving. However, they also have many challenges in design. One of the biggest challenges is the structural design of the inner wing (fuselage). Unlike the conventional fuselage of a tube configuration, the flying-wing aircraft inner wing cross section is limited to a noncircular shape, which is not structurally efficient to resist the internal pressure load. In o...

  18. Subtractive Structural Modification of Morpho Butterfly Wings.

    Science.gov (United States)

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

    2015-11-11

    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. PMID:26397977

  19. Veins improve fracture toughness of insect wings.

    Directory of Open Access Journals (Sweden)

    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.

  20. Subtractive Structural Modification of Morpho Butterfly Wings.

    Science.gov (United States)

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

    2015-11-11

    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.

  1. Wing Damage Effects on Dragonfly's maneuverability

    Science.gov (United States)

    Ning, Zhe; Gai, Kuo; Zeyghami, Samane; Dong, Haibo; Flow Simulation Research Group (FSRG) Team

    2011-11-01

    In this work, how the insect flight behavior contributes to its adaptability to limited performance condition is studied through a combined experimental and computational study. High speed photogrammetry is used to collect the data of dragonflies' takeoffs with intact and damaged wings along the chord and span separately. Then the effect of the spanwise and chordwise damage on the dragonfly wing is investigated. Results show that both changes have different effects on the wing and body kinematics and the merit of maneuverability. Two theories will be introduced to explain the wing damage tolerance behavior of the dragonfly flight. This work is supported by NSF CBET-1055949.

  2. The sedimentary source, planform stability and shore normal morphological change of the Xichong beach on the southern coast of the Dapeng Peninsula of Shenzhen, Guangdong Province, China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Song; WANG Wei; HUANG Rihui; XU Liubing

    2015-01-01

    The coast of the Dapeng Peninsula has been honored as one of “the eight most beautiful coasts in China”. The most precious tourism resource for the peninsula is headland bay beaches, among which the beach at Xichong on the southern coast of the peninsula is the longest and the most important one. The information of the stability, sedimentary source and shape change of the beach is very important for maintaining the beach in terms of sustainable development of the peninsula. Heavy minerals in the sand of the beach and the inland stream at Xichong are compared with those of a nearby beach on the same coast to determine the beach sand source; with help of a computer software, MEPBAY, the equilibrium planforms of the beaches on the peninsula are compared with those of an island without rivers to evaluate the stream's effects on the beach stability; cross shore profiles along the Xichong beach are also surveyed in different seasons of a year to assess the annual shore normal beach changes affected by the stream input, and the relation between the equilibrium planform state and cross shore changes of the beach. It is shown that (1) stream is the main sedimentary source of the beach and the weathering materials of the rocky headlands on both sides of the bay transported by waves are the second source for the beach but it is limited, sand from an inner shelf is not the sedimentary source for the beach at present and was not even during the Holocene transgression; (2) the Xichong beach cannot reach static equilibrium around the entire bay shoreline, the segment of the shore-line where a stream outlet is located is in dynamic equilibrium, and the unstable section occurs in the wave shadow region in the lee of an offshore island; (3) no matter whether the section of the beach shoreline at Xichong is in an equilibrium state or not, it is eroded in the typhoon season and recovered after the season, the maximum change in erosion and accretion occurs in the unstable segment

  3. Propulsion Airframe Aeroacoustic Integration Effects for a Hybrid Wing Body Aircraft Configuration

    Science.gov (United States)

    Czech, Michael J.; Thomas, Russell H; Elkoby, Ronen

    2012-01-01

    An extensive experimental investigation was performed to study the propulsion airframe aeroacoustic effects of a high bypass ratio engine for a hybrid wing body aircraft configuration where the engine is installed above the wing. The objective was to provide an understanding of the jet noise shielding effectiveness as a function of engine gas condition and location as well as nozzle configuration. A 4.7% scale nozzle of a bypass ratio seven engine was run at characteristic cycle points under static and forward flight conditions. The effect of the pylon and its orientation on jet noise was also studied as a function of bypass ratio and cycle condition. The addition of a pylon yielded significant spectral changes lowering jet noise by up to 4 dB at high polar angles and increasing it by 2 to 3 dB at forward angles. In order to assess jet noise shielding, a planform representation of the airframe model, also at 4.7% scale was traversed such that the jet nozzle was positioned from downstream of to several diameters upstream of the airframe model trailing edge. Installations at two fan diameters upstream of the wing trailing edge provided only limited shielding in the forward arc at high frequencies for both the axisymmetric and a conventional round nozzle with pylon. This was consistent with phased array measurements suggesting that the high frequency sources are predominantly located near the nozzle exit and, consequently, are amenable to shielding. The mid to low frequency sources were observed further downstream and shielding was insignificant. Chevrons were designed and used to impact the distribution of sources with the more aggressive design showing a significant upstream migration of the sources in the mid frequency range. Furthermore, the chevrons reduced the low frequency source levels and the typical high frequency increase due to the application of chevron nozzles was successfully shielded. The pylon was further modified with a technology that injects air

  4. Evolutionary trajectory of channel planforms in the middle Garonne River (Toulouse, SW France) over a 130-year period: Contribution of mixed multiple factor analysis (MFAmix)

    Science.gov (United States)

    David, Mélodie; Labenne, Amaury; Carozza, Jean-Michel; Valette, Philippe

    2016-04-01

    The purpose of this study is to propose a methodological essay for defining evolutionary trajectories of channel planforms and to examine the channel change in the middle Garonne River (southwest France) over a 130-year period. The study focuses on a reach of ~ 90 km situated downstream from the city of Toulouse. A set of four historical maps (1868, 1940s, 1970s, and 2000s) is used to build a geomorphometric diachronic database. Data processing through mixed multiple factor analysis (MFAmix) and hierarchical cluster analysis (HCA) allows distinction between four homogeneous zones within the study reach, depending on their evolutionary trajectories. Channel behavior in the upstream and median zones evolved as of the beginning of the study period (narrowing of the fluvial area, colonization by vegetation, and removal of alluvial bars), likely owing to punctual anthropogenic actions. The downstream zone is characterized by stabilization of the channel and alluvial bar removal over the second half of the twentieth century, coinciding with the campaign undertaken by French local authorities between 1960 and 1984 to protect river banks. The role of climate transition between the Little Ice Age (LIA) and the onset of the Global Warming period (GW) is also discussed. Results generally are consistent with the chronology established for most European rivers.

  5. Strain monitoring of a composite wing

    Science.gov (United States)

    Strathman, Joseph; Watkins, Steve E.; Kaur, Amardeep; Macke, David C.

    2016-04-01

    An instrumented composite wing is described. The wing is designed to meet the load and ruggedness requirements for a fixed-wing unmanned aerial vehicle (UAV) in search-and-rescue applications. The UAV supports educational systems development and has a 2.1-m wingspan. The wing structure consists of a foam core covered by a carbon-fiber, laminate composite shell. To quantify the wing characteristics, a fiber-optic strain sensor was surface mounted to measure distributed strain. This sensor is based on Rayleigh scattering from local index variations and it is capable of high spatial resolution. The use of the Rayleigh-scattering fiber-optic sensors for distributed measurements is discussed.

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

    Science.gov (United States)

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

    2015-06-01

    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

  7. Nanostructured Antireflective and Thermoisolative Cicada Wings.

    Science.gov (United States)

    Morikawa, Junko; Ryu, Meguya; Seniutinas, Gediminas; Balčytis, Armandas; Maximova, Ksenia; Wang, Xuewen; Zamengo, Massimiliano; Ivanova, Elena P; Juodkazis, Saulius

    2016-05-10

    Inter-related mechanical, thermal, and optical macroscopic properties of biomaterials are defined at the nanoscale by their constituent structures and patterns, which underpin complex functions of an entire bio-object. Here, the temperature diffusivity of a cicada (Cyclochila australasiae) wing with nanotextured surfaces was measured using two complementary techniques: a direct contact method and IR imaging. The 4-6-μm-thick wing section was shown to have a thermal diffusivity of α⊥ = (0.71 ± 0.15) × 10(-7) m(2)/s, as measured by the contact temperature wave method along the thickness of the wing; it corresponds to the inherent thermal property of the cuticle. The in-plane thermal diffusivity value of the wing was determined by IR imaging and was considerably larger at α∥ = (3.6 ± 0.2) × 10(-7) m(2)/s as a result of heat transport via air. Optical properties of wings covered with nanospikes were numerically simulated using an accurate 3D model of the wing pattern and showed that light is concentrated between spikes where intensity is enhanced by up to 3- to 4-fold. The closely packed pattern of nanospikes reduces the reflectivity of the wing throughout the visible light spectrum and over a wide range of incident angles, hence acting as an antireflection coating. PMID:27101865

  8. Induce Drag Reduction of an Airplane Wing

    Directory of Open Access Journals (Sweden)

    Md. Fazle Rabbi

    2015-06-01

    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.

  9. The plane problem of the flapping wing

    Science.gov (United States)

    Birnbaum, Walter

    1954-01-01

    In connection with an earlier report on the lifting vortex sheet which forms the basis of the following investigations this will show how the methods developed there are also suitable for dealing with the air forces for a wing with a circulation variable with time. The theory of a propulsive wing flapping up and down periodically in the manner of a bird's wing is developed. This study shows how the lift and its moment result as a function of the flapping motion, what thrust is attainable, and how high is the degree of efficiency of this flapping propulsion unit if the air friction is disregarded.

  10. Static aeroelastic analysis for generic configuration wing

    Science.gov (United States)

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

    1991-01-01

    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.

  11. A Miniature Controllable Flapping Wing Robot

    Science.gov (United States)

    Arabagi, Veaceslav Gheorghe

    The agility and miniature size of nature's flapping wing fliers has long baffled researchers, inspiring biological studies, aerodynamic simulations, and attempts to engineer their robotic replicas. Flapping wing flight is characterized by complex reciprocating wing kinematics, transient aerodynamic effects, and very small body lengths. These characteristics render robotic flapping wing aerial vehicles ideal for surveillance and defense applications, search and rescue missions, and environment monitoring, where their ability to hover and high maneuverability is immensely beneficial. One of the many difficulties in creating flapping wing based miniature robotic aerial vehicles lies in generating a proper wing trajectory that would result in sufficient lift forces for hovering and maneuvering. Since design of a flapping wing system is a balance between overall weight and the number of actuated inputs, we take the approach of having minimal controlled inputs, allowing passive behavior wherever possible. Hence, we propose a completely passive wing pitch reversal design that relies on wing inertial dynamics, an elastic energy storage mechanism, and low Reynolds number aerodynamic effects. Theoretical models, compiling previous research on piezoelectric actuators, four-bar transmissions, and aerodynamics effects, are developed and used as basis for a complete numerical simulation. Limitations of the model are discussed in comparison to experimental results obtained from a working prototype of the proposed passive pitch reversal flapping wing mechanism. Given that the mechanism is under-actuated, methods to control lift force generation by actively varying system parameters are proposed, discussed, and tested experimentally. A dual wing aerial platform is developed based on the passive pitch reversal wing concept. Design considerations are presented, favoring controllability and structural rigidity of the final platform. Finite element analysis and experimental

  12. Unemployment and Right-Wing Extremist Crime

    OpenAIRE

    Falk, Armin; Zweimüller, Josef

    2005-01-01

    Right-wing extremism is a serious problem in many societies. A prominent hypothesis states that unemployment plays a crucial role for the occurrence of right-wing extremist crime. In this paper we empirically test this hypothesis. We use a previously not used data set which includes all officially recorded right-wing criminal acts in Germany. These data are recorded by the German Federal Criminal Police Office on a monthly and state level basis. Our main finding is that there is in fact a sig...

  13. Moveable Leading Edge Device for a Wing

    Science.gov (United States)

    Pitt, Dale M. (Inventor); Eckstein, Nicholas Stephen (Inventor)

    2013-01-01

    A method and apparatus for managing a flight control surface system. A leading edge section on a wing of an aircraft is extended into a deployed position. A deformable section connects the leading edge section to a trailing section. The deformable section changes from a deformed shape to an original shape when the leading edge section is moved into the deployed position. The leading edge section on the wing is moved from the deployed position to an undeployed position. The deformable section changes to the deformed shape inside of the wing.

  14. A Hindu right wing day out

    OpenAIRE

    Mehta, Akanksha

    2014-01-01

    My PhD research examines public space and the politics of women in India’s Hindu right wing movement. Clad in saffron, the colour of the movement, millions of women embrace the violent and cultural/ethnic nationalist politics of the populist project, bringing it into their homes and classrooms. My photograph, A Hindu Right Wing Day Out, depicts a young boy and his schoolmates, dressed up by their mothers as revered founding Hindu nationalist leaders. It examines how right wing women ritually ...

  15. CineVersum BlackWing Four

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    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,

  16. Computational Evaluation of Inlet Distortion on an Ejector Powered Hybrid Wing Body at Takeoff and Landing Conditions

    Science.gov (United States)

    Tompkins, Daniel M.; Sexton, Matthew R.; Mugica, Edward A.; Beyar, Michael D.; Schuh, Michael J.; Stremel, Paul M.; Deere, Karen A.; McMillin, Naomi; Carter, Melissa B.

    2016-01-01

    Due to the aft, upper surface engine location on the Hybrid Wing Body (HWB) planform, there is potential to shed vorticity and separated wakes into the engine when the vehicle is operated at off-design conditions and corners of the envelope required for engine and airplane certification. CFD simulations were performed of the full-scale reference propulsion system, operating at a range of inlet flow rates, flight speeds, altitudes, angles of attack, and angles of sideslip to identify the conditions which produce the largest distortion and lowest pressure recovery. Pretest CFD was performed by NASA and Boeing, using multiple CFD codes, with various turbulence models. These data were used to make decisions regarding model integration, characterize inlet flow distortion patterns, and help define the wind tunnel test matrix. CFD was also performed post-test; when compared with test data, it was possible to make comparisons between measured model-scale and predicted full-scale distortion levels. This paper summarizes these CFD analyses.

  17. Thin tailored composite wing for civil tiltrotor

    Science.gov (United States)

    Rais-Rohani, Masoud

    1994-01-01

    The tiltrotor aircraft is a flight vehicle which combines the efficient low speed (i.e., take-off, landing, and hover) characteristics of a helicopter with the efficient cruise speed of a turboprop airplane. A well-known example of such vehicle is the Bell-Boeing V-22 Osprey. The high cruise speed and range constraints placed on the civil tiltrotor require a relatively thin wing to increase the drag-divergence Mach number which translates into lower compressibility drag. It is required to reduce the wing maximum thickness-to-chord ratio t/c from 23% (i.e., V-22 wing) to 18%. While a reduction in wing thickness results in improved aerodynamic efficiency, it has an adverse effect on the wing structure and it tends to reduce structural stiffness. If ignored, the reduction in wing stiffness leads to susceptibility to aeroelastic and dynamic instabilities which may consequently cause a catastrophic failure. By taking advantage of the directional stiffness characteristics of composite materials the wing structure may be tailored to have the necessary stiffness, at a lower thickness, while keeping the weight low. The goal of this study is to design a wing structure for minimum weight subject to structural, dynamic and aeroelastic constraints. The structural constraints are in terms of strength and buckling allowables. The dynamic constraints are in terms of wing natural frequencies in vertical and horizontal bending and torsion. The aeroelastic constraints are in terms of frequency placement of the wing structure relative to those of the rotor system. The wing-rotor-pylon aeroelastic and dynamic interactions are limited in this design study by holding the cruise speed, rotor-pylon system, and wing geometric attributes fixed. To assure that the wing-rotor stability margins are maintained a more rigorous analysis based on a detailed model of the rotor system will need to ensue following the design study. The skin-stringer-rib type architecture is used for the wing

  18. AFM Study of Structure Influence on Butterfly Wings Coloration

    Directory of Open Access Journals (Sweden)

    Dinara Sultanovna Dallaeva

    2012-01-01

    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.

  19. Functional gustatory role of chemoreceptors in drosophila wings

    OpenAIRE

    Raad, Hussein; Ferveur, Jean-François; Ledger, Neil; Capovilla, Maria

    2016-01-01

    Neuroanatomical evidence argues for the presence of taste sensilla in Drosophila wings; however, the taste physiology of insect wings remains hypothetical, and a comprehensive link to mechanical functions, such as flight, wing flapping, and grooming, is lacking. Our data show that the sensilla of the Drosophila anterior wing margin respond to both sweet and bitter molecules through an increase in cytosolic Ca2+ levels. Conversely, genetically modified flies presenting a wing-specific reductio...

  20. Coriolis effects enhance lift on revolving wings.

    Science.gov (United States)

    Jardin, T; David, L

    2015-03-01

    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.

  1. Trajectory Optimization Design for Morphing Wing Missile

    Institute of Scientific and Technical Information of China (English)

    Ruisheng Sun; Chao Ming; Chuanjie Sun

    2015-01-01

    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.

  2. Left-Wing Extremism: The Current Threat

    Energy Technology Data Exchange (ETDEWEB)

    Karl A. Seger

    2001-04-30

    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.

  3. Unsteady flow computation of oscillating flexible wings

    Science.gov (United States)

    Kandil, Osama A.; Chuang, H. Andrew; Salman, Ahmed A.

    1990-01-01

    The problem of unsteady flow around flexible wings is solved using the unsteady, compressible, thin-layer Navier-Stokes equations in conjunction with the unsteady, linearized, Navier-displacement equations. Starting with the initial shape of the wing, the Navier-Stokes equations are solved on an initial structured grid to obtain the steady-flow solution which is used for the initial conditions. The forced deformation motion of the wing boundaries is then applied, and the problem is solved accurately in time. During the time-accurate stepping, the Navier-displacement equations are used to solve for the grid deformation and sequently, the Navier-Stokes equations are used to solve for the flowfield. Two applications are presented; the first is for a pulsating oscillation of a bending-mode airfoil in transonic flow, and the second is for a bending-mode oscillation of a sharp-edged delta wing in supersonic flow.

  4. Analysis of the Wing Tsun Punching Methods

    Directory of Open Access Journals (Sweden)

    Jeff Webb

    2012-07-01

    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.

  5. Prostate carcinoma mimicking a sphenoid wing meningioma

    OpenAIRE

    Lucas H. Bradley; Matthew Burton; Murat Gokden; Demitre Serletis

    2015-01-01

    Introduction: We report here on a rare case of a large, lateral sphenoid wing tumor with radiographic and intraoperative findings highly suggestive of meningioma, yet pathology was in fact consistent with metastatic prostate adenocarcinoma. Presentation of case: An 81 year-old male presented with expressive dysphasia, right-sided weakness and headaches. Imaging revealed a heterogeneously-enhancing lesion based on the left lateral sphenoid wing. The presumed diagnosis was strongly in favor ...

  6. Wetting Characteristics of Insect Wing Surfaces

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

    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.

  7. Functional Gustatory Role of Chemoreceptors in Drosophila Wings.

    Science.gov (United States)

    Raad, Hussein; Ferveur, Jean-François; Ledger, Neil; Capovilla, Maria; Robichon, Alain

    2016-05-17

    Neuroanatomical evidence argues for the presence of taste sensilla in Drosophila wings; however, the taste physiology of insect wings remains hypothetical, and a comprehensive link to mechanical functions, such as flight, wing flapping, and grooming, is lacking. Our data show that the sensilla of the Drosophila anterior wing margin respond to both sweet and bitter molecules through an increase in cytosolic Ca(2+) levels. Conversely, genetically modified flies presenting a wing-specific reduction in chemosensory cells show severe defects in both wing taste signaling and the exploratory guidance associated with chemodetection. In Drosophila, the chemodetection machinery includes mechanical grooming, which facilitates the contact between tastants and wing chemoreceptors, and the vibrations of flapping wings that nebulize volatile molecules as carboxylic acids. Together, these data demonstrate that the Drosophila wing chemosensory sensilla are a functional taste organ and that they may have a role in the exploration of ecological niches. PMID:27160896

  8. Functional Gustatory Role of Chemoreceptors in Drosophila Wings.

    Science.gov (United States)

    Raad, Hussein; Ferveur, Jean-François; Ledger, Neil; Capovilla, Maria; Robichon, Alain

    2016-05-17

    Neuroanatomical evidence argues for the presence of taste sensilla in Drosophila wings; however, the taste physiology of insect wings remains hypothetical, and a comprehensive link to mechanical functions, such as flight, wing flapping, and grooming, is lacking. Our data show that the sensilla of the Drosophila anterior wing margin respond to both sweet and bitter molecules through an increase in cytosolic Ca(2+) levels. Conversely, genetically modified flies presenting a wing-specific reduction in chemosensory cells show severe defects in both wing taste signaling and the exploratory guidance associated with chemodetection. In Drosophila, the chemodetection machinery includes mechanical grooming, which facilitates the contact between tastants and wing chemoreceptors, and the vibrations of flapping wings that nebulize volatile molecules as carboxylic acids. Together, these data demonstrate that the Drosophila wing chemosensory sensilla are a functional taste organ and that they may have a role in the exploration of ecological niches.

  9. Effect of wing flexibility in dragonfly hovering flight

    Science.gov (United States)

    Naidu, Vishal; Young, John; Lai, Joseph

    2011-11-01

    Dragonflies have two pairs of tandem wings, which can be operated independently. Most studies on tandem wings are based on rigid wings, which is in strong contradiction to the natural, flexible dragonfly wings. The effect of wing flexibility in tandem wings is little known. We carry out a comparative, computational study between rigid and flexible, dragonfly shaped wings for hovering flight. In rigid wings during downstroke, a leading edge vortex (LEV) is formed on the upper surface, which forms a low pressure zone. This conical LEV joins the tip vortex and shortly after the mid downstroke when the wing starts to rotate, these vortices are gradually shed resulting in a drop in lift. The vortex system creates a net downwards momentum in the form of a jet. The flexible wings while in motion deform due to aerodynamic and inertial forces. Since there is a strong interaction between wing deformation and air flow around the deformed wings, flexible wing simulations are carried out using a two way fluid structure interaction. The effect of wing flexibility on the flow structure and the subsequent effect on the aerodynamic forces will be studied and presented.

  10. Experimental investigation of a flapping wing model

    Science.gov (United States)

    Hubel, Tatjana Y.; Tropea, Cameron

    The main objective of this research study was to investigate the aerodynamic forces of an avian flapping wing model system. The model size and the flow conditions were chosen to approximate the flight of a goose. Direct force measurements, using a three-component balance, and PIV flow field measurements parallel and perpendicular to the oncoming flow, were performed in a wind tunnel at Reynolds numbers between 28,000 and 141,000 (3-15 m/s), throughout a range of reduced frequencies between 0.04 and 0.20. The appropriateness of quasi-steady assumptions used to compare 2D, time-averaged particle image velocimetry (PIV) measurements in the wake with direct force measurements was evaluated. The vertical force coefficient for flapping wings was typically significantly higher than the maximum coefficient of the fixed wing, implying the influence of unsteady effects, such as delayed stall, even at low reduced frequencies. This puts the validity of the quasi-steady assumption into question. The (local) change in circulation over the wing beat cycle and the circulation distribution along the wingspan were obtained from the measurements in the tip and transverse vortex planes. Flow separation could be observed in the distribution of the circulation, and while the circulation derived from the wake measurements failed to agree exactly with the absolute value of the circulation, the change in circulation over the wing beat cycle was in excellent agreement for low and moderate reduced frequencies. The comparison between the PIV measurements in the two perpendicular planes and the direct force balance measurements, show that within certain limitations the wake visualization is a powerful tool to gain insight into force generation and the flow behavior on flapping wings over the wing beat cycle.

  11. Wing Torsional Stiffness Tests of the Active Aeroelastic Wing F/A-18 Airplane

    Science.gov (United States)

    Lokos, William A.; Olney, Candida D.; Crawford, Natalie D.; Stauf, Rick; Reichenbach, Eric Y.

    2002-01-01

    The left wing of the Active Aeroelastic Wing (AAW) F/A-18 airplane has been ground-load-tested to quantify its torsional stiffness. The test has been performed at the NASA Dryden Flight Research Center in November 1996, and again in April 2001 after a wing skin modification was performed. The primary objectives of these tests were to characterize the wing behavior before the first flight, and provide a before-and-after measurement of the torsional stiffness. Two streamwise load couples have been applied. The wing skin modification is shown to have more torsional flexibility than the original configuration has. Additionally, structural hysteresis is shown to be reduced by the skin modification. Data comparisons show good repeatability between the tests.

  12. Flow field of flexible flapping wings

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  14. Gliding swifts attain laminar flow over rough wings.

    Directory of Open Access Journals (Sweden)

    David Lentink

    Full Text Available Swifts are among the most aerodynamically refined gliding birds. However, the overlapping vanes and protruding shafts of their primary feathers make swift wings remarkably rough for their size. Wing roughness height is 1-2% of chord length on the upper surface--10,000 times rougher than sailplane wings. Sailplanes depend on extreme wing smoothness to increase the area of laminar flow on the wing surface and minimize drag for extended glides. To understand why the swift does not rely on smooth wings, we used a stethoscope to map laminar flow over preserved wings in a low-turbulence wind tunnel. By combining laminar area, lift, and drag measurements, we show that average area of laminar flow on swift wings is 69% (n = 3; std 13% of their total area during glides that maximize flight distance and duration--similar to high-performance sailplanes. Our aerodynamic analysis indicates that swifts attain laminar flow over their rough wings because their wing size is comparable to the distance the air travels (after a roughness-induced perturbation before it transitions from laminar to turbulent. To interpret the function of swift wing roughness, we simulated its effect on smooth model wings using physical models. This manipulation shows that laminar flow is reduced and drag increased at high speeds. At the speeds at which swifts cruise, however, swift-like roughness prolongs laminar flow and reduces drag. This feature gives small birds with rudimentary wings an edge during the evolution of glide performance.

  15. Computational aerodynamic analysis on perimeter reinforced (PR)-compliant wing

    Institute of Scientific and Technical Information of China (English)

    NI Ismail; AH Zulkifli; MZ Abdullah; M Hisyam Basri; Norazharuddin Shah Abdullah

    2013-01-01

    Implementing the morphing technique on a micro air vehicle (MAV) wing is a very chal-lenging task, due to the MAV’s wing size limitation and the complex morphing mechanism. As a result, understanding aerodynamic characteristics and flow configurations, subject to wing structure deformation of a morphing wing MAV has remained obstructed. Thus, this paper presents the investigation of structural deformation, aerodynamics performance and flow formation on a pro-posed twist morphing MAV wing design named perimeter reinforced (PR)-compliant wing. The numerical simulation of two-way fluid structure interaction (FSI) investigation consist of a quasi-static aeroelastic structural analysis coupled with 3D incompressible Reynolds-averaged Navier-Stokes and shear-stress-transport (RANS-SST) solver utilized throughout this study. Verification of numerical method on a rigid rectangular wing achieves a good correlation with available exper-imental results. A comparative aeroelastic study between PR-compliant to PR and rigid wing per-formance is organized to elucidate the morphing wing performances. Structural deformation results show that PR-compliant wing is able to alter the wing’s geometric twist characteristic, which has directly influenced both the overall aerodynamic performance and flow structure behavior. Despite the superior lift performance result, PR-compliant wing also suffers from massive drag penalty, which has consequently affected the wing efficiency in general. Based on vortices investigation, the results reveal the connection between these aerodynamic performances with vortices formation on PR-compliant wing.

  16. Investigating the Force Production of Functionally-Graded Flexible Wings in Flapping Wing Flight

    Science.gov (United States)

    Mudbhari, Durlav; Erdogan, Malcolm; He, Kai; Bateman, Daniel; Lipkis, Rory; Moored, Keith

    2015-11-01

    Birds, insects and bats oscillate their wings to propel themselves over long distances and to maneuver with unprecedented agility. A key element to achieve their impressive aerodynamic performance is the flexibility of their wings. Numerous studies have shown that homogeneously flexible wings can enhance force production, propulsive efficiency and lift efficiency. Yet, animal wings are not homogenously flexible, but instead have varying material properties. The aim of this study is to characterize the force production and energetics of functionally-graded flexible wings. A partially-flexible wing composed of a rigid section and a flexible section is used as a first-order model of functionally-graded materials. The flexion occurs in the spanwise direction and it is affected by the spanwise flexion ratio, that is, the ratio of the length of the rigid section compared to the total span length. By varying the flexion ratio as well as the material properties of the flexible section, the study aims to examine the force production and energetics of flapping flight with functionally-graded flexible wings. Supported by the Office of Naval Research under Program Director Dr. Bob Brizzolara, MURI grant number N00014-14-1-0533.

  17. Transonic flow theory of airfoils and wings

    Energy Technology Data Exchange (ETDEWEB)

    Garabedian, P R

    1976-01-01

    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.

  18. An Experimental Investigation on Flapping Flexible Membrane Wings

    Science.gov (United States)

    Hu, Hui; Abate, Gregg; Albertani, Roberto

    2008-11-01

    Thin and flexible membrane wings are unique to flying and gliding mammals, such as bats, flying squirrels and sugar gliders. These animals exhibit extraordinary flight capabilities with respect to maneuvering and agility that are not observed in other species of comparable size. In this study, comprehensive wind tunnel experiments are conducted to assess the effects of membrane flexibility (rigidity) on the aerodynamic performance of the flapping flexible membrane wings to quantify the benefits of using flexible membrane wings compared with conventional rigid wings for flapping-wing Micro-Air-Vehicle (MAV) applications. The present study is conducted from the viewpoint of aerospace engineers to try to leverage the unique feature of flexible membrane airfoils/wings found in bats and other flying/gliding mammals as an effective aerodynamic control method to explore the potential applications of such non-traditional, bio-inspired flexible membrane wings to flapping-wing MAVs to improve their flight agility and maneuverability.

  19. Wing flexibility enhances load-lifting capacity in bumblebees.

    Science.gov (United States)

    Mountcastle, Andrew M; Combes, Stacey A

    2013-05-22

    The effect of wing flexibility on aerodynamic force production has emerged as a central question in insect flight research. However, physical and computational models have yielded conflicting results regarding whether wing deformations enhance or diminish flight forces. By experimentally stiffening the wings of live bumblebees, we demonstrate that wing flexibility affects aerodynamic force production in a natural behavioural context. Bumblebee wings were artificially stiffened in vivo by applying a micro-splint to a single flexible vein joint, and the bees were subjected to load-lifting tests. Bees with stiffened wings showed an 8.6 per cent reduction in maximum vertical aerodynamic force production, which cannot be accounted for by changes in gross wing kinematics, as stroke amplitude and flapping frequency were unchanged. Our results reveal that flexible wing design and the resulting passive deformations enhance vertical force production and load-lifting capacity in bumblebees, locomotory traits with important ecological implications. PMID:23536604

  20. Wing Leading Edge Concepts for Noise Reduction

    Science.gov (United States)

    Shmilovich, Arvin; Yadlin, Yoram; Pitera, David M.

    2010-01-01

    This study focuses on the development of wing leading edge concepts for noise reduction during high-lift operations, without compromising landing stall speeds, stall characteristics or cruise performance. High-lift geometries, which can be obtained by conventional mechanical systems or morphing structures have been considered. A systematic aerodynamic analysis procedure was used to arrive at several promising configurations. The aerodynamic design of new wing leading edge shapes is obtained from a robust Computational Fluid Dynamics procedure. Acoustic benefits are qualitatively established through the evaluation of the computed flow fields.

  1. Algorithmic Identification for Wings in Butterfly Diagrams.

    Science.gov (United States)

    Illarionov, E. A.; Sokolov, D. D.

    2012-12-01

    We investigate to what extent the wings of solar butterfly diagrams can be separated without an explicit usage of Hale's polarity law as well as the location of the solar equator. Two algorithms of cluster analysis, namely DBSCAN and C-means, have demonstrated their ability to separate the wings of contemporary butterfly diagrams based on the sunspot group density in the diagram only. Here we generalize the method for continuous tracers, give results concerning the migration velocities and presented clusters for 12 - 20 cycles.

  2. Nonlinear Dynamics of Wind Turbine Wings

    DEFF Research Database (Denmark)

    Larsen, Jesper Winther

    , large wind turbines become increasingly flexible and dynamically sensitive. This project focuses on the structural analysis of highly flexible wind turbine wings, and the aerodynamic loading of wind turbine wings under large changes in flow field due to elastic deformations and changing wind conditions.......Wind turbines with a nominal effect of 5MW with a rotor diameter of up to 126m are produced today. With the increasing size wind turbines also become more and more optimized with respect to structural dimensions and material usage, without increasing the stiffness proportionally. Consequently...

  3. A revised interpretation of the wing base structure in Odonata

    OpenAIRE

    Ninomiya, Tomoya; Yoshizawa, Kazunori

    2009-01-01

    Homology of the wing base structure in the Odonata is highly controversial, and many different interpretations for this structure have been proposed to date. In extreme cases, two independent origins of the insect wings have been suggested based on comparative morphology between the odonate and other pterygote wing bases. Difficulties in establishing homology of the wing base structures between Odonata and other Pterygota are mainly due to their extreme differences in morphology and function....

  4. Kinematic Design and Analysis of a Morphing Wing

    OpenAIRE

    Stubbs, Matthew D.

    2003-01-01

    In order to optimize the flight characteristics of aircraft, wings must be designed for the specific mission an aircraft will see. An airplane rarely has one specific mission, and therefore is usually designed as a compromise to meet many flight objectives with a single wing surface. Large-scale shape change of a wing would enable a wing design to be optimized for multiple missions. Engineers at the National Aeronautics and Space Administration (NASA) Langley Research Center are investigat...

  5. Design of Insect-Scale Flapping Wing Vehicles

    OpenAIRE

    Ahmed Nabawy, Mostafa Ramadan

    2015-01-01

    This thesis contributes to the state of the art in integrated design of insect-scale piezoelectric actuated flapping wing vehicles through the development of novel theoretical models for flapping wing aerodynamics and piezoelectric actuator dynamics, and integration of these models into a closed form design process.A comprehensive literature review of available engineered designs of miniature rotary and flapping wing vehicles is provided. A novel taxonomy based on wing and actuator kinematics...

  6. Deterioration of Damselfly Flight Performance due to Wing Damage

    CERN Document Server

    Ren, Yan; Gai, Kuo; Li, Chengyu; Zeyghami, Samane; Dong, Haibo

    2011-01-01

    In this video, effect of chordwise damage on a damselfly (American Rubyspot)'s wings is investigated. High speed photogrammetry was used to collect the data of damselflies' flight with intact and damaged wings along the wing chord. Different level of deterioration of flight performance can be observed. Further investigation will be on the dynamic and aerodynamic roles of each wing with and without damage.

