Khechiba, Khaled; Mamou, Mahmoud; Hachemi, Madjid; Delenda, Nassim; Rebhi, Redha
2017-06-01
The present study is focused on Lapwood convection in isotropic porous media saturated with non-Newtonian shear thinning fluid. The non-Newtonian rheological behavior of the fluid is modeled using the general viscosity model of Carreau-Yasuda. The convection configuration consists of a shallow porous cavity with a finite aspect ratio and subject to a vertical constant heat flux, whereas the vertical walls are maintained impermeable and adiabatic. An approximate analytical solution is developed on the basis of the parallel flow assumption, and numerical solutions are obtained by solving the full governing equations. The Darcy model with the Boussinesq approximation and energy transport equations are solved numerically using a finite difference method. The results are obtained in terms of the Nusselt number and the flow fields as functions of the governing parameters. A good agreement is obtained between the analytical approximation and the numerical solution of the full governing equations. The effects of the rheological parameters of the Carreau-Yasuda fluid and Rayleigh number on the onset of subcritical convection thresholds are demonstrated. Regardless of the aspect ratio of the enclosure and thermal boundary condition type, the subcritical convective flows are seen to occur below the onset of stationary convection. Correlations are proposed to estimate the subcritical Rayleigh number for the onset of finite amplitude convection as a function of the fluid rheological parameters. Linear stability of the convective motion, predicted by the parallel flow approximation, is studied, and the onset of Hopf bifurcation, from steady convective flow to oscillatory behavior, is found to depend strongly on the rheological parameters. In general, Hopf bifurcation is triggered earlier as the fluid becomes more and more shear-thinning.
Thermal convection of viscoelastic shear-thinning fluids
International Nuclear Information System (INIS)
Albaalbaki, Bashar; Khayat, Roger E; Ahmed, Zahir U
2016-01-01
The Rayleigh–Bénard convection for non-Newtonian fluids possessing both viscoelastic and shear-thinning behaviours is examined. The Phan-Thien–Tanner (PTT) constitutive equation is implemented to model the non-Newtonian character of the fluid. It is found that while the shear-thinning and viscoelastic effects could annihilate one another for the steady roll flow, presence of both behaviours restricts the roll stability limit significantly compared to the cases when the fluid is either inelastic shear-thinning or purely viscoelastic with constant viscosity. (paper)
A computational analysis on homogeneous-heterogeneous mechanism in Carreau fluid flow
Khan, Imad; Rehman, Khalil Ur; Malik, M. Y.; Shafquatullah
2018-03-01
In this article magnetohydrodynamic Carreau fluid flow towards stretching cylinder is considered in the presence of homogeneous-heterogeneous reactions effect. The flow model is structured by utilizing theoretical grounds. For the numerical solution a shooting method along with Runge-Kutta algorithm is executed. The outcomes are provided through graphs. It is observed that the Carreau fluid concentration shows decline values via positive iterations of homogeneous-heterogeneous reaction parameters towards both shear thinning and thickening case. The present work is certified through comparison with already existing literature in a limiting sense.
Swimming efficiency in a shear-thinning fluid
Nganguia, Herve; Pietrzyk, Kyle; Pak, On Shun
2017-12-01
Micro-organisms expend energy moving through complex media. While propulsion speed is an important property of locomotion, efficiency is another factor that may determine the swimming gait adopted by a micro-organism in order to locomote in an energetically favorable manner. The efficiency of swimming in a Newtonian fluid is well characterized for different biological and artificial swimmers. However, these swimmers often encounter biological fluids displaying shear-thinning viscosities. Little is known about how this nonlinear rheology influences the efficiency of locomotion. Does the shear-thinning rheology render swimming more efficient or less? How does the swimming efficiency depend on the propulsion mechanism of a swimmer and rheological properties of the surrounding shear-thinning fluid? In this work, we address these fundamental questions on the efficiency of locomotion in a shear-thinning fluid by considering the squirmer model as a general locomotion model to represent different types of swimmers. Our analysis reveals how the choice of surface velocity distribution on a squirmer may reduce or enhance the swimming efficiency. We determine optimal shear rates at which the swimming efficiency can be substantially enhanced compared with the Newtonian case. The nontrivial variations of swimming efficiency prompt questions on how micro-organisms may tune their swimming gaits to exploit the shear-thinning rheology. The findings also provide insights into how artificial swimmers should be designed to move through complex media efficiently.
Empirical resistive-force theory for slender biological filaments in shear-thinning fluids
Riley, Emily E.; Lauga, Eric
2017-06-01
Many cells exploit the bending or rotation of flagellar filaments in order to self-propel in viscous fluids. While appropriate theoretical modeling is available to capture flagella locomotion in simple, Newtonian fluids, formidable computations are required to address theoretically their locomotion in complex, nonlinear fluids, e.g., mucus. Based on experimental measurements for the motion of rigid rods in non-Newtonian fluids and on the classical Carreau fluid model, we propose empirical extensions of the classical Newtonian resistive-force theory to model the waving of slender filaments in non-Newtonian fluids. By assuming the flow near the flagellum to be locally Newtonian, we propose a self-consistent way to estimate the typical shear rate in the fluid, which we then use to construct correction factors to the Newtonian local drag coefficients. The resulting non-Newtonian resistive-force theory, while empirical, is consistent with the Newtonian limit, and with the experiments. We then use our models to address waving locomotion in non-Newtonian fluids and show that the resulting swimming speeds are systematically lowered, a result which we are able to capture asymptotically and to interpret physically. An application of the models to recent experimental results on the locomotion of Caenorhabditis elegans in polymeric solutions shows reasonable agreement and thus captures the main physics of swimming in shear-thinning fluids.