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

    Science.gov (United States)

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

    1972-01-01

    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.

  8. How swifts control their glide performance with morphing wings

    NARCIS (Netherlands)

    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.

    2007-01-01

    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

  9. How swifts control their glide performance with morphing wings

    NARCIS (Netherlands)

    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.

    2007-01-01

    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

  10. 14 CFR 23.201 - Wings level stall.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Wings level stall. 23.201 Section 23.201... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Flight Stalls § 23.201 Wings level... airplane stalls. (b) The wings level stall characteristics must be demonstrated in flight as...

  11. A study of the effects of aeroelastic divergence on the wing structure of an oblique-wing supersonic transport configuration

    Science.gov (United States)

    1973-01-01

    The aerodynamic characteristics of transport aircraft with oblique wing flying at supersonic speeds are discussed. Aeroelastic divergence of the forward swept portion of the wing is analyzed. The effect of aspect ratio as a method for avoiding aeroelastic divergence is examined. A relatively low aspect ratio appears necessary for an oblique wing when constructed of conventional aluminum alloy materials. The aspect ratio may be increased by increasing the wing thickness ratio and by utilizing materials with higher moduli of elasticity and rigidity.

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

    Indian Academy of Sciences (India)

    Daxiang Yang

    2007-01-01

    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.

  13. Optimal design of a composite wing structure for a flying-wing aircraft subject to multi-constraint

    OpenAIRE

    Xu, Rongxin

    2012-01-01

    This thesis presents a research project and results of design and optimization of a composite wing structure for a large aircraft in flying wing configuration. The design process started from conceptual design and preliminary design, which includes initial sizing and stressing followed by numerical modelling and analysis of the wing structure. The research was then focused on the minimum weight optimization of the /composite wing structure /subject to multiple design /constraints. The modelli...

  14. Fiber-optically sensorized composite wing

    Science.gov (United States)

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

    2014-04-01

    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.

  15. Mother Nature inspires new wind turbine wing

    DEFF Research Database (Denmark)

    Sønderberg Petersen, L.

    2007-01-01

    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...

  16. Structural Analysis of a wing box

    Directory of Open Access Journals (Sweden)

    Layston Ferroni Soares,

    2015-05-01

    Full Text Available The structural analysis is an important tool that allows the research for weight reduction, the choose of the best materials and to satisfy specifications and requirements. In an aircraft’s design, several analyzes are made to prove that this aircraft will stand the set of maneuvers that it was designed to accomplish. This work will consider the preliminar project of an aircraft seeking to check the behavior of the wing under certain loading conditions in the flight envelope.To get to this load set, it has been done all the process of specification of an aircraft, such as mission definition, calculation of weight and c.g. envelope, definition of the geometric characteristics of the aircraft, the airfoil choice, preliminary performance equations, aerodynamic coefficients and the aircraft’s balancing for the equilibrium condition, but such things will not be considered in this article. For the structural analysis of the wing will be considered an arbitrary flight condition, disregarding the effect of gusts loads. With the acquisition of the items mentioned, the main forces acting on the wing structure and their equations will be calculated. The use of finite element method will enable the application of loads obtained just as the development of a method of calculation, along with the construction of a three-dimensional model that represents a chosen condition. The results will be discussed in order to explain the influence of the applied loads in the structural behavior of the wing principal structure.

  17. Aerodynamics of a rigid curved kite wing

    CERN Document Server

    Maneia, Gianmauro; Tordella, Daniela; Iovieno, Michele

    2013-01-01

    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...

  18. Migration on Wings Aerodynamics and Energetics

    CERN Document Server

    Kantha, Lakshmi

    2012-01-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

    LIANG Bin; SUN Mao

    2011-01-01

    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.

  20. OmegaWINGS: OmegaCAM@VST observations of WINGS galaxy clusters

    CERN Document Server

    Gullieuszik, M; Fasano, G; Zaggia, S; Paccagnella, A; Moretti, A; Bettoni, D; D'Onofrio, M; Couch, W J; Vulcani, B; Fritz, J; Omizzolo, A; Baruffolo, A; Schipani, P; Capaccioli, M; Varela, J

    2015-01-01

    The Wide-field Nearby Galaxy-cluster Survey (WINGS) is a wide-field multi-wavelength survey of X-ray selected clusters at z =0.04-0.07. The original 34'x34' WINGS field-of- view has now been extended to cover a 1 sq.deg field with both photometry and spectroscopy. In this paper we present the Johnson B and V-band OmegaCAM/VST observations of 46 WINGS clusters, together with the data reduction, data quality and Sextractor photometric catalogs. With a median seeing of 1arcs in both bands, our 25-minutes exposures in each band typically reach the 50% completeness level at V=23.1 mag. The quality of the astrometric and photometric accuracy has been verified by comparison with the 2MASS as well as with SDSS astrometry, and SDSS and previous WINGS imaging. Star/galaxy separation and sky-subtraction procedure have been tested comparing with previous WINGS data. The Sextractor photometric catalogues are publicly available at the CDS, and will be included in the next release of the WINGS database on the VO together wi...

  1. Optimization of aerodynamic efficiency for twist morphing MAV wing

    OpenAIRE

    N. I. Ismail; A.H. Zulkifli; M.Z. Abdullah; M. Hisyam Basri; Norazharuddin Shah Abdullah

    2014-01-01

    Twist morphing (TM) is a practical control technique in micro air vehicle (MAV) flight. However, TM wing has a lower aerodynamic efficiency (CL/CD) compared to membrane and rigid wing. This is due to massive drag penalty created on TM wing, which had overwhelmed the successive increase in its lift generation. Therefore, further CL/CDmax optimization on TM wing is needed to obtain the optimal condition for the morphing wing configuration. In this paper, two-way fluid–structure interaction (FSI...

  2. Aircraft energy efficiency laminar flow control wing design study

    Science.gov (United States)

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

    1977-01-01

    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.

  3. Wing Flexion and Aerodynamics Performance of Insect Free Flights

    Science.gov (United States)

    Dong, Haibo; Liang, Zongxian; Ren, Yan

    2010-11-01

    Wing flexion in flapping flight is a hallmark of insect flight. It is widely thought that wing flexibility and wing deformation would potentially provide new aerodynamic mechanisms of aerodynamic force productions over completely rigid wings. However, there are lack of literatures on studying fluid dynamics of freely flying insects due to the presence of complex shaped moving boundaries in the flow domain. In this work, a computational study of freely flying insects is being conducted. High resolution, high speed videos of freely flying dragonflies and damselflies is obtained and used as a basis for developing high fidelity geometrical models of the dragonfly body and wings. 3D surface reconstruction technologies are used to obtain wing topologies and kinematics. The wing motions are highly complex and a number of different strategies including singular vector decomposition of the wing kinematics are used to examine the various kinematical features and their impact on the wing performance. Simulations are carried out to examine the aerodynamic performance of all four wings and understand the wake structures of such wings.

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

    Directory of Open Access Journals (Sweden)

    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.

  5. On the natural frequencies and mode shapes of dragonfly wings

    Science.gov (United States)

    Chen, Jen-San; Chen, Jeng-Yu; Chou, Yuan-Fang

    2008-06-01

    A base-excitation modal testing technique is adopted to measure the natural frequencies and mode shapes of dragonfly wings severed from thoraxes. The severed wings are glued onto the base of a shaker, which is capable of inducing translational motion in the lateral direction of the wing plane. Photonic probes are used to measure the displacement history of the shaker base and the painted spots of the wing simultaneously. A spectrum analyzer is employed to calculate the frequency response functions, from which the natural frequencies and the associated mode shapes of the wing structure can be extracted. Our experimental results show that the fundamental natural frequency of dragonfly wings is in the order of 170 Hz when it is clamped at the wing base. The average flapping frequency 27 Hz of dragonflies is about 16% of the fundamental natural frequency. At this frequency ratio, the inertial force of the wing is negligible compared to the elastic force. In other words, the wing deformation during flapping flight is solely due to the balance between the external aerodynamic force and the elastic force of the wing structure. The wing structures are generally lightly damped, with damping ratio in the order less than 5%.

  6. Mimicking unfolding motion of a beetle hind wing

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

    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.

  7. Survival of the fastest: Evolving wings for flapping flight

    Science.gov (United States)

    Ramananarivo, Sophie; Mitchel, Thomas; Ristroph, Leif

    2014-11-01

    To optimize flapping flight with regard to wing shape, we use an evolutionary or genetic algorithm to improve the forward speed of 3d-printed wings or hydrofoils that heave up-and-down and self-propel within water. In this scheme, ``genes'' are mathematical parameters specifying wing shape, and ``breeding'' involves the merging and mutation of genes from two parent wings to form a child. A wing's swimming speed is its ``fitness'', which dictates the likelihood of breeding and thus passing on its genes to the next generation. We find that this iterative process leads to marked improvements in relatively few generations, and several distinct shape features are shared among the fastest wings. We also investigate the favorable flow structures produced by these elite swimmers and compare their shape and performance to biologically evolved wings, fins, tails, and flippers.

  8. Preoperative judging of T-staging of rectal cancer by transrectal biplane ultrasound%经直肠双平面超声判断直肠癌术前T分期

    Institute of Scientific and Technical Information of China (English)

    李敬; 焦彤; 吴中权

    2012-01-01

    Objective To explore the accuracy of judging the T-staging of rectal cancer by biplane transrectal ultrasound.Methods Pathological enteroscopic biopsy was carried out for 197 cases of rectal cancer.Cases of middle and lower rectal cancer without serious obstruction were examined by means of transrectal biplane ultrasound through which to observe the changes of the echoes and to detect the depth of the infiltration in the intestinal walls and the presence of invasions in prostate glands,seminal in male or vesicles,uterine cervix in female.On the basis of the findings,the preoperative tumor staging was made.Postoperatively,the ultrasound results were compared with the pathological examination.Their consistency was evaluated by using Kappa test.Results Transrectal biplane ultrasound examination showed the total accuracy rate in T-staging of rectal cancer was as high as 83.8% with the diagnostic sensitivity rate for T1to T4 as 77.8 %,73.1%,89.3% and 94.4%,while its diagnostic specificity rate degree was 97.3%,93.1 %,85.1 %,97.8% respectively,The k -value was 0.732 which suggested that the ultrasound staging was highly consistent with the pathological staging(P<0.05).Conclusions Transrectal biplane ultrasound has a great value in the preoperative T-staging of rectal cancer and is helpful in the planning of treatment.%目的 探讨经直肠双平面超声判断直肠癌T分期的准确性.方法 197例经肠镜活检病理证实、无严重肠梗阻的中低位直肠癌患者,应用经直肠双平面超声观察肠壁回声改变、癌肿浸润肠壁深度及有无前列腺、精囊腺或宫颈、阴道等侵犯,并进行术前分期,将检查结果与术后病理对照,Kappa检验评估两者结果的一致性.结果 经直肠双平面超声判断直肠癌T分期的总正确率为83.8%,T1~T4诊断敏感度分别为77.8%、73.1%、89.3%和94.4%,特异度分别为97.3%、93.1%、85.1%、97.8%.k值为0.732,超声分期与

  9. System Noise Assessment and the Potential for a Low Noise Hybrid Wing Body Aircraft with Open Rotor Propulsion

    Science.gov (United States)

    Thomas, Russell H.; Burley, Casey L.; Lopes, Leonard V.; Bahr, Christopher J.; Gern, Frank H.; VanZante, Dale E.

    2014-01-01

    An aircraft system noise assessment was conducted for a hybrid wing body freighter aircraft concept configured with three open rotor engines. The primary objective of the study was to determine the aircraft system level noise given the significant impact of installation effects including shielding the open rotor noise by the airframe. The aircraft was designed to carry a payload of 100,000 lbs on a 6,500 nautical mile mission. An experimental database was used to establish the propulsion airframe aeroacoustic installation effects including those from shielding by the airframe planform, interactions with the control surfaces, and additional noise reduction technologies. A second objective of the study applied the impacts of projected low noise airframe technology and a projection of advanced low noise rotors appropriate for the NASA N+2 2025 timeframe. With the projection of low noise rotors and installation effects, the aircraft system level was 26.0 EPNLdB below Stage 4 level with the engine installed at 1.0 rotor diameters upstream of the trailing edge. Moving the engine to 1.5 rotor diameters brought the system level noise to 30.8 EPNLdB below Stage 4. At these locations on the airframe, the integrated level of installation effects including shielding can be as much as 20 EPNLdB cumulative in addition to lower engine source noise from advanced low noise rotors. And finally, an additional set of technology effects were identified and the potential impact at the system level was estimated for noise only without assessing the impact on aircraft performance. If these additional effects were to be included it is estimated that the potential aircraft system noise could reach as low as 38.0 EPNLdB cumulative below Stage 4.

  10. Wing shape allometry and aerodynamics in calopterygid damselflies: a comparative approach

    OpenAIRE

    Outomuro, David; Adams, Dean C; Johansson, Frank

    2013-01-01

    Background: Wing size and shape have important aerodynamic implications on flight performance. We explored how wing size was related to wing shape in territorial males of 37 taxa of the damselfly family Calopterygidae. Wing coloration was also included in the analyses because it is sexually and naturally selected and has been shown to be related to wing shape. We studied wing shape using both the non-dimensional radius of the second moment of wing area (RSM) and geometric morphometrics. Lower...

  11. The Crest Wing Wave Energy Device

    DEFF Research Database (Denmark)

    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....

  12. Interceptive management of winged maxillary central incisors

    Directory of Open Access Journals (Sweden)

    Mamta Dali

    2013-01-01

    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.

  13. Charge Capacity of Piezoelectric Membrane Wings

    Science.gov (United States)

    Grybas, Matthew; Hubner, J. Paul

    2015-11-01

    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.

  14. WOODEN DOOR WINGS OF ADIYAMAN GREAT MOSQUE

    Directory of Open Access Journals (Sweden)

    Muhammet ARSLAN

    2010-06-01

    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.

  15. Optimization of aerodynamic efficiency for twist morphing MAV wing

    Directory of Open Access Journals (Sweden)

    N.I. Ismail

    2014-06-01

    Full Text Available Twist morphing (TM is a practical control technique in micro air vehicle (MAV flight. However, TM wing has a lower aerodynamic efficiency (CL/CD compared to membrane and rigid wing. This is due to massive drag penalty created on TM wing, which had overwhelmed the successive increase in its lift generation. Therefore, further CL/CDmax optimization on TM wing is needed to obtain the optimal condition for the morphing wing configuration. In this paper, two-way fluid–structure interaction (FSI simulation and wind tunnel testing method are used to solve and study the basic wing aerodynamic performance over (non-optimal TM, membrane and rigid wings. Then, a multifidelity data metamodel based design optimization (MBDO process is adopted based on the Ansys-DesignXplorer frameworks. In the adaptive MBDO process, Kriging metamodel is used to construct the final multifidelity CL/CD responses by utilizing 23 multi-fidelity sample points from the FSI simulation and experimental data. The optimization results show that the optimal TM wing configuration is able to produce better CL/CDmax magnitude by at least 2% than the non-optimal TM wings. The flow structure formation reveals that low TV strength on the optimal TM wing induces low CD generation which in turn improves its overall CL/CDmax performance.

  16. Effects of Dragonfly Wing Structure on the Dynamic Performances

    Institute of Scientific and Technical Information of China (English)

    Huaihui Ren; Xishu Wang; Xudong Li; Yinglong Chen

    2013-01-01

    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.

  17. CFD Analysis of UAV Flying Wing

    Directory of Open Access Journals (Sweden)

    Vasile PRISACARIU

    2016-09-01

    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.

  18. Flutter behaviour of composite aircraft wings

    OpenAIRE

    Ashawesh, Gamal Mohamed

    1999-01-01

    This research work presents series of investigations into the structural dynamics and dynamic aeroelastic (flutter) behaviour of composite and metal wings. The study begins with a literature review where the development and an over view of the previous investigations in this field are presented. Static stiffness is very important to any type of analysis, especially in both dynamic and flutter analysis as in this case. Therefore, different methods are presented and used for the ...

  19. Integrated aerodynamic-structural-control wing design

    Science.gov (United States)

    Rais-Rohani, M.; Haftka, R. T.; Grossman, B.; Unger, E. R.

    1992-01-01

    The aerodynamic-structural-control design of a forward-swept composite wing for a high subsonic transport aircraft is considered. The structural analysis is based on a finite-element method. The aerodynamic calculations are based on a vortex-lattice method, and the control calculations are based on an output feedback control. The wing is designed for minimum weight subject to structural, performance/aerodynamic and control constraints. Efficient methods are used to calculate the control-deflection and control-effectiveness sensitivities which appear as second-order derivatives in the control constraint equations. To suppress the aeroelastic divergence of the forward-swept wing, and to reduce the gross weight of the design aircraft, two separate cases are studied: (1) combined application of aeroelastic tailoring and active controls; and (2) aeroelastic tailoring alone. The results of this study indicated that, for this particular example, aeroelastic tailoring is sufficient for suppressing the aeroelastic divergence, and the use of active controls was not necessary.

  20. Fiber Optic Wing Shape Sensing on NASA's Ikhana UAV

    Science.gov (United States)

    Richards, Lance; Parker, Allen R.; Ko, William L.; Piazza, Anthony

    2008-01-01

    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.

  1. Video measurements of instantaneous forces of flapping wing vehicles

    Science.gov (United States)

    Jennings, Alan; Mayhew, Michael; Black, Jonathan

    2015-12-01

    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.

  2. Analysis and Flexible Structural Modeling for Oscillating Wing Utilizing Aeroelasticity

    Institute of Scientific and Technical Information of China (English)

    Shao Ke; Wu Zhigang; Yang Chao

    2008-01-01

    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.

  3. Buffet characteristics of the F-8 supercritical wing airplane

    Science.gov (United States)

    Deangelis, V. M.; Monaghan, R. C.

    1977-01-01

    The buffet characteristics of the F-8 supercritical wing airplane were investigated. Wing structural response was used to determine the buffet characteristics of the wing and these characteristics are compared with wind tunnel model data and the wing flow characteristics at transonic speeds. The wingtip accelerometer was used to determine the buffet onset boundary and to measure the buffet intensity characteristics of the airplane. The effects of moderate trailing edge flap deflections on the buffet onset boundary are presented. The supercritical wing flow characteristics were determined from wind tunnel and flight static pressure measurements and from a dynamic pressure sensor mounted on the flight test airplane in the vicinity of the shock wave that formed on the upper surface of the wing at transonic speeds. The comparison of the airplane's structural response data to the supercritical flow characteristics includes the effects of a leading edge vortex generator.

  4. The aerodynamic and structural study of flapping wing vehicles

    OpenAIRE

    Zhou, Liangchen

    2013-01-01

    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...

  5. Effect of wing flexibility on aircraft flight dynamics

    OpenAIRE

    Qiao, Yuqing

    2012-01-01

    The purpose of this thesis is to give a preliminary investigation into the effect of wing deformation on flight dynamics. The candidate vehicle is FW-11 which is a flying wing configuration aircraft with high altitude and long endurance characteristics. The aeroelastic effect may be significant for this type of configuration. Two cases, the effect of flexible wing on lift distribution and on roll effectiveness during the cruise condition with different inertial parameters are investigated. ...

  6. An inflatable wing using the principle of Tensairity

    OpenAIRE

    Breuer, J; Ockels, W,J; Luchsinger, R.H.

    2007-01-01

    The paper describes the new concept Tensairity which can be used to significantly improve the load bearing capacity of inflatable wings. The basic principle of Tensairity is to use an inflatable structure to stabilize conventional compression and tension elements. So far, Tensairity has been mainly used in civil engineering application like roof structures and bridges. In this work, considerations to apply Tensairity to wing structures are given and the construction of two wing-like Tensairit...

  7. Optimization of a Composite Wing Subject to Multi Constraints

    OpenAIRE

    Fu, Qiang

    2013-01-01

    In this thesis, an investigation has been carried out into a minimum weight optimization analysis of a composite wing with multi design constraints under both static and dynamic loadings. The study includes the influence of a morphing leading edge on the wing stiffness and gust load reduction by employing a passive gust alleviation device at the wing tip. The design process started from a generic study of optimal structure against buckling for three typical types of reinforced skin panel s...

  8. Predicting power-optimal kinematics of avian wings

    OpenAIRE

    Parslew, Ben

    2015-01-01

    A theoretical model of avian flight is developed which simulates wing motion through a class of methods known as predictive simulation. This approach uses numerical optimization to predict power-optimal kinematics of avian wings in hover, cruise, climb and descent. The wing dynamics capture both aerodynamic and inertial loads. The model is used to simulate the flight of the pigeon, Columba livia, and the results are compared with previous experimental measurements. In cruise, the model uneart...

  9. Wing Sails for Hybrid Propulsion of a Ship

    OpenAIRE

    Dalija Milić Kralj; Branko Klarin

    2016-01-01

    Various types of hybrid drives are increasingly being applied in transportation. Wing sails can provide additional propulsion to a motor-driven ship, thereby decreasing fossil fuel consumption. This article contributes to the selection and consideration of the influencing parameters for applying wing sails for ship propulsion. Basic developmental factors and application of wing sails are described. In addition, influential parameters and their relations are discussed. These parameters are con...

  10. Patterning of a compound eye on an extinct dipteran wing

    OpenAIRE

    Dinwiddie, April; Rachootin, Stan

    2010-01-01

    We have discovered unexpected similarities between a novel and characteristic wing organ in an extinct biting midge from Baltic amber, Eohelea petrunkevitchi, and the surface of a dipteran's compound eye. Scanning electron microscope images now reveal vestigial mechanoreceptors between the facets of the organ. We interpret Eohelea's wing organ as the blending of these two developmental systems: the formation and patterning of the cuticle in the eye and of the wing.

  11. Winging of scapula due to serratus anterior tear

    Institute of Scientific and Technical Information of China (English)

    Varun Kumar Singh; Gauresh Shantaram Vargaonkar

    2014-01-01

    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.

  12. Flow field interference characteristic of axial ring wing configuration

    OpenAIRE

    Qi, Duo; Jinfu, Feng; Jiaqiang, Zhang; Yongli, Li

    2016-01-01

    To analyze the air flow interference between upper and lower wings in axial ring wing configuration, NASA SC(2)-1006 supercritical airfoil is chosen as the basic airfoil. Flow field around the double-wing structure with different relative distances between upper and lower wings is numerically simulated, using SST  turbulence model, and the numerical conclusion about the influence of relative distance D/L on the aerodynamic performance is drawn. It is shown that, at the speed Ma = 0.8, reflect...

  13. Design, Fabrication and Testing Of Flapping Wing Micro Air Vehicle

    Directory of Open Access Journals (Sweden)

    K. P. Preethi Manohari Sai

    2016-01-01

    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.

  14. Embedded Fiber Optic Shape Sensing for Aeroelastic Wing Components Project

    Data.gov (United States)

    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...

  15. Experimental investigations of the functional morphology of dragonfly wings

    Institute of Scientific and Technical Information of China (English)

    H.Rajabi; A.Darvizeh

    2013-01-01

    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.

  16. Feedback Linearization Controller Of The Delta WingRock Phenomena

    Directory of Open Access Journals (Sweden)

    Mohammed Alkandari

    2015-05-01

    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.

  17. The effect of wing stroke and aspect ratio on the force generation a compliant membrane flapping wing

    Science.gov (United States)

    Schunk, Cosima; Swartz, Sharon M.; Breuer, Kenneth S.

    2015-11-01

    Aspect ratio is one parameter used in efforts to predict a bat species' flight performance based on wing shape. Bats with high aspect ratio wings are expected to have superior lift-to-drag ratios and therefore to fly faster or be able to sustain longer flights. In contrast, bats with lower aspect ratio wings are usually thought to exhibit higher maneuverability. These assumptions are often based on fixed-wing aerodynamic theory, and do not take the wide variation in flapping kinematics observed in bats into account. To examine the influence of different stroke patterns, we measure lift and drag of highly compliant membrane wings with different bat-relevant aspect ratios. A two degree of freedom shoulder joint allows for independent control of flapping amplitude and wing sweep. We test five models with the same variations of stroke patterns, flapping frequencies, and wind speeds.

  18. Basal Complex and Basal Venation of Odonata Wings: Structural Diversity and Potential Role in the Wing Deformation.

    Science.gov (United States)

    Rajabi, H; Ghoroubi, N; Malaki, M; Darvizeh, A; Gorb, S N

    2016-01-01

    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

  19. Biomechanics of smart wings in a bat robot: morphing wings using SMA actuators

    International Nuclear Information System (INIS)

    This paper presents the design of a bat-like micro aerial vehicle with actuated morphing wings. NiTi shape memory alloys (SMAs) acting as artificial biceps and triceps muscles are used for mimicking the morphing wing mechanism of the bat flight apparatus. Our objective is twofold. Firstly, we have implemented a control architecture that allows an accurate and fast SMA actuation. This control makes use of the electrical resistance measurements of SMAs to adjust morphing wing motions. Secondly, the feasibility of using SMA actuation technology is evaluated for the application at hand. To this purpose, experiments are conducted to analyze the control performance in terms of nominal and overloaded operation modes of the SMAs. This analysis includes: (i) inertial forces regarding the stretchable wing membrane and aerodynamic loads, and (ii) uncertainties due to impact of airflow conditions over the resistance–motion relationship of SMAs. With the proposed control, morphing actuation speed can be increased up to 2.5 Hz, being sufficient to generate lift forces at a cruising speed of 5 m s−1. (paper)

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

    Science.gov (United States)

    Stowers, Amanda K; Lentink, David

    2015-04-01

    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. Three-dimensional winged nanocone optical antennas.

    Science.gov (United States)

    Huttunen, Mikko J; Lindfors, Klas; Andriano, Domenico; Mäkitalo, Jouni; Bautista, Godofredo; Lippitz, Markus; Kauranen, Martti

    2014-06-15

    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.

  2. New aeroelastic studies for a morphing wing

    OpenAIRE

    Ruxandra Mihaela BOTEZ; Andrei Vladimir POPOV; Samuel COURCHESNE

    2012-01-01

    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 C...

  3. The effect of phase angle and wing spacing on tandem flapping wings

    Institute of Scientific and Technical Information of China (English)

    Timothy M.Broering; Yong-Sheng Lian

    2012-01-01

    In a tandem wing configuration,the hindwing often operates in the wake of the forewing and,hence,its performance is affected by the vortices shed by the forewing.Changes in the phase angle between the flapping motions of the fore and the hind wings,as well as the spacing between them,can affect the resulting vortex/wing and vortex/vortex interactions.This study uses 2D numerical simulations to investigate how these changes affect the leading dege vortexes (LEV) generated by the hindwing and the resulting effect on the lift and thrust coefficients as well as the efficiencies,The tandem wing configuration was simulated using an incompressible Navier-Stokes solver at a chord-based Reynolds number of 5 000.A harmonic single frequency sinusoidal oscillation consisting of a combined pitch and plunge motion was used for the flapping wing kinematics at a Strouhal number of 0.3.Four different spacings ranging from 0.1 chords to 1 chord were tested at three different phase angles,0°,90° and 180°.It was found that changes in the spacing and phase angle affected the timing of the interaction between the vortex shed from the forewing and the hindwing.Such an interaction affects the LEV formation on the hindwing and results in changes in aerodynamic force production and efficiencies of the hindwing.It is also observed that changing the phase angle has a similar effect as changing the spacing.The results further show that at different spacings the peak force generation occurs at different phase angles,as do the peak efficiencies.

  4. Do the Golden-winged Warbler and Blue-winged Warbler Exhibit Species-specific Differences in their Breeding Habitat Use?

    OpenAIRE

    David S. Maehr; Laura L. Patton; Joseph E. Duchamp; Songlin Fei; Jonathan W. Gassett; Jeffery L. Larkin

    2010-01-01

    We compared habitat features of Golden-winged Warbler (Vermivora chrysoptera) territories in the presence and absence of the Blue-winged Warbler (V. cyanoptera) on reclaimed coal mines in southeastern Kentucky, USA. Our objective was to determine whether there are species specific differences in habitat that can be manipulated to encourage population persistence of the Golden-winged Warbler. When compared with Blue-winged Warblers, Golden-winged Warblers established territories at higher elev...

  5. Morphing Wing Design with an Innovative Three-Dimensional Warping Actuation Project

    Data.gov (United States)

    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...

  6. Variable Geometry Aircraft Wing Supported by Struts And/Or Trusses

    Science.gov (United States)

    Melton, John E. (Inventor); Dudley, Michael R. (Inventor)

    2016-01-01

    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.

  7. Chicken or Egg? Resolving the Relative Roles of Non-Native Vegetation Invasion and Changing Flow Regime in Channel Narrowing and Planform Simplification of Large Rivers of the American Southwest

    Science.gov (United States)

    Schmidt, J. C.; Dean, D. J.; Manners, R.; Fortney, S. T.

    2012-12-01

    Channel narrowing and planform simplification have been ubiquitous processes on those parts of the Colorado River, the Green River and its tributaries, and the Rio Grande where suspended sediment loads are large. These rivers have been subject to (1) significant flow regime changes caused by dams and diversions and (2) large-scale invasion of non-native tamarisk (Tamarix spp.) and/or giant cane (Arundo donax). Because the timing of flow regime changes and non-native vegetation invasion is similar, it is difficult to evaluate the relative role of these forcing mechanisms. Narrowing and planform simplification have occurred by vertical accretion of stagnating alternate bars in meandering alluvial river segments, colonization of eddy bars in debris fan-affected canyons, and by abandonment of secondary channels where the channels are multi-threaded. Positive feedbacks occur among vegetation establishment, channel narrowing, and vertical accretion, because vegetation strengthens the banks, reduces channel-margin flow velocities, and contributes to reduced channel conveyance. Thus, even where flows have been greatly reduced, sediment deposition can occur at high stages wherever channels shrink in size. The field studies on which these findings are based depend on a rigorous mix of temporally robust studies of channel change at the cross-section scale and spatially robust determination of channel change over long channel segments. Temporally robust studies include detailed stratigraphic interpretation of floodplain deposits that take advantage of recent advances in interpretation of tree-ring chronologies. Future geomorphic research must address the effectiveness of non-native vegetation removal on floodplains in alluvial and debris fan-affected canyons, because these management activities are now widespread. There is a widespread assumption that mechanical removal of tamarisk and tamarisk defoliation by the tamarisk leaf beetle (Diorhabda elongata) have the potential to

  8. Inertial Force Coupling to Nonlinear Aeroelasticity of Flexible Wing Aircraft

    Science.gov (United States)

    Nguyen, Nhan T.; Ting, Eric

    2016-01-01

    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.

  9. Selective reinforcement of wing structure for flutter prevention.

    Science.gov (United States)

    Cooper, P. A.; Stroud, W. J.

    1972-01-01

    The results of an analytical study are presented on the use of boron polyimide filamentary composite material for the purpose of increasing the flutter speed of a simple titanium full depth sandwich wing structure designed for strength. The results clearly demonstrate that selective reinforcement of wing surfaces, using judiciously placed filamentary composites, promises sizable mass savings in the design of advanced aircraft structures.

  10. Automated optimum design of wing structures. Deterministic and probabilistic approaches

    Science.gov (United States)

    Rao, S. S.

    1982-01-01

    The automated optimum design of airplane wing structures subjected to multiple behavior constraints is described. The structural mass of the wing is considered the objective function. The maximum stress, wing tip deflection, root angle of attack, and flutter velocity during the pull up maneuver (static load), the natural frequencies of the wing structure, and the stresses induced in the wing structure due to landing and gust loads are suitably constrained. Both deterministic and probabilistic approaches are used for finding the stresses induced in the airplane wing structure due to landing and gust loads. A wing design is represented by a uniform beam with a cross section in the form of a hollow symmetric double wedge. The airfoil thickness and chord length are the design variables, and a graphical procedure is used to find the optimum solutions. A supersonic wing design is represented by finite elements. The thicknesses of the skin and the web and the cross sectional areas of the flanges are the design variables, and nonlinear programming techniques are used to find the optimum solution.

  11. Drosophila wing modularity revisited through a quantitative genetic approach.

    Science.gov (United States)

    Muñoz-Muñoz, Francesc; Carreira, Valeria Paula; Martínez-Abadías, Neus; Ortiz, Victoria; González-José, Rolando; Soto, Ignacio M

    2016-07-01

    To predict the response of complex morphological structures to selection it is necessary to know how the covariation among its different parts is organized. Two key features of covariation are modularity and integration. The Drosophila wing is currently considered a fully integrated structure. Here, we study the patterns of integration of the Drosophila wing and test the hypothesis of the wing being divided into two modules along the proximo-distal axis, as suggested by developmental, biomechanical, and evolutionary evidence. To achieve these goals we perform a multilevel analysis of covariation combining the techniques of geometric morphometrics and quantitative genetics. Our results indicate that the Drosophila wing is indeed organized into two main modules, the wing base and the wing blade. The patterns of integration and modularity were highly concordant at the phenotypic, genetic, environmental, and developmental levels. Besides, we found that modularity at the developmental level was considerably higher than modularity at other levels, suggesting that in the Drosophila wing direct developmental interactions are major contributors to total phenotypic shape variation. We propose that the precise time at which covariance-generating developmental processes occur and/or the magnitude of variation that they produce favor proximo-distal, rather than anterior-posterior, modularity in the Drosophila wing. PMID:27272402

  12. Unsteady Aerodynamics of Flapping Wing of a Bird

    Directory of Open Access Journals (Sweden)

    M. Agoes Moelyadi

    2013-04-01

    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.

  13. Right-Wing Extremist Violence among Adolescents in Germany

    Science.gov (United States)

    Sitzer, Peter; Heitmeyer, Wilhelm

    2008-01-01

    What are the preconditions for right-wing extremist violence among German youths? For several years, the rate of this violence has been increasing in Germany, and the same can be observed for right-wing extremist orientations characterized by the coming together of ideologies of unequal worth and the acceptance of violence as a mode of action. And…

  14. Influence of anisotropic piezoelectric actuators on wing aerodynamic forces

    Institute of Scientific and Technical Information of China (English)

    GUAN De; LI Min; LI Wei; WANG MingChun

    2008-01-01

    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.

  15. Closed-type wing for drones: positive and negative characteristics

    Directory of Open Access Journals (Sweden)

    Leonid I. Gretchihin

    2014-02-01

    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.

  16. Energy-based Aeroelastic Analysis and Optimisation of Morphing Wings

    NARCIS (Netherlands)

    De Breuker, R.

    2011-01-01

    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

  17. Gliding Swifts Attain Laminar Flow over Rough Wings

    NARCIS (Netherlands)

    Lentink, D.; Kat, de R.

    2014-01-01

    Swifts are among the most aerodynamically refined gliding birds. However, the overlapping vanes and protruding shafts of their primary feathers make swift wings remarkably rough for their size. Wing roughness height is 1–2% of chord length on the upper surface—10,000 times rougher than sailplane win

  18. Influence of anisotropic piezoelectric actuators on wing aerodynamic forces

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    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. Global Local Structural Optimization of Transportation Aircraft Wings

    NARCIS (Netherlands)

    Ciampa, P.D.; Nagel, B.; Van Tooren, M.J.L.

    2010-01-01

    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

  20. Hydraulic Evaluation of the Crest Wing Wave Energy Converter

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Antonishen, Michael Patrick

    This report presents the results of an experimental study of the wave energy converting abilities of the Crest Wing wave energy converter (WEC). 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 a scal...

  1. Anisotropism of the Non-Smooth Surface of Butterfly Wing

    Institute of Scientific and Technical Information of China (English)

    Gang Sun; Yan Fang; Qian Cong; Lu-quan Ren

    2009-01-01

    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.

  2. Multivariate coupling mechanism of NOCTUIDAE moth wings' surface superhydrophobicity

    Institute of Scientific and Technical Information of China (English)

    WANG XiaoJun; CONG Qian; ZHANG JianJun; WAN YanLing

    2009-01-01

    The surface shape, structure, biomaterial and wettability of moth wings (10 NOCTUIDAE species) from the northeast region of China were qualitatively and quantitatively studied by means of a stereoscopic microscope, a scanning electronic microscope, fourier transform infrared spectroscopy(FT-IR) and the interface contact angle measurement. The observation shows that there are scales arranged like over-lapping tiles on the surface of the moth wings. The shapes of the scales are different between species. They overlap horizontally and there is particular space vertically in the direction of the wing veins. The surface of the scale is structured by micron-class grooves and nanometer-class vertical gibbosities. The biomaterial components of the moth wing scale are mostly made up of protein, lipids and chitin. The observation also shows that the contact angle for wings with scales is in the range from 144.8° to 152.9°, while that for those without scales is from 90.0° to 115.9°. It indicates that the surfaces of the wings with scales are more hydrophobic. According as Cassie model, the equation of wettability on the NOCTUIDAE moth wing surface is established and the hydrophobic mechanism is analyzed. It is con-cluded that the hydrophobicity of the moth wings is induced by the multivariate coupling of the shape, structures and biomaterial of the scales.

  3. Wing flexibility effects in clap-and-fling

    NARCIS (Netherlands)

    Percin, M.; Hu, Y.; Van Oudheusden, B.W.; Remes, B.; Scarano, F.

    2011-01-01

    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

  4. New aeroelastic studies for a morphing wing

    Directory of Open Access Journals (Sweden)

    Ruxandra Mihaela BOTEZ*

    2012-06-01

    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. Unusual scapular winging - A case report.

    Science.gov (United States)

    Dori, Zohar; Sarig Bahat, Hilla

    2016-08-01

    Scapular mobility has a central role in maintaining normal upper limb function. Scapular winging is characterized by a failure in the dynamic stabilization of the scapula against the thoracic wall resulting in a condition in which the medial border of the scapula is prominent. The following case describes a patient who was referred to physiotherapy due to abnormal scapular protrusion. The main findings of the physical examination showed weakness of the scapular stabilizers more prominent on the right side than of the left. Additionally, the physical examination demonstrated weakness of the abdominal muscles, hip adductors, and ankle dorsi-flexors, as well as some facial muscles. The electromyography results were inconclusive. Further examination led to clinical suspicion of Facioscapulohumeral Dystrophy (FSHD) as a diagnosis, which was confirmed by genetic testing. Facioscapulohumeral Dystrophy is characterized by symptoms related to motor function and in most cases becomes evident in patients in their 20s and 30s. The disease signs and symptoms are often identified in a clinical setting. Currently, there are no reports describing an effective treatment for the disease. However, physiotherapy, moderate physical exercise, counselling, and use of suitable aids and orthoses may help improve functionality and mobility. This case report aims to increase the awareness of musculoskeletal physiotherapists to this unique dystrophy, when encountering complex presentations with scapular winging. PMID:26759220

  6. On the Minimum Induced Drag of Wings

    Science.gov (United States)

    Bowers, Albion H.

    2011-01-01

    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.

  7. Galaxy Luminosity Functions in WINGS clusters

    CERN Document Server

    Moretti, A; Poggianti, B M; Fasano, G; Varela, J; D'Onofrio, M; Vulcani, B; Cava, A; Fritz, J; Couch, W J; Moles, M; Kjærgaard, P

    2015-01-01

    Using V band photometry of the WINGS survey, we derive galaxy luminosity functions (LF) in nearby clusters. This sample is complete down to Mv=-15.15, and it is homogeneous, thus allowing the study of an unbiased sample of clusters with different characteristics. We constructed the photometric LF for 72 out of the original 76 WINGS clusters, excluding only those without a velocity dispersion estimate. For each cluster we obtained the LF for galaxies in a region of radius=0.5 x r200, and fitted them with single and double Schechter's functions. We also derive the composite LF for the entire sample, and those pertaining to different morphological classes. Finally we derive the spectroscopic cumulative LF for 2009 galaxies that are cluster members. The double Schechter fit parameters are neither correlated with the cluster velocity dispersion, nor with the X-ray luminosity. Our median values of the Schechter's fit slope are, on average, in agreement with measurements of nearby clusters, but are less steep that t...

  8. Gender identification of white-winged doves

    Science.gov (United States)

    Oyler-McCance, Sara J.; Braun, Clait E.

    2007-01-01

    White-winged doves (Zenaida asiatica) are migratory game birds with an expanding distribution. Reasons for the range expansion are largely unknown as are characteristics of populations in newly occupied areas. This species is avidly sought in states having large white-wing populations and where it is hunted with specific hunting seasons designed to prevent local over-harvest. Increasing distribution and apparent population size in other states may result in legalizing or liberalization of hunting regulations in those states. Prior to any liberalization, more knowledge is needed on population characteristics including population demography in both the Central Flyway and Pacific Flyway portions of the species' range. These needs should be specific by age and gender as hunting may over exploit one gender (or age class). Harvest rates may be measured through banding programs; these rates should be gender specific to examine possible rates of hunting loss on population composition, which could affect breeding population size. Harvest by gender can also be measured through use of hunter bag checks and collections use of parts collection surveys.

  9. Freight Wing Trailer Aerodynamics Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Sean Graham

    2007-10-31

    Freight Wing Incorporated utilized the opportunity presented by a DOE category two Inventions and Innovations grant to commercialize and improve upon aerodynamic technology for semi-tuck trailers, capable of decreasing heavy vehicle fuel consumption, related environmental damage, and U.S. consumption of foreign oil. Major project goals included the demonstration of aerodynamic trailer technology in trucking fleet operations, and the development and testing of second generation products. A great deal of past scientific research has demonstrated that streamlining box shaped semi-trailers can significantly reduce a truck’s fuel consumption. However, significant design challenges have prevented past concepts from meeting industry needs. Freight Wing utilized a 2003 category one Inventions and Innovations grant to develop practical solutions to trailer aerodynamics. Fairings developed for the front, rear, and bottom of standard semi-trailers together demonstrated a 7% improvement to fuel economy in scientific tests conducted by the Transportation Research Center (TRC). Operational tests with major trucking fleets proved the functionality of the products, which were subsequently brought to market. This category two grant enabled Freight Wing to further develop, test and commercialize its products, resulting in greatly increased understanding and acceptance of aerodynamic trailer technology. Commercialization was stimulated by offering trucking fleets 50% cost sharing on trial implementations of Freight Wing products for testing and evaluation purposes. Over 230 fairings were implemented through the program with 35 trucking fleets including industry leaders such as Wal-Mart, Frito Lay and Whole Foods. The feedback from these testing partnerships was quite positive with product performance exceeding fleet expectations in many cases. Fleet feedback also was also valuable from a product development standpoint and assisted the design of several second generation products

  10. Design and Construction of Passively Articulated Ornithopter Wings

    Science.gov (United States)

    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.

  11. Propeller slipstream/wing interaction in the transonic regime

    Science.gov (United States)

    Rizk, M. H.

    1980-01-01

    An inviscid model for the interaction between a thin wing and a nearly uniform propeller slipstream is presented. The model allows the perturbation velocities due to the interaction to be potential although the undisturbed slipstream velocity is rotational. A finite difference scheme is used to solve the governing equation. Numerical examples indicate that the slipstream has a strong effect on the aerodynamic properties of the wing section within the slipstream and lesser effects elsewhere. The slipstream swirling motion strongly affects the wing load distribution, however, its effect on the wing's total lift and wave drag is small. The axial velocity increment in the slipstream has a small effect on the wing lift, however, it causes a large increase in wave drag.

  12. STUDY OF WING SHIELDING EFFECT OF PROPELLER AIRCRAFT

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    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.

  13. Four-winged flapping flyer in forward flight

    CERN Document Server

    Godoy-Diana, Ramiro; Centeno, Mariana; Weinreb, Alexis; Thiria, Benjamin

    2015-01-01

    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.

  14. Optimization of Kinematics of a Flapping Wing Mechanism

    Science.gov (United States)

    George, Ryan; Thomson, Scott; Mattson, Christopher; Colton, Mark; Tree, Mike

    2010-11-01

    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.

  15. Experimental Investigation of a Wing-in-Ground Effect Craft

    Directory of Open Access Journals (Sweden)

    M. Mobassher Tofa

    2014-01-01

    Full Text Available The aerodynamic characteristics of the wing-in-ground effect (WIG craft model that has a noble configuration of a compound wing was experimentally investigated and Universiti Teknologi Malaysia (UTM wind tunnel with and without endplates. Lift and drag forces, pitching moment coefficients, and the centre of pressure were measured with respect to the ground clearance and the wing angle of attack. The ground effect and the existence of the endplates increase the wing lift-to-drag ratio at low ground clearance. The results of this research work show new proposed design of the WIG craft with compound wing and endplates, which can clearly increase the aerodynamic efficiency without compromising the longitudinal stability. The use of WIG craft is representing an ambitious technology that will help in reducing time, effort, and money of the conventional marine transportation in the future.

  16. The Aerodynamics of Deforming Wings at Low Reynolds Number

    Science.gov (United States)

    Medina, Albert

    Flapping flight has gained much attention in the past decade driven by the desire to understand capabilities observed in nature and the desire to develop agile small-scale aerial vehicles. Advancing our current understanding of unsteady aerodynamics is an essential component in the development of micro-air vehicles (MAV) intended to utilize flight mechanics akin to insect flight. Thus the efforts undertaken that of bio-mimicry. The complexities of insect wing motion are dissected and simplified to more tractable problems to elucidate the fundamentals of unsteady aerodynamics in biologically inspired kinematics. The MAV's fruition would satisfy long established needs in both the military and civilian sectors. Although recent studies have provided great insight into the lift generating mechanisms of flapping wings the deflection response of such wings remains poorly understood. This dissertation numerically and experimentally investigates the aerodynamic performance of passively and actively deflected wings in hover and rotary kinematics. Flexibility is distilled to discrete lines of flexion which acknowledging major flexion lines in insect wings to be the primary avenue for deformation. Of primary concern is the development of the leading-edge vortex (LEV), a high circulation region of low pressure above the wing to which much of the wing's lift generation is attributed. Two-dimensional simulations of wings with chord-wise flexibility in a freestream reveal a lift generating mechanism unavailable to rigid wings with origins in vortical symmetry breaking. The inclusion of flexibility in translating wings accelerated from rest revealed the formation time of the initial LEV was very weakly dependent on the flexible stiffness of the wing, maintaining a universal time scale of four to five chords of travel before shedding. The frequency of oscillatory shedding of the leading and trailing-edge vortices that develops after the initial vortex shedding was shown to be

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

    Science.gov (United States)

    Meftah, S. M. A.; Belhenniche, M.; Madani Fouatih, O.; Imine, B.

    2014-03-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Meftah S.M.A

    2014-03-01

    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.

  19. Ontogeny of aerial righting and wing flapping in juvenile birds

    CERN Document Server

    Evangelista, Dennis; Huynh, Tony; Krivitskiy, Igor; Dudley, Robert

    2014-01-01

    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.

  20. Dynamic Pattern Formation for Wings of Pterygota in an Eclosion ---Pattern Analysis for Wings with the Imago---

    Science.gov (United States)

    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.

  1. Flight-measured buffet characteristics of a supercritical wing and a conventional wing on a variable-sweep airplane

    Science.gov (United States)

    Monaghan, R. C.

    1978-01-01

    Windup-turn maneuvers were performed to assess the buffet characteristics of the F-111A aircraft and the same aircraft with a supercritical wing, which is referred to as the F-111 transonic aircraft technology (TACT) aircraft. Data were gathered at wing sweep angles of 26, 35, and 58 deg for Mach numbers from 0.60 to 0.95. Wingtip accelerometer data were the primary source of buffet information. The analysis was supported by wing strain-gage and pressure data taken in flight, and by oil-flow photographs taken during tests of a wind tunnel model. In the transonic speed range, the overall buffet characteristics of the aircraft having a supercritical wing are significantly improved over those of the aircraft having a conventional wing.

  2. Ornithopter Type Flapping Wings for Autonomous Micro Air Vehicles

    Directory of Open Access Journals (Sweden)

    Sutthiphong Srigrarom

    2015-05-01

    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

  3. Transonic wing analysis using advanced computational methods

    Science.gov (United States)

    Henne, P. A.; Hicks, R. M.

    1978-01-01

    This paper discusses the application of three-dimensional computational transonic flow methods to several different types of transport wing designs. The purpose of these applications is to evaluate the basic accuracy and limitations associated with such numerical methods. The use of such computational methods for practical engineering problems can only be justified after favorable evaluations are completed. The paper summarizes a study of both the small-disturbance and the full potential technique for computing three-dimensional transonic flows. Computed three-dimensional results are compared to both experimental measurements and theoretical results. Comparisons are made not only of pressure distributions but also of lift and drag forces. Transonic drag rise characteristics are compared. Three-dimensional pressure distributions and aerodynamic forces, computed from the full potential solution, compare reasonably well with experimental results for a wide range of configurations and flow conditions.

  4. Equivalent plate modeling for conceptual design of aircraft wing structures

    Science.gov (United States)

    Giles, Gary L.

    1995-01-01

    This paper describes an analysis method that generates conceptual-level design data for aircraft wing structures. A key requirement is that this data must be produced in a timely manner so that is can be used effectively by multidisciplinary synthesis codes for performing systems studies. Such a capability is being developed by enhancing an equivalent plate structural analysis computer code to provide a more comprehensive, robust and user-friendly analysis tool. The paper focuses on recent enhancements to the Equivalent Laminated Plate Solution (ELAPS) analysis code that significantly expands the modeling capability and improves the accuracy of results. Modeling additions include use of out-of-plane plate segments for representing winglets and advanced wing concepts such as C-wings along with a new capability for modeling the internal rib and spar structure. The accuracy of calculated results is improved by including transverse shear effects in the formulation and by using multiple sets of assumed displacement functions in the analysis. Typical results are presented to demonstrate these new features. Example configurations include a C-wing transport aircraft, a representative fighter wing and a blended-wing-body transport. These applications are intended to demonstrate and quantify the benefits of using equivalent plate modeling of wing structures during conceptual design.

  5. Primitive wing feather arrangement in Archaeopteryx lithographica and Anchiornis huxleyi.

    Science.gov (United States)

    Longrich, Nicholas R; Vinther, Jakob; Meng, Qingjin; Li, Quangguo; Russell, Anthony P

    2012-12-01

    In modern birds (Neornithes), the wing is composed of a layer of long, asymmetrical flight feathers overlain by short covert feathers. It has generally been assumed that wing feathers in the Jurassic bird Archaeopteryx and Cretaceous feathered dinosaurs had the same arrangement. Here, we redescribe the wings of the archaic bird Archaeopteryx lithographica and the dinosaur Anchiornis huxleyi and show that their wings differ from those of Neornithes in being composed of multiple layers of feathers. In Archaeopteryx, primaries are overlapped by long dorsal and ventral coverts. Anchiornis has a similar configuration but is more primitive in having short, slender, symmetrical remiges. Archaeopteryx and Anchiornis therefore appear to represent early experiments in the evolution of the wing. This primitive configuration has important functional implications: although the slender feather shafts of Archaeopteryx and Anchiornis make individual feathers weak, layering of the wing feathers may have produced a strong airfoil. Furthermore, the layered arrangement may have prevented the feathers from forming a slotted tip or separating to reduce drag on the upstroke. The wings of early birds therefore may have lacked the range of functions seen in Neornithes, limiting their flight ability. PMID:23177480

  6. The design and testing of subscale smart aircraft wing bolts

    International Nuclear Information System (INIS)

    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. (paper)

  7. The design and testing of subscale smart aircraft wing bolts

    Science.gov (United States)

    Vugampore, J. M. V.; Bemont, C.

    2012-07-01

    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.

  8. Optimal aeroelastic design of an oblique wing structure

    Science.gov (United States)

    Gwin, L. B.

    1974-01-01

    A procedure is presented for determining the optimal cover panel thickness of a wing structure to meet specified strength and static aeroelastic divergence requirements for minimum weight. Efficient reanalysis techniques using discrete structural and aerodynamic methods are used in conjunction with redesign algorithms driven by optimality criteria. The optimality conditions for the divergence constraint are established, and expressions are obtained for derivatives of the dynamic pressure at divergence with respect to design variables. The procedure is applied to an oblique wing aircraft where strength and stiffness are critical design considerations for sizing the cover thickness of the wing structure.

  9. Structural Health Monitoring Analysis for the Orbiter Wing Leading Edge

    Science.gov (United States)

    Yap, Keng C.

    2010-01-01

    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.

  10. Laminar-turbulent transition on the flying wing model

    Science.gov (United States)

    Pavlenko, A. M.; Zanin, B. Yu.; Katasonov, M. M.

    2016-10-01

    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.

  11. Slipstream-induced pressure fluctuations on a wing panel

    Science.gov (United States)

    Ljunggren, Sten; Samuelsson, Ingemar; Widig, Kurt

    1989-10-01

    Propeller-induced pressure fluctuations have been measured on a wind-tunnel model. The results show that the main contribution on the wing panels can be attributed to the propeller tip vortex, which gives a pressure level at least 20 dB above the level from the inner parts of the propeller. The pressure fluctuations are predominantly periodic and the spectrum shows strong peaks at the blade passage frequency and its harmonics. The pressure level at the blade passage frequency is approximately the same on wing panel and fuselage, while the level of the higher harmonics is substantially higher on the wing panel than on the fuselage.

  12. Winging of scapula due to serratus anterior tear

    Directory of Open Access Journals (Sweden)

    Varun Singh Kumar

    2014-10-01

    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. Experimental Investigation on Wing Aerodynamic Characteristics of Flapping-Wing Aerocraft with Wing-Blade%扑翼飞行器带翼刀机翼气动特性实验研究

    Institute of Scientific and Technical Information of China (English)

    张亚锋; 宋文萍; 宋笔锋; 李占科; 杨文青

    2011-01-01

    In order to investigate the effect of camber wing with wing-blade located beneath the wing surface on the aerodynamic characteristics of flapping-wing micro air vehicle, wind tunnel test of flapping-wing MAV(Micro Air Vehicle) was performed in a special micro air vehicle wind tunnel of NPU(Northwestern Polytechnical University).Wing with wing-blade and wing without wing-blade were employed for wind tunnel tests at different attack angle.Experimental results indicate that the lift coefficient of wing with wing-blade is larger than that of wing without wing-blade.So it is proved that wing-blade can prevent spanwise airflow beneath wing surface and increase wing lift.At small attack angles, wing with wing-blade can increase effectively aerodynamic efficiency of flapping-wing air vehicle and improve flight performance.Results of wind tunnel test provide technology support for application of wing with wing-blade in flapping-wing micro air vehicle.%通过进行微型扑翼飞行器低速风洞试验,研究了带弯度机翼下翼面翼刀对扑翼飞行器升阻特性的影响.文中进行了带翼刀机翼和不带翼刀机翼在不同迎角下的风洞吹风试验.试验结果表明,带翼刀机翼升力系数大于不带翼刀机翼升力系数,从而证明了翼刀可以阻止机翼下表面气流展向流动,起到增加机翼升力的作用.当扑翼在小迎角飞行时,带翼刀机翼可以有效地提高扑翼的气动效率,改善扑翼的飞行性能.研究结果可为带冀刀机翼在扑翼飞行器上的应用提供技术支持.

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

    Directory of Open Access Journals (Sweden)

    Toshio Sekimura

    Full Text Available The development of eyespots on the wing surface of butterflies of the family Nympalidae is one of the most studied examples of biological pattern formation.However, little is known about the mechanism that determines the number and precise locations of eyespots on the wing. Eyespots develop around signaling centers, called foci, that are located equidistant from wing veins along the midline of a wing cell (an area bounded by veins. A fundamental question that remains unsolved is, why a certain wing cell develops an eyespot, while other wing cells do not.We illustrate that the key to understanding focus point selection may be in the venation system of the wing disc. Our main hypothesis is that changes in morphogen concentration along the proximal boundary veins of wing cells govern focus point selection. Based on previous studies, we focus on a spatially two-dimensional reaction-diffusion system model posed in the interior of each wing cell that describes the formation of focus points. Using finite element based numerical simulations, we demonstrate that variation in the proximal boundary condition is sufficient to robustly select whether an eyespot focus point forms in otherwise identical wing cells. We also illustrate that this behavior is robust to small perturbations in the parameters and geometry and moderate levels of noise. Hence, we suggest that an anterior-posterior pattern of morphogen concentration along the proximal vein may be the main determinant of the distribution of focus points on the wing surface. In order to complete our model, we propose a two stage reaction-diffusion system model, in which an one-dimensional surface reaction-diffusion system, posed on the proximal vein, generates the morphogen concentrations that act as non-homogeneous Dirichlet (i.e., fixed boundary conditions for the two-dimensional reaction-diffusion model posed in the wing cells. The two-stage model appears capable of generating focus point distributions

  15. KC-135 wing and winglet flight pressure distributions, loads, and wing deflection results with some wind tunnel comparisons

    Science.gov (United States)

    Montoya, L. C.; Jacobs, P.; Flechner, S.; Sims, R.

    1982-01-01

    A full-scale winglet flight test on a KC-135 airplane with an upper winglet was conducted. Data were taken at Mach numbers from 0.70 to 0.82 at altitudes from 34,000 feet to 39,000 feet at stabilized flight conditions for wing/winglet configurations of basic wing tip, 15/-4 deg, 15/-2 deg, and 0/-4 deg winglet cant/incidence. An analysis of selected pressure distribution and data showed that with the basic wing tip, the flight and wind tunnel wing pressure distribution data showed good agreement. With winglets installed, the effects on the wing pressure distribution were mainly near the tip. Also, the flight and wind tunnel winglet pressure distributions had some significant differences primarily due to the oilcanning in flight. However, in general, the agreement was good. For the winglet cant and incidence configuration presented, the incidence had the largest effect on the winglet pressure distributions. The incremental flight wing deflection data showed that the semispan wind tunnel model did a reasonable job of simulating the aeroelastic effects at the wing tip. The flight loads data showed good agreement with predictions at the design point and also substantiated the predicted structural penalty (load increase) of the 15 deg cant/-2 deg incidence winglet configuration.

  16. Fruit flies modulate passive wing pitching to generate in-flight turns

    CERN Document Server

    Bergou, Attila J; Guckenheimer, John; Cohen, Itai; Wang, Z Jane

    2009-01-01

    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.

  17. Review of delta wing space shuttle vehicle dynamics

    Science.gov (United States)

    Reding, J. P.; Ericsson, L. E.

    1972-01-01

    The unsteady aerodynamics of the delta planform, high cross range, shuttle orbiter were investigated. It has been found that these vehicles are subject to five unsteady flow phenomena that could compromise the flight dynamics. They are: (1) leeside shock induced separation, (2) sudden leading edge stall, (3) vortex burst, (4) bow shock-flap shock interaction, (5) forebody vorticity. Trajectory shaping is seen as the most powerful means of avoiding the detrimental effects of the stall phenomena. However, stall must be fixed or controlled when traversing the stall region. The other phenomena may be controlled by carefully programmed control deflections and some configuration modification. Ways to alter the occurrence of the various flow conditions are explored.

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

    OpenAIRE

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

    2012-01-01

    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 ...

  19. Insect-inspired wing actuation structures based on ring-type resonators

    OpenAIRE

    Bolsman, C.T.; Goosen, J.F.L.; Van Keulen, F.

    2008-01-01

    In this paper, we illustrate and study the opportunities of resonant ring type structures as wing actuation mechanisms for a flapping wing Micro Air Vehicle (MAV). Various design alternatives are presented and studied based on computational and physical models. Insects provide an excellent source of inspiration for the development of the wing actuation mechanisms for flapping wing MAVs. The insect thorax is a structure which in essence provides a mechanism to couple the wing muscles to the wi...

  20. Development of laminar flow control wing surface porous structure

    Science.gov (United States)

    Klotzsche, M.; Pearce, W.; Anderson, C.; Thelander, J.; Boronow, W.; Gallimore, F.; Brown, W.; Matsuo, T.; Christensen, J.; Primavera, G.

    1984-01-01

    It was concluded that the chordwise air collection method, which actually combines chordwise and spanwise air collection, is the best of the designs conceived up to this time for full chord laminar flow control (LFC). Its shallower ducting improved structural efficiency of the main wing box resulting in a reduction in wing weight, and it provided continuous support of the chordwise panel joints, better matching of suction and clearing airflow requirements, and simplified duct to suction source minifolding. Laminar flow control on both the upper and lower surfaces was previously reduced to LFC suction on the upper surface only, back to 85 percent chord. The study concludes that, in addition to reduced wing area and other practical advantages, this system would be lighter because of the increase in effective structural wing thickness.

  1. Gyroid cuticular structures in butterfly wing scales : biological photonic crystals

    NARCIS (Netherlands)

    Michielsen, K.; Stavenga, D. G.

    2008-01-01

    We present a systematic study of the cuticular structure in the butterfly wing scales of some papilionids (Parides sesostris and Teinopalpus imperialis) and lycaenids (Callophrys rubi, Cyanophrys remus, Mitoura gryneus and Callophrys dumetorum). Using published scanning and transmission electron mic

  2. Sparse Sensing of Aerodynamic Loads on Insect Wings

    Science.gov (United States)

    Manohar, Krithika; Brunton, Steven; Kutz, J. Nathan

    2015-11-01

    We investigate how insects use sparse sensors on their wings to detect aerodynamic loading and wing deformation using a coupled fluid-structure model given periodically flapping input motion. Recent observations suggest that insects collect sensor information about their wing deformation to inform control actions for maneuvering and rejecting gust disturbances. Given a small number of point measurements of the chordwise aerodynamic loads from the sparse sensors, we reconstruct the entire chordwise loading using sparsesensing - a signal processing technique that reconstructs a signal from a small number of measurements using l1 norm minimization of sparse modal coefficients in some basis. We compare reconstructions from sensors randomly sampled from probability distributions biased toward different regions along the wing chord. In this manner, we determine the preferred regions along the chord for sensor placement and for estimating chordwise loads to inform control decisions in flight.

  3. Metagenomics of Glassy-Winged Sharpshooter, Homalodisca vitripennis (Hemiptera: Cicadellidae)

    Science.gov (United States)

    A Metagenomics approach was used to identify unknown organisms which live in association with the glassy-winged sharpshooter, Homalodisca vitripennis (Hemiptera: Cicadellidae). Metagenomics combines molecular biology and genetics to identify, and characterize genetic material from unique biological ...

  4. A novel posture alignment system for aircraft wing assembly

    Institute of Scientific and Technical Information of China (English)

    Bin ZHANG; Bao-guo YAO; Ying-lin KE

    2009-01-01

    A novel 6-degree of freedom (DOF) posture alignment system, based on 3-DOF positioners, is presented for the assembly of aircraft wings. Each positioner is connected with the wing through a rotational and adsorptive half-ball shaped end-effector, and the positioners together with the wing are considered as a 3-PPPS (P denotes a prismatic joint and S denotes a spherical joint) redundantly actuated parallel mechanism. The kinematic model of this system is established and a trajectory planning method is introduced. A complete analysis of inverse dynamics is carried out with the Newton-Euler algorithm, which is used to find the desired actuating torque in the design and path planning phase. Simulation analysis of the displacement and actuating torque of each joint of the positioners based on inverse kinematics and dynamics is conducted, and the results show that the system is feasible for the posture alignment of aircraft wings.

  5. Simulated propeller slipstream effects on a supercritical wing

    Science.gov (United States)

    Welge, H. R.; Crowder, J. P.

    1978-01-01

    To quantify the installed performance of high speed (M = 0.8) turboprop propulsion systems, an experimental program designed to assess the magnitude of the aerodynamic interference of a propeller slipstream on a supercritical wing has been conducted. The test was conducted in the NASA Ames 14-foot wind tunnel. An ejector-nacelle propeller slipstream simulator was used to produce a slipstream with characteristics typical of advanced propellers presently being investigated. A supercritical wing-body configuration was used to evaluate the interference effects. A traversing total pressure rake was used to make flow field measurements behind the wing and to calibrate the slipstream simulator. The force results indicated that the interference drag amounted to an increase of ten counts or about 3% of the wing-body drag for a two engine configuration at the nominal propeller operating conditions. However, at the higher swirl angles (11 deg vs. 7 deg nominally) the interference drag was favorable by about the same magnitude.

  6. 14 CFR 23.697 - Wing flap controls.

    Science.gov (United States)

    2010-01-01

    ... wing flap control lever settings corresponding to those positions must be positively located such that a definite change of direction of movement of the lever is necessary to select settings beyond...

  7. Dynamic distributions and population declines of Golden-winged Warblers

    Science.gov (United States)

    Rosenberg, Kenneth V.; Will, Tom; Buehler, David A.; Barker Swarthout, Sara; Thogmartin, Wayne E.; Chandler, Richard

    2016-01-01

    With an estimated breeding population in 2010 of 383,000 pairs, the Golden-winged Warbler (Vermivora chrysoptera) is among the most vulnerable and steeply declining of North American passerines. This species also has exhibited among the most dynamic breeding distributions, with populations expanding and then contracting over the past 150 years in response to regional habitat changes, interactions with closely related Blue-winged Warblers (V. cyanoptera), and possibly climate change. Since 1966, the rangewide population has declined by >70% (-2.3% per year; latest North American Breeding Bird Survey data), with much steeper declines in the Appalachian Mountains bird conservation region (-8.3% per year, 98% overall decline). Despite apparently stable or increasing populations in the northwestern part of the range (Minnesota, Manitoba), population estimates for Golden-winged Warbler have continued to decline by 18% from the decade of the 1990s to the 2000s. Population modeling predicts a further decline to roughly 37,000 individuals by 2100, with the species likely to persist only in Manitoba, Minnesota, and possibly Ontario. To delineate the present-day distribution and to identify population concentrations that could serve as conservation focus areas, we compiled rangewide survey data collected in 2000-2006 in 21 states and 3 Canadian provinces, as part of the Golden-winged Warbler Atlas Project (GOWAP), supplemented by state and provincial Breeding Bird Atlas data and more recent observations in eBird. Based on >8,000 GOWAP surveys for Golden-winged and Blue-winged warblers and their hybrids, we mapped occurrence of phenotypically pure and mixed populations in a roughly 0.5-degree grid across the species’ ranges. Hybrids and mixed Golden-winged-Blue-winged populations occurred in a relatively narrow zone across Minnesota, Wisconsin, Michigan, southern Ontario, and northern New York. Phenotypically pure Golden-winged Warbler populations occurred north of this

  8. Silent and Efficient Supersonic Bi-Directional Flying Wing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a Phase I study for a novel concept of a supersonic bi-directional (SBiDir) flying wing (FW) that has the potential to revolutionize supersonic flight...

  9. Resonance and propulsion performance of a heaving flexible wing

    CERN Document Server

    Michelin, S

    2009-01-01

    The influence of the bending rigidity of a flexible heaving wing on its propulsive performance in a two-dimensional imposed parallel flow is investigated in the inviscid limit. Potential flow theory is used to describe the flow over the flapping wing. The vortical wake of the wing is accounted for by the shedding of point vortices with unsteady intensity from the wing's trailing edge. The trailing-edge flapping amplitude is shown to be maximal for a discrete set of values of the rigidity, at which a resonance occurs between the forcing frequency and a natural frequency of the system. A quantitative comparison of the position of these resonances with linear stability analysis results is presented. Such resonances induce maximum values of the mean developed thrust and power input. The flapping efficiency is also shown to be greatly enhanced by flexibility.

  10. Glaucous-winged gull nesting on Amchitka Island

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The glaucous-winged gull (Larus glaucescens) is the most common gull in the north Pacific (Bent 1921, Murie 1959). It is also one of the most abundant permanent...

  11. Comparative Analysis of Uninhibited and Constrained Avian Wing Aerodynamics

    Science.gov (United States)

    Cox, Jordan A.

    The flight of birds has intrigued and motivated man for many years. Bird flight served as the primary inspiration of flying machines developed by Leonardo Da Vinci, Otto Lilienthal, and even the Wright brothers. Avian flight has once again drawn the attention of the scientific community as unmanned aerial vehicles (UAV) are not only becoming more popular, but smaller. Birds are once again influencing the designs of aircraft. Small UAVs operating within flight conditions and low Reynolds numbers common to birds are not yet capable of the high levels of control and agility that birds display with ease. Many researchers believe the potential to improve small UAV performance can be obtained by applying features common to birds such as feathers and flapping flight to small UAVs. Although the effects of feathers on a wing have received some attention, the effects of localized transient feather motion and surface geometry on the flight performance of a wing have been largely overlooked. In this research, the effects of freely moving feathers on a preserved red tailed hawk wing were studied. A series of experiments were conducted to measure the aerodynamic forces on a hawk wing with varying levels of feather movement permitted. Angle of attack and air speed were varied within the natural flight envelope of the hawk. Subsequent identical tests were performed with the feather motion constrained through the use of externally-applied surface treatments. Additional tests involved the study of an absolutely fixed geometry mold-and-cast wing model of the original bird wing. Final tests were also performed after applying surface coatings to the cast wing. High speed videos taken during tests revealed the extent of the feather movement between wing models. Images of the microscopic surface structure of each wing model were analyzed to establish variations in surface geometry between models. Recorded aerodynamic forces were then compared to the known feather motion and surface

  12. Surface photometry of WINGS galaxies with GASPHOT

    Science.gov (United States)

    D'Onofrio, M.; Bindoni, D.; Fasano, G.; Bettoni, D.; Cava, A.; Fritz, J.; Gullieuszik, M.; Kjærgaard, P.; Moretti, A.; Moles, M.; Omizzolo, A.; Poggianti, B. M.; Valentinuzzi, T.; Varela, J.