Pore scale simulations for the extension of the Darcy-Forchheimer law to shear thinning fluids
Tosco, Tiziana; Marchisio, Daniele; Lince, Federica; Boccardo, Gianluca; Sethi, Rajandrea
2014-05-01
Flow of non-Newtonian fluids through porous media at high Reynolds numbers is often encountered in chemical, pharmaceutical and food as well as petroleum and groundwater engineering and in many other industrial applications (1 - 2). In particular, the use of shear thinning polymeric solutions has been recently proposed to improve colloidal stability of micro- and nanoscale zerovalent iron particles (MZVI and NZVI) for groundwater remediation. In all abovementioned applications, it is of paramount importance to correctly predict the pressure drop resulting from non-Newtonian fluid flow through the porous medium. For small Reynolds numbers, usually up to 1, typical of laboratory column tests, the extended Darcy law is known to be applicable also to non Newtonian fluids, provided that all non-Newtonian effects are lumped together into a proper viscosity parameter (1,3). For higher Reynolds numbers (eg. close to the injection wells) non linearities between pressure drop and flow rate arise, and the Darcy-Forchheimer law holds for Newtonian fluids, while for non-Newtonian fluids, it has been demonstrated that, at least for simple rheological models (eg. power law fluids) a generalized Forchheimer law can be applied, even if the determination of the flow parameters (permeability K, inertial coefficient β, and equivalent viscosity) is not straightforward. This work (co-funded by European Union project AQUAREHAB FP7 - Grant Agreement Nr. 226565) aims at proposing an extended formulation of the Darcy-Forchheimer law also for shear-thinning fluids, and validating it against results of pore-scale simulations via computational fluid dynamics (4). Flow simulations were performed using Fluent 12.0 on four different 2D porous domains for Newtonian and non-Newtonian fluids (Cross, Ellis and Carreau models). The micro-scale flow simulation results are analyzed in terms of 'macroscale' pressure drop between inlet and outlet of the model domain as a function of flow rate. The
Turbulent characteristics of shear-thinning fluids in recirculating flows
Energy Technology Data Exchange (ETDEWEB)
Pereira, A.S. [Inst. Superior de Engenharia do Porto (Portugal). Dept. de Engenharia Quimica; Pinho, F.T. [Centro de Estudos de Fenomenos de Transporte, Departamento de Engenharia Mecanica e Gestao Industrial, Faculdade de Engenharia da Universidade do Porto, Rua dos Bragas, 4050-123 Porto (Portugal)
2000-03-01
A miniaturised fibre optic laser-Doppler anemometer was used to carry out a detailed hydrodynamic investigation of the flow downstream of a sudden expansion with 0.1-0.2% by weight shear-thinning aqueous solutions of xanthan gum. Upstream of the sudden expansion the pipe flow was fully-developed and the xanthan gum solutions exhibited drag reduction with corresponding lower radial and tangential normal Reynolds stresses, but higher axial Reynolds stress near the wall and a flatter axial mean velocity profile in comparison with Newtonian flow. The recirculation bubble length was reduced by more than 20% relative to the high Reynolds number Newtonian flow, and this was attributed to the occurrence further upstream of high turbulence for the non-Newtonian solutions, because of advection of turbulence and earlier high turbulence production in the shear layer. Comparisons with the measurements of Escudier and Smith (1999) with similar fluids emphasized the dominating role of inlet turbulence. The present was less anisotropic, and had lower maximum axial Reynolds stresses (by 16%) but higher radial turbulence (20%) than theirs. They reported considerably longer recirculating bubble lengths than we do for similar non-Newtonian fluids and Reynolds numbers. (orig.)
On multiple solutions of non-Newtonian Carreau fluid flow over an inclined shrinking sheet
Khan, Masood; Sardar, Humara; Gulzar, M. Mudassar; Alshomrani, Ali Saleh
2018-03-01
This paper presents the multiple solutions of a non-Newtonian Carreau fluid flow over a nonlinear inclined shrinking surface in presence of infinite shear rate viscosity. The governing boundary layer equations are derived for the Carreau fluid with infinite shear rate viscosity. The suitable transformations are employed to alter the leading partial differential equations to a set of ordinary differential equations. The consequential non-linear ODEs are solved numerically by an active numerical approach namely Runge-Kutta Fehlberg fourth-fifth order method accompanied by shooting technique. Multiple solutions are presented graphically and results are shown for various physical parameters. It is important to state that the velocity and momentum boundary layer thickness reduce with increasing viscosity ratio parameter in shear thickening fluid while opposite trend is observed for shear thinning fluid. Another important observation is that the wall shear stress is significantly decreased by the viscosity ratio parameter β∗ for the first solution and opposite trend is observed for the second solution.
A. Mahammedi; H. Ameur; A. Ariss
2017-01-01
The laminar flow of non-Newtonian fluids through a Kenics static mixer is investigated by using the CFD (Computational Fluid Dynamics) tool. The working fluids have a shear thinning behavior modeled by the Ostwald De Waele law. We focus on the effect of Reynolds number, fluid properties, twist angle and blade pitch on the flow characteristics and energy cost. The pressure drop information obtained from the simulations was compared to several experimental correlations and data available in the...