    2014-12-01

    Aims: We present the B, V, and K band surface photometry catalogs obtained by running the automatic software GASPHOT on galaxies from the WINGS cluster survey with isophotal areas larger than 200 pixels. The catalogs can be downloaded at the Centre de Données Astronomiques de Strasbourg. Methods: The luminosity growth curves of stars and galaxies in a given catalog relative to a given cluster image were obtained simultaneously by slicing the image with a fixed surface brightness step in several SExtractor runs. Then, using a single Sersic law convolved with a space-varying point spread function (PSF), GASPHOT performed a simultaneous χ2 best-fit of the major- and minor-axis luminosity growth curves of galaxies. We outline the GASPHOT performances and compare our surface photometry with that obtained by SExtractor, GALFIT, and GIM2D. This analysis is aimed at providing statistical information about the accuracy that is generally achieved by the softwares for automatic surface photometry of galaxies. Results: The GASPHOT catalogs provide the parameters of the Sersic law that fit the luminosity profiles for each galaxy and for each photometric band. They are the sky coordinates of the galaxy center (RA, Dec), the total magnitude (m), the semi-major axis of the effective isophote (Re), the Sersic index (n), the axis ratio (b/a), and a flag parameter (QFLAG) that generally indicates the fit quality. The WINGS-GASPHOT database includes 41 463 galaxies in the B band, 42 275 in the V band, and 71 687 in the K band. The bright early-type galaxies have higher Sersic indices and larger effective radii, as well as redder colors in their center. In general, the effective radii increase systematically from the K to the V and B band. Conclusions: The GASPHOT photometry agrees well with the surface photometry obtained by GALFIT and GIM2D, and with the aperture photometry provided by SExtractor. In particular, the direct comparison of structural parameters derived by different

  13. Unveiling spatial correlations in biophotonic architecture of transparent insect wings

    OpenAIRE

    Kumar, Pramod; Shamoon, Danish; Singh, Dhirendra P.; Mandal, Sudip; Singh, Kamal P.

    2014-01-01

    We probe the natural complex structures in the transparent insect wings by a simple, non-invasive, real time optical technique using both monochromatic and broadband femtosecond lasers. A stable, reproducible and novel diffraction pattern is observed unveiling long range spatial correlations and structural-symmetry at various length scales for a large variety of wings. While matching the sensitivity of SEM for such microstructures, it is highly efficient for extracting long range structural o...

  14. Ontogeny of aerial righting and wing flapping in juvenile birds

    OpenAIRE

    Evangelista, Dennis; Cam, Sharlene; Huynh, Tony; Krivitskiy, Igor; Dudley, Robert

    2014-01-01

    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,...

  15. Flight in slow motion: aerodynamics of the pterosaur wing

    OpenAIRE

    Palmer, Colin

    2010-01-01

    The flight of pterosaurs and the extreme sizes of some taxa have long perplexed evolutionary biologists. Past reconstructions of flight capability were handicapped by the available aerodynamic data, which was unrepresentative of possible pterosaur wing profiles. I report wind tunnel tests on a range of possible pterosaur wing sections and quantify the likely performance for the first time. These sections have substantially higher profile drag and maximum lift coefficients than those assumed b...

  16. Unveiling spatial correlations in biophotonic architecture of transparent insect wings

    CERN Document Server

    Kumar, Pramod; Singh, Dhirendra P; Mandal, Sudip; Singh, Kamal P

    2014-01-01

    We probe the natural complex structures in the transparent insect wings by a simple, non-invasive, real time optical technique using both monochromatic and broadband femtosecond lasers. A stable, reproducible and novel diffraction pattern is observed unveiling long range spatial correlations and structural-symmetry at various length scales for a large variety of wings. While matching the sensitivity of SEM for such microstructures, it is highly efficient for extracting long range structural organization with potentially broad applicability.

  17. The Phase Shifts of the Paired Wings of Butterfly Diagrams

    OpenAIRE

    Li, Kejun; Liang, Hongfei; Feng, Wen

    2010-01-01

    Sunspot groups observed by Royal Greenwich Observatory/US Air Force/NOAA from May 1874 to November 2008 and the Carte Synoptique solar filaments from March 1919 to December 1989 are used to investigate the relative phase shift of the paired wings of butterfly diagrams of sunspot and filament activities. Latitudinal migration of sunspot groups (or filaments) does asynchronously occur in the northern and southern hemispheres, and there is a relative phase shift between the paired wings of their...

  18. Nest placement by azure-winged magpies (Cyanopica cyana)

    OpenAIRE

    Redondo, T.; Hidalgo de Trucios, S.J.; Medina, Rosario

    1989-01-01

    Nest site selection of Azure-winged Magpies (Cyanopica cyana) was studied in relation to their proximity to the nests of Japanese Lesser Sparrowhawks (Accipiter gularis). Magpies used nest sites that were more concealed when not nesting in ssociation with the hawk, and nests with a higher rate of leaf cover were less frequently depredated. Magpies preferred to nest close to hawk nests, and such siteshad higher breeding success. However, Azure-winged Magpies nested in places with l...

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

    OpenAIRE

    Ericsson, Max

    2012-01-01

    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 ...

  20. Do the Golden-winged Warbler and Blue-winged Warbler Exhibit Species-specific Differences in their Breeding Habitat Use?

    Directory of Open Access Journals (Sweden)

    David S. Maehr

    2010-12-01

    Full Text Available We compared habitat features of Golden-winged Warbler (Vermivora chrysoptera territories in the presence and absence of the Blue-winged Warbler (V. cyanoptera on reclaimed coal mines in southeastern Kentucky, USA. Our objective was to determine whether there are species specific differences in habitat that can be manipulated to encourage population persistence of the Golden-winged Warbler. When compared with Blue-winged Warblers, Golden-winged Warblers established territories at higher elevations and with greater percentages of grass and canopy cover. Mean territory size (minimum convex polygon was 1.3 ha (se = 0.1 for Golden-winged Warbler in absence of Blue-winged Warbler, 1.7 ha (se = 0.3 for Golden-winged Warbler coexisting with Blue-winged Warbler, and 2.1 ha (se = 0.3 for Blue-winged Warbler. Territory overlap occurred within and between species (18 of n = 73 territories, 24.7%. All Golden-winged and Blue-winged Warblers established territories that included an edge between reclaimed mine land and mature forest, as opposed to establishing territories in open grassland/shrubland habitat. The mean distance territories extended from a forest edge was 28.0 m (se = 3.8 for Golden-winged Warbler in absence of Blue-winged Warbler, 44.7 m (se = 5.7 for Golden-winged Warbler coexisting with Blue-winged Warbler, and 33.1 m (se = 6.1 for Blue-winged Warbler. Neither territory size nor distances to forest edges differed significantly between Golden-winged Warbler in presence or absence of Blue-winged Warbler. According to Monte Carlo analyses, orchardgrass (Dactylis glomerata, green ash (Fraxinus pennsylvanica seedlings and saplings, and black locust (Robinia pseudoacacia saplings were indicative of sites with only Golden-winged Warblers. Sericea lespedeza, goldenrod (Solidago spp., clematis vine (Clematis spp., and blackberry (Rubus spp. were indicative of sites where both species occurred. Our findings complement recent genetic studies and add

  1. Equivalent Skin Analysis of Wing Structures Using Neural Networks

    Science.gov (United States)

    Liu, Youhua; Kapania, Rakesh K.

    2000-01-01

    An efficient method of modeling trapezoidal built-up wing structures is developed by coupling. in an indirect way, an Equivalent Plate Analysis (EPA) with Neural Networks (NN). Being assumed to behave like a Mindlin-plate, the wing is solved using the Ritz method with Legendre polynomials employed as the trial functions. This analysis method can be made more efficient by avoiding most of the computational effort spent on calculating contributions to the stiffness and mass matrices from each spar and rib. This is accomplished by replacing the wing inner-structure with an "equivalent" material that combines to the skin and whose properties are simulated by neural networks. The constitutive matrix, which relates the stress vector to the strain vector, and the density of the equivalent material are obtained by enforcing mass and stiffness matrix equities with rec,ard to the EPA in a least-square sense. Neural networks for the material properties are trained in terms of the design variables of the wing structure. Examples show that the present method, which can be called an Equivalent Skin Analysis (ESA) of the wing structure, is more efficient than the EPA and still fairly good results can be obtained. The present ESA is very promising to be used at the early stages of wing structure design.

  2. A low-cost simulation platform for flapping wing MAVs

    Science.gov (United States)

    Kok, J. M.; Chahl, J. S.

    2015-03-01

    This paper describes the design of a flight simulator for analysing the systems level performance of a Dragonfly-Inspired Micro Air Vehicle (DIMAV). A quasi-steady blade element model is used to analyse the aerodynamic forces. Aerodynamic and environmental forces are then incorporated into a real world flight dynamics model to determine the dynamics of the DIMAV system. The paper also discusses the implementation of the flight simulator for analysing the manoeuvrability of a DIMAV, specifically several modes of flight commonly found in dragonflies. This includes take-off, roll turns and yaw turns. Our findings with the simulator are consistent with results from wind tunnel studies and slow motion cinematography of dragonflies. In the take-off mode of flight, we see a strong dependence of take-off accelerations with flapping frequency. An increase in wing-beat frequency of 10% causes the maximum vertical acceleration to increase by 2g which is similar to that of dragonflies in nature. For the roll and yaw modes of manoeuvring, asymmetrical inputs are applied between the left and right set of wings. The flapping amplitude is increased on the left pair of wings which causes a time averaged roll rate to the right of 1.76rad/s within two wing beats. In the yaw mode, the stroke plane angle is reduced in the left pair of wings to initiate the yaw manoeuvre. In two wing beats, the time averaged yaw rate is 2.54rad/s.

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

    Science.gov (United States)

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

    2016-03-01

    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.

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

    Directory of Open Access Journals (Sweden)

    R. Martinez-Val

    2007-01-01

    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. 

  5. The Phase Shifts of the Paired Wings of Butterfly Diagrams

    CERN Document Server

    Li, Kejun; Feng, Wen

    2010-01-01

    Sunspot groups observed by Royal Greenwich Observatory/US Air Force/NOAA from May 1874 to November 2008 and the Carte Synoptique solar filaments from March 1919 to December 1989 are used to investigate the relative phase shift of the paired wings of butterfly diagrams of sunspot and filament activities. Latitudinal migration of sunspot groups (or filaments) does asynchronously occur in the northern and southern hemispheres, and there is a relative phase shift between the paired wings of their butterfly diagrams in a cycle, making the paired wings spatially asymmetrical on the solar equator. It is inferred that hemispherical solar activity strength should evolve in a similar way within the paired wings of a butterfly diagram in a cycle, making the paired wings just and only keep the phase relationship between the northern and southern hemispherical solar activity strengths, but a relative phase shift between the paired wings of a butterfly diagram should bring about an almost same relative phase shift of hemis...

  6. Phase shifts of the paired wings of butterfly diagrams

    Institute of Scientific and Technical Information of China (English)

    Ke-Jun Li; Hong-Fei Liang; Wen Feng

    2010-01-01

    Sunspot groups observed by the Royal Greenwich Observatory/US Air Force/NOAA from 1874 May to 2008 November and the Carte Synoptique solar filaments from 1919 March to 1989 December are used to investigate the relative phase shift of the paired wings of butterfly diagrams of sunspot and filament activities.Latitudinal migration of sunspot groups(or filaments)does asynchronously occur in the northern and southern hemispheres,and there is a relative phase shift between the paired wings of their butterfly diagrams in a cycle,making the paired wings spatially asymmetrical on the solar equator.It is inferred that hemispherical solar activity strength should evolve in a similar way within the paired wings of a butterfly diagram in a cycle,demonstrating the paired wings phenomenon and showing the phase relationship between the northern and southern hemispherical solar activity strengths,as well as a relative phase shift between the paired wings of a butterfly diagram,which should bring about almost the same relative phase shift of hemispheric solar activity strength.

  7. Phase shifts of the paired wings of butterfly diagrams

    Science.gov (United States)

    Li, Ke-Jun; Liang, Hong-Fei; Feng, Wen

    2010-11-01

    Sunspot groups observed by the Royal Greenwich Observatory/US Air Force/NOAA from 1874 May to 2008 November and the Carte Synoptique solar filaments from 1919 March to 1989 December are used to investigate the relative phase shift of the paired wings of butterfly diagrams of sunspot and filament activities. Latitudinal migration of sunspot groups (or filaments) does asynchronously occur in the northern and southern hemispheres, and there is a relative phase shift between the paired wings of their butterfly diagrams in a cycle, making the paired wings spatially asymmetrical on the solar equator. It is inferred that hemispherical solar activity strength should evolve in a similar way within the paired wings of a butterfly diagram in a cycle, demonstrating the paired wings phenomenon and showing the phase relationship between the northern and southern hemispherical solar activity strengths, as well as a relative phase shift between the paired wings of a butterfly diagram, which should bring about almost the same relative phase shift of hemispheric solar activity strength.

  8. Effect of flexibility on flapping wing characteristics under forward flight

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Jianyang; Jiang, Lin [School of Machinery and Automation, Wuhan University of Science and Technology, Wuhan, 430081, People’s Republic of China (China); Zhou, Chaoying; Wang, Chao, E-mail: cyzhou@hit.edu.cn [Shenzhen Graduate School, Harbin Institute of Technology, Xili Shenzhen University Town, Shenzhen 518055, People’s Republic of China (China)

    2014-10-01

    Through two-dimensional numerical simulation and by solving the unsteady incompressible Navier–Stokes (NS) equations, coupled with the structural dynamic equation for the motion of the wing, the effect of flexibility on flapping wing characteristics during forward flight is systematically studied. The flapping wing is considered as a cantilever, which performs the translational and rotational motion at its leading edge, and the other part is passively deformed by the aerodynamic force. The frequency ratio ω* and mass ratio m* are defined and used to characterize the flexibility of the flapping wing. It has been found that an optimal range of the frequency ratio exists in which the flexible wing possesses both a larger propulsive efficiency and lifting efficiency than their rigid counterpart. Also, the flexible wing with the smaller mass ratio may be of benefit to generate thrust, while the larger mass ratio may be of benefit to generate lift. In addition, a stronger leading edge vortex and reattachment vortex are observed around the appropriate flexibility wing’s surface, which therefore leads to better aerodynamic characteristics. (paper)

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

    Directory of Open Access Journals (Sweden)

    Genç Mustafa Serdar

    2016-01-01

    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.

  10. Aerodynamic Performances of Corrugated Dragonfly Wings at Low Reynolds Numbers

    Science.gov (United States)

    Tamai, Masatoshi; He, Guowei; Hu, Hui

    2006-11-01

    The cross-sections of dragonfly wings have well-defined corrugated configurations, which seem to be not very suitable for flight according to traditional airfoil design principles. However, previous studies have led to surprising conclusions of that corrugated dragonfly wings would have better aerodynamic performances compared with traditional technical airfoils in the low Reynolds number regime where dragonflies usually fly. Unlike most of the previous studies of either measuring total aerodynamics forces (lift and drag) or conducting qualitative flow visualization, a series of wind tunnel experiments will be conducted in the present study to investigate the aerodynamic performances of corrugated dragonfly wings at low Reynolds numbers quantitatively. In addition to aerodynamics force measurements, detailed Particle Image Velocimetry (PIV) measurements will be conducted to quantify of the flow field around a two-dimensional corrugated dragonfly wing model to elucidate the fundamental physics associated with the flight features and aerodynamic performances of corrugated dragonfly wings. The aerodynamic performances of the dragonfly wing model will be compared with those of a simple flat plate and a NASA low-speed airfoil at low Reynolds numbers.

  11. Reassessment of the wing feathers of Archaeopteryx lithographica suggests no robust evidence for the presence of elongated dorsal wing coverts.

    Directory of Open Access Journals (Sweden)

    Robert L Nudds

    Full Text Available Recently it was proposed that the primary feathers of Archaeopteryx lithographica (HMN1880 were overlaid by long covert feathers, and that a multilayered feathered wing was a feature of early fossils with feathered forelimbs. The proposed long covert feathers of Archaeopteryx were previously interpreted as dorsally displaced remiges or a second set of impressions made by the wing. The following study shows that the qualitative arguments forwarded in support of the elongated covert hypothesis are neither robust nor supported quantitatively. The idea that the extant bird wing with its single layer of overlapping primaries evolved from an earlier multilayered heavily coveted feathered forelimb as seen in Anchiornis huxleyi is reasonable. At this juncture, however, it is premature to conclude unequivocally that the wing of Archaeopteryx consisted of primary feathers overlaid with elongated coverts.

  12. Exhaust Plume Effects on Sonic Boom for a Delta Wing and a Swept Wing-Body Model

    Science.gov (United States)

    Castner, Raymond; Lake, Troy

    2012-01-01

    Supersonic travel is not allowed over populated areas due to the disturbance caused by the sonic boom. Research has been performed on sonic boom reduction and has included the contribution of the exhaust nozzle plume. Plume effect on sonic boom has progressed from the study of isolated nozzles to a study with four exhaust plumes integrated with a wing-body vehicle. This report provides a baseline analysis of the generic wing-body vehicle to demonstrate the effect of the nozzle exhaust on the near-field pressure profile. Reductions occurred in the peak-to-peak magnitude of the pressure profile for a swept wing-body vehicle. The exhaust plumes also had a favorable effect as the nozzles were moved outward along the wing-span.

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

    Directory of Open Access Journals (Sweden)

    Yasmeen Moussa

    2014-12-01

    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.

  14. Fuzzy Model-based Pitch Stabilization and Wing Vibration Suppression of Flexible Wing Aircraft.

    Science.gov (United States)

    Ayoubi, Mohammad A.; Swei, Sean Shan-Min; Nguyen, Nhan T.

    2014-01-01

    This paper presents a fuzzy nonlinear controller to regulate the longitudinal dynamics of an aircraft and suppress the bending and torsional vibrations of its flexible wings. The fuzzy controller utilizes full-state feedback with input constraint. First, the Takagi-Sugeno fuzzy linear model is developed which approximates the coupled aeroelastic aircraft model. Then, based on the fuzzy linear model, a fuzzy controller is developed to utilize a full-state feedback and stabilize the system while it satisfies the control input constraint. Linear matrix inequality (LMI) techniques are employed to solve the fuzzy control problem. Finally, the performance of the proposed controller is demonstrated on the NASA Generic Transport Model (GTM).

  15. Pigs taking wing with transposons and recombinases

    Science.gov (United States)

    Clark, Karl J; Carlson, Daniel F; Fahrenkrug, Scott C

    2007-01-01

    Swine production has been an important part of our lives since the late Mesolithic or early Neolithic periods, and ranks number one in world meat production. Pig production also contributes to high-value-added medical markets in the form of pharmaceuticals, heart valves, and surgical materials. Genetic engineering, including the addition of exogenous genetic material or manipulation of the endogenous genome, holds great promise for changing pig phenotypes for agricultural and medical applications. Although the first transgenic pigs were described in 1985, poor survival of manipulated embryos; inefficiencies in the integration, transmission, and expression of transgenes; and expensive husbandry costs have impeded the widespread application of pig genetic engineering. Sequencing of the pig genome and advances in reproductive technologies have rejuvenated efforts to apply transgenesis to swine. Pigs provide a compelling new resource for the directed production of pharmaceutical proteins and the provision of cells, vascular grafts, and organs for xenotransplantation. Additionally, given remarkable similarities in the physiology and size of people and pigs, swine will increasingly provide large animal models of human disease where rodent models are insufficient. We review the challenges facing pig transgenesis and discuss the utility of transposases and recombinases for enhancing the success and sophistication of pig genetic engineering. 'The paradise of my fancy is one where pigs have wings.' (GK Chesterton). PMID:18047690

  16. Age determination of blue-winged teal

    Science.gov (United States)

    Dane, C.W.

    1968-01-01

    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.

  17. Performance of the bio-inspired leading edge protuberances on a static wing and a pitching wing

    Institute of Scientific and Technical Information of China (English)

    胡文蓉; 张仕栋; 王雅赟

    2014-01-01

    It is shown that the leading edge protuberances on the flippers of a humpback whale can significantly improve the hydrodynamic performance. The present study numerically investigates the flow control mechanisms of the leading edge protuberances on a static wing and a pitching wing. For static wings, the performance in both laminar flow and turbulent flow are studied in the context of the flow control mechanisms. It is shown that the protuberances have slight effects on the performance of static wings in laminar flow. Also, it could be deduced that non-uniform downwash does not delay the stall occurrence in either laminar flow or turbulent flow. In turbulent flow, the leading edge protuberances act in a manner similar to vortex generators, enhancing the momentum exchange within the boundary layer. Streamwise vortices do contribute to the delay of the stall occurrence. The normal vorticity component also plays an important role in delaying the stall occurrence. However, for the pitching wing, the effect of leading edge protuberances is negligible in turbulent flow. Detailed analysis of the flow field indicates that for the wing with the leading edge protuberances, the leading edge vortices become more complex, while the thrust jet and the vortices in the wake are not changed significantly by the leading edge protuberances.

  18. A new technique for investigating the induced and profile drag coefficients of a smooth wing and a tubercled wing

    Directory of Open Access Journals (Sweden)

    Bolzon Michael

    2016-01-01

    Full Text Available The induced and profile drag coefficients of a wing are typically determined through a complex experimental technique, such as wake surveying. Such a technique requires measurement of all three orthogonal components of the downstream velocity to find the components of drag, which results in the necessary usage of a sophisticated and costly measurement device, such as multi-hole pressure probe. However, in this paper data is presented which demonstrate that the relative changes in the induced and profile drag coefficients can largely be determined through the sole measurement of the downstream, streamwise velocity. To demonstrate this, the induced and profile drags of two NACA 0021 wings, one with a smooth leading edge and the other wing a tubercled leading edge for comparison, are determined through the measurement of the three orthogonal velocities. The downstream, streamwise velocity distribution of each wing is then constructed and relationships can be determined. The wings were surveyed at 3°, 9°, and 12°. It has been found that the relative magnitude of the profile drag coefficient can be found for all considered angles of attack, while the relative magnitude of the induced drag coefficient can be found at 9° and 12°. These findings produce an innovative, simpler, and more cost effective experimental technique in determining the components of drag of a wing, and reduces the burdensome requirement of a sophisticated measurement device for such an experiment. Further investigation is required to determine the induced drag at 3°.

  19. Pulsed eddy current inspection of CF-188 inner wing spar

    Science.gov (United States)

    Horan, Peter Francis

    Royal Canadian Air Force (RCAF) CF-188 Hornet aircraft engineering authorities have stated a requirement for a Non-Destructive Evaluation (NDE) technique to detect Stress Corrosion Cracking (SCC) in the inner wing spars without fastener or composite wing skin removal. Current radiographic inspections involve significant aircraft downtime, and Pulsed Eddy Current (PEC) inspection is proposed as a solution. The aluminum inner wing spars of CF-188 Hornet aircraft may undergo stress corrosion cracking (SCC) along the spar between the fasteners that secure carbon-fiber/ epoxy composite skin to the wing. Inspection of the spar through the wing skin is required to avoid wing disassembly. The thickness of the wing skin varies between 8 and 20 mm (0.3 to 0.8 inch) and fasteners may be either titanium or ferrous. PEC generated by a probe centered over a fastener, demonstrates capability of detecting simulated cracks within spars with the wing skin present. Comparison of signals from separate sensors, mounted to either side of the excitation coil, is used to detect differences in induced eddy current fields, which arise in the presence of cracks. To overcome variability in PEC signal response due to variation in 1) skin thickness, 2) fastener material and size, and 3) centering over fasteners, a large calibration data set is acquired. Multi-dimensional scores from a Modified Principal Components Analysis (PCA) of the data are reduced to one dimension (1D) using a Discriminant Analysis method. Under inspection conditions, calibrated PCA scores combined with discriminant analysis permit rapid real time go/no-go PEC detection of cracks in CF-188 inner wing spar. Probe designs using both pickup coils and Giant Magnetoresistive (GMR) sensors were tested on samples with the same ferrous and titanium fasteners found on the CF-188. Flaws were correctly detected at lift-offs of up to 21mm utilizing a variety of insulating skin materials simulating the carbon-fibre reinforced polymer

  20. Analysis of Mach number 0.8 turboprop slipstream wing/nacelle interactions

    Science.gov (United States)

    Welge, H. R.; Neuhart, D. H.; Dahlin, J. A.

    1981-01-01

    Data from wind tunnel tests of a powered propeller and nacelle mounted on a supercritical wing are analyzed. Installation of the nacelle significantly affected the wing flow and the flow on the upper surface of the wing is separated near the leading edge under powered conditions. Comparisons of various theories with the data indicated that the Neumann surface panel solution and the Jameson transonic solution gave results adequate for design purposes. A modified wing design was developed (Mod 3) which reduces the wing upper surface pressure coefficients and section lift coefficients at powered conditions to levels below those of the original wing without nacelle or power. A contoured over the wing nacelle that can be installed on the original wing without any appreciable interference to the wing upper surface pressure is described.

  1. Performance Assessment in a Heat Exchanger Tube with Opposite/Parallel Wing Twisted Tapes

    Directory of Open Access Journals (Sweden)

    S. Eiamsa-ard

    2015-02-01

    Full Text Available The thermohydraulic performance in a tube containing a modified twisted tape with alternate-axes and wing arrangements is reported. This work aims to investigate the effects of wing arrangements (opposite (O and parallel (P wings at different wing shapes (triangle (Tri, rectangular (Rec, and trapezoidal (Tra wings and on the thermohydraulic performance characteristics. The obtained results show that wing twisted tapes with all wing shape arrangements (O-Tri/O-Rec/O-Tra/P-Tri/P-Rec/P-Tra give superior thermohydraulic performance and heat transfer rate to the typical twisted tape. In addition, the tapes with opposite wing arrangement of O-Tra, O-Rec, and O-Tri give superior thermohydraulic performances to those with parallel wing arrangement of P-Tra, P-Rec, and P-Tri around 2.7%, 3.5%, and 3.2%, respectively.

  2. Analysis of Low Speed Stall Aerodynamics of a Swept Wing with Laminar Flow Glove

    Science.gov (United States)

    Bui, Trong T.

    2014-01-01

    Reynolds-Averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) analysis was conducted to study the low-speed stall aerodynamics of a GIII aircraft's swept wing modified with a laminar-flow wing glove. The stall aerodynamics of the gloved wing were analyzed and compared with the unmodified wing for the flight speed of 120 knots and altitude of 2300 ft above mean sea level (MSL). The Star-CCM+ polyhedral unstructured CFD code was first validated for wing stall predictions using the wing-body geometry from the First American Institute of Aeronautics and Astronautics (AIAA) CFD High-Lift Prediction Workshop. It was found that the Star-CCM+ CFD code can produce results that are within the scattering of other CFD codes considered at the workshop. In particular, the Star-CCM+ CFD code was able to predict wing stall for the AIAA wing-body geometry to within 1 degree of angle of attack as compared to benchmark wind-tunnel test data. Current results show that the addition of the laminar-flow wing glove causes the gloved wing to stall much earlier than the unmodified wing. Furthermore, the gloved wing has a different stall characteristic than the clean wing, with no sharp lift drop-off at stall for the gloved wing.

  3. Analysis of Low-Speed Stall Aerodynamics of a Swept Wing with Laminar-Flow Glove

    Science.gov (United States)

    Bui, Trong T.

    2014-01-01

    Reynolds-Averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) analysis was conducted to study the low-speed stall aerodynamics of a GIII aircraft's swept wing modified with a laminar-flow wing glove. The stall aerodynamics of the gloved wing were analyzed and compared with the unmodified wing for the flight speed of 120 knots and altitude of 2300 ft above mean sea level (MSL). The Star-CCM+ polyhedral unstructured CFD code was first validated for wing stall predictions using the wing-body geometry from the First American Institute of Aeronautics and Astronautics (AIAA) CFD High-Lift Prediction Workshop. It was found that the Star-CCM+ CFD code can produce results that are within the scattering of other CFD codes considered at the workshop. In particular, the Star-CCM+ CFD code was able to predict wing stall for the AIAA wing-body geometry to within 1 degree of angle of attack as compared to benchmark wind-tunnel test data. Current results show that the addition of the laminar-flow wing glove causes the gloved wing to stall much earlier than the unmodified wing. Furthermore, the gloved wing has a different stall characteristic than the clean wing, with no sharp lift drop-off at stall for the gloved wing.

  4. Flow structures around a flapping wing considering ground effect

    Science.gov (United States)

    Van Truong, Tien; Kim, Jihoon; Kim, Min Jun; Park, Hoon Cheol; Yoon, Kwang Joon; Byun, Doyoung

    2013-07-01

    Over the past several decades, there has been great interest in understanding the aerodynamics of flapping flight, namely the two flight modes of hovering and forward flight. However, there has been little focus on the aerodynamic characteristics during takeoff of insects. In a previous study we found that the Rhinoceros Beetle ( Trypoxylusdichotomus) takes off without jumping, which is uncommon for other insects. In this study we built a scaled-up electromechanical model of a flapping wing and investigated fluid flow around the beetle's wing model. In particular, the present dynamically scaled mechanical model has the wing kinematics pattern achieved from the real beetle's wing kinematics during takeoff. In addition, we could systematically change the three-dimensional inclined motion of the flapping model through each stroke. We used digital particle image velocimetry with high spatial resolution, and were able to qualitatively and quantitatively study the flow field around the wing at a Reynolds number of approximately 10,000. The present results provide insight into the aerodynamics and the evolution of vortical structures, as well as the ground effect experienced by a beetle's wing during takeoff. The main unsteady mechanisms of beetles have been identified and intensively analyzed as the stability of the leading edge vortex (LEV) during strokes, the delayed stall during upstroke, the rotational circulation in pronation periods, and wake capture in supination periods. Due to the ground effect, the LEV was enhanced during half downstroke, and the lift force could thus be increased to lift the beetle during takeoff. This is useful for researchers in developing a micro air vehicle that has a beetle-like flapping wing motion.

  5. Simplified physical models of the flow around flexible insect wings at low Reynolds numbers

    Science.gov (United States)

    Harenberg, Steve; Reis, Johnny; Miller, Laura

    2011-11-01

    Some of the smallest insects fly at Reynolds numbers in the range of 5-100. We built a dynamically scaled physical model of a flexible insect wing and measured the resulting wing deformations and flow fields. The wing models were submerged in diluted corn syrup and rotated about the root of the wing for Reynolds numbers ranging from 1-100. Spatially resolved flow fields were obtained using particle image velocimetry (PIV). Deformations of the wing were tracked using DLTdv software to determine the motion and induced curvature of the wing.

  6. Aeroelasticity Benchmark Assessment: Subsonic Fixed Wing Program

    Science.gov (United States)

    Florance, Jennifer P.; Chwalowski, Pawel; Wieseman, Carol D.

    2010-01-01

    Aeroelasticity Branch will examine other experimental efforts within the Subsonic Fixed Wing (SFW) program (such as testing of the NASA Common Research Model (CRM)) and other NASA programs and assess aeroelasticity issues and research topics.

  7. Age-class separation of blue-winged ducks

    Science.gov (United States)

    Hohman, W.L.; Moore, J.L.; Twedt, D.J.; Mensik, John G.; Logerwell, E.

    1995-01-01

    Accurate determination of age is of fundamental importance to population and life history studies of waterfowl and their management. Therefore, we developed quantitative methods that separate adult and immature blue-winged teal (Anas discors), cinnamon teal (A. cyanoptera), and northern shovelers (A. clypeata) during spring and summer. To assess suitability of discriminant models using 9 remigial measurements, we compared model performance (% agreement between predicted age and age assigned to birds on the basis of definitive cloacal or rectral feather characteristics) in different flyways (Mississippi and Pacific) and between years (1990-91 and 1991-92). We also applied age-classification models to wings obtained from U.S. Fish and Wildlife Service harvest surveys in the Mississippi and Central-Pacific flyways (wing-bees) for which age had been determined using qualitative characteristics (i.e., remigial markings, shape, or wear). Except for male northern shovelers, models correctly aged lt 90% (range 70-86%) of blue-winged ducks. Model performance varied among species and differed between sexes and years. Proportions of individuals that were correctly aged were greater for males (range 63-86%) than females (range 39-69%). Models for northern shovelers performed better in flyway comparisons within year (1991-92, La. model applied to Calif. birds, and Calif. model applied to La. birds: 90 and 94% for M, and 89 and 76% for F, respectively) than in annual comparisons within the Mississippi Flyway (1991-92 model applied to 1990-91 data: 79% for M, 50% for F). Exclusion of measurements that varied by flyway or year did not improve model performance. Quantitative methods appear to be of limited value for age separation of female blue-winged ducks. Close agreement between predicted age and age assigned to wings from the wing-bees suggests that qualitative and quantitative methods may be equally accurate for age separation of male blue-winged ducks. We interpret annual

  8. U-band photometry of 17 WINGS clusters

    CERN Document Server

    Omizzolo, A; Paya, D Reverte; De Santis, C; Grado, A; Bettoni, D; Poggianti, B; D'Onofrio, M; Moretti, A; Varela, J; Fritz, J; Gullieuszik, M; Cava, A; Grazian, A; Moles, M

    2013-01-01

    This paper belongs to a series presenting the WIde Field Nearby Galaxy-cluster Survey (WINGS). The WINGS project has collected wide-field, optical (B,V) and near-infrared (J,K) imaging, as well as medium resolution spectroscopy of galaxies in a sample of 76 X-ray selected nearby clusters (0.04 < z < 0.07), with the aim of establishing a reference sample for evolutionary studies of galaxies and galaxy clusters. In this paper we present the U-band photometry of galaxies and stars in the fields of 17 clusters of the WINGS sample. We also extend to a larger field of view the original B- and V-band photometry (WINGS-OPT) for 9 and 6 WINGS clusters, respectively. We use both the new and the already existing B-band photometry to get reliable (U-B) colors of galaxies within three fixed apertures in kpc. To this aim, in the reduction procedure we put particular care in the astrometric precision. Since not all the observations have been taken in good transparency conditions, the photometric calibration was partly...