EMHD micro-pumping of a non-conducting shear-thinning fluid under EDL phenomena
International Nuclear Information System (INIS)
Gaikwad, Harshad; Borole, Chetan; Basu, Dipankar N.; Mondal, Pranab K.
2016-01-01
The Electro-Magneto-Hydrodynamic (EMHD) pumping of a binary fluid system constituted by one non-conducting shear-thinning fluid (top layer) by exploiting the transverse momentum exchange through the interfacial viscous shearing effect from a conducting Newtonian fluid layer (bottom layer) in a microfluidic channel is investigated. An externally applied electric field drives the conducting fluid layer under the influence of an applied magnetic field as well. The study reveals that the volume transport of shear-thinning fluid gets augmented for low magnetic field strength, higher electrical double layer (EDL) effect, low viscosity ratio and moderate potential ratio. It is also established that the volumetric flow rate reduces significantly for the higher magnetic field strength. (author)
Instabilities of convection patterns in a shear-thinning fluid between plates of finite conductivity
Varé, Thomas; Nouar, Chérif; Métivier, Christel
2017-10-01
Rayleigh-Bénard convection in a horizontal layer of a non-Newtonian fluid between slabs of arbitrary thickness and finite thermal conductivity is considered. The first part of the paper deals with the primary bifurcation and the relative stability of convective patterns at threshold. Weakly nonlinear analysis combined with Stuart-Landau equation is used. The competition between squares and rolls, as a function of the shear-thinning degree of the fluid, the slabs' thickness, and the ratio of the thermal conductivity of the slabs to that of the fluid is investigated. Computations of heat transfer coefficients are in agreement with the maximum heat transfer principle. The second part of the paper concerns the stability of the convective patterns toward spatial perturbations and the determination of the band width of the stable wave number in the neighborhood of the critical Rayleigh number. The approach used is based on the Ginzburg-Landau equations. The study of rolls stability shows that: (i) for low shear-thinning effects, the band of stable wave numbers is bounded by zigzag instability and cross-roll instability. Furthermore, the marginal cross-roll stability boundary enlarges with increasing shear-thinning properties; (ii) for high shear-thinning effects, Eckhaus instability becomes more dangerous than cross-roll instability. For square patterns, the wave number selection is always restricted by zigzag instability and by "rectangular Eckhaus" instability. In addition, the width of the stable wave number decreases with increasing shear-thinning effects. Numerical simulations of the planform evolution are also presented to illustrate the different instabilities considered in the paper.
Directory of Open Access Journals (Sweden)
I.L. Animasaun
2017-12-01
Full Text Available Geometrically, the upper pointed surface of an aircraft and bonnet of a car are examples of upper horizontal surfaces of a paraboloid of revolution (uhspr. The motion of these objects strongly depends on the boundary layer that is formed within the immediate space on it. However, each of these surfaces is neither a horizontal/vertical nor cone/wedge and neither a cone nor a wedge. This article presents the motion of 2-dimensional Blasius flow of Carreau fluid on the surface of such object. The case in which the reaction between the Carreau fluid and catalyst at the surface produces significant temperature differences which consequently set up buoyancy-driven flows within the boundary layer is investigated. Single first-order Arrhenius kinetics is adopted to model the reaction on the surface of the catalyst situated on uhspr which initiates the free convection. Suitable similarity variables are applied to non-dimensionalized, parameterized and reduce the governing partial differential equations to a coupled ordinary differential equations (BVP. The BVP is solved numerically using the shooting technique. Temperature distribution in the flow of viscoelastic Carreau fluid is greater than that of a Newtonian fluid. Local heat transfer rate decreases faster when the Carreau fluid is characterized as shear-thinning. Maximum concentration is guaranteed at a small value of power-law index n and large value of thickness parameter. Keywords: Viscoelastic-Carreau fluid, Catalitic surface, Paraboloid of revolution, Numerical method, Uhspr, Boundary layer analysis
Directory of Open Access Journals (Sweden)
Kun Sang Lee
2011-08-01
Full Text Available Assessment of the potential of a polymer flood for mobility control requires an accurate model on the viscosities of displacement fluids involved in the process. Because most polymers used in EOR exhibit shear-thinning behavior, the effective viscosity of a polymer solution is a highly nonlinear function of shear rate. A reservoir simulator including the model for the shear-rate dependence of viscosity was used to investigate shear-thinning effects of polymer solution on the performance of the layered reservoir in a five-spot pattern operating under polymer flood followed by waterflood. The model can be used as a quantitative tool to evaluate the comparative studies of different polymer flooding scenarios with respect to shear-rate dependence of fluids’ viscosities. Results of cumulative oil recovery and water-oil ratio are presented for parameters of shear-rate dependencies, permeability heterogeneity, and crossflow. The results of this work have proven the importance of taking non-Newtonian behavior of polymer solution into account for the successful evaluation of polymer flood processes. Horizontal and vertical permeabilities of each layer are shown to impact the predicted performance substantially. In reservoirs with a severe permeability contrast between horizontal layers, decrease in oil recovery and sudden increase in WOR are obtained by the low sweep efficiency and early water breakthrough through highly permeable layer, especially for shear-thinning fluids. An increase in the degree of crossflow resulting from sufficient vertical permeability is responsible for the enhanced sweep of the low permeability layers, which results in increased oil recovery. It was observed that a thinning fluid coefficient would increase injectivity significantly from simulations with various injection rates. A thorough understanding of polymer rheology in the reservoir and accurate numerical modeling are of fundamental importance for the exact estimation
Reverse flow and vortex breakdown in a shear-thinning fluid
International Nuclear Information System (INIS)
Cabeza, C; Sarasua, G; Barrere, N; Marti, A C
2011-01-01
The effect of polymer concentration on the development of reverse secondary flow and vortex breakdown was studied using a viscoelastic solution of polyacrlylamide in water. The fluid was contained in cylindrical containers of two different radii, the top end wall of which rotated at a varying speed, thus, imparting a circulating motion to the fluid. Whereas using a newtonian fluid, streamlines will occupy the entire container, the flow of a shear-thinning fluid may divide into two cells of opposite circulating motion. The curve of critical Reynolds and elasticity numbers (Re, E) values corresponding to the development of reverse flow was obtained over a wide range of Re values. Vortex breakdown was found to occur at extremely low Re values.