  9. Numerical modeling of flexible insect wings using volume penalization

    Science.gov (United States)

    Engels, Thomas; Kolomenskiy, Dmitry; Schneider, Kai; Sesterhenn, Joern

    2012-11-01

    We consider the effects of chordwise flexibility on the aerodynamic performance of insect flapping wings. We developed a numerical method for modeling viscous fluid flows past moving deformable foils. It extends on the previously reported model for flows past moving rigid wings (J Comput Phys 228, 2009). The two-dimensional Navier-Stokes equations are solved using a Fourier pseudo-spectral method with the no-slip boundary conditions imposed by the volume penalization method. The deformable wing section is modeled using a non-linear beam equation. We performed numerical simulations of heaving flexible plates. The results showed that the optimal stroke frequency, which maximizes the mean thrust, is lower than the resonant frequency, in agreement with the experiments by Ramananarivo et al. (PNAS 108(15), 2011). The oscillatory part of the force only increases in amplitude when the frequency increases, and at the optimal frequency it is about 3 times larger than the mean force. We also study aerodynamic interactions between two heaving flexible foils. This flow configuration corresponds to the wings of dragonflies. We explore the effects of the phase difference and spacing between the fore- and hind-wing.

  10. a New Efficient Control Method for Blended Wing Body

    Science.gov (United States)

    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.

  11. Stability of Alfvén wings in uniform plasmas

    Science.gov (United States)

    Sallago, P. A.; Platzeck, A. M.

    2007-12-01

    A conducting source moving uniformly through a magnetized plasma generates, among a variety of perturbations, Alfvén waves. An interesting characteristic of Alfvén waves is that they can build up structures in the plasma called Alfvén wings. These wings have been detected and measured in many solar system bodies, and their existence has also been theoretically proven. However, their stability remains to be studied. The aim of this paper is to analyze the stability of an Alfvén wing developed in a uniform background field, in the presence of an incompressible perturbation that has the same symmetry as the Alfvén wing, in the magnetohydrodynamic approximation. The study of the stability of a magnetohydrodynamic system is often performed by linearizing the equations and using either the normal modes method or the energy method. In spite of being applicable for many problems, both methods become algebraically complicated if the structure under analysis is a highly non-uniform one. Palumbo has developed an analytical method for the study of the stability of static structures with a symmetry in magnetized plasmas, in the presence of incompressible perturbations with the same symmetry as the structure (Palumbo 1998 Thesis, Universidad de Firenze, Italia). In the present paper we extend this method for Alfvén wings that are stationary structures, and conclude that in the presence of this kind of perturbation they are stable.

  12. Do hummingbirds use a different mechanism than insects to flip and twist their wings?

    Science.gov (United States)

    Song, Jialei; Luo, Haoxiang; Hedrick, Tyson

    2014-11-01

    Hovering hummingbirds flap their wings in an almost horizontal stroke plane and flip the wings to invert the angle of attack after stroke reversal, a strategy also utilized by many hovering insects such as fruit flies. However, unlike insects whose wing actuation mechanism is only located at the base, hummingbirds have a vertebrate musculoskeletal system and their wings contain bones and muscles and thus, they may be capable of both actively flipping and twisting their wings. To investigate this issue, we constructed a hummingbird wing model and study its pitching dynamics. The wing kinematics are reconstructed from high-speed imaging data, and the inertial torques are calculated in a rotating frame of reference using mass distribution data measured from dissections of hummingbird wings. Pressure data from a previous CFD study of the same wing kinematics are used to calculate the aerodynamic torque. The results show that like insect wings, the hummingbird wing pitching is driven by its own inertia during reversal, and the aerodynamic torque is responsible for wing twist during mid-stroke. In conclusion, our study suggests that their wing dynamics are very similar even though their actuation systems are entirely different. This research was supported by the NSF.

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

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

    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.

  14. EBF3GLWingOpt: A Framework for Multidisciplinary Design Optimization of Wings Using SpaRibs

    OpenAIRE

    Liu, Qiang

    2014-01-01

    A global/local framework for multidisciplinary optimization of generalized aircraft wing structure has been developed. The concept of curvilinear stiffening members (spars, ribs and stiffeners) has been applied in the optimization of a wing structure. A global wing optimization framework EBF3WingOpt, which integrates the static aeroelastic, flutter and buckling analysis, has been implemented for exploiting the optimal design at the wing level. The wing internal structure is optimized using cu...

  15. Silencing abnormal wing disc gene of the Asian citrus psyllid, Diaphorina citri disrupts adult wing development and increases nymph mortality.

    Science.gov (United States)

    El-Shesheny, Ibrahim; Hajeri, Subhas; El-Hawary, Ibrahim; Gowda, Siddarame; Killiny, Nabil

    2013-01-01

    Huanglongbing (HLB) causes considerable economic losses to citrus industries worldwide. Its management depends on controlling of the Asian citrus Psyllid (ACP), the vector of the bacterium, Candidatus Liberibacter asiaticus (CLas), the causal agent of HLB. Silencing genes by RNA interference (RNAi) is a promising tool to explore gene functions as well as control pests. In the current study, abnormal wing disc (awd) gene associated with wing development in insects is used to interfere with the flight of psyllids. Our study showed that transcription of awd is development-dependent and the highest level was found in the last instar (5(th)) of the nymphal stage. Micro-application (topical application) of dsRNA to 5(th) instar of nymphs caused significant nymphal mortality and adult wing-malformation. These adverse effects in ACP were positively correlated with the amounts of dsRNA used. A qRT-PCR analysis confirmed the dsRNA-mediated transcriptional down-regulation of the awd gene. Significant down-regulation was required to induce a wing-malformed phenotype. No effect was found when dsRNA-gfp was used, indicating the specific effect of dsRNA-awd. Our findings suggest a role for awd in ACP wing development and metamorphosis. awd could serve as a potential target for insect management either via direct application of dsRNA or by producing transgenic plants expressing dsRNA-awd. These strategies will help to mitigate HLB by controlling ACP.

  16. Silencing abnormal wing disc gene of the Asian citrus psyllid, Diaphorina citri disrupts adult wing development and increases nymph mortality.

    Directory of Open Access Journals (Sweden)

    Ibrahim El-Shesheny

    Full Text Available Huanglongbing (HLB causes considerable economic losses to citrus industries worldwide. Its management depends on controlling of the Asian citrus Psyllid (ACP, the vector of the bacterium, Candidatus Liberibacter asiaticus (CLas, the causal agent of HLB. Silencing genes by RNA interference (RNAi is a promising tool to explore gene functions as well as control pests. In the current study, abnormal wing disc (awd gene associated with wing development in insects is used to interfere with the flight of psyllids. Our study showed that transcription of awd is development-dependent and the highest level was found in the last instar (5(th of the nymphal stage. Micro-application (topical application of dsRNA to 5(th instar of nymphs caused significant nymphal mortality and adult wing-malformation. These adverse effects in ACP were positively correlated with the amounts of dsRNA used. A qRT-PCR analysis confirmed the dsRNA-mediated transcriptional down-regulation of the awd gene. Significant down-regulation was required to induce a wing-malformed phenotype. No effect was found when dsRNA-gfp was used, indicating the specific effect of dsRNA-awd. Our findings suggest a role for awd in ACP wing development and metamorphosis. awd could serve as a potential target for insect management either via direct application of dsRNA or by producing transgenic plants expressing dsRNA-awd. These strategies will help to mitigate HLB by controlling ACP.

  17. Impact and Penetration Simulations for Composite Wing-like Structures

    Science.gov (United States)

    Knight, Norman F.

    1998-01-01

    The goal of this research project was to develop methodologies for the analysis of wing-like structures subjected to impact loadings. Low-speed impact causing either no damage or only minimal damage and high-speed impact causing severe laminate damage and possible penetration of the structure were to be considered during this research effort. To address this goal, an assessment of current analytical tools for impact analysis was performed. Assessment of the analytical tools for impact and penetration simulations with regard to accuracy, modeling, and damage modeling was considered as well as robustness, efficient, and usage in a wing design environment. Following a qualitative assessment, selected quantitative evaluations will be performed using the leading simulation tools. Based on this assessment, future research thrusts for impact and penetration simulation of composite wing-like structures were identified.

  18. Surface roughness measurement on a wing aircraft by speckle correlation.

    Science.gov (United States)

    Salazar, Félix; Barrientos, Alberto

    2013-09-05

    The study of the damage of aeronautical materials is important because it may change the microscopic surface structure profiles. The modification of geometrical surface properties can cause small instabilities and then a displacement of the boundary layer. One of the irregularities we can often find is surface roughness. Due to an increase of roughness and other effects, there may be extra momentum losses in the boundary layer and a modification in the parasite drag. In this paper we present a speckle method for measuring the surface roughness on an actual unmanned aircraft wing. The results show an inhomogeneous roughness distribution on the wing, as expected according to the anisotropic influence of the winds over the entire wing geometry. A calculation of the uncertainty of the technique is given.

  19. Leading-edge vortex shedding from rotating wings

    CERN Document Server

    Kolomenskiy, Dmitry; Schneider, Kai

    2014-01-01

    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.

  20. Effect of Propeller Slipstream on Wing and Tail

    Science.gov (United States)

    Stuper, J

    1938-01-01

    The results of wind tunnel tests for the determination of the effect of a jet on the lift and downwash of a wing are presented in this report. In the first part, a jet without rotation and with constant velocity distribution is considered - the jet being produced by a specially designed fan. Three-component, pressure distribution, and downwash measurements were made and the results compared with existing theory. The effect of a propeller slipstream was investigated in the second part. In the two cases the jet axis coincided with the undisturbed wind direction. In the third part the effect of the inclination of the propeller axis to the wing chord was considered, the results being obtained for a model wing with running propeller.

  1. The Rise of Right-Wing Extremism in European Union

    Directory of Open Access Journals (Sweden)

    Stevkovski Ljupcho

    2015-12-01

    Full Text Available It is a fact that in the European Union there is a strengthening of right-wing extremism, radical right movement, populism and nationalism. The consequences of the economic crisis, such as a decline in living standards, losing of jobs, rising unemployment especially among young people, undoubtedly goes in favor of strengthening the right-wing extremism. In the research, forms of manifestation will be covered of this dangerous phenomenon and response of the institutions. Western Balkan countries, as a result of right-wing extremism, are especially sensitive region on possible consequences that might occur, since there are several unresolved political problems, which can very easily turn into a new cycle of conflicts, if European integration processes get delayed indefinitely.

  2. Multi-objective optimization design of airfoil and wing

    Institute of Scientific and Technical Information of China (English)

    ZHU; Ziqiang; FU; Hongyan; YU; Rixin; LIU; Jie

    2004-01-01

    To extend available monoobjective optimization methods to multiobjective and multidisciplinary optimization, the construction of a suitable resultant objective function(in deterministic method-DM) or a fitness function(in genetic algorithm-GA) is important. An objective function combination method (OFCM) of constructing such a function for constrained optimization problems is suggested. How to use both deterministic and genetic algorithms to biobjective and bidisciplinary optimal design of high performance airfoils and wings is discussed. Numerical results in both 2D (airfoil) and 3D (wing) cases show that the present method can be used to optimaize different kinds of initial airfoils and wings. The performance of optimized shape is improved significantly. The method is successful and effective.

  3. Leading-edge vortex shedding from rotating wings

    Energy Technology Data Exchange (ETDEWEB)

    Kolomenskiy, Dmitry [Centre de Recherches Mathématiques (CRM), Department of Mathematics and Statistics, McGill University, 805 Sherbrooke W., Montreal, QC H3A 0B9 (Canada); Elimelech, Yossef [Faculty of Aerospace Engineering, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Schneider, Kai, E-mail: dkolom@gmail.com [M2P2–CNRS, Université d' Aix-Marseille, 39, rue Frédéric Joliot-Curie, F-13453 Marseille Cedex 13 (France)

    2014-06-01

    This 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. (papers)

  4. Fluid-structure interaction of reticulated porous wings

    Science.gov (United States)

    Strong, Elizabeth; Jawed, Mohammad; Reis, Pedro

    Insects of the orders Neuroptera and Hymenoptera locomote via flapping flight with reticulated wings that have porous structures that confers them with remarkable lightweight characteristics. Yet these porous wings still perform as contiguous plates to provide the necessary aerodynamic lift and drag required for flight. Even though the fluid flow past the bulk of these insects may be in high Reynolds conditions, viscosity can dominate over inertia in the flow through the porous sub-features. Further considering the flexibility of these reticulated wings yields a highly nonlinear fluid-structure interaction problem. We perform a series of dynamically-scaled precision model experiments to gain physical insight into this system. Our experiments are complemented with computer simulations that combine the Discrete Elastic Rods method and a model for the fluid loading that takes into account the `leakiness' through the porous structure. Our results are anticipated to find applications in micro-air vehicle aerodynamics.

  5. Consequences of outbreeding on phenotypic plasticity in Drosophila mercatorum wings

    DEFF Research Database (Denmark)

    Krag, Kristian; Thomsen, Hans Paarup; Faurby, Søren;

    2009-01-01

    in strain 2) and complex changes in wing shape. Hence, we cannot conclude whether outbreeding lowers or increases the capacity to respond to environmental change via plastic responses and via changes of the level of DI. The degree of change of phenotypic plasticity and DI is trait specific, depending...... of genotype-environment interactions, which can increase the phenotypic variability. The same pattern of phenotypic plasticity of wing size between the homozygous parental strains and the heterozygous offspring was found in both strains with an apparent heterotic effect for wing size in the F1 at 25°C. At 20...... at three different temperatures: 20, 25, or 28°C. This design allows a comparison of completely homozygous individuals (parental generation) with identical heterozygote offspring (F1), which makes an analysis of phenotypic plasticity of morphometric traits possible, without a potentially confounding effect...

  6. Miocene winged fruits of Loxopterygium (Anacardiaceae) from the Ecuadorian Andes.

    Science.gov (United States)

    Burnham, Robyn J; Carranco, Nina L

    2004-11-01

    A new species of asymmetrically winged fruit is described from Miocene sediments of Andean Ecuador. The new fruit is readily placed in the genus Loxopterygium of the Anacardiaceae based on the size, position of the stigma, wing venation, and serration of the wing tip. The new fossil species is very similar to extant species of Loxopterygium now distributed in dry habitats of coastal Ecuador and Peru, as well as dry interior forests of Bolivia and northern Argentina. We use the fossil to calibrate a molecular-based phylogeny of some members of the Anacardiaceae, showing that dry forest habitats may have been present in South America for more than 10 million years. PMID:21652323

  7. Application of variable-sweep wings to commuter aircraft

    Science.gov (United States)

    Robins, A. W.; Beissner, F. L., Jr.; Lovell, W. A.; Price, J. E.; Turriiziani, R. V.; Washburn, F. F.

    1983-01-01

    The effects of using variable-sweep wings on the riding quality and mission-performance characteristics of commuter-type aircraft were studied. A fixed-wing baseline vehicle and a variable-sweep version of the baseline were designed and evaluated. Both vehicles were twin-turboprop, pressurized-cabin, 30-passenger commuter aircraft with identical mission requirements. Mission performance was calculated with and without various ride-quality constraints for several combinations of cruise altitude and stage lengths. The variable-sweep aircraft had a gross weight of almost four percent greater than the fixed-wing baseline in order to meet the design-mission requirements. In smooth air, the variable sweep configuration flying with low sweep had a two to three percent fuel-use penalty. However, the imposition of quality constraints in rough air can result in advantages in both fuel economy and flight time for the variable-sweep vehicle flying with high sweep.

  8. Sensitivity Analysis of Transonic Flow over J-78 Wings

    Directory of Open Access Journals (Sweden)

    Alexander Kuzmin

    2015-01-01

    Full Text Available 3D transonic flow over swept and unswept wings with an J-78 airfoil at spanwise sections is studied numerically at negative and vanishing angles of attack. Solutions of the unsteady Reynolds-averaged Navier-Stokes equations are obtained with a finite-volume solver on unstructured meshes. The numerical simulation shows that adverse Mach numbers, at which the lift coefficient is highly sensitive to small perturbations, are larger than those obtained earlier for 2D flow. Due to the larger Mach numbers, there is an onset of self-exciting oscillations of shock waves on the wings. The swept wing exhibits a higher sensitivity to variations of the Mach number than the unswept one.

  9. The Effect of Wing Scales on Monarch Butterfly Flight Characteristics

    Science.gov (United States)

    Shaw, Angela; Jones, Robert; Lang, Amy

    2010-11-01

    Recent research has shown that the highly flexible wings of butterflies in flapping flight develop vortices along their leading and trailing edges. Butterfly scales (approximately 100 microns in length) have a shingled pattern and extend into the boundary layer. These scales, which make up approximately 3% of the body weight or less, could play a part in controlling separation and vortex formation in this unsteady, three-dimensional complex flow field. A better understanding of this mechanism may lead to bio-inspired applications for flapping wing micro-air vehicles. In this study, the flight performance of Monarch (Danaus plexippus) butterflies with and without scales was analyzed. Scales were removed from the upper and lower wing surfaces and specimens were videotaped at 600 frames per second. Variation in flapping patterns and flight fitness were observed.

  10. Prediction and control of slender-wing rock

    Science.gov (United States)

    Kandil, Osama A.; Salman, Ahmed A.

    1992-01-01

    The unsteady Euler equations and the Euler equations of rigid-body dynamics, both written in the moving frame of reference, are sequentially solved to simulate the limit-cycle rock motion of slender delta wings. The governing equations of the fluid flow and the dynamics of the present multidisciplinary problem are solved using an implicit, approximately-factored, central-difference-like, finite-volume scheme and a four-stage Runge-Kutta scheme, respectively. For the control of wing-rock motion, leading-edge flaps are forced to oscillate anti-symmetrically at prescribed frequency and amplitude, which are tuned in order to suppress the rock motion. Since the computational grid deforms due to the leading-edge flaps motion, the grid is dynamically deformed using the Navier-displacement equations. Computational applications cover locally-conical and three-dimensional solutions for the wing-rock simulation and its control.

  11. Non-linear dynamics of wind turbine wings

    DEFF Research Database (Denmark)

    Larsen, Jesper Winther; Nielsen, Søren R.K.

    2006-01-01

    The paper deals with the formulation of non-linear vibrations of a wind turbine wing described in a wing fixed moving coordinate system. The considered structural model is a Bernoulli-Euler beam with due consideration to axial twist. The theory includes geometrical non-linearities induced...... by the rotation of the aerodynamic load and the curvature, as well as inertial induced non-linearities caused by the support point motion. The non-linear partial differential equations of motion in the moving frame of reference have been discretized, using the fixed base eigenmodes as a functional basis....... Important non-linear couplings between the fundamental blade mode and edgewise modes have been identified based on a resonance excitation of the wing, caused by a harmonically varying support point motion with the circular frequency omega. Assuming that the fundamental blade and edgewise eigenfrequencies...

  12. Environment Identification in Flight using Sparse Approximation of Wing Strain

    CERN Document Server

    Manohar, Krithika; Kutz, J Nathan

    2016-01-01

    This paper addresses the problem of identifying different flow environments from sparse data collected by wing strain sensors. Insects regularly perform this feat using a sparse ensemble of noisy strain sensors on their wing. First, we obtain strain data from numerical simulation of a Manduca sexta hawkmoth wing undergoing different flow environments. Our data-driven method learns low-dimensional strain features originating from different aerodynamic environments using Proper Orthogonal Decomposition (POD) modes in the frequency domain, and leverages compressed sensing and sparse approximation to classify a set of strain frequency signatures using a dictionary of POD modes. This bio-inspired machine learning architecture for dictionary learning and sparse classification permits fewer costly physical strain sensors while being simultaneously robust to sensor noise. A sensor placement algorithm identifies the frequency samples that best separate the different aerodynamic environments in rank-reduced POD feature...

  13. A Simple Model of Wings in Heavy-Ion Collisions

    CERN Document Server

    Parikh, Aditya

    2015-01-01

    We create a simple model of heavy ion collisions independent of any generators as a way of investigating a possible source of the wings seen in data. As a first test, we reproduce a standard correlations plot to verify the integrity of the model. We then proceed to test whether an η dependent v2 could be a source of the wings and take projections along multiple Δφ intervals and compare with data. Other variations of the model are tested by having dN/dφ and v2 depend on η as well as including pions and protons into the model to make it more realistic. Comparisons with data seem to indicate that an η dependent v2 is not the main source of the wings.

  14. Development and Experiments of the Sea-Wing Underwater Glider

    Institute of Scientific and Technical Information of China (English)

    YU Jian-cheng; ZHANG Ai-qun; JIN Wen-ming; CHEN Qi; TIAN Yu; LIU Chong-jie

    2011-01-01

    Underwater gliders,which glide through water columns by use of a pair of wings,are efficient long-distance,long-duration marine environment observatory platforms.The Sea-Wing underwater glider,developed by the Shenyang Institute of Automation,CAS,is designed for the application of deep-sea environment variables observation.The system components,the mechanical design,and the control system design of the Sea-Wing underwater glider are described in this paper.The pitch and roll adjusting models are derived based on the mechanical design,and the adjusting capabilities for the pitch and roll are analyzed according to the models.Field experiments have been carried out for validating the gliding motion and the ability of measuring ocean environment variables.Experimental results of the motion performances of the glider are presented.

  15. Design, realization and structural testing of a compliant adaptable wing

    Science.gov (United States)

    Molinari, G.; Quack, M.; Arrieta, A. F.; Morari, M.; Ermanni, P.

    2015-10-01

    This paper presents the design, optimization, realization and testing of a novel wing morphing concept, based on distributed compliance structures, and actuated by piezoelectric elements. The adaptive wing features ribs with a selectively compliant inner structure, numerically optimized to achieve aerodynamically efficient shape changes while simultaneously withstanding aeroelastic loads. The static and dynamic aeroelastic behavior of the wing, and the effect of activating the actuators, is assessed by means of coupled 3D aerodynamic and structural simulations. To demonstrate the capabilities of the proposed morphing concept and optimization procedure, the wings of a model airplane are designed and manufactured according to the presented approach. The goal is to replace conventional ailerons, thus to achieve controllability in roll purely by morphing. The mechanical properties of the manufactured components are characterized experimentally, and used to create a refined and correlated finite element model. The overall stiffness, strength, and actuation capabilities are experimentally tested and successfully compared with the numerical prediction. To counteract the nonlinear hysteretic behavior of the piezoelectric actuators, a closed-loop controller is implemented, and its capability of accurately achieving the desired shape adaptation is evaluated experimentally. Using the correlated finite element model, the aeroelastic behavior of the manufactured wing is simulated, showing that the morphing concept can provide sufficient roll authority to allow controllability of the flight. The additional degrees of freedom offered by morphing can be also used to vary the plane lift coefficient, similarly to conventional flaps. The efficiency improvements offered by this technique are evaluated numerically, and compared to the performance of a rigid wing.

  16. Introduction to the Abrupt Wing Stall (AWS) Program

    Science.gov (United States)

    Hall, Robert M.; Woodson, Shawn H.

    2003-01-01

    The Abrupt Wing Stall (AWS) Program has addressed the problem of uncommanded, transonic lateral motions, such as wing drop, with experimental, computational, and simulation tools. Background to the establishment of the AWS program is given as well as program objectives. In order to understand the fundamental flow mechanisms that caused the undesirable motions for a pre-production version of the F/A-18E, steady and unsteady flow field details were gathered from dedicated transonic wind-tunnel testing and computational studies. The AWS program has also adapted a free-to- roll (FTR) wind-tunnel testing technique traditionally used for low-speed studies of lateral dynamic stability to the transonic flow regime. This FTR capability was demonstrated first in a proof-of-concept study and then applied to an assessment of four different aircraft configurations. Figures of merit for static testing and for FTR testing have been evaluated for two configurations that demonstrated wing drop susceptibility during full-scale flight conditions (the pre-production F/A-l8E and the AV-8B at the extremes of its flight envelope) and two configurations that do not exhibit wing drop (the F/A-l8C and the F-l6C). Design insights have been obtained from aerodynamic computational studies of the four aircraft configurations and from computations quantifying the impact of the various geometric wing differences between the F/A-18C and the F/A-l8E wings. Finally, the AWS program provides guidance for assessing, in the simulator, the impact of experimentally determined lateral activity on flight characteristics before going to flight.

  17. Morphometric Wing Characters as a Tool for Mosquito Identification

    Science.gov (United States)

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

    2016-01-01

    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

  18. Design of a hybrid rocket / inflatable wing UAV

    Science.gov (United States)

    Sudduth, Cory

    This paper discusses the design challenges and development of a UAV that transitions from a rocket, which allows the aircraft to reach a target altitude rapidly, and then deploys an inflatable wing from an enclosed shell in midflight to allow for loitering and surveillance. The wing deployment and transition is tested in static and dynamic environments, while the performance and stability of both the aircraft mode and rocket mode are examined analytically. An in-depth discussion of key components, including the design, analysis and testing, is also included. Designing an UAV that transitions from a high velocity rocket, to a slow velocity UAV provides many difficult and unique design challenges. For example, the incorporation of deployable wing technology into a full UAV system results in many design constraints. In this particular design inflatable wings are used to generate lift during aircraft mode, and the stabilizing fins for the main wing also acted as the fins for the vehicle during its rocket phase. This required the balancing of the two different vehicle configurations to ensure that the aircraft would be able to fly stably in both modes, and transition between them without catastrophic failure. Significant research, and testing went into the finding the best method of storing the inflatable wing, as well as finding the required inflation rate to minimize unsteady aerodynamic affects. Design work was also invested in the development of an inflation system, as it had to be highly reliable, and yet very light weight for use in this small UAV. This paper discusses how these design challenges were overcome, the development and testing of individual sub-components and how they are incorporated into the overall vehicle. The analysis that went into this UAV, as well as methods used to optimize the design in order to minimize weight and maximize the aircraft performance and loitering time is also discussed.

  19. Morphometric Wing Characters as a Tool for Mosquito Identification.

    Science.gov (United States)

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

    2016-01-01

    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

  20. Flutter study of an advanced composite wing with external stores

    Science.gov (United States)

    Cole, Stanley R.; Rivera, Jose A., Jr.; Nagaraja, K. S.

    1987-01-01

    A flutter test using a scaled model of an advanced composite wing for a Navy attack aircraft has been conducted in the NASA Langley Research Center Transonic Dynamics Tunnel. The model was a wall-mounted half-span wing with a semi-span of 6.63 ft. The wing had an aspect ratio of 5.31, taper ratio of 0.312, and quarter-chord sweep of 25 degrees. The model was supported in a manner that simulated the load path in the carry-through structure of the aircraft and the symmetric boundary condition at the fuselage centerline. The model was capable of carrying external stores from three pylon locations on the wing. Flutter tests were conducted for the wing with and without external stores. No flutter was encountered for the clean wing at test conditions which simulated the scaled airplane operating envelope. Flutter boundaries were obtained for several external store configurations. The flutter boundaries for the fuel tanks were nearly Mach number independent (occurring at constant dynamic pressure). To study the aerodynamic effect of the fuel tank stores, pencil stores (slender cylindrical rods) which had the same mass and pitch and yaw inertia as the fuel tanks were tested on the model. These pencil store configurations exhibited a transonic dip in the flutter dynamic pressure, indicating that the aerodynamic effect of the actual fuel tanks on flutter was significant. Several flutter analyses methods were used in an attempt to predict the flutter phenomenon exhibited during the wind-tunnel test. The analysis gave satisfactory predictions of flutter for the pencil store configurations, but unsatisfactory correlation for the actual fuel tank configurations.

  1. VISCOELASTIC CONSTITUTIVE MODEL RELATED TO DEFORMATION OF INSECT WING UNDER LOADING IN FLAPPING MOTION

    Institute of Scientific and Technical Information of China (English)

    BAO Lin; HU Jin-song; YU Yong-liang; CHENG Peng; XU Bo-qing; TONG Bing-gang

    2006-01-01

    Flexible insect wings deform passively under the periodic loading during flapping flight. The wing flexibility is considered as one of the specific mechanisms on improving insect flight performance. The constitutive relation of the insect wing material plays a key role on the wing deformation, but has not been clearly understood yet. A viscoelastic constitutive relation model was established based on the stress relaxation experiment of a dragonfly wing (in vitro). This model was examined by the finite clement analysis of the dynamic deformation response for a model insect wing under the action of the periodical inertial force in flapping. It is revealed that the viscoelastic constitutive relation is rational to characterize the biomaterial property of insect wings in contrast to the elastic one. The amplitude and form of the passive viscoelastic deformation of the wing is evidently dependent on the viscous parameters in the constitutive relation.

  2. The structure and mechanical properties of dragonfly wings and their role on flyability

    Science.gov (United States)

    Sun, Jiyu; Bhushan, Bharat

    2012-01-01

    Dragonfly wings possess great stability and high load-bearing capacity during flapping flight, glide, and hover. Scientists have been intrigued by them and have carried out research for biomimetic applications. Relative to the large number of works on its flight aerodynamics, few researchers have focused on the insect wing structure and its mechanical properties. The wings of dragonflies are mainly composed of veins and membranes, a typical nanocomposite material. The veins and membranes have a complex design within the wing that give rise to whole-wing characteristics which result in dragonflies being supremely versatile, maneuverable fliers. The wing structure, especially corrugation, on dragonflies is believed to enhance aerodynamic performance. The mechanical properties of dragonfly wings need to be understood in order to perform simulated models. This paper focuses on the effects of structure, mechanical properties, and morphology of dragonfly wings on their flyability, followed by the implications in fabrication and modeling.

  3. Prediction Approach to Life on Wing for Civil Aeroengine

    Institute of Scientific and Technical Information of China (English)

    RONG Xiang; ZUO Hong-fu; ZHANG Hai-jun

    2008-01-01

    To reduce engine maintenance cost and support safe operation, a prediction method of engine life on wing was proposed. This method is a kind of regression model which is a function of the condition monitoring and failure data. Key causes of engine removals were analyzed, and the life limit due to performance deterioration was predicted by proportional hazards model. Then the scheduled removal causes were considered as constraints of engine life to predicte the final life on wing. Application of the proposed prediction method to the case of CF6-80C2A5 engine fleet in an airline proved its effectiveness.

  4. Wing analysis using a transonic potential flow computational method

    Science.gov (United States)

    Henne, P. A.; Hicks, R. M.

    1978-01-01

    The ability of the method to compute wing transonic performance was determined by comparing computed results with both experimental data and results computed by other theoretical procedures. Both pressure distributions and aerodynamic forces were evaluated. Comparisons indicated that the method is a significant improvement in transonic wing analysis capability. In particular, the computational method generally calculated the correct development of three-dimensional pressure distributions from subcritical to transonic conditions. Complicated, multiple shocked flows observed experimentally were reproduced computationally. The ability to identify the effects of design modifications was demonstrated both in terms of pressure distributions and shock drag characteristics.

  5. The Development and Control of Axial Vortices over Swept Wings

    OpenAIRE

    Klute, Sandra M.

    1999-01-01

    The natural unsteadiness in the post-breakdown flowfield of a 75° sweep delta wing at 40° angle of attack was studied with dual and single point hot-wire anemometry in the Engineering Science and Mechanics (ESM) Wind Tunnel at a Reynolds number Re = 210,000. Data were taken in five crossflow planes surrounding the wing's trailing edge. Results showed a dominant narrowband Strouhal frequency of St = 1.5 covering approximately 80% of the area with lower-intensity broadband secondary freque...

  6. Insect wing deformation measurements using high speed digital holographic interferometry.

    Science.gov (United States)

    Aguayo, Daniel D; Mendoza Santoyo, Fernando; De la Torre-I, Manuel H; Salas-Araiza, Manuel D; Caloca-Mendez, Cristian; Gutierrez Hernandez, David Asael

    2010-03-15

    An out-of-plane digital holographic interferometry system is used to detect and measure insect's wing micro deformations. The in-vivo phenomenon of the flapping is registered using a high power cw laser and a high speed camera. A series of digital holograms with the deformation encoded are obtained. Full field deformation maps are presented for an eastern tiger swallowtail butterfly (Pterourus multicaudata). Results show no uniform or symmetrical deformations between wings. These deformations are in the order of hundreds of nanometers over the entire surface. Out-of-plane deformation maps are presented using the unwrapped phase maps. PMID:20389581

  7. Electric Loading Simulation System for Missile Wings and Rudders

    Institute of Scientific and Technical Information of China (English)

    QI Rong; LIN Hui; CHEN Ming

    2006-01-01

    The design and the realization of missile wings and rudders loading simulation system based on digital signal processor (DSP) TMS320LF2407 and direct torque control (DTC) servo driver ACS600 are discussed. The structure and opration principle for the system are presented. Speediness and elimination of superabundant torque are two key difficulties for electric loading simulation system. The method which can eliminate the superabundant torque is researched. Test results show the airflow resistance when missile wings and rudders are spreading can be rapidly simulated with high accuracy.

  8. Wind tunnel tests of four flexible wing ultralight gliders

    Science.gov (United States)

    Ormiston, R. A.

    1979-01-01

    The aerodynamic lift, drag, and pitching moment characteristics of four full scale, flexible wing, ultralight gliders were measured in the settling chamber of a low speed wind tunnel. The gliders were tested over a wide range of angle of attack and at two different velocities. Particular attention was devoted to the lift and pitching moment behavior at low and negative angles of attack because of the potential loss of longitudinal stability of flexible wing gliders in this regime. The test results were used to estimate the performance and longitudinal control characteristics of the gliders.

  9. Transmittance characteristics of plasmonic graphene ribbons with a wing

    Science.gov (United States)

    Yuan, Lin; Yan, Xin; Wang, Yueke; Sang, Tian; Yang, Guofeng

    2016-09-01

    We numerically investigate the transmittance characteristics of graphene ribbons with a wing by the finite element method. By determining the dispersion relation of edge graphene plasmon (EGP) modes and analyzing the mode distributions, it is considered that the transmission dips originate from the resonances of three EGP modes, namely, the symmetrical EGPs, antisymmetrical EGPs, and EGPs of a semi-infinite sheet. By changing the width and length of the wing, it was further confirmed that transmission dips originate from the EGP modes. Owing to the tunable permittivity of graphene by adjusting the gate voltage, the transmittance dips can be easily tuned.

  10. X-31 Wing Storage for Shipping

    Science.gov (United States)

    1995-01-01

    The right wing of the X-31 Enhanced Fighter Maneuverability Technology Demonstrator Aircraft is seen here being put into a shipping container May 18, 1995, at NASA's Dryden Flight Research Center, Edwards, California, by U.S. and German members of the program. To fit inside an Air Force Reserve C-5 transport, which was used to ferry the X-31 to Europe on May 22, 1995, the right wing had to be removed. Manching, Germany, was used as a staging base to prepare the aircraft for participation in the Paris Air Show. At the air show on June 11 through the 18th, the X-31 demonstrated the value of using thrust vectoring (directing engine exhaust flow) coupled with advanced flight control systems to provide controlled flight at very high angles of attack. The aircraft arrived back at Edwards in an Air Force Reserve C-5 on June 25, 1995, and off loaded at Dryden the 27th. The X-31 aircraft was developed jointly by Rockwell International's North American Aircraft Division (now part of Boeing) and Daimler-Benz Aerospace (formerly Messerschmitt-Bolkow-Blohm), under sponsorship by the U.S. Department of Defense and The German Federal Ministry of Defense. The X-31 Enhanced Fighter Maneuverability (EFM) demonstrator flew at the Ames- Dryden Flight Research Facility, Edwards, California (redesignated the Dryden Flight Research Center in 1994) from February 1992 until 1995 and before that at the Air Force's Plant 42 in Palmdale, California. The goal of the project was to provide design information for the next generation of highly maneuverable fighter aircraft. This program demonstrated the value of using thrust vectoring (directing engine exhaust flow) coupled with an advanced flight control system to provide controlled flight to very high angles of attack. The result was a significant advantage over most conventional fighters in close-in combat situations. The X-31 flight program focused on agile flight within the post-stall regime, producing technical data to give aircraft

  11. Flapping wing actuation using resonant compliant mechanisms: An insect-inspired design

    OpenAIRE

    Bolsman, C.T.

    2010-01-01

    The realization of a wing actuation mechanism for a flapping wing micro air vehicle requires a move away from traditional designs based on gears and links. An approach inspired by nature’s flyers is better suited. For flapping flight two wing motions are important: the sweeping and the pitching motion. The current design is set up to exploit resonant properties, as exhibited by flying insects, to reduce the energy expenditure and to provide amplitude amplification for the wing sweeping motion...

  12. Experimental Research and Numerical Simulation of Wing Boxes under Pure Bending Load

    OpenAIRE

    Peiyan Wang; Shile Yao; Xinmei Wang; Zhufeng Yue

    2014-01-01

    Two full-scale wing boxes with different types of butt joints were investigated under pure bending load, and numerical methods, including global analysis and detailed analysis, were proposed to determine the reasons for failure of the wing boxes. Wing boxes were tested under bending loads applied by a multichannel force control system. The experimental results showed that the region of the butt joint was the weakest location of the wing boxes, and the damage loads were far less than the desig...

  13. Wing base morphology of Aetalionidae (Hemiptera: Cicadomorpha) and its phylogenetic implications

    OpenAIRE

    Ogawa, Naoki; Maruyama, Munetoshi; Yoshizawa, Kazunori

    2015-01-01

    The Aetalionidae is a small family belonging to the treehopper superfamily Membracoidea (Hemiptera: Cicadomorpha). Although the wing-base morphology of Cicadomorpha was examined in detail recently, the wing base of this family has not been investigated to date. We examined morphology of the wing-base structure of Aetalionidae. Using the characters selected from the wing base, we inferred the phylogenetic placement of this family and confirmed that it belongs to the superfamily Membracoidea an...

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

    Directory of Open Access Journals (Sweden)

    ArimalaParamasivamSruthi

    2015-08-01

    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.

  15. Morphometric geometric study of wing shape in Culex quinquefasciatus Say (Diptera: Culicidae from Tamil Nadu, India

    Directory of Open Access Journals (Sweden)

    K. Manimegalai

    2009-05-01

    Full Text Available The morphometric geometric study was carried out in 10 males and 10 females of Culex quinquefasciatus. There are 23 landmarks corresponding to points at which wing veins either branch or intersect the margin of the wing. Relative warp analysis has been proved to be very efficient in distinguishing the variation of shape in male and female wings. The multivariate analysis of co-variance (MANCOVA showed a clear separation of the male and female wings.

  16. Flapping wing actuation using resonant compliant mechanisms: An insect-inspired design

    NARCIS (Netherlands)

    Bolsman, C.T.

    2010-01-01

    The realization of a wing actuation mechanism for a flapping wing micro air vehicle requires a move away from traditional designs based on gears and links. An approach inspired by nature’s flyers is better suited. For flapping flight two wing motions are important: the sweeping and the pitching moti

  17. The aerodynamic forces and pressure distribution of a revolving pigeon wing

    Science.gov (United States)

    Usherwood, James R.

    The aerodynamic forces acting on a revolving dried pigeon wing and a flat card replica were measured with a propeller rig, effectively simulating a wing in continual downstroke. Two methods were adopted: direct measurement of the reaction vertical force and torque via a forceplate, and a map of the pressures along and across the wing measured with differential pressure sensors. Wings were tested at Reynolds numbers up to 108,000, typical for slow-flying pigeons, and considerably above previous similar measurements applied to insect and hummingbird wing and wing models. The pigeon wing out-performed the flat card replica, reaching lift coefficients of 1.64 compared with 1.44. Both real and model wings achieved much higher maximum lift coefficients, and at much higher geometric angles of attack (43°), than would be expected from wings tested in a windtunnel simulating translating flight. It therefore appears that some high-lift mechanisms, possibly analogous to those of slow-flying insects, may be available for birds flapping with wings at high angles of attack. The net magnitude and orientation of aerodynamic forces acting on a revolving pigeon wing can be determined from the differential pressure maps with a moderate degree of precision. With increasing angle of attack, variability in the pressure signals suddenly increases at an angle of attack between 33° and 38°, close to the angle of highest vertical force coefficient or lift coefficient; stall appears to be delayed compared with measurements from wings in windtunnels.

  18. File list: Unc.Lar.20.AllAg.Imaginal_wing_disc [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Lar.20.AllAg.Imaginal_wing_disc dm3 Unclassified Larvae Imaginal wing disc http...://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Unc.Lar.20.AllAg.Imaginal_wing_disc.bed ...

  19. File list: Pol.Lar.50.AllAg.Imaginal_wing_disc [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Lar.50.AllAg.Imaginal_wing_disc dm3 RNA polymerase Larvae Imaginal wing disc SR...X026743,SRX661503,SRX026742,SRX182775 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Pol.Lar.50.AllAg.Imaginal_wing_disc.bed ...

  20. File list: Unc.Lar.10.AllAg.Imaginal_wing_disc [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Lar.10.AllAg.Imaginal_wing_disc dm3 Unclassified Larvae Imaginal wing disc http...://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Unc.Lar.10.AllAg.Imaginal_wing_disc.bed ...

  1. File list: His.Lar.10.AllAg.Imaginal_wing_disc [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Lar.10.AllAg.Imaginal_wing_disc dm3 Histone Larvae Imaginal wing disc SRX661498...00 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/His.Lar.10.AllAg.Imaginal_wing_disc.bed ...

  2. File list: ALL.Lar.50.AllAg.Imaginal_wing_disc [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  3. File list: Pol.Lar.05.AllAg.Imaginal_wing_disc [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Lar.05.AllAg.Imaginal_wing_disc dm3 RNA polymerase Larvae Imaginal wing disc SR...X026743,SRX026742,SRX182775,SRX661503 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Pol.Lar.05.AllAg.Imaginal_wing_disc.bed ...

  4. File list: ALL.Lar.10.AllAg.Imaginal_wing_disc [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Lar.10.AllAg.Imaginal_wing_disc dm3 All antigens Larvae Imaginal wing disc SRX6...RX182774,SRX131083,SRX661500,SRX187588 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Lar.10.AllAg.Imaginal_wing_disc.bed ...

  5. File list: ALL.Lar.05.AllAg.Imaginal_wing_disc [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  6. File list: His.Lar.05.AllAg.Imaginal_wing_disc [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  7. File list: Unc.Lar.50.AllAg.Imaginal_wing_disc [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  8. File list: His.Lar.50.AllAg.Imaginal_wing_disc [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Lar.50.AllAg.Imaginal_wing_disc dm3 Histone Larvae Imaginal wing disc SRX661498...00 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/His.Lar.50.AllAg.Imaginal_wing_disc.bed ...

  9. File list: ALL.Lar.20.AllAg.Imaginal_wing_disc [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  10. File list: Pol.Lar.10.AllAg.Imaginal_wing_disc [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  11. File list: Pol.Lar.20.AllAg.Imaginal_wing_disc [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  12. File list: His.Lar.20.AllAg.Imaginal_wing_disc [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  13. File list: Unc.Lar.05.AllAg.Imaginal_wing_disc [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Lar.05.AllAg.Imaginal_wing_disc dm3 Unclassified Larvae Imaginal wing disc http...://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Unc.Lar.05.AllAg.Imaginal_wing_disc.bed ...

  14. Note on the glide of a bird with wings bent downwards

    NARCIS (Netherlands)

    Sparenberg, J. A.

    2006-01-01

    This note considers the influence of the bending down of the wings of a bird on the performance of its glide. The induced drag of bent wings is compared with the induced drag of a corresponding straight wing. Numerical results are given.

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

    NARCIS (Netherlands)

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

    2015-01-01

    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

  16. Moult of wing and tail-feathers in the Ostrich, Struthio camelus

    NARCIS (Netherlands)

    Brom, Tim G.; Dekker, René W.R.J.

    1990-01-01

    Structure and moult of wing and tail of a full-grown Ostrich, Struthio camelus, are described. In the wing, at least three feather generations could be recognized. The pattern of moult is more or less symmetrical in both wings and the sequence of feather replacement is not random. The tail consisted

  17. A NASTRAN model of a large flexible swing-wing bomber. Volume 3: NASTRAN model development-wing structure

    Science.gov (United States)

    Mock, W. D.; Latham, R. A.

    1982-01-01

    The NASTRAN model plan for the wing structure was expanded in detail to generate the NASTRAN model for this substructure. The grid point coordinates were coded for each element. The material properties and sizing data for each element were specified. The wing substructure model was thoroughly checked out for continuity, connectivity, and constraints. This substructure was processed for structural influence coefficients (SIC) point loadings and the deflections were compared to those computed for the aircraft detail model. Finally, a demonstration and validation processing of this substructure was accomplished using the NASTRAN finite element program. The bulk data deck, stiffness matrices, and SIC output data were delivered.

  18. Aerodynamic performance and particle image velocimetery of piezo actuated biomimetic manduca sexta engineered wings towards the design and application of a flapping wing flight vehicle

    Science.gov (United States)

    DeLuca, Anthony M.

    Considerable research and investigation has been conducted on the aerodynamic performance, and the predominate flow physics of the Manduca Sexta size of biomimetically designed and fabricated wings as part of the AFIT FWMAV design project. Despite a burgeoning interest and research into the diverse field of flapping wing flight and biomimicry, the aerodynamics of flapping wing flight remains a nebulous field of science with considerable variance into the theoretical abstractions surrounding aerodynamic mechanisms responsible for aerial performance. Traditional FWMAV flight models assume a form of a quasi-steady approximation of wing aerodynamics based on an infinite wing blade element model (BEM). An accurate estimation of the lift, drag, and side force coefficients is a critical component of autonomous stability and control models. This research focused on two separate experimental avenues into the aerodynamics of AFIT's engineered hawkmoth wings|forces and flow visualization. 1. Six degree of freedom force balance testing, and high speed video analysis was conducted on 30°, 45°, and 60° angle stop wings. A novel, non-intrusive optical tracking algorithm was developed utilizing a combination of a Gaussian Mixture Model (GMM) and ComputerVision (OpenCV) tools to track the wing in motion from multiple cameras. A complete mapping of the wing's kinematic angles as a function of driving amplitude was performed. The stroke angle, elevation angle, and angle of attack were tabulated for all three wings at driving amplitudes ranging from A=0.3 to A=0.6. The wing kinematics together with the force balance data was used to develop several aerodynamic force coefficient models. A combined translational and rotational aerodynamic model predicted lift forces within 10%, and vertical forces within 6%. The total power consumption was calculated for each of the three wings, and a Figure of Merit was calculated for each wing as a general expression of the overall efficiency of

  19. An inflatable wing using the principle of Tensairity

    NARCIS (Netherlands)

    Breuer, J.; Ockels, W.; Luchsinger, R.H.

    2007-01-01

    The paper describes the new concept Tensairity which can be used to significantly improve the load bearing capacity of inflatable wings. The basic principle of Tensairity is to use an inflatable structure to stabilize conventional compression and tension elements. So far, Tensairity has been mainly

  20. Wing coloration and pigment gradients in scales of pierid butterflies

    NARCIS (Netherlands)

    Giraldo, Marco A.; Stavenga, Doekele G.

    2008-01-01

    Depending on the species, the individual scales of butterfly wings have a longitudinal gradient in structure and reflectance properties, as shown by scanning electron microscopy and microspectrophotometry. White scales of the male Small White, Pieris rapae crucivora, show a strong gradient in both t

  1. Monitoring of a Full-Scale Wing Fatigue Test

    NARCIS (Netherlands)

    Heida, Jaap; Hwang, Jason

    2014-01-01

    A wing of a decommissioned aircraft of the Royal Netherlands Air Force (RNLAF) was fatigue tested to more than two times the design life. Part of the test was the evaluation of load monitoring and Structural Health Monitoring (SHM) techniques. For load monitoring the data of conventional resistance

  2. Flight mechanics of a tailless articulated wing aircraft

    Energy Technology Data Exchange (ETDEWEB)

    Paranjape, Aditya A; Chung, Soon-Jo; Selig, Michael S, E-mail: sjchung@illinois.edu [Department of Aerospace Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States)

    2011-06-15

    This paper investigates the flight mechanics of a micro aerial vehicle without a vertical tail in an effort to reverse-engineer the agility of avian flight. The key to stability and control of such a tailless aircraft lies in the ability to control the incidence angles and dihedral angles of both wings independently. The dihedral angles can be varied symmetrically on both wings to control aircraft speed independently of the angle of attack and flight path angle, while asymmetric dihedral can be used to control yaw in the absence of a vertical stabilizer. It is shown that wing dihedral angles alone can effectively regulate sideslip during rapid turns and generate a wide range of equilibrium turn rates while maintaining a constant flight speed and regulating sideslip. Numerical continuation and bifurcation analysis are used to compute trim states and assess their stability. This paper lays the foundation for design and stability analysis of a flapping wing aircraft that can switch rapidly from flapping to gliding flight for agile manoeuvring in a constrained environment.

  3. Surfzone monitoring using rotary wing unmanned aerial vehicles

    NARCIS (Netherlands)

    Brouwer, R.L.; De Schipper, M.A.; Rynne, P.F.; Graham, F.J.; Reniers, A.J.H.M.; Macmahan, J.H.

    2015-01-01

    This study investigates the potential of rotary wing unmanned aerial vehicles (UAVs) to monitor the surfzone. This paper shows that these UAVs are extremely flexible surveying platforms that can gather nearcontinuous moderate spatial resolution and high temporal resolution imagery from a fixed posit

  4. Propeller slipstream wing interactions at Mach no. 0.8

    Science.gov (United States)

    Bencze, D. P.; Smith, R. C.; Welge, H. R.; Crowder, J. P.

    1978-01-01

    Configuration and results of a wind tunnel test of the aerodynamic interactions between propeller slipstream and a supercritical wing at transonic Mach numbers are discussed. The test was conducted over a free-stream Mach number range from 0.7 to 0.84, with the slipstream simulator and the wing-body model installed in the tunnel. The angle of attack and the spanning lift coefficients were varied from 1 to 3 deg and from 0.4 to 0.7 deg respectively, while the slipstream swirl angle was varied from 0 to 11 deg with an upwash on the inboard side of the wing. It was found that at a free-stream Mach number of 0.8 and a lift coefficient of 0.5, incremental drag results for 7 deg of swirl and a slipstream Mach number of 0.87 indicated a penalty equivalent to a 0.024 loss in propeller efficiency, whereas at 11 deg the drag increment was favorable. Swirl had significant effects on the chordwise pressure distributions of the inboard section of the wing within the slipstream. Neither surface nor wake pressures showed signs of significant flow separation induced by the slipstream.

  5. 2D scaled model of the TURBOPROP wing

    Directory of Open Access Journals (Sweden)

    Adrian DOBRE

    2011-12-01

    Full Text Available The 2D Turbo Prop wing is part of the European Clean Sky JTI GRA Low Noise programme. For this, the model is equipped with interchangeable T.E. noise reducing systems.The scope of the tests in the INCAS Subsonic wind tunnel is to investigate and compare the aerodynamic and aero acoustic performances of a series of different T.E. High Lift Devices noise reducing systems of the “Turbo Prop wing configuration”. For this, the distribution of the pressure at the surface of the model should be determined. The measurement of the pressure is classically made through orifices of small size connected to a common transducer via a tubing system and a scanning device. The aerodynamic forces and moments are obtained by integration of the pressure and shear stress distributions. The wing span of the model is equal to the width of the test section.Due to the large wing span B = 2500 mm and the testing speed V = 90 m/s, the aerodynamic forces and moments occurring on the model exceed more than two times the measuring capacity of the TEM external balance of the INCAS Subsonic wind tunnel. This imposes attaching the model to supports situated outside the wind tunnel.

  6. A New Structural Design Concept for Blended Wing Body Cabins

    NARCIS (Netherlands)

    Vos, R.; Geuskens, F.J.J.M.M.; Hoogreef, M.F.M.

    2012-01-01

    This paper outlines a new concept for a pressure cabin design for blended-wing-body aircraft. An overview is presented of the wide oval cabin and why it is believed to be a possible alternative to existing designs of non-circular pressurized cabins. The perimeter of the oval cross section is formed

  7. Rotational accelerations stabilize leading edge vortices on revolving fly wings

    NARCIS (Netherlands)

    Lentink, D.; Dickinson, M.H.

    2009-01-01

    The aerodynamic performance of hovering insects is largely explained by the presence of a stably attached leading edge vortex (LEV) on top of their wings. Although LEVs have been visualized on real, physically modeled, and simulated insects, the physical mechanisms responsible for their stability ar

  8. Biofluiddynamic scaling of flapping, spinning and translating fins and wings

    NARCIS (Netherlands)

    Lentink, D.; Dickinson, M.H.

    2009-01-01

    Organisms that swim or fly with fins or wings physically interact with the surrounding water and air. The interactions are governed by the morphology and kinematics of the locomotory system that form boundary conditions to the Navier–Stokes (NS) equations. These equations represent Newton's law of m

  9. Relapsing and remitting scapular winging in a pediatric patient.

    Science.gov (United States)

    Scott, David A; Alexander, James R

    2010-06-01

    Scapular winging (scapula alata) is a condition in which the scapula is rotated or displaced away from the body. The nature of this rotation or displacement can vary depending on the origin. There are many different causes of scapular winging including neurogenic, structural, muscular, and bursal (Frontera, Silver, Essentials of Physical Medicine and Rehabilitation. Philadelphia, Hanley and Belfus, 2002, pp 99-102). Structural causes are not frequently at the top of a clinician's differential diagnosis, but they must always be considered. We review the case of a teenage boy who developed intermittent scapular winging after tackling his brother in a backyard football game. His symptoms resolved and recurred over a period of 9 mos. Approximately 1 yr after the initial episode of winging, during a recurrence of his symptoms, a repeat shoulder x-ray was ordered. This study revealed a previously undetected osteochondroma. The patient subsequently underwent resection of the inferior angle of his right scapula and had complete resolution of his symptoms. PMID:20357648

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

    Science.gov (United States)

    Mukhopadhyay, Vivek

    1995-01-01

    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.

  11. Flow visualization of swept wing boundary layer transition

    NARCIS (Netherlands)

    Serpieri, J.; Kotsonis, M.

    2015-01-01

    In this work the flow visualization of the transition pattern occurring on a swept wing in a subsonic flow is presented. This is done by means of fluorescent oil flow technique and boundary layer hot-wire scans. The experiment was performed at Reynolds number of 2:15 . 106 and at angle of attack of

  12. FIRST `Winged' and `X'-shaped Radio Source Candidates

    CERN Document Server

    Cheung, C C

    2008-01-01

    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 ...

  13. Design of a new tandem wings hybrid airship

    Science.gov (United States)

    Li, Feng; Ye, ZhengYin; Gao, Chao

    2012-10-01

    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.

  14. Determination of trim curves for a flapping-wing MAV

    NARCIS (Netherlands)

    Armanini, S.F.; Verboom, J.L.; De Croon, G.C.H.E.; De Visser, C.C.

    2014-01-01

    This paper presents the results of a series of flight tests conducted in order to assess the steady-state flight characteristics and basic control behaviour of the DelFly, a flapping-wing micro aerial vehicle (FWMAV). Flights were conducted in an indoor motion tracking facility and included steady-l

  15. Numerical Characterization of a Composite Bonded Wing-Box

    Science.gov (United States)

    Smeltzer, Stanley S., III; Lovejoy, Andrew E.; Satyanarayana, Arunkumar

    2008-01-01

    The development of composite wing structures has focused on the use of mechanical fasteners to join heavily-loaded areas, while bonded joints have been used only for select locations. The focus of this paper is the examination of the adhesive layer in a generic bonded wing box that represents a "fastenerless" or unitized structure in order to characterize the general behavior and failure mechanisms. A global/local approach was applied to study the response of the adhesive layer using a global shell model and a local shell/solid model. The wing box was analyzed under load to represent a high-g up-bending condition such that the strains in the composite sandwich face sheets are comparable to an expected design allowable. The global/local analysis indicates that at these wing load levels the strains in the adhesive layer are well within the adhesive's elastic region, such that yielding would not be expected in the adhesive layer. The global/local methodology appears to be a promising approach to evaluate the structural integrity of the adhesively bonded structures.

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

    Science.gov (United States)

    Kruyt, Jan W; van Heijst, GertJan F; Altshuler, Douglas L; Lentink, David

    2015-04-01

    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 of attack without stalling. Instead, they generate an attached vortex along the leading edge of the wing that elevates lift. Previous studies have demonstrated that this vortex and high lift can be reproduced by revolving the animal wing at the same angle of attack. How do flapping and revolving animal wings delay stall and reduce power? It has been hypothesized that stall delay derives from having a short radial distance between the shoulder joint and wing tip, measured in chord lengths. This non-dimensional measure of wing length represents the relative magnitude of inertial forces versus rotational accelerations operating in the boundary layer of revolving and flapping wings. Here we show for a suite of aspect ratios, which represent both animal and aircraft wings, that the attachment of the leading edge vortex on a revolving wing is determined by wing aspect ratio, defined with respect to the centre of revolution. At high angle of attack, the vortex remains attached when the local radius is shorter than four chord lengths and separates outboard on higher aspect ratio wings. This radial stall limit explains why revolving high aspect ratio wings (of helicopters) require less power compared with low aspect ratio wings (of hummingbirds) at low angle of attack and vice versa at high angle of attack. PMID:25788539

  17. Shape optimisation and performance analysis of flapping wings

    KAUST Repository

    Ghommem, Mehdi

    2012-09-04

    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

  18. Aerodynamic Classification of Swept-Wing Ice Accretion

    Science.gov (United States)

    Diebold, Jeff M.; Broeren, Andy P.; Bragg, Michael B.

    2013-01-01

    The continued design, certification and safe operation of swept-wing airplanes in icing conditions rely on the advancement of computational and experimental simulation methods for higher fidelity results over an increasing range of aircraft configurations and performance, and icing conditions. The current stateof- the-art in icing aerodynamics is mainly built upon a comprehensive understanding of two-dimensional geometries that does not currently exist for fundamentally three-dimensional geometries such as swept wings. The purpose of this report is to describe what is known of iced-swept-wing aerodynamics and to identify the type of research that is required to improve the current understanding. Following the method used in a previous review of iced-airfoil aerodynamics, this report proposes a classification of swept-wing ice accretion into four groups based upon unique flowfield attributes. These four groups are: ice roughness, horn ice, streamwise ice and spanwise-ridge ice. In the case of horn ice it is shown that a further subclassification of "nominally 3D" or "highly 3D" horn ice may be necessary. For all of the proposed ice-shape classifications, relatively little is known about the three-dimensional flowfield and even less about the effect of Reynolds number and Mach number on these flowfields. The classifications and supporting data presented in this report can serve as a starting point as new research explores swept-wing aerodynamics with ice shapes. As further results are available, it is expected that these classifications will need to be updated and revised.

  19. A study on the utilization of advanced composites in commercial aircraft wing structure: Executive summary

    Science.gov (United States)

    Watts, D. J.

    1978-01-01

    The overall wing study objectives are to study and plan the effort by commercial transport aircraft manufacturers to accomplish the transition from current conventional materials and practices to extensive use of advanced composites in wings of aircraft that will enter service in the 1985-1990 time period. Specific wing study objectives are to define the technology and data needed to support an aircraft manufacturer's commitment to utilize composites primary wing structure in future production aircraft and to develop plans for a composite wing technology program which will provide the needed technology and data.

  20. Simulation of Flapping-wing Unmanned Aerial Vehicle using X-plane and Matlab/Simulink

    OpenAIRE

    A. Kaviyarasu; K. Senthil Kumar

    2014-01-01

    This paper presents the simulation of flapping-wing unmanned aerial vehicle model using X-plane and Matlab/ Simulink. The flapping-wing ornithopter model (i.e. an aircraft that flies by flapping its wings) has been developed in plane maker software and executed in the X-plane environment. The key idea of flapping-wing mechanism in X-plane software is by varying its dihedral angle sinusoidally. This sinusoidally varying dihedral angle of wing creates upward and downward stroke moments inturn t...

  1. Design and fabrication of insect-inspired composite wings for MAV application using MEMS technology

    International Nuclear Information System (INIS)

    Insect wings consist of supporting veins and flexible membranes using fibrous composite material. This paper describes a method of wing design and fabrication based on composite, mimicking insect wings through advanced microelectromechanical system (MEMS) technology. SU-8 'fiber' reinforced polydimethylsiloxane (PDMS) membrane forms a fine structure, approaching real wings not only in material conception but also in mechanical performance. Based on a design in its initial stage, a new process was developed integrating all steps into a single procedure. We use a tailored AZ 4562 resist layer as the mold for PDMS wing membrane structuring. A 20 nm hydrophilic oxide layer was grown on the substrate to solve the final lift-off problems which become more severe when the wing membrane gets thinner. The vein thickness can be controlled with high precision by the spin-coating technique. The thickness of artificial membrane can be thinned down to a few microns, thus emulating those of some insects. Our process is compatible with common MEMS technology, and eligible to produce artificial wings of complex geometry and morphology mimicking natural insect wings. Our conclusion is that natural wings can be well mimicked in material conception, weight, venation, size, mass distribution and wing rigidity using hybrid materials. We also show that even using exceedingly compliant material as one composition, composite airfoils can be as light and stiff as insect wings, thereby highlighting the merit of smart material hybridization.

  2. Measured and predicted structural behavior of the HiMAT tailored composite wing

    Science.gov (United States)

    Nelson, Lawrence H.

    1987-01-01

    A series of load tests was conducted on the HiMAT tailored composite wing. Coupon tests were also run on a series of unbalanced laminates, including the ply configuration of the wing, the purpose of which was to compare the measured and predicted behavior of unbalanced laminates, including - in the case of the wing - a comparison between the behavior of the full scale structure and coupon tests. Both linear and nonlinear finite element (NASTRAN) analyses were carried out on the wing. Both linear and nonlinear point-stress analyses were performed on the coupons. All test articles were instrumented with strain gages, and wing deflections measured. The leading and trailing edges were found to have no effect on the response of the wing to applied loads. A decrease in the stiffness of the wing box was evident over the 27-test program. The measured load-strain behavior of the wing was found to be linear, in contrast to coupon tests of the same laminate, which were nonlinear. A linear NASTRAN analysis of the wing generally correlated more favorably with measurements than did a nonlinear analysis. An examination of the predicted deflections in the wing root region revealed an anomalous behavior of the structural model that cannot be explained. Both hysteresis and creep appear to be less significant in the wing tests than in the corresponding laminate coupon tests.

  3. Piezoelectric energy harvesting from morphing wing motions for micro air vehicles

    KAUST Repository

    Abdelkefi, Abdessattar

    2013-09-10

    Wing flapping and morphing can be very beneficial to managing the weight of micro air vehicles through coupling the aerodynamic forces with stability and control. In this letter, harvesting energy from the wing morphing is studied to power cameras, sensors, or communication devices of micro air vehicles and to aid in the management of their power. The aerodynamic loads on flapping wings are simulated using a three-dimensional unsteady vortex lattice method. Active wing shape morphing is considered to enhance the performance of the flapping motion. A gradient-based optimization algorithm is used to pinpoint the optimal kinematics maximizing the propellent efficiency. To benefit from the wing deformation, we place piezoelectric layers near the wing roots. Gauss law is used to estimate the electrical harvested power. We demonstrate that enough power can be generated to operate a camera. Numerical analysis shows the feasibility of exploiting wing morphing to harvest energy and improving the design and performance of micro air vehicles.

  4. Efficient passive pitching motion caused by elastic deformation in flexible flapping wing MAVs

    Science.gov (United States)

    Nguyen, Trong; Truong, Tien; Yeo, Khoon Seng; Lim, Tee Tai

    2015-11-01

    Computational and experimental models which mimic Hawkmoth wings were constructed to investigate the effects of wing flexibility. The wing actuation mechanism is minimal with only one degree of freedom in sweeping motion with neither active pitching nor elevation. Despite the simplicity of the imparted motion, the wing models in both computations and experiments delivered convincing deformation features such as wing twisting and camber which closely resembles the ones observed in real Hawkmoth wings. The generated aerodynamic forces are remarkable both in magnitude and efficiency. The study hence reveals that a complicated actuation mechanism might not be required to produce the sophisticated and efficient motion of insect wings, which in fact could be the result of collective elastic deformation thanks to their highly optimized structure mainly comprised of well-organized veins and membranes.

  5. Multi-objective Aerodynamic Design Optimization of a Flying Wing usin g Su rrogate Model%基于代理模型的飞翼多目标气动优化设计

    Institute of Scientific and Technical Information of China (English)

    刘俊; 宋文萍; 韩忠华

    2015-01-01

    A multi-point and multi-objective aerodynamic design optimization which simultaneously con-sidering the taking-offperformance and cruise performance of a flying wing is studied in this research .In the optimization procedure ,the flow around the wing is simulated using the RANS solver; the planform shape ,section shapes ,and twist angle of section shapes are taken as design variables ,which results in 58 design variables in total;maximizing the lift coefficient at taking-off condition and the lift-to-drag ratio at cruise condition are taken as the two objectives ,while the moment coefficients at the two operating con-ditions are taken as constraints ,and the planform area as well as the thickness of sections are also taken as constraints.Although there are a large number of design variables ,a good Pareto optimal front is ob-tained with a small number of candidate design evaluationby the use of surrogate model and a sequential updating strategy .The performance of a shape arbitrarily selected from the Pareto front is checked and compared with the baseline ,it shows that the optimized shape outperforms the baseline at the concerned conditions with all the constraints fulfilled .%针对飞翼布局飞行器,采用雷诺平均N-S方程( RANS)计算流场,使用基于代理模型的多目标优化方法进行了同时考虑起飞性能和巡航性能的多点多目标气动优化设计。在设计过程中,将飞翼的平面形状、剖面形状及扭转角同时作为设计变量(共58个设计变量),将提高起飞时的升力系数和提高巡航升阻比为设计目标,以起飞状态和巡航状态的力矩系数作为气动约束,并以飞翼平面面积不减和剖面厚度不减作为几何约束。通过采用基于Kriging模型的多目标优化方法,以较小的计算花费得到了较好的Perato前沿。取Pareto前沿中一个最优解与基准外形的性能进行了对比,结果显示,优化外形的性能较基准外形

  6. Force measurements of flexible tandem wings in hovering and forward flights

    International Nuclear Information System (INIS)

    Aerodynamic forces, power consumptions and efficiencies of flexible and rigid tandem wings undergoing combined plunging/pitching motion were measured in a hovering flight and two forward flights with Strouhal numbers of 0.6 and 0.3. Three flexible dragonfly-like tandem wing models termed Wing I, Wing II, and Wing III which are progressively less flexible, as well as a pair of rigid wings as the reference were operated at three phase differences of 0°, 90° and 180°. The results showed that both the flexibility and phase difference have significant effects on the aerodynamic performances. In both hovering and forward flights at a higher oscillation frequency of 1 Hz (St = 0.6), the Wing III model outperformed the other wing models with larger total horizontal force coefficient and efficiency. In forward flight at the lower frequency of 0.5 Hz (St = 0.3), Wing III, rigid wings and Wing II models performed best at 0°, 90° and 180° phase difference, respectively. From the time histories of force coefficients of fore- and hind-wings, different peak values, phase lags, and secondary peaks were found to be the important reasons to cause the differences in the average horizontal force coefficients. Particle image velocimetry and deformation measurements were performed to provide the insights into how the flexibility affects the aerodynamic performance of the tandem wings. The spanwise bending deformation was found to contribute to the horizontal force, by offering a more beneficial position to make LEV more attached to the wing model in both hovering and forward flights, and inducing a higher-velocity region in forward flight. (paper)

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

    Institute of Scientific and Technical Information of China (English)

    X. Q. Bao; E. Cattan

    2011-01-01

    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.

  8. Insights into insect wing origin provided by functional analysis of vestigial in the red flour beetle, Tribolium castaneum

    OpenAIRE

    Clark-Hachtel, Courtney M.; Linz, David M.; Tomoyasu, Yoshinori

    2013-01-01

    Insect wings are a core example of morphological novelty, yet their acquisition remains a biological conundrum. More than a century of debates and observations has culminated in two prominent hypotheses on the origin of insect wings. Here, we show that there are two separate wing serial homologs in the wingless first thoracic segment of a beetle, Tribolium. These two tissues are merged to form an ectopic wing structure in homeotic transformation. Intriguingly, the two wing serial homologs may...