Squeeze flow of a Carreau fluid during sphere impact
Uddin, J.
2012-07-19
We present results from a combined numerical and experimental investigation into the squeeze flow induced when a solid sphere impacts onto a thin, ultra-viscous film of non-Newtonian fluid. We examine both the sphere motion through the liquid as well as the fluid flow field in the region directly beneath the sphere during approach to a solid plate. In the experiments we use silicone oil as the model fluid, which is well-described by the Carreau model. We use high-speed imaging and particle tracking to achieve flow visualisation within the film itself and derive the corresponding velocity fields. We show that the radial velocity either diverges as the gap between the sphere and the wall diminishes (Z tip → 0) or that it reaches a maximum value and then decays rapidly to zero as the sphere comes to rest at a non-zero distance (Z tip = Z min ) away from the wall. The horizontal shear rate is calculated and is responsible for significant viscosity reduction during the approach of the sphere. Our model of this flow, based on lubrication theory, is solved numerically and compared to experimental trials. We show that our model is able to correctly describe the physical features of the flow observed in the experiments.
Squeeze flow of a Carreau fluid during sphere impact
Uddin, J.; Marston, J. O.; Thoroddsen, Sigurdur T
2012-01-01
We present results from a combined numerical and experimental investigation into the squeeze flow induced when a solid sphere impacts onto a thin, ultra-viscous film of non-Newtonian fluid. We examine both the sphere motion through the liquid as well as the fluid flow field in the region directly beneath the sphere during approach to a solid plate. In the experiments we use silicone oil as the model fluid, which is well-described by the Carreau model. We use high-speed imaging and particle tracking to achieve flow visualisation within the film itself and derive the corresponding velocity fields. We show that the radial velocity either diverges as the gap between the sphere and the wall diminishes (Z tip → 0) or that it reaches a maximum value and then decays rapidly to zero as the sphere comes to rest at a non-zero distance (Z tip = Z min ) away from the wall. The horizontal shear rate is calculated and is responsible for significant viscosity reduction during the approach of the sphere. Our model of this flow, based on lubrication theory, is solved numerically and compared to experimental trials. We show that our model is able to correctly describe the physical features of the flow observed in the experiments.
Buoyant miscible displacement flow of shear-thinning fluids: Experiments and Simulations
Ale Etrati Khosroshahi, Seyed Ali; Frigaard, Ian
2017-11-01
We study displacement flow of two miscible fluids with density and viscosity contrast in an inclined pipe. Our focus is mainly on displacements where transverse mixing is not significant and thus a two-layer, stratified flow develops. Our experiments are carried out in a long pipe, covering a wide range of flow-rates, inclination angles and viscosity ratios. Density and viscosity contrasts are achieved by adding Glycerol and Xanthan gum to water, respectively. At each angle, flow rate and viscosity ratio are varied and density contrast is fixed. We identify and map different flow regimes, instabilities and front dynamics based on Fr , Re / Frcosβ and viscosity ratio m. The problem is also studied numerically to get a better insight into the flow structure and shear-thinning effects. Numerical simulations are completed using OpenFOAM in both pipe and channel geometries and are compared against the experiments. Schlumberger, NSERC.
Syrakos, Alexandros; Dimakopoulos, Yannis; Tsamopoulos, John
2018-03-01
The flow inside a fluid damper where a piston reciprocates sinusoidally inside an outer casing containing high-viscosity silicone oil is simulated using a finite volume method, at various excitation frequencies. The oil is modeled by the Carreau-Yasuda (CY) and Phan-Thien and Tanner (PTT) constitutive equations. Both models account for shear-thinning, but only the PTT model accounts for elasticity. The CY and other generalised Newtonian models have been previously used in theoretical studies of fluid dampers, but the present study is the first to perform full two-dimensional (axisymmetric) simulations employing a viscoelastic constitutive equation. It is found that the CY and PTT predictions are similar when the excitation frequency is low, but at medium and higher frequencies, the CY model fails to describe important phenomena that are predicted by the PTT model and observed in experimental studies found in the literature, such as the hysteresis of the force-displacement and force-velocity loops. Elastic effects are quantified by applying a decomposition of the damper force into elastic and viscous components, inspired from large amplitude oscillatory shear theory. The CY model also overestimates the damper force relative to the PTT model because it underpredicts the flow development length inside the piston-cylinder gap. It is thus concluded that (a) fluid elasticity must be accounted for and (b) theoretical approaches that rely on the assumption of one-dimensional flow in the piston-cylinder gap are of limited accuracy, even if they account for fluid viscoelasticity. The consequences of using lower-viscosity silicone oil are also briefly examined.