  9. Pretreated Butterfly Wings for Tuning the Selective Vapor Sensing.

    Science.gov (United States)

    Piszter, Gábor; Kertész, Krisztián; Bálint, Zsolt; Biró, László Péter

    2016-01-01

    Photonic nanoarchitectures occurring in the scales of Blue butterflies are responsible for their vivid blue wing coloration. These nanoarchitectures are quasi-ordered nanocomposites which are constituted from a chitin matrix with embedded air holes. Therefore, they can act as chemically selective sensors due to their color changes when mixing volatile vapors in the surrounding atmosphere which condensate into the nanoarchitecture through capillary condensation. Using a home-built vapor-mixing setup, the spectral changes caused by the different air + vapor mixtures were efficiently characterized. It was found that the spectral shift is vapor-specific and proportional with the vapor concentration. We showed that the conformal modification of the scale surface by atomic layer deposition and by ethanol pretreatment can significantly alter the optical response and chemical selectivity, which points the way to the efficient production of sensor arrays based on the knowledge obtained through the investigation of modified butterfly wings. PMID:27618045

  10. Tailoring of composite wing structures for elastically produced camber deformations

    Science.gov (United States)

    Rehfield, Lawrence W.; Chang, Stephen; Zischka, Peter J.; Pickings, Richard D.; Holl, Michael W.

    1991-01-01

    Structural concepts have been created which produce chordwise camber deformation that results in enhanced lift. A wing box can be tailored to utilize these concepts with composites. In attempting to optimize the aerodynamic benefits, it is found that there are two optimum designs that are of interest. There is a 'weight' optimum which corresponds to the maximum lift per unit structural weight. There is also a 'lift' optimum that corresponds to maximum absolute lift. Experience indicates that a large weight penalty accompanies the transition from weight to lift optimum designs. New structural models, the basic deformation mechanisms that are utilized and typical analytical results are presented. It appears that lift enhancements of sufficient magnitude can be produced to render this type of wing tailoring of practical interest.

  11. Hypersonic wing test structure design, analysis, and fabrication

    Science.gov (United States)

    Plank, P. P.; Penning, F. A.

    1973-01-01

    An investigation to provide the analyses, data, and hardware required to experimentally validate the beaded panel concept and demonstrate its usefulness as a basis for design of a Hypersonic Research Airplane (HRA) wing is reported. Combinations of the beaded panel structure, heat shields, channel caps and corrugated webs for ribs and spars were analyzed for the wing of a specified HRA to operate at Mach 8 with a lifespan of 150 flights. Detailed analyses were conducted in accordance with established design criteria and included aerodynamic heating and load predictions, transient structural thermal calculations, extensive NASTRAN computer modeling, and structural optimization. Optimum beaded panel tests at 922 K (1200 F) were performed to verify panel performance. Close agreement of predicted and actual critical loads permitted use of design procedures and equations for the beaded panel concept without modification.

  12. Probabilistic Structural Health Monitoring of the Orbiter Wing Leading Edge

    Science.gov (United States)

    Yap, Keng C.; Macias, Jesus; Kaouk, Mohamed; Gafka, Tammy L.; Kerr, Justin H.

    2011-01-01

    A structural health monitoring (SHM) system can contribute to the risk management of a structure operating under hazardous conditions. An example is the Wing Leading Edge Impact Detection System (WLEIDS) that monitors the debris hazards to the Space Shuttle Orbiter s Reinforced Carbon-Carbon (RCC) panels. Since Return-to-Flight (RTF) after the Columbia accident, WLEIDS was developed and subsequently deployed on board the Orbiter to detect ascent and on-orbit debris impacts, so as to support the assessment of wing leading edge structural integrity prior to Orbiter re-entry. As SHM is inherently an inverse problem, the analyses involved, including those performed for WLEIDS, tend to be associated with significant uncertainty. The use of probabilistic approaches to handle the uncertainty has resulted in the successful implementation of many development and application milestones.

  13. Relaxation techniques for three-dimensional transonic flow about wings.

    Science.gov (United States)

    Bailey, F. R.; Steger, J. L.

    1972-01-01

    A relaxation procedure has been developed to treat the three-dimensional, transonic small perturbation equations about finite lifting wings. A combination of two schemes is employed. For flow forward of the wing trailing edge the equations are written in terms of a velocity potential in order to minimize computer algebra and storage. For the remaining flow field the equations are written in terms of the velocity components in order to simplify the enforcement of the Kutta condition. Difference equations and relaxation procedures are described for both schemes. The computational method automatically captures the imbedded shock wave in the three-dimensional flow field. Computed results are given and compared to experiment and other inviscid methods.

  14. Waste Assessment Baseline for the IPOC Second Floor, West Wing

    Energy Technology Data Exchange (ETDEWEB)

    McCord, Samuel A [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Waste Management and Pollution Prevention

    2015-04-01

    Following a building-wide waste assessment in September, 2014, and subsequent presentation to Sandia leadership regarding the goal of Zero Waste by 2025, the occupants of the IPOC Second Floor, West Wing contacted the Materials Sustainability and Pollution Prevention (MSP2) team to guide them to Zero Waste in advance of the rest of the site. The occupants are from Center 3600, Public Relations and Communications , and Center 800, Independent Audit, Ethics and Business Conduct . To accomplish this, MSP2 conducted a new limited waste assessment from March 2-6, 2015 to compare the second floor, west wing to the building as a whole. The assessment also serves as a baseline with which to mark improvements in diversion in approximately 6 months.

  15. Modern wing flutter analysis by computational fluid dynamics methods

    Science.gov (United States)

    Cunningham, Herbert J.; Batina, John T.; Bennett, Robert M.

    1988-01-01

    The application and assessment of the recently developed CAP-TSD transonic small-disturbance code for flutter prediction is described. The CAP-TSD code has been developed for aeroelastic analysis of complete aircraft configurations and was previously applied to the calculation of steady and unsteady pressures with favorable results. Generalized aerodynamic forces and flutter characteristics are calculated and compared with linear theory results and with experimental data for a 45 deg sweptback wing. These results are in good agreement with the experimental flutter data which is the first step toward validating CAP-TSD for general transonic aeroelastic applications. The paper presents these results and comparisons along with general remarks regarding modern wing flutter analysis by computational fluid dynamics methods.

  16. Structural colors from Morpho peleides butterfly wing scales

    KAUST Repository

    Ding, Yong

    2009-01-01

    A male Morpho peleides butterfly wing is decorated by two types of scales, cover and ground scales. We have studied the optical properties of each type of scales in conjunction with the structural information provided by cross-sectional transmission electron microscopy and computer simulation. The shining blue color is mainly from the Bragg reflection of the one-dimensional photonic structure, e.g., the shelf structure packed regularly in each ridges on cover scales. A thin-film-like interference effect from the base plate of the cover scale enhances such blue color and further gives extra reflection peaks in the infrared and ultraviolet regions. The analogy in the spectra acquired from the original wing and that from the cover scales suggests that the cover scales take a dominant role in its structural color. This study provides insight of using the biotemplates for fabricating smart photonic structures. © 2009 American Institute of Physics.

  17. Structural Weight Optimization of Aircraft Wing Component Using FEM Approach.

    Directory of Open Access Journals (Sweden)

    Arockia Ruban M,

    2015-06-01

    Full Text Available One of the main challenges for the civil aviation industry is the reduction of its environmental impact by better fuel efficiency by virtue of Structural optimization. Over the past years, improvements in performance and fuel efficiency have been achieved by simplifying the design of the structural components and usage of composite materials to reduce the overall weight of the structure. This paper deals with the weight optimization of transport aircraft with low wing configuration. The Linear static and Normal Mode analysis were carried out using MSc Nastran & Msc Patran under different pressure conditions and the results were verified with the help of classical approach. The Stress and displacement results were found and verified and hence arrived to the conclusion about the optimization of the wing structure.

  18. Flying with Abrupt Wing Flapping: Damselfly in Darting Flight

    CERN Document Server

    Li, Chengyu; Zhang, Wen

    2013-01-01

    Damselflies show abrupt, darting flight, which is the envy of aero-engineers. This amazing ability is used both to capture prey and, by males, to establish territories that can attract females. In this work, high-resolution, high-speed videos of a damselfly (Hetaerina Americana) in darting flight were obtained using a photogrammetry system. Using a 3D subdivision surface reconstruction methodology, the damselfly's wing deformation and kinematics were modeled and reconstructed from those videos. High fidelity simulations were then carried out in order to understand vortex formation in both near-field and far-field of damselfly wings and examine the associated aerodynamic performance. A Cartesian grid based sharp interface immersed boundary solver was used to handle such flows in all their complexity.

  19. Wing shape variation among central Asian populations of Calopteryx splendens

    Directory of Open Access Journals (Sweden)

    Saber Sadeghi

    2015-07-01

    Full Text Available We applied geometric morphometric techniques to explore the morphological variation of forewings between 10 Asian Calopteryx splendens populations including Azerbaijan, Russia, Turkey, Uzbekistan, Iran, Turkmenistan, Tajikistan, Kazakhstan, and Kyrgyzstan countries. We focused on the study of the phenetic relationships among the populations in central Asia. The results showed that the northern and western populations of Iran had the largest and smallest centroid size of the wings, respectively. In addition, differences among wing shape of the 10 studied populations of C. splendens were significant. Our results indicated that Tajikistan population has quite distinct divergence and also Turkmenistan and northern part of Iran populations both were very close each other and located in a separate clade. The Azerbaijan, Russia, Turkey, Uzbekistan, west Iran, Kazakhstan and Kyrgyzstan populations were revealed to be more interrelated to each other, although Kazakhstan and Kyrgyzstan populations seems to be more closer than the other.

  20. Design Optimization of a Micro Air Vehicle (MAV Fixed Wing

    Directory of Open Access Journals (Sweden)

    D.V.A. Rama Sastry

    2015-05-01

    Full Text Available Air vehicles are gaining attention due to their wide range of applications in civilian and defense fields. The wings of these vehicles generate a particular flow regime which is to be explored further. Since the theories on the aerodynamics of all affects are still to be investigated, simulation based computational fluid dynamics is a good approach rather than wind tunnel experiments which involves cost and long periods of experimentation. This study mainly emphasize on the lift, lift coefficient, drag and drag coefficient with respect to Reynold’s number and angle of attack, by modelling and analyzing the fixed wing of a micro air vehicle. The analysis has been done selecting NACA25411 air foil. Modelling has been done in Gambit and analysis is taken up using Fluent. Angle of attack and Reynold’s number have been optimized to increase the lift and decrease the drag.

  1. Blue-winged teals in the waters around KSC

    Science.gov (United States)

    1999-01-01

    The furious beating wings of a blue-winged teal launch it from the water as another swims calmly beneath it in the Merritt Island National Wildlife Refuge, which shares a boundary with Kennedy Space Center. Inhabiting marshes, shallow ponds and lakes from British Columbia, Quebec and Newfoundland to North Carolina, the Gulf Coast and southern California, the teal winters as far south as South America. The 92,000-acre refuge is a habitat for more than 310 species of birds, 25 mammals, 117 fishes and 65 amphibians and reptiles. The marshes and open water of the refuge also provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds.

  2. Natural Laminar Flow Design for Wings with Moderate Sweep

    Science.gov (United States)

    Campbell, Richard L.; Lynde, Michelle N.

    2016-01-01

    A new method for the aerodynamic design of wings with natural laminar flow is under development at the NASA Langley Research Center. The approach involves the addition of new flow constraints to an existing knowledge-based design module for use with advanced flow solvers. The uniqueness of the new approach lies in the tailoring of target pressure distributions to achieve laminar flow on transonic wings with leading-edge sweeps and Reynolds numbers typical of current transports. The method is demonstrated on the Common Research Model configuration at critical N-factor levels representative of both flight and high-Reynolds number wind tunnel turbulence levels. The design results for the flight conditions matched the target extent of laminar flow very well. The design at wind tunnel conditions raised some design issues that prompted further improvements in the method, but overall has given promising results.

  3. Mummified precocial bird wings in mid-Cretaceous Burmese amber.

    Science.gov (United States)

    Xing, Lida; McKellar, Ryan C; Wang, Min; Bai, Ming; O'Connor, Jingmai K; Benton, Michael J; Zhang, Jianping; Wang, Yan; Tseng, Kuowei; Lockley, Martin G; Li, Gang; Zhang, Weiwei; Xu, Xing

    2016-01-01

    Our knowledge of Cretaceous plumage is limited by the fossil record itself: compression fossils surrounding skeletons lack the finest morphological details and seldom preserve visible traces of colour, while discoveries in amber have been disassociated from their source animals. Here we report the osteology, plumage and pterylosis of two exceptionally preserved theropod wings from Burmese amber, with vestiges of soft tissues. The extremely small size and osteological development of the wings, combined with their digit proportions, strongly suggests that the remains represent precocial hatchlings of enantiornithine birds. These specimens demonstrate that the plumage types associated with modern birds were present within single individuals of Enantiornithes by the Cenomanian (99 million years ago), providing insights into plumage arrangement and microstructure alongside immature skeletal remains. This finding brings new detail to our understanding of infrequently preserved juveniles, including the first concrete examples of follicles, feather tracts and apteria in Cretaceous avialans. PMID:27352215

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

    Directory of Open Access Journals (Sweden)

    WakkasAli Rasheed, NabeelAbdulhadiGhyadh, Sahib Shihab Ahmed

    2016-01-01

    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.

  5. Theoretical analysis of an augmentor wing for a VTOL fighter

    Science.gov (United States)

    Dillenius, M. F. E.; Mendenhall, M. R.

    1979-01-01

    A method based on potential flow theory was developed for predicting forces and moments acting on augmentor wings for prescribed ejector jet characteristics. A three dimensional nonplanar vortex lattice is laid out on the chordal planes of the augmentor wing components. Jet induced effects are included in the boundary condition from which the horseshoe vortex strengths are obtained. The jet within the diffusor is made to expand from the primary nozzles to the diffusor exit and is represented by a distribution of vorticity on the jet boundary to provide proper entrainment. The jet downstream of the diffusor exit is modeled by a vorticity distribution and blockage panels and its centerline location and spreading rate are taken from experimental data. The vortex lattice and jet models are used in an iterative manner until the predicted diffusor exit velocity matches the specified one. Some comparisons with available data show good agreement at lower power settings.

  6. Pretreated Butterfly Wings for Tuning the Selective Vapor Sensing

    Science.gov (United States)

    Piszter, Gábor; Kertész, Krisztián; Bálint, Zsolt; Biró, László Péter

    2016-01-01

    Photonic nanoarchitectures occurring in the scales of Blue butterflies are responsible for their vivid blue wing coloration. These nanoarchitectures are quasi-ordered nanocomposites which are constituted from a chitin matrix with embedded air holes. Therefore, they can act as chemically selective sensors due to their color changes when mixing volatile vapors in the surrounding atmosphere which condensate into the nanoarchitecture through capillary condensation. Using a home-built vapor-mixing setup, the spectral changes caused by the different air + vapor mixtures were efficiently characterized. It was found that the spectral shift is vapor-specific and proportional with the vapor concentration. We showed that the conformal modification of the scale surface by atomic layer deposition and by ethanol pretreatment can significantly alter the optical response and chemical selectivity, which points the way to the efficient production of sensor arrays based on the knowledge obtained through the investigation of modified butterfly wings. PMID:27618045

  7. Pretreated Butterfly Wings for Tuning the Selective Vapor Sensing

    Directory of Open Access Journals (Sweden)

    Gábor Piszter

    2016-09-01

    Full Text Available Photonic nanoarchitectures occurring in the scales of Blue butterflies are responsible for their vivid blue wing coloration. These nanoarchitectures are quasi-ordered nanocomposites which are constituted from a chitin matrix with embedded air holes. Therefore, they can act as chemically selective sensors due to their color changes when mixing volatile vapors in the surrounding atmosphere which condensate into the nanoarchitecture through capillary condensation. Using a home-built vapor-mixing setup, the spectral changes caused by the different air + vapor mixtures were efficiently characterized. It was found that the spectral shift is vapor-specific and proportional with the vapor concentration. We showed that the conformal modification of the scale surface by atomic layer deposition and by ethanol pretreatment can significantly alter the optical response and chemical selectivity, which points the way to the efficient production of sensor arrays based on the knowledge obtained through the investigation of modified butterfly wings.

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

    Science.gov (United States)

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

    2016-03-01

    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.

  9. Insect-inspired wing actuation structures based on ring-type resonators

    Science.gov (United States)

    Bolsman, Caspar T.; Goosen, Johannes F. L.; van Keulen, Fred

    2008-03-01

    In this paper, we illustrate and study the opportunities of resonant ring type structures as wing actuation mechanisms for a flapping wing Micro Air Vehicle (MAV). Various design alternatives are presented and studied based on computational and physical models. Insects provide an excellent source of inspiration for the development of the wing actuation mechanisms for flapping wing MAVs. The insect thorax is a structure which in essence provides a mechanism to couple the wing muscles to the wings while offering weight reduction through application of resonance, using tailored elasticity. The resonant properties of the thorax are a very effective way to reducing the power expenditure of wing movement. The wing movement itself is fairly complex and is guided by a set of control muscles and thoracic structures which are present in proximity of the wing root. The development of flapping wing MAVs requires a move away from classical structures and actuators. The use of gears and rotational electric motors is hard to justify at the small scale. Resonant structures provide a large design freedom whilst also providing various options for actuation. The move away from deterministic mechanisms offers possibilities for mass reduction.

  10. Analysis of Kinematics of Flapping Wing UAV Using OptiTrack Systems

    Directory of Open Access Journals (Sweden)

    Matthew Ng Rongfa

    2016-07-01

    Full Text Available An analysis of the kinematics of a flapping membrane wing using experimental kinematic data is presented. This motion capture technique tracks the positon of the retroreflective marker(s placed on the left wing of a 1.3-m-wingspan ornithopter. The time-varying three-dimensional data of the wing kinematics were recorded for a single frequency. The wing shape data was then plotted on a two-dimensional plane to understand the wing dynamic behaviour of an ornithopter. Specifically, the wing tip path, leading edge bending, wing membrane shape, local twist, stroke angle and wing velocity were analyzed. As the three characteristic angles can be expressed in the Fourier series as a function of time, the kinematics of the wing can be computationally generated for the aerodynamic study of flapping flight through the Fourier coefficients presented. Analysis of the ornithopter wing showed how the ornithopter closely mimics the flight motions of birds despite several physical limitations.

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

    Directory of Open Access Journals (Sweden)

    Genç Mustafa Serdar

    2016-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  13. Identification of Bombus species based on wing venation structure

    OpenAIRE

    Kozmus, Peter; Virant-Doberlet, Meta; Meglič, Vladimir; Dovč, Peter

    2011-01-01

    International audience About 250 bumblebee species in 15 subgenera are known in the world. Identification of some species is difficult due to small morphological differences. In this study, wing venation patterns were analysed to obtain characters for species identification. Four hundred and sixty-nine bumblebees from 121 localities in Slovenia and 61 imported individuals were included in the analyses. The coordinates of 19 vein junctions on the forewings were measured and used in the calc...

  14. Out of the Blue NATO SOF Air Wing

    OpenAIRE

    Jett, Andrew M.

    2012-01-01

    Approved for public release; distribution is unlimited There is a critical shortfall in dedicated special operations aviation support for the North Atlantic Treaty Organizations (NATO) special operations forces (SOF). One way this shortfall can be addressed is through the procurement and sustainment of an organic NATO SOF Air Wing. In 2006, NATOs Heads of State and Governments endorsed the NATO Special Operations Forces Transformation Initiative, creating what would eventually become the N...

  15. Gyroid cuticular structures in butterfly wing scales: biological photonic crystals

    OpenAIRE

    Michielsen, K.; Stavenga, D.G.

    2007-01-01

    We present a systematic study of the cuticular structure in the butterfly wing scales of some papilionids (Parides sesostris and Teinopalpus imperialis) and lycaenids (Callophrys rubi, Cyanophrys remus, Mitoura gryneus and Callophrys dumetorum). Using published scanning and transmission electron microscopy (TEM) images, analytical modelling and computer-generated TEM micrographs, we find that the three-dimensional cuticular structures can be modelled by gyroid structures with various filling ...

  16. Thermal analysis of a hypersonic wing test structure

    Science.gov (United States)

    Sandlin, Doral R.; Swanson, Neil J., Jr.

    1989-01-01

    The three-dimensional finite element modeling techniques developed for the thermal analysis of a hypersonic wing test structure (HWTS) are described. The computed results are compared to measured test data. In addition, the results of a NASA two-dimensional parameter finite difference local thermal model and the results of a contractor two-dimensional lumped parameter finite difference local thermal model will be presented.

  17. The genomewide transcriptional response underlying the pea aphid wing polyphenism.

    Science.gov (United States)

    Vellichirammal, Neetha N; Madayiputhiya, Nandakumar; Brisson, Jennifer A

    2016-09-01

    Phenotypic plasticity is a key life history strategy used by many plants and animals living in heterogeneous environments. A multitude of studies have investigated the costs and limits of plasticity, as well as the conditions under which it evolves. Much less well understood are the molecular genetic mechanisms that enable an organism to sense its environment and respond in a plastic manner. The pea aphid wing polyphenism is a compelling laboratory model to study these mechanisms. In this polyphenism, environmental stressors like high density cause asexual, viviparous adult female aphids to change the development of their embryos from wingless to winged morphs. The life history trade-offs between the two morphs have been intensively studied, but the molecular mechanisms underlying this process remain largely unknown. We therefore performed a genomewide study of the maternal transcriptome at two time points with and without a crowding stress to discover the maternal molecular changes that lead to the development of winged vs. wingless offspring. We observed significant transcriptional changes in genes associated with odorant binding, neurotransmitter transport, hormonal activity and chromatin remodelling in the maternal transcriptome. We also found that titres of serotonin, dopamine and octopamine were higher in solitary compared to crowded aphids. We use these results to posit a model for how maternal signals inform a developing embryo to be winged or wingless. Our findings add significant insights into the identity of the molecular mechanisms that underlie environmentally induced morph determination and suggest a possible role for biogenic amine regulation in polyphenisms generally. PMID:27393739

  18. Wing motion measurement and aerodynamics of hovering true hoverflies.

    Science.gov (United States)

    Mou, Xiao Lei; Liu, Yan Peng; Sun, Mao

    2011-09-01

    Most hovering insects flap their wings in a horizontal plane (body having a large angle from the horizontal), called `normal hovering'. But some of the best hoverers, e.g. true hoverflies, hover with an inclined stroke plane (body being approximately horizontal). In the present paper, wing and body kinematics of four freely hovering true hoverflies were measured using three-dimensional high-speed video. The measured wing kinematics was used in a Navier-Stokes solver to compute the aerodynamic forces of the insects. The stroke amplitude of the hoverflies was relatively small, ranging from 65 to 85 deg, compared with that of normal hovering. The angle of attack in the downstroke (∼50 deg) was much larger that in the upstroke (∼20 deg), unlike normal-hovering insects, whose downstroke and upstroke angles of attack are not very different. The major part of the weight-supporting force (approximately 86%) was produced in the downstroke and it was contributed by both the lift and the drag of the wing, unlike the normal-hovering case in which the weight-supporting force is approximately equally contributed by the two half-strokes and the lift principle is mainly used to produce the force. The mass-specific power was 38.59-46.3 and 27.5-35.4 W kg(-1) in the cases of 0 and 100% elastic energy storage, respectively. Comparisons with previously published results of a normal-hovering true hoverfly and with results obtained by artificially making the insects' stroke planes horizontal show that for the true hoverflies, the power requirement for inclined stroke-plane hover is only a little (<10%) larger than that of normal hovering.

  19. Transonic Wing Shape Optimization Using a Genetic Algorithm

    Science.gov (United States)

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

    2002-01-01

    A method for aerodynamic shape optimization based on a genetic algorithm approach is demonstrated. The algorithm is coupled with a transonic full potential flow solver and is used to optimize the flow about transonic wings including multi-objective solutions that lead to the generation of pareto fronts. The results indicate that the genetic algorithm is easy to implement, flexible in application and extremely reliable.

  20. Linear and Nonlinear Controllers Applied to Fixed-Wing UAV

    Directory of Open Access Journals (Sweden)

    Tadeo Espinoza

    2013-01-01

    Full Text Available This article presents a comparison of controllers which have been applied to a fixed‐wing Unmanned Aerial Vehicle (UAV. The comparison is realized between classical linear controllers and nonlinear control laws. The concerned linear controllers are: Proportional‐ Derivative (PD and Proportional‐Integral‐Derivative (PID, while the nonlinear controllers are: backstepping, sliding modes, nested saturation and fuzzy control. These controllers are compared and analysed for altitude, yaw and roll by using simulation tests.

  1. Wing Shya眼球相机待你支持

    Institute of Scientific and Technical Information of China (English)

    新潮

    2002-01-01

    成为香港大导演王家卫御用的摄影师Wing Shya夏永康也冲出亚洲,先替英国Cult书《i-D》操刀拍照,还有日本型书《Brutus》合作设计的Cool爆_Bal旧艮球相机推出市面!有多Cool?现在鉴赏!

  2. AEROELASTIC FLUTTER ANALYSIS OF SUPERSONIC WING WITH MULTIPLE EXTERNAL STORES

    OpenAIRE

    Nur Azam; Erwin Sulaeman

    2014-01-01

    ABSTRACT: Flutter may be considered to be one of the most dangerous aeroelastic failure phenomenon. The flutter characteristic differs for each aircraft type, and depends on the wing geometry as well as its operational region of subsonic, transonic or supersonic speeds. Prior to performing a flight flutter test, extensive numerical simulations and Ground Vibration Test should be conducted where the structural finite element modes and the experimentation results should be matched, otherwise th...

  3. Structural Weight Optimization of Aircraft Wing Component Using FEM Approach.

    OpenAIRE

    Arockia Ruban M,; Kaveti Aruna

    2015-01-01

    One of the main challenges for the civil aviation industry is the reduction of its environmental impact by better fuel efficiency by virtue of Structural optimization. Over the past years, improvements in performance and fuel efficiency have been achieved by simplifying the design of the structural components and usage of composite materials to reduce the overall weight of the structure. This paper deals with the weight optimization of transport aircraft with low wing configuratio...

  4. An MDO concept for large civil airliner wings

    OpenAIRE

    Gantois, K.

    1998-01-01

    This thesis investigates the application of Multi-Disciplinary Design, Anal- ysis and Optimisation to the design of a large civil airliner, similar in size as the future A3XX. For the first time structural optimisation, manufacturing cost and aerodynamic effects are simultaneously integrated within a realistic, complex aircraft design problem: the wing box of such a large airliner. A novel multi-level system was developed to incorporate structural effects and manufacturing c...

  5. Flying with Abrupt Wing Flapping: Damselfly in Darting Flight

    OpenAIRE

    Li, Chengyu; Dong, Haibo; Zhang, Wen

    2013-01-01

    Damselflies show abrupt, darting flight, which is the envy of aero-engineers. This amazing ability is used both to capture prey and, by males, to establish territories that can attract females. In this work, high-resolution, high-speed videos of a damselfly (Hetaerina Americana) in darting flight were obtained using a photogrammetry system. Using a 3D subdivision surface reconstruction methodology, the damselfly's wing deformation and kinematics were modeled and reconstructed from those video...

  6. Linear and Nonlinear Controllers Applied to Fixed-Wing UAV

    OpenAIRE

    Tadeo Espinoza; Alejandro Dzul; Miguel Llama

    2013-01-01

    This article presents a comparison of controllers which have been applied to a fixed‐wing Unmanned Aerial Vehicle (UAV). The comparison is realized between classical linear controllers and nonlinear control laws. The concerned linear controllers are: Proportional‐ Derivative (PD) and Proportional‐Integral‐Derivative (PID), while the nonlinear controllers are: backstepping, sliding modes, nested saturation and fuzzy control. These controllers are compared and analysed for altitude, yaw and rol...

  7. Wing Panel Design with Novel Skin-Buckling Containment Features

    OpenAIRE

    Houston, G; Quinn, D.; Murphy, A; Bron, F.

    2016-01-01

    The impact of buckling containment features on the stability of thin-gauge fuselage, metallic stiffened panels has previously been demonstrated. With the continuing developments in manufacturing technology, such as welding, extrusion, machining, and additive layer manufacture, understanding the benefits of additional panel design features on heavier applications, such as wing panels, is timely. This compression testing of thick-gauge panels with and without buckling containment features has b...

  8. THE AERODYNAMIC ANALYSIS OF THE PROFILES FOR FLYING WINGS

    Directory of Open Access Journals (Sweden)

    Vasile PRISACARIU

    2013-01-01

    Full Text Available The possibility of using an un-piloted aerial vector is determined by the aerodynamic characteristics and performances. The design for a tailless unmanned aerial vehicles starts from defining the aerial vector mission and implies o series of geometrical and aerodynamic aspects for stability. This article proposes to remark the aerodynamic characteristics of three profiles used at flying wing airship through 2D software analysis.

  9. Wind-tunnel investigation of a large-scale VTOL aircraft model with wing root and wing thrust augmentors. [Ames 40 by 80 foot wind tunnel

    Science.gov (United States)

    Aoyagi, K.; Aiken, T. N.

    1979-01-01

    Tests were conducted in the Ames 40 by 80 foot wind tunnel to determine the aerodynamic characteristics of a large-scale V/STOL aircraft model with thrust augmentors. The model had a double-delta wing of aspect ratio 1.65 with augmentors located in the wing root and the wing trailing edge. The supply air for the augmentor primary nozzles was provided by the YJ-97 turbojet engine. The airflow was apportioned approximately 74 percent to the wing root augmentor and 24 percent to wing augmentor. Results were obtained at several trailing-edge flap deflections with the nozzle jet-momentum coefficients ranging from 0 to 7.9. Three-component longitudinal data are presented with the agumentor operating with and without the horizontal tail. A limited amount of six component data are also presented.

  10. Super-hydrophobic characteristics of butterfly wing surface

    Institute of Scientific and Technical Information of China (English)

    CONG Qian; CHEN Guang-hua; FANG Yan; REN Lu-quan

    2004-01-01

    Many biological surface are hydrophobic because of their complicated composition and surface microstructure. Eleven species (four families) of butterflies were selected to study their micro-, nano-structure and super-hydrophobic characteristic by means of Confocal Light Microscopy, Scanning Electron Microscopy and Contact Angle Measurement. The contact angles of water droplets on the butterfly wing surface were consistently measured to be about 150° and 100° with and without the squamas, respectively. The dust on the surface can be easily cleaned by moving spherical droplets when the inclining angle is larger than 3°. It can be concluded that the butterfly wing surface possess a super-hydrophobic, water-repellent,self-cleaning, or "Lotus-effect" characteristic. The contact angle measurement of water droplets on the wing surface with and without the squamas showed that the water-repellent characteristic is a consequence of the microstructure of the squamas.Each water droplet (diameter 2 mm) can cover about 700 squamas with a size of 40 μm×80 μm of each squama. The regular riblets with a width of 1000 nm to 1500 nm are clearly observed on each single squama. Such nanostructure should play a very important role in their super-hydrophobic and self-cleaning characteristic.

  11. Notch inhibits Yorkie activity in Drosophila wing discs.

    Directory of Open Access Journals (Sweden)

    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.

  12. The Microstructures of Butterfly Wing Scales in Northeast of China

    Institute of Scientific and Technical Information of China (English)

    Li-yan Wu; Zhi-wu Han; Zhao-mei Qiu; Hui-ying Guan; Lu-quan Ren

    2007-01-01

    There are billions of tiny scales on the butterfly wings,which array regularly as the tiles on the roof.Such tilts can form various colors of the wing and afford the species many abilities to survive and propagate.Morphological experiments on the wing scales of six buttertly species living in northeast of China were conducted.By the optics microscope,the form,geometry dimension and array of the scales were observed generally.By using scanning electron microscope(SEM),the 2D scanning and measurement were carried out and the surface micro configurations of scales were observed.The dimension and microstructure characteristics of the cross section of single scale were achieved through transmission electron microscope(TEM).Finally,by using 3D software,three 3D models were described and the 3D visual effect was achieved.This work can put forward a basic method for the future study on the morphology of biological microstructure.

  13. Multidimensional analysis of Drosophila wing variation in Evolution Canyon

    Indian Academy of Sciences (India)

    Vincent Debat; Raphael Cornette; Abraham B. Koral; Eviatar Nevo; David Soulet; Jean R. David

    2008-12-01

    Environmental stress has been suggested to be a major evolutionary force, both through inducing strong selection and because of its direct impact on developmental buffering processes that alter the evolvability of organisms. In particular, temperature has attracted much attention because of its importance as an ecological feature and the relative ease with which it can be experimentally manipulated in the lab. Evolution Canyon, Lower Nahal Oren, Israel, is a well studied natural site where ecological parameters are suspected to drive evolutionary differentiation. In this study, using Drosophila melanogaster isofemale lines derived from wild flies collected on both slopes of the canyon, we investigated the effect of developmental temperature upon the different components of phenotypic variation of a complex trait: the wing. Combining geometric and traditional morphometrics, we find only limited evidence for a differentiation among slopes. Investigating simultaneously phenotypic plasticity, genetic variation among isofemale lines, variation among individuals and fluctuating asymmetry, we could not identify a consistent effect of the stressful conditions encountered on the south facing slope. The prevailing structuring effect is that of the experimentally manipulated temperature which clearly influences wing mean size and shape. Variability, in contrast, is not consistently affected by temperature. Finally, we investigated the specific relationship between individual variation and fluctuating asymmetry. Using metric multi-dimensional scaling we show that the related patterns of wing shape variation are not identical, supporting the view that the underlying developmental processes are to a certain extent different.

  14. Optimization of a tensegrity wing for biomimetic applications

    Science.gov (United States)

    Moored, Keith W., III; Taylor, Stuart A.; Bart-Smith, Hilary

    2006-03-01

    Current attempts to build fast, efficient, and maneuverable underwater vehicles have looked to nature for inspiration. However, they have all been based on traditional propulsive techniques, i.e. rotary motors. In the current study a promising and potentially revolutionary approach is taken that overcomes the limitations of these traditional methods-morphing structure concepts with integrated actuation and sensing. Inspiration for this work comes from the manta ray (Manta birostris) and other batoid fish. These creatures are highly maneuverable but are also able to cruise at high speeds over long distances. In this paper, the structural foundation for the biomimetic morphing wing is a tensegrity structure. A preliminary procedure is presented for developing morphing tensegrity structures that include actuating elements. A shape optimization method is used that determines actuator placement and actuation amount necessary to achieve the measured biological displacement field of a ray. Lastly, an experimental manta ray wing is presented that measures the static and dynamic pressure field acting on the ray's wings during a normal flapping cycle.