Field Test of Enhanced Remedial Amendment Delivery Using a Shear-Thinning Fluid
Energy Technology Data Exchange (ETDEWEB)
Truex, Michael J.; Vermeul, Vincent R.; Adamson, David; Oostrom, Martinus; Zhong, Lirong; Mackley, Rob D.; Fritz, Brad G.; Horner, Jacob A.; Johnson, Timothy C.; Thomle, Jonathan N.; Newcomer, Darrell R.; Johnson, Christian D.; Rysz, Michal; Wietsma, Thomas W.; Newell, Charles J.
2015-03-01
Heterogeneity of hydraulic properties in aquifers may lead to contaminants residing in lower-permeability zones where it is difficult to deliver remediation amendments using conventional injection processes. The focus of this effort is to examine use of a shear-thinning fluid (STF) to improve the uniformity of remedial amendment distribution within a heterogeneous aquifer. Previous studies have demonstrated the significant potential of STFs for improving remedial amendment delivery in heterogeneous aquifers, but quantitative evaluation of these improvements from field applications are lacking. A field-scale test was conducted that compares data from successive injection of a tracer in water followed by injection of a tracer in a STF to evaluate the impact of the STF on tracer distribution uniformity in the presence of permeability contrasts within the targeted injection zone. Data from tracer breakthrough at multiple depth-discrete monitoring intervals and electrical resistivity tomography showed that inclusion of STF in the injection solution slowed movement in high-permeability pathways, improved delivery of amendment to low-permeability materials, and resulted in better uniformity in injected fluid distribution within the targeted treatment zone.
Directory of Open Access Journals (Sweden)
Fan Wenyuan
2017-01-01
Full Text Available A laser image system has been established to quantify the characteristics of growing bubbles in quiescent shear-thinning fluids. Bubble formation mechanism was investigated by comparing the evolutions of bubble instantaneous shape, volume and surface area in two shear-thinning liquids with those in Newtonian liquid. The effects of solution mass concentration, gas chamber volume and orifice diameter on bubble detachment volume are discussed. By dimensional analysis, a single bubble volume detached within a moderate gas flowrate range was developed as a function of Reynolds number ,Re, Weber number, We, and gas chamber number, Vc, based on the orifice diameter. The results reveal that the generated bubble presents a slim shape due to the shear-thinning effect of the fluid. Bubble detachment volume increases with the solution mass concentration, gas chamber volume and orifice diameter. The results predicted by the present correlation agree better with the experimental data than the previous ones within the range of this paper.
Nelson, Arif Z.; Ewoldt, Randy H.
2017-11-01
Design in fluid mechanics often focuses on optimizing geometry (airfoils, surface textures, microfluid channels), but here we focus on designing fluids themselves. The dramatically shear-thinning ``yield-stress fluid'' is currently the most utilized non-Newtonian fluid phenomenon. These rheologically complex materials, which undergo a reversible transition from solid-like to liquid-like fluid flow, are utilized in pedestrian products such as paint and toothpaste, but also in emerging applications like direct-write 3D printing. We present a paradigm for yield-stress fluid design that considers constitutive model representation, material property databases, available predictive scaling laws, and the many ways to achieve a yield stress fluid, flipping the typical structure-to-rheology analysis to become the inverse: rheology-to-structure with multiple possible materials as solutions. We describe case studies of 3D printing inks and other flow scenarios where designed shear-thinning enables performance remarkably beyond that of Newtonian fluids. This work was supported by Wm. Wrigley Jr. Company and the National Science Foundation under Grant No. CMMI-1463203.
Khan, Imad; Ullah, Shafquat; Malik, M. Y.; Hussain, Arif
2018-06-01
The current analysis concentrates on the numerical solution of MHD Carreau fluid flow over a stretching cylinder under the influences of homogeneous-heterogeneous reactions. Modelled non-linear partial differential equations are converted into ordinary differential equations by using suitable transformations. The resulting system of equations is solved with the aid of shooting algorithm supported by fifth order Runge-Kutta integration scheme. The impact of non-dimensional governing parameters on the velocity, temperature, skin friction coefficient and local Nusselt number are comprehensively delineated with the help of graphs and tables.
Peristaltic Flow of Carreau Fluid in a Rectangular Duct through a Porous Medium
Directory of Open Access Journals (Sweden)
R. Ellahi
2012-01-01
Full Text Available We have examined the peristaltic flow of Carreau fluid in a rectangular channel through a porous medium. The governing equations of motion are simplified by applying the long wavelength and low Reynolds number approximations. The reduced highly nonlinear partial differential equations are solved jointly by homotopy perturbation and Eigen function expansion methods. The expression for pressure rise is computed numerically by evaluating the numerical integration. The physical features of pertinent parameters have been discussed by plotting graphs of velocity, pressure rise, pressure gradient, and stream functions.
Enhanced In Situ Chemical Oxidation Using Surfactants and Shear Thinning Fluids
Hauswirth, S.; Sadeghi, S.; Cerda, C. C.; Espinoza, I.; Schultz, P. B.; Miller, C. T.
2017-12-01
In situ chemical oxidation (ISCO) is an attractive approach for the remediation of recalcitrant contaminants, due to the fact that target compounds are degraded in place, precluding the need for ex situ treatment or disposal. However, field applications of ISCO approaches have been plagued by "rebound" of contaminant concentrations in groundwater weeks to months after treatment. The cause of rebound at a given site may vary, but is typically associated with back-diffusion from finer grained, low permeability units or the presence of non-aqueous phase liquids (NAPLs) that are incompletely degraded during treatment. Modifications to traditional ISCO methods have been proposed to overcome these challenges, including the use of shear-thinning polymers to improve delivery of oxidants to low permeability units and the addition of surfactants to improve dissolution of contaminants from NAPLs. In this work, we investigate the application of these approaches to the oxidation of manufactured gas plant (MGP) tars—NAPLs composed primarily of polycyclic aromatic hydrocarbons (PAHs). We conducted experiments to determine the mutual impact of each chemical component on the physical and chemical properties of the overall system. Specifically, experiments were designed to: determine the kinetics and overall effectiveness of contaminant-oxidant reactions for multiple oxidant-activator combinations; screen several common surfactants in terms of their ability to increase MGP tar solubility and their compatibility with oxidant systems; measure the impact of oxidants and surfactants on the rheology of several common polymer additives; and assess the effect of surfactants and polymers on the consumption of oxidants/activators and on the kinetics of contaminant-oxidant reactions. The results of this work provide insight into the chemical and physical mechanisms associated with enhanced ISCO approaches and an improved basis with which to model and design ISCO applications at both the lab
Mamatha Upadhya, S.; Mahesha; Raju, C. S. K.
2018-04-01
A theoretical analysis is carried out to investigate the magnetohydrodynamic unsteady flow of Eyring-Powell and Carreau non-Newtonian fluids in a suspension of dust and nickel nanoparticles by considering variable thermal conductivity and thermal radiation. Dispersion of nickel nanoparticles in dusty fluids finds applications in heat exchanger systems, rechargeable batteries, chemical catalysts, metallurgy, conducting paints, magnetic recording media, drug delivery, nanofibers, textiles, etc. The initially arising set of physical governing partial differential equations is transformed to ordinary differential equations (ODEs) with the aid of similarity transformations. Consequentially, the nonlinear ODEs are solved numerically through the Runge-Kutta Fehlberg scheme (RKFS). The computational results for non-dimensional temperature and velocity profiles are presented through graphs. Furthermore, the numerical values of friction factor and heat transfer rate are tabulated numerically for the unsteady and steady cases of the Eyring and Carreau fluid cases and of the dusty non-Newtonian (φ=0) and the dusty non-Newtonian nanofluid (φ≠ 0) cases of the unsteady flow. We also validated the present results with previous published studies and found them to be highly satisfactory. The formulated model reveals that the rate of heat transfer is higher in the mixture of the nickel + Eyring-Powell case compared to the nickel + Carreau case. From this we can highlight that, depending on the industrial appliances, we can use heating or cooling processes for Eyring and Carreau fluids, respectively.
On Cattaneo-Christov heat flux model for Carreau fluid flow over a slendering sheet
Hashim; Khan, Masood
The underlying intentions of this article are to investigate the impact of non-Fourier heat flux model on the stagnation-point flow of non-Newtonian Carreau fluid. In this study, the innovative Cattaneo-Christov constitutive model is introduced to study the characteristics of thermal relaxation time. The flow is impelled by a slendering surface which is of the variable thickness. In the model, the physical mechanism responsible for homogeneous-heterogeneous reactions are further taken into account. Also, the diffusion coefficients of the reactant and auto catalyst are considered to be equal. The governing non-linear partial differential equations consisting of the momentum, energy and concentration equations are reduced to the coupled ordinary differential equations by means of local similarity transformations. The transformed ODEs are tackled numerically by employing an effective shooting algorithm along with the Runge-Kutta Fehlberg scheme. The physical characteristics of the fluid velocity, temperature and concentration profiles are illuminated with the variation of numerous governing factors and are presented graphically. For instance, our result indicates that the temperature and thermal boundary layer thickness are lower in case of Cattaneo-Christov heat flux model when compared to classical Fourier's heat model. Meanwhile, the rate of heat transfer is significantly improved by a high wall thickness parameter and an opposite influence is found due to the thermal relaxation parameter. We further noticed that a higher value of homogeneous and heterogeneous reaction parameter corresponds to a deceleration in the concentration field and it shows an inverse relation for the Schmidt number. A correlation with accessible results for specific cases is found with fabulous consent.
Energy Technology Data Exchange (ETDEWEB)
Khan, Masood [Department of Mathematics, Quaid-i-Azam University, Islamabad 44000 (Pakistan); Hashim, E-mail: hashim_alik@yahoo.com [Department of Mathematics, Quaid-i-Azam University, Islamabad 44000 (Pakistan); Hussain, M. [Department of Sciences and Humanities, National University of Computer and Emerging Sciences, Islamabad 44000 (Pakistan); Azam, M. [Department of Mathematics, Quaid-i-Azam University, Islamabad 44000 (Pakistan)
2016-08-15
This paper presents a study of the magnetohydrodynamic (MHD) boundary layer flow of a non-Newtonian Carreau fluid over a convectively heated surface. The analysis of heat transfer is further performed in the presence of non-linear thermal radiation. The appropriate transformations are employed to bring the governing equations into dimensionless form. The numerical solutions of the partially coupled non-linear ordinary differential equations are obtained by using the Runge-Kutta Fehlberg integration scheme. The influence of non-dimensional governing parameters on the velocity, temperature, local skin friction coefficient and local Nusselt number is studied and discussed with the help of graphs and tables. Results proved that there is significant decrease in the velocity and the corresponding momentum boundary layer thickness with the growth in the magnetic parameter. However, a quite the opposite is true for the temperature and the corresponding thermal boundary layer thickness. - Highlights: • We investigated the Magnetohydrodynamic flow of Carreau constitutive fluid model. • Impact of non-linear thermal radiation is further taken into account. • Runge-Kutta Fehlberg method is employed to obtain the numerical solutions. • Fluid velocity is higher in case of hydromagnetic flow in comparison with hydrodynamic flow. • The local Nusselt number is a decreasing function of the thermal radiation parameter.