  15. Lifting Wing in Constructing Tall Buildings —Aerodynamic Testing

    Directory of Open Access Journals (Sweden)

    Ian Skelton

    2014-05-01

    Full Text Available This paper builds on previous research by the authors which determined the global state-of-the-art of constructing tall buildings by surveying the most active specialist tall building professionals around the globe. That research identified the effect of wind on tower cranes as a highly ranked, common critical issue in tall building construction. The research reported here presents a design for a “Lifting Wing,” a uniquely designed shroud which potentially allows the lifting of building materials by a tower crane in higher and more unstable wind conditions, thereby reducing delay on the programmed critical path of a tall building. Wind tunnel tests were undertaken to compare the aerodynamic performance of a scale model of a typical “brick-shaped” construction load (replicating a load profile most commonly lifted via a tower crane against the aerodynamic performance of the scale model of the Lifting Wing in a range of wind conditions. The data indicate that the Lifting Wing improves the aerodynamic performance by a factor of up to 50%.

  16. Dynamical deformed Airy beams with arbitrary angles between two wings.

    Science.gov (United States)

    Liang, Yi; Hu, Yi; Ye, Zhuoyi; Song, Daohong; Lou, Cibo; Zhang, Xinzheng; Xu, Jingjun; Morandotti, Roberto; Chen, Zhigang

    2014-07-01

    We study both numerically and experimentally the acceleration and propagation dynamics of 2D Airy beams with arbitrary initial angles between their "two wings." Our results show that the acceleration of these generalized 2D Airy beams strongly depends on the initial angles and cannot be simply described by the vector superposition principle (except for the normal case of a 90° angle). However, as a result of the "Hyperbolic umbilic" catastrophe (a two-layer caustic), the main lobes of these 2D Airy beams still propagate along parabolic trajectories even though they become highly deformed. Under such conditions, the peak intensity (leading energy flow) of the 2D Airy beams cannot be confined along the main lobe, in contrast to the normal 90° case. Instead, it is found that there are two parabolic trajectories describing the beam propagation: one for the main lobe, and the other for the peak intensity. Both trajectories can be readily controlled by varying the initial wing angle. Due to their self-healing property, these beams tend to evolve into the well-known 1D or 2D Airy patterns after a certain propagation distance. The theoretical analysis corroborates our experimental observations, and explains clearly why the acceleration of deformed Airy beams increases with the opening of the initial wing angle. PMID:25121433

  17. Hierarchical Dragonfly Wing: Microstructure-Biomechanical Behavior Relations

    Institute of Scientific and Technical Information of China (English)

    Yinglong Chen; Xishu Wang; Huaihui Ren; Hang Yin; Su Jia

    2012-01-01

    The dragonfly wing,which consists of veins and membrane,is of biological hierarchical material.We observed the cross-sections of longitudinal veins and membrane using Environmental Scanning Electron Microscopy (ESEM).Based on the experiments and previous studies,we described the longitudinal vein and the membrane in terms of two hierarchical levels of organization of composite materials at the micro- and nano-scales.The longitudinal vein of dragonfly wing has a complex sandwich structure with two chitinous shells and a protein layer,and it is considered as the first hierarchical level of the vein.Moreover,the chitinous shells are concentric multilayered structures.Clusters of nano-fibrils grow along the circumferential orientation embedded into the protein layer.It is considered as the second level of the hierarchy.Similarly,the upper and lower epidermises of membrane constitute the first hierarchical level of organization in micro scale.Similar to the vein shell,the membrane epidermises were found to be a paralleled multilayered structure,defined as the second hierarchical level of the membrane.Combining with the mechanical behavior analysis of the dragonfly wing,we concluded that the growth orientation of the hierarchical structure of the longitudinal vein and membrane is relevant to its biomechanical behavior.

  18. Robust Design of Supercritical Wing Aerodynamic Optimization Considering Fuselage Interfering

    Institute of Scientific and Technical Information of China (English)

    Huang Jiangtao; Gao Zhenghong; Zhao Ke; Bai Junqiang

    2010-01-01

    Robust optimization approach for aerodynamic design has been developed and applied to supercritical wing aerodynamic de-sign.The aerodynamic robust optimization design system consists of genetic optimization algorithm,improved back propagation (BP) neural network and deformation grid technology.In this article,the BP neural network has been improved in two major aspects to enhance the training speed and precision.Uniformity sampling is adopted to generate samples which will be used to establish surrogate model.The testing results show that the prediction precision of the improved BP neural network is reliable.On the assumption that the law of Mach number obeys normal distribution,supereritical wing configuration considering fuselage interfering of a certain aerobus has been taken as a typical example,and five design sections and twist angles have been opti-mized.The results show that the optimized wing,which considers robust design,has better aerodynamic characteristics.What's more,the intensity of shock wave has been reduced.

  19. Experiences with Light Weight Fixed Wing Aerial Mapping UAVs

    Directory of Open Access Journals (Sweden)

    W. Mayr

    2014-11-01

    Full Text Available UAVs seem to be the next "cloud" like topic, not only in geomatics. Unmanned Airborne Vehicles are not a wonder-tool, but a complementary approach to resolve some tasks more efficiently than before or at all. Since 2006 we commercially apply fixed wing, light weight UAVs for aerial mapping purposes. In this paper we like to share our experiences with UAVs of less than 5 kg and illuminate some limitations as well as potentials. Whereas multicopters seem to be in use everywhere, fixed wing UAVs more frequently seem to be applied in specific and geospatially oriented applications. Having processed several hundred UAV aerial mapping projects there forms a stable picture of this technology. Our impressions on durability, handling, and reliability of fixed wing UAVs get presented. We report on our day-to-day experiences and point to often simple hurdles to overcome. Various cameras were flown, different approaches of handling their geometries with different software packages were undertaken. Remarks to achieved geometric accuracies as well as the consequences of using dual frequency GPS instead of simple yet great single frequency GPS are discussed. All of this packed into the subsequent paper.

  20. Flutter of wings involving a locally distributed flexible control surface

    Science.gov (United States)

    Mozaffari-Jovin, S.; Firouz-Abadi, R. D.; Roshanian, J.

    2015-11-01

    This paper undertakes to facilitate appraisal of aeroelastic interaction of a locally distributed, flap-type control surface with aircraft wings operating in a subsonic potential flow field. The extended Hamilton's principle serves as a framework to ascertain the Euler-Lagrange equations for coupled bending-torsional-flap vibration. An analytical solution to this boundary-value problem is then accomplished by assumed modes and the extended Galerkin's method. The developed aeroelastic model considers both the inherent flexibility of the control surface displaced on the wing and the inertial coupling between these two flexible bodies. The structural deformations also obey the Euler-Bernoulli beam theory, along with the Kelvin-Voigt viscoelastic constitutive law. Meanwhile, the unsteady thin-airfoil and strip theories are the tools of producing the three-dimensional airloads. The origin of aerodynamic instability undergoes analysis in light of the oscillatory loads as well as the loads owing to arbitrary motions. After successful verification of the model, a systematic flutter survey was conducted on the theoretical effects of various control surface parameters. The results obtained demonstrate that the flapping modes and parameters of the control surface can significantly impact the flutter characteristics of the wings, which leads to a series of pertinent conclusions.

  1. Analysis of a Hybrid Wing Body Center Section Test Article

    Science.gov (United States)

    Wu, Hsi-Yung T.; Shaw, Peter; Przekop, Adam

    2013-01-01

    The hybrid wing body center section test article is an all-composite structure made of crown, floor, keel, bulkhead, and rib panels utilizing the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) design concept. The primary goal of this test article is to prove that PRSEUS components are capable of carrying combined loads that are representative of a hybrid wing body pressure cabin design regime. This paper summarizes the analytical approach, analysis results, and failure predictions of the test article. A global finite element model of composite panels, metallic fittings, mechanical fasteners, and the Combined Loads Test System (COLTS) test fixture was used to conduct linear structural strength and stability analyses to validate the specimen under the most critical combination of bending and pressure loading conditions found in the hybrid wing body pressure cabin. Local detail analyses were also performed at locations with high stress concentrations, at Tee-cap noodle interfaces with surrounding laminates, and at fastener locations with high bearing/bypass loads. Failure predictions for different composite and metallic failure modes were made, and nonlinear analyses were also performed to study the structural response of the test article under combined bending and pressure loading. This large-scale specimen test will be conducted at the COLTS facility at the NASA Langley Research Center.

  2. Variation in wing characteristics of monarch butterflies during migration: Earlier migrants have redder and more elongated wings

    Directory of Open Access Journals (Sweden)

    Satterfield Dara A.

    2014-01-01

    Full Text Available The migration of monarch butterflies (Danaus plexippus in North America has a number of parallels with long-distance bird migration, including the fact that migratory populations of monarchs have larger and more elongated forewings than residents. These characteristics likely serve to optimize flight performance in monarchs, as they also do with birds. A question that has rarely been addressed thus far in birds or monarchs is if and how wing characteristics vary within a migration season. Individuals with superior flight performance should migrate quickly, and/or with minimal stopovers, and these individuals should be at the forefront of the migratory cohort. Conversely, individuals with poor flight performance and/or low endurance would be more likely to fall behind, and these would comprise the latest migrants. Here we examined how the wing morphology of migrating monarchs varies to determine if wing characteristics of early migrants differ from late migrants. We measured forewing area, elongation (length/width, and redness, which has been shown to predict flight endurance in monarchs. Based on a collection of 75 monarchs made one entire season (fall 2010, results showed that the earliest migrants (n = 20 in this cohort had significantly redder and more elongated forewings than the latest migrants (n = 17. There was also a non-significant tendency for early migrants to have larger forewing areas. These results suggest that the pace of migration in monarchs is at least partly dependent on the properties of their wings. Moreover, these data also raise a number of questions about the ultimate fate of monarchs that fall behind

  3. Variation in wing characteristics of monarch butterflies during migration: Earlier migrants have redder and more elongated wings

    OpenAIRE

    Satterfield Dara A.; Davis Andrew K.

    2014-01-01

    The migration of monarch butterflies (Danaus plexippus) in North America has a number of parallels with long-distance bird migration, including the fact that migratory populations of monarchs have larger and more elongated forewings than residents. These characteristics likely serve to optimize flight performance in monarchs, as they also do with birds. A question that has rarely been addressed thus far in birds or monarchs is if and how wing characteristics vary within a migration season. In...

  4. AEROELASTIC FLUTTER ANALYSIS OF SUPERSONIC WING WITH MULTIPLE EXTERNAL STORES

    Directory of Open Access Journals (Sweden)

    Nur Azam

    2014-12-01

    Full Text Available ABSTRACT: Flutter may be considered to be one of the most dangerous aeroelastic failure phenomenon. The flutter characteristic differs for each aircraft type, and depends on the wing geometry as well as its operational region of subsonic, transonic or supersonic speeds. Prior to performing a flight flutter test, extensive numerical simulations and Ground Vibration Test should be conducted where the structural finite element modes and the experimentation results should be matched, otherwise the numerical simulation model must be rejected. In this paper, the analysis of simulation of a supersonic wing equipped with external missiles loaded on the wing is presented. The structural mode shapes at each generated frequency are also visually presented. The analysis is carried out using MSC Nastran FEM software. The wing flutter with the external stores was simulated at different altitudes. The result shows that the flutter velocity is sensitive to the flight altitude. For this reason, the flutter analysis is conducted also for a negative altitude. The negative altitude is obtained by considering the constant equivalent speed-Mach number rule at the flutter speed boundary as a requirement in standard regulation of transport aircraft. ABSTRAK: Salah satu fenomena kegagalan aeroelastik yang paling membahayakan adalah kipasan (flutter. Ciri-ciri kegagalan kipasan (flutter adalah berbeza untuk setiap jenis pesawat bergantung pada geometri sayap dan regim operasi sama ada subsonik, transonik atau supersonik. Sebelum melakukan ujian penerbangan kipasan , simulasi berangka luas dan ujian getaran peringkat bawahan (darat perlu dijalankan di mana struktur mod unsur terhingga dan keputusan eksperimen harus dipadankan, sebaliknya model simulasi berangka boleh ditolak. Dalam kertas kerja ini, simulasi sayap supersonik dilengkapi dengan beban luaran peluru berpandu di sayap telah dianalisis di daerah supersonik tinggi. Bentuk mod struktur pada setiap mod frekuensi

  5. An analytical comparison of two wing structures for Mach 5 cruise airplanes

    Science.gov (United States)

    Taylor, A. H.; Jackson, L. R.; Cerro, J. A.; Scotti, S. J.

    1983-01-01

    Mach 5 cruise research conducted by NASA is related to aerodynamics, propulsion, and structures. The study of structures includes the propulsion system, fuselage, and wings. Various studies have shown that the achievement of adequate range is largely dependent on a low structural mass fraction. The present investigation is concerned with a study of two wing structure configurations for Mach 5 aircraft. An uprated version (Ti-6242 replacing B-120 titanium) of the YF-12/SR-71 wing structure is considered. The B-120 titanium structure represents the current art of high speed aircraft wing structures. The YF-12 wing structure was designed about 20 years ago when the analytical methods for calculating thermal stresses were limited. The second wing structural configuration studied in the present investigation also used Ti-6242 materials but replaced the corrugated-beaded panels with diffusion bonded honeycomb-core sandwich panels, and replaced the z-stiffened shear webs with sine-wave stiffened shear webs.

  6. Experimental Wing Damage Affects Foraging Effort and Foraging Distance in Honeybees Apis mellifera

    Directory of Open Access Journals (Sweden)

    Andrew D. Higginson

    2011-01-01

    Full Text Available Bees acquire wing damage as they age, and loss of wing area affects longevity and behaviour. This may influence colony performance via effects on worker behaviour. The effects of experimental wing damage were studied in worker honeybees in observation hives by recording survivorship, how often and for how long bees foraged, and by decoding waggle dances. Mortality rate increased with both age and wing damage. Damaged bees carried out shorter and/or less frequent foraging trips, foraged closer to the hive, and reported the profitability of flower patches to be lower than did controls. These results suggest that wing damage caused a reduction in foraging ability, and that damaged bees adjusted their foraging behaviour accordingly. Furthermore, the results suggest that wing damage affects the profitability of nectar sources. These results have implications for the colony dynamics and foraging efficiency in honeybees.

  7. Numerical and Experimental Investigation on Aerodynamic Characteristics of SMA Actuated Smart Wing Model

    Directory of Open Access Journals (Sweden)

    Iyyappan Balaguru

    2013-10-01

    Full Text Available Due to the advancements in smart actuators, morphing (changing of aircraft wings has been investigated by increasing number of researchers in recent years. In this research article, the concept of morphing is introduced to the conventional aircraft wing model with the utilization of Shape memory alloys (SMAs. An actuating mechanism is developed and built inside the aircraft wing model along with the SMA actuators which is used to morph its shape. The aircraft wing model with the SMA actuating mechanism is known as, ‘the smart wing model’. The aerodynamic characteristics (Lift, Drag, Velocity, and Pressure of the conventional and smart wing model are investigated by using the FLUENT numerical codes. The experimental aerodynamic test is carried out at various angles of incidence in an open circuit subsonic wind tunnel to validate the numerical results.

  8. Wind-tunnel Tests of the Fowler Variable-area Wing

    Science.gov (United States)

    Weick, Fred E; Platt, Robert C

    1932-01-01

    The lift, drag, and center of pressure characteristics of a model of the Fowler variable-area wing were measured in the NACA 7 by 10 foot wind tunnel. The Fowler wing consists of a combination of a main wing and an extension surface, also of airfoil section. The extension surface can be entirely retracted within the lower rear portion of the main wing or it can be moved to the rear and downward. The tests were made with the nose of the extension airfoil in various positions near the trailing edge of the main wing and with the surface at various angular deflections. The highest lift coefficient obtained was C(sub L) = 3.17 as compared with 1.27 for the main wing alone.

  9. Effects of flexibility on aerodynamic performance of delta wings with different sweep angles

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Force measurement and surface oil flow visualization experiments were conducted in a wind tunnel to investigate the effects of flexibility on aerodynamic performance of delta wings with different sweep angles.The experimental results indicate that the maximum lift coefficient is increased and the stall angle is delayed as the sweep angle increases for both rigid and flexible wings.It is also found that the maximum lift coefficients of the flexible wings with a sweep angle from 35° to 50° are higher than those of the rigid ones.The increment of the maximum lift coefficient in particular achieves 32.9% compared with the case without lift enhancement for the 40° flexible delta wing.Moreover,the surface oil flow visualization experiments show that the stall of the flexible wing of the moderate low sweep angle is accompanied by helical flow structure,while the vortex bursting appears on the corresponding rigid wing.

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

    Directory of Open Access Journals (Sweden)

    Daisuke Sasaki

    2011-01-01

    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.

  11. Gene expression following induction of regeneration in Drosophila wing imaginal discs. Expression profile of regenerating wing discs

    Directory of Open Access Journals (Sweden)

    Blanco Enrique

    2010-09-01

    Full Text Available Abstract Background Regeneration is the ability of an organism to rebuild a body part that has been damaged or amputated, and can be studied at the molecular level using model organisms. Drosophila imaginal discs, which are the larval primordia of adult cuticular structures, are capable of undergoing regenerative growth after transplantation and in vivo culture into the adult abdomen. Results Using expression profile analyses, we studied the regenerative behaviour of wing discs at 0, 24 and 72 hours after fragmentation and implantation into adult females. Based on expression level, we generated a catalogue of genes with putative role in wing disc regeneration, identifying four classes: 1 genes with differential expression within the first 24 hours; 2 genes with differential expression between 24 and 72 hours; 3 genes that changed significantly in expression levels between the two time periods; 4 genes with a sustained increase or decrease in their expression levels throughout regeneration. Among these genes, we identified members of the JNK and Notch signalling pathways and chromatin regulators. Through computational analysis, we recognized putative binding sites for transcription factors downstream of these pathways that are conserved in multiple Drosophilids, indicating a potential relationship between members of the different gene classes. Experimental data from genetic mutants provide evidence of a requirement of selected genes in wing disc regeneration. Conclusions We have been able to distinguish various classes of genes involved in early and late steps of the regeneration process. Our data suggests the integration of signalling pathways in the promoters of regulated genes.

  12. Centurion in Flight with Internal Wing Structure Visible

    Science.gov (United States)

    1998-01-01

    The lightweight wing structure and covering of the Centurion remotely piloted flying wing can be clearly seen in this photo of the plane during one of its initial low-altitude, battery-powered test flights in late 1998 at NASA's Dryden Flight Research Center, Edwards, California. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight

  13. Advancements in adaptive aerodynamic technologies for airfoils and wings

    Science.gov (United States)

    Jepson, Jeffrey Keith

    Although aircraft operate over a wide range of flight conditions, current fixed-geometry aircraft are optimized for only a few of these conditions. By altering the shape of the aircraft, adaptive aerodynamics can be used to increase the safety and performance of an aircraft by tailoring the aircraft for multiple flight conditions. Of the various shape adaptation concepts currently being studied, the use of multiple trailing-edge flaps along the span of a wing offers a relatively high possibility of being incorporated on aircraft in the near future. Multiple trailing-edge flaps allow for effective spanwise camber adaptation with resulting drag benefits over a large speed range and load alleviation at high-g conditions. The research presented in this dissertation focuses on the development of this concept of using trailing-edge flaps to tailor an aircraft for multiple flight conditions. One of the major tasks involved in implementing trailing-edge flaps is in designing the airfoil to incorporate the flap. The first part of this dissertation presents a design formulation that incorporates aircraft performance considerations in the inverse design of low-speed laminar-flow adaptive airfoils with trailing-edge cruise flaps. The benefit of using adaptive airfoils is that the size of the low-drag region of the drag polar can be effectively increased without increasing the maximum thickness of the airfoil. Two aircraft performance parameters are considered: level-flight maximum speed and maximum range. It is shown that the lift coefficients for the lower and upper corners of the airfoil low-drag range can be appropriately adjusted to tailor the airfoil for these two aircraft performance parameters. The design problem is posed as a part of a multidimensional Newton iteration in an existing conformal-mapping based inverse design code, PROFOIL. This formulation automatically adjusts the lift coefficients for the corners of the low-drag range for a given flap deflection as

  14. Localised JAK/STAT Pathway Activation Is Required for Drosophila Wing Hinge Development

    OpenAIRE

    Kirsty Johnstone; Wells, Richard E.; David Strutt; Zeidler, Martin P

    2013-01-01

    Extensive morphogenetic remodelling takes place during metamorphosis from a larval to an adult insect body plan. These changes are particularly intricate in the generation of the dipteran wing hinge, a complex structure that is derived from an apparently simple region of the wing imaginal disc. Using the characterisation of original outstretched alleles of the unpaired locus as a starting point, we demonstrate the role of JAK/STAT pathway signalling in the process of wing hinge development. W...

  15. Modal Response of Trapezoidal Wing Structures Using Second Order Shape Sensitivities

    Science.gov (United States)

    Liu, Youhua; Kapania, Rakesh K.

    2000-01-01

    The modal response of wing structures is very important for assessing their dynamic response including dynamic aeroelastic instabilities. Moreover, in a recent study an efficient structural optimization approach was developed using structural modes to represent the static aeroelastic wing response (both displacement and stress). In this paper, the modal response of general trapezoidal wing structures is approximated using shape sensitivities up to the 2nd order. Also different approaches of computing the derivatives are investigated.

  16. Study on utilization of advanced composites in commercial aircraft wing structures, volume 2

    Science.gov (United States)

    Sakata, I. F.; Ostrom, R. B.

    1978-01-01

    A plan is defined for a composite wing development effort which will assist commercial transport manufacturers in reaching a level of technology readiness where the utilization of composite wing structure is a cost competitive option for a new aircraft production plan. The recommended development effort consists of two programs: a joint government/industry material development program and a wing structure development program. Both programs are described in detail.

  17. Moult of wing and tail-feathers in the Ostrich, Struthio camelus

    OpenAIRE

    Brom, Tim G.; Dekker, René W. R. J.

    1990-01-01

    Structure and moult of wing and tail of a full-grown Ostrich, Struthio camelus, are described. In the wing, at least three feather generations could be recognized. The pattern of moult is more or less symmetrical in both wings and the sequence of feather replacement is not random. The tail consisted of 93 feathers of two different generations. Moult in the tail proceeds asymmetrically and seems to be fully irregular. The phylogenetic significance of these findings is discussed.

  18. Scaling law and enhancement of lift generation of an insect-size hovering flexible wing

    OpenAIRE

    Kang, Chang-kwon; Shyy, Wei

    2013-01-01

    We report a comprehensive scaling law and novel lift generation mechanisms relevant to the aerodynamic functions of structural flexibility in insect flight. Using a Navier–Stokes equation solver, fully coupled to a structural dynamics solver, we consider the hovering motion of a wing of insect size, in which the dynamics of fluid–structure interaction leads to passive wing rotation. Lift generated on the flexible wing scales with the relative shape deformation parameter, whereas the optimal l...

  19. Analysis of the Wing Mechanism Movement Parameters of Selected Beetle Species (Coleoptera)

    OpenAIRE

    Geisler T.; Topczewska S.

    2015-01-01

    This study presents a structural and functional analysis of the wing bending and folding mechanism of a selected beetle species. Insect motility studies, with regard to the anatomical structure, were performed. The main inner wing structures were highlighted and their mechanical properties and functions were determined. The structure parameters as mechanisms bodies that allow wings of various beetle species to bend and fold were defined.

  20. Damage tolerant wing-fuselage integration structural design applicable to future BWB transport aircraft

    OpenAIRE

    Sodzi, P.

    2009-01-01

    Wing joint design is one of the most critical areas in aircraft structures. Efficient and damage tolerant wing-fuselage integration structure, applicable to the next generation of transport aircraft, will facilitate the realisation of the benefits offered by new aircraft concepts. The Blended Wing Body (BWB) aircraft concept represents a potential revolution in subsonic transport efficiency for large airplanes. Studies have shown the BWB to be superior to conventional airframes...

  1. Structural Optimization and Design of a Strut-Braced Wing Aircraft

    OpenAIRE

    Naghshineh-Pour, Amir H.

    1998-01-01

    A significant improvement can be achieved in the performance of transonic transport aircraft using Multidisciplinary Design Optimization (MDO) by implementing truss-braced wing concepts in combination with other advanced technologies and novel design innovations. A considerable reduction in drag can be obtained by using a high aspect ratio wing with thin airfoil sections and tip-mounted engines. However, such wing structures could suffer from a significant weight penalty. Thus, the use of an ...

  2. Aerodynamic performance of a hovering hawkmoth with flexible wings: a computational approach

    OpenAIRE

    Nakata, Toshiyuki; Liu, Hao

    2011-01-01

    Insect wings are deformable structures that change shape passively and dynamically owing to inertial and aerodynamic forces during flight. It is still unclear how the three-dimensional and passive change of wing kinematics owing to inherent wing flexibility contributes to unsteady aerodynamics and energetics in insect flapping flight. Here, we perform a systematic fluid-structure interaction based analysis on the aerodynamic performance of a hovering hawkmoth, Manduca, with an integrated comp...

  3. Nanomorphology of the blue iridescent wings of a giant tropical wasp, ''Megascolia procer javanensis'' (Hymenoptera)

    CERN Document Server

    Sarrazin, Michael; Welch, Victoria; Rassart, Marie

    2007-01-01

    The wings of the giant wasp ''Megascolia Procer Javanensis'' are opaque and iridescent. The origin of the blue-green iridescence is studied in detail, using reflection spectroscopy, scanning electron microscopy and physical modelling. It is shown that the structure responsible for the iridescence is a single homogeneous transparent wax layer covering the whole surface of each wing. The opacity is essentially due to the presence of melanin in the stratified medium which forms the mechanical core of the wing.

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

    Science.gov (United States)

    Spreiter, John R

    1950-01-01

    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.

  5. An investigation of two-propeller tilt wing V/STOL aircraft flight characteristics

    OpenAIRE

    Neiusma, William J., Jr.

    1993-01-01

    Approved for public release, distribution is unlimited The results of a two-propeller tilt wing aircraft static stability and performance simulation utilizing a NASA-Ames computer code, Tilt Wing Application General (TWANG), are presented with comparisons to actual test flight data. The Canadair CL-84 tilt wing aircraft was used as a model for the geometric data utilized by the computer simulation. Aerodynamic data for the simulation were obtained from previous NASA Ames research rela...

  6. On the Effects of an Installed Propeller Slipstream on Wing Aerodynamic Characteristics

    OpenAIRE

    F. M. Catalano

    2004-01-01

    This work presents an experimental study of the effect of an installed propeller slipstream on a wing boundary layer. The main objective was to analyse through wind tunnel experiments the effect of the propeller slipstream on the wing boundary layer characteristics such as: laminar flow extension and transition, laminar separation bubbles and reattachment and turbulent separation. Two propeller/wing configurations were studied: pusher and tractor. Experimental work was performed using two dif...

  7. The Multidisciplinary Design Optimization of a Distributed Propulsion Blended-Wing-Body Aircraft

    OpenAIRE

    Ko, Yan-Yee Andy

    2003-01-01

    The purpose of this study is to examine the multidisciplinary design optimization (MDO) of a distributed propulsion blended-wing-body (BWB) aircraft. The BWB is a hybrid shape resembling a flying wing, placing the payload in the inboard sections of the wing. The distributed propulsion concept involves replacing a small number of large engines with many smaller engines. The distributed propulsion concept considered here ducts part of the engine exhaust to exit out along the trailing edge of th...

  8. Studies on wings symmetry and honey bee races discrimination by using standard and geometric morphometrics

    OpenAIRE

    Abou-Shaara H.F.; Al-Ghamdi A.A.

    2012-01-01

    Morphometric is an essential tool for honey bee races discrimination and characterization. Such vital tool has been applied widely in honey bee researches. Unfortunately there is no available literature for confirming honey bee wings symmetry. Therefore, standard and geometric morphometric analyses were employed for investigating wings symmetry as well as for discriminating between Carniolan and Yemeni honey bees. Moreover, three angles of hind wings (H1, H...

  9. Applications of Displacement Transfer Functions to Deformed Shape Predictions of the GIII Swept-Wing Structure

    Science.gov (United States)

    Lung, Shun-Fat; Ko, William L.

    2016-01-01

    The displacement transfer functions (DTFs) were applied to the GIII swept wing for the deformed shape prediction. The calculated deformed shapes are very close to the correlated finite element results as well as the measured data. The convergence study showed that using 17 strain stations, the wing-tip displacement prediction error was 1.6 percent, and that there is no need to use a large number of strain stations for G-III wing shape predictions.

  10. THUGS OR TERRORISTS? A TYPOLOGY OF RIGHT-WING TERRORISM AND VIOLENCE IN WESTERN EUROPE

    OpenAIRE

    Jacob Aasland Ravndal

    2015-01-01

    Despite Western Europe’s extensive history of right-wing terrorism, a systematic categorization of key actors and events is lacking. This article aims to narrow this gap by proposing the first empirically derived typology of right-wing terrorism and violence in Western Europe. The article begins by introducing a method for reviewing and developing typologies, informed by relevant social science literature. This method is first used to review Ehud Sprinzak’s seminal typology of right-wing terr...

  11. Unsteady Aerodynamic Investigation of the Propeller-Wing Interaction for a Rocket Launched Unmanned Air Vehicle

    OpenAIRE

    Zhang, G Q; Yu, S. C. M.; A. Chien; Xu, Y

    2013-01-01

    The aerodynamic characteristics of propeller-wing interaction for the rocket launched UAV have been investigated numerically by means of sliding mesh technology. The corresponding forces and moments have been collected for axial wing placements ranging from 0.056 to 0.5D and varied rotating speeds. The slipstream generated by the rotating propeller has little effects on the lift characteristics of the whole UAV. The drag can be seen to remain unchanged as the wing's location moves progressive...

  12. DEVELOPMENT OF EDUCATIONAL SOFTWARE FOR STRESS ANALYSIS OF AN AIRCRAFT WING

    Directory of Open Access Journals (Sweden)

    TAZKERA SADEQ

    2012-06-01

    Full Text Available A stress analysis software based on MATLAB, Graphic user interface (GUI has been developed. The developed software can be used to estimate load on a wing and to compute the stresses at any point along the span of the wing of a given aircraft. The generalized formulation allows performing stress analysis even for a multispar (multicell wing. The software is expected to be a useful tool for effective teaching learning process of courses on aircraft structures and aircraft structural design.

  13. Analysis of the Wing Mechanism Movement Parameters of Selected Beetle Species (Coleoptera

    Directory of Open Access Journals (Sweden)

    Geisler T.

    2015-02-01

    Full Text Available This study presents a structural and functional analysis of the wing bending and folding mechanism of a selected beetle species. Insect motility studies, with regard to the anatomical structure, were performed. The main inner wing structures were highlighted and their mechanical properties and functions were determined. The structure parameters as mechanisms bodies that allow wings of various beetle species to bend and fold were defined.

  14. Small Engine Technology (SET) Task 23 ANOPP Noise Prediction for Small Engines, Wing Reflection Code

    Science.gov (United States)

    Lieber, Lysbeth; Brown, Daniel; Golub, Robert A. (Technical Monitor)

    2000-01-01

    The work performed under Task 23 consisted of the development and demonstration of improvements for the NASA Aircraft Noise Prediction Program (ANOPP), specifically targeted to the modeling of engine noise enhancement due to wing reflection. This report focuses on development of the model and procedure to predict the effects of wing reflection, and the demonstration of the procedure, using a representative wing/engine configuration.

  15. Evaluation of Chemical Preparation on Insect Wing Shape for Geometric Morphometrics

    OpenAIRE

    Lorenz, Camila; Suesdek, Lincoln

    2013-01-01

    Geometric morphometrics is an approach that has been increasingly applied in studies with insects. A limiting factor of this technique is that some mosquitoes have wings with dark spots or many scales, which jeopardizes the visualization of landmarks for morphometric analysis. Recently, in some studies, chemically treatment (staining) of the wings was used to improve the viewing of landmarks. In this study, we evaluated whether this method causes deformation of the wing veins and tested wheth...

  16. Design and demonstration of a biomimetic wing section using lightweight piezoceramic composite actuator (LIPCA)

    Science.gov (United States)

    Lim, Sahng M.; Lee, Sangki; Park, Hoon C.; Yoon, Kwang J.; Goo, Nam Seo

    2003-08-01

    Biomimetic wing sections actuated by piezoceramics actuator LIPCA have been designed and their actuation displacements estimated by using the thermal analogy and MSC/NASTRAN based on the linear elasticity. The wing sections are fabricated as the design and tested for evaluation. Measured actuation displacements were larger than the estimated values mainly due to the material non-linearity of the PZT wafer. The biomimetic wing sections can be used for control surfaces of small scale UAVs.

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

    OpenAIRE

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

    2016-01-01

    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 ...

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

    Institute of Scientific and Technical Information of China (English)

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

    2004-01-01

    @@ 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.

  19. Phasing of dragonfly wings can improve aerodynamic efficiency by removing swirl

    OpenAIRE

    Usherwood, James R.; Lehmann, Fritz-Olaf

    2008-01-01

    Dragonflies are dramatic, successful aerial predators, notable for their flight agility and endurance. Further, they are highly capable of low-speed, hovering and even backwards flight. While insects have repeatedly modified or reduced one pair of wings, or mechanically coupled their fore and hind wings, dragonflies and damselflies have maintained their distinctive, independently controllable, four-winged form for over 300 Myr. Despite efforts at understanding the implications of flapping fli...

  20. Direct Wing Design and Inverse Airfoil Identification with the Nonlinear Weissinger Method

    CERN Document Server

    Ranneberg, Maximilian

    2015-01-01

    A vortex-lattice method for wing aerodynamics that uses nonlinear airfoil data is presented. Two applications of this procedure are presented: Direct Design of a Flying Wing and Inverse Identification from wind tunnel measurements with low-aspect ratio wings. A Newton method is employed, which not only allows very fast solutions to the nonlinear equations but enables the calculation of static and dynamic stability and control derivatives without further cost.