On CattaneoâChristov heat flux model for Carreau fluid flow over a slendering sheet
Directory of Open Access Journals (Sweden)
Hashim
Full Text Available The underlying intentions of this article are to investigate the impact of non-Fourier heat flux model on the stagnation-point flow of non-Newtonian Carreau fluid. In this study, the innovative CattaneoâChristov constitutive model is introduced to study the characteristics of thermal relaxation time. The flow is impelled by a slendering surface which is of the variable thickness. In the model, the physical mechanism responsible for homogeneousâheterogeneous reactions are further taken into account. Also, the diffusion coefficients of the reactant and auto catalyst are considered to be equal. The governing non-linear partial differential equations consisting of the momentum, energy and concentration equations are reduced to the coupled ordinary differential equations by means of local similarity transformations. The transformed ODEs are tackled numerically by employing an effective shooting algorithm along with the RungeâKutta Fehlberg scheme. The physical characteristics of the fluid velocity, temperature and concentration profiles are illuminated with the variation of numerous governing factors and are presented graphically. For instance, our result indicates that the temperature and thermal boundary layer thickness are lower in case of CattaneoâChristov heat flux model when compared to classical Fourierâs heat model. Meanwhile, the rate of heat transfer is significantly improved by a high wall thickness parameter and an opposite influence is found due to the thermal relaxation parameter. We further noticed that a higher value of homogeneous and heterogeneous reaction parameter corresponds to a deceleration in the concentration field and it shows an inverse relation for the Schmidt number. A correlation with accessible results for specific cases is found with fabulous consent. Keywords: CattaneoâChristov model, Carreau fluid, Slendering sheet, Homogeneousâheterogeneous reactions, RungeâKutta method
Story, Anna; Jaworski, Zdzisław
2017-01-01
Results of numerical simulations of momentum transfer for a highly shear-thinning fluid (0.2% Carbopol) in a stirred tank equipped with a Prochem Maxflo T type impeller are presented. The simulation results were validated using LDA data and both tangential and axial force measurements in the laminar and early transitional flow range. A good agreement between the predicted and experimental results of the local fluid velocity components was found. From the predicted and experimental values of both tangential and axial forces, the power number, Po , and thrust number, Th , were also calculated. Values of the absolute relative deviations were below 4.0 and 10.5%, respectively, for Po and Th , which confirms a satisfactory agreement with experiments. An intensive mixing zone, known as cavern, was observed near the impeller. In this zone, the local values of fluid velocity, strain rate, Metzner-Otto coefficient, shear stress and intensity of energy dissipation were all characterized by strong variability. Based on the results of experimental study a new model using non-dimensional impeller force number was proposed to predict the cavern diameter. Comparative numerical simulations were also carried out for a Newtonian fluid (water) and their results were similarly well verified using LDA measurements, as well as experimental power number values.
Abdollahzadeh Jamalabadi, Mohammad Yaghoub; Daqiqshirazi, Mohammadreza; Nasiri, Hossein; Safaei, Mohammad Reza; Nguyen, Truong Khang
2018-01-01
We present a numerical investigation of tapered arteries that addresses the transient simulation of non-Newtonian bio-magnetic fluid dynamics (BFD) of blood through a stenosis artery in the presence of a transverse magnetic field. The current model is consistent with ferro-hydrodynamic (FHD) and magneto-hydrodynamic (MHD) principles. In the present work, blood in small arteries is analyzed using the Carreau-Yasuda model. The arterial wall is assumed to be fixed with cosine geometry for the stenosis. A parametric study was conducted to reveal the effects of the stenosis intensity and the Hartman number on a wide range of flow parameters, such as the flow velocity, temperature, and wall shear stress. Current findings are in a good agreement with recent findings in previous research studies. The results show that wall temperature control can keep the blood in its ideal blood temperature range (below 40°C) and that a severe pressure drop occurs for blockages of more than 60 percent. Additionally, with an increase in the Ha number, a velocity drop in the blood vessel is experienced.
Directory of Open Access Journals (Sweden)
M. Farooq
Full Text Available This article studies MHD double stratified stagnation point flow of Carreau fluid towards a non linear stretchable surface with radiation. Features of heat and mass transfer are evaluated by using convective boundary conditions. Resulting nonlinear problems are solved and studied for the velocity, temperature and concentration fields. Heat and mass transfer rates in addition to skin friction are discussed. Besides this for the verification of the present findings, the results of presented analysis have been compared with the available works in particular situations and reasonable agreement is noted. Keywords: Convective boundary condition, Thermal radiation, Double stratification, Stagnation point flow
Stretched flow of Carreau nanofluid with convective boundary ...
Indian Academy of Sciences (India)
journal of. January 2016 physics pp. 3–17. Stretched flow of Carreau nanofluid with ... fluid over a flat plate subjected to convective surface condition. ... the steady laminar boundary layer flow over a permeable plate with a convective boundary.
Energy Technology Data Exchange (ETDEWEB)
Zolper, Thomas J.; He, Yifeng; Delferro, Massimiliano; Shiller, Paul; Doll, Gary; LotfizadehDehkordi, Babak; Ren, Ning; Lockwood, Frances; Marks, Tobin J.; Chung, Yip-Wah; Greco, Aaron; Erdemir, Ali; Wang, Qian
2016-08-11
This study investigates the rheological properties, elastohydrodynamic (EHD) film-forming capability, and friction coefficients of low molecular mass poly-alpha-olefin (PAO) base stocks with varying contents of high molecular mass olefin copolymers (OCPs) to assess their shear stability and their potential for energy-efficient lubrication. Several PAO-OCP mixtures were blended in order to examine the relationship between their additive content and tribological performance. Gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR) spectroscopy were used to characterize the molecular masses and structures, respectively. Density, viscosity, EHD film thickness, and friction were measured at 303 K, 348 K, and 398 K. Film thickness and friction were studied at entrainment speeds relevant to the boundary, mixed, and full-film lubrication regimes. The PAO-OCP mixtures underwent temporary shear-thinning resulting in decreases in film thickness and hydrodynamic friction. These results demonstrate that the shear characteristics of PAO-OCP mixtures can be tuned with the OCP content and provide insight into the effects of additives on EHD characteristics.
Shear thinning behaviors in magmas
Vetere, F. P.; Cassetta, M.; Perugini, D.
2017-12-01
Studies on magma rheology are of fundamental importance to understanding magmatic processes from depth to surface. Since viscosity is one of the most important parameter controlling eruption mechanisms, as well as lava flow emplacement, a comprehensive knowledge on the evolution of magma viscosities during crystallization is required. We present new viscosity data on partly crystalized basalt, andesite and analogue lavas comparable to those erupted on Mercury's northern volcanic plains. High-temperature viscosity measurements were performed using a rotational Anton Paar RheolabQC viscometer head at the PVRG labs, in Perugia (Italy) (http://pvrg.unipg.it). The relative proportion of phases in each experimental run were determined by image analysis on BS-SEM images at different magnifications; phases are glasses, clinopyroxene, spinel, plagioclase for the basalt, plagioclase and spinel for the andesite and pure enstatite and clinopyroxenes, for the analogue Mercury's composition. Glass and crystalline fractions determined by image analysis well correlate with compositions of residual melts. In order to constrain the viscosity (η) variations as a function of crystallinity, shear rate (γ) was varied from 0.1 to 5 s-1. Viscosity vs. time at constant temperature shows a typical S-shape curve. In particular, for basaltic composition η vary from 3.1-3.8 Pa s [log η] at 1493 K and crystallinity of 19 area % as γ vary from 1.0 to 0.1 s-1; the andesite viscosity evolution is 3.2 and 3.7 Pa s [log η] as γ varies from 1 to 0.1 at 1493 K and crystal content of 17 area %; finally, Mercury's analogue composition was investigated at different temperature ranging from 1533 to 1502 K (Vetere et al., 2017). Results, for γ = 0.1, 1.0 and 5.0 s-1, show viscosity variation between 2.7-4.0, 2.5-3.4 and 2.0-3.0 [log η inPa s] respectively while crystallinity vary from 9 to 27 (area %). As viscosity decreases as shear rate increases, these data points to a shear thinning behaviour
Simulation of forced convection in non-Newtonian fluid through sandstones
Gokhale, M. Y.; Fernandes, Ignatius
2017-11-01
Numerical simulation is carried out to study forced convection in non-Newtonian fluids flowing through sandstones. Simulation is carried out using lattice Boltzmann method (LBM) for both shear-thinning and shear-thickening, by varying the power law index from 0.5 to 1.5 in Carreau-Yasuda model. Parameters involved in LBM and Carreau model are identified to achieve numerical convergence. Permeability and porosity are varied in the range of 10-10-10-6 and 0.1-0.7, respectively, to match actual geometrical properties of sandstone. Numerical technology is validated by establishing Darcy's law by plotting the graph between velocity and pressure gradient. Consequently, investigation is carried out to study the influence of material properties of porous media on flow properties such as velocity profiles, temperature profiles, and Nusselt number.
Droplet breakup driven by shear thinning solutions in a microfluidic T-junction
Chiarello, Enrico; Gupta, Anupam; Mistura, Giampaolo; Sbragaglia, Mauro; Pierno, Matteo
2017-12-01
Droplet-based microfluidics turned out to be an efficient and adjustable platform for digital analysis, encapsulation of cells, drug formulation, and polymerase chain reaction. Typically, for most biomedical applications, the handling of complex, non-Newtonian fluids is involved, e.g., synovial and salivary fluids, collagen, and gel scaffolds. In this study, we investigate the problem of droplet formation occurring in a microfluidic T-shaped junction, when the continuous phase is made of shear thinning liquids. At first, we review in detail the breakup process, providing extensive, side-by-side comparisons between Newtonian and non-Newtonian liquids over unexplored ranges of flow conditions and viscous responses. The non-Newtonian liquid carrying the droplets is made of Xanthan solutions, a stiff, rodlike polysaccharide displaying a marked shear thinning rheology. By defining an effective Capillary number, a simple yet effective methodology is used to account for the shear-dependent viscous response occurring at the breakup. The droplet size can be predicted over a wide range of flow conditions simply by knowing the rheology of the bulk continuous phase. Experimental results are complemented with numerical simulations of purely shear thinning fluids using lattice Boltzmann models. The good agreement between the experimental and numerical data confirm the validity of the proposed rescaling with the effective Capillary number.
Asymmetric bubble collapse and jetting in generalized Newtonian fluids
Shukla, Ratnesh K.; Freund, Jonathan B.
2017-11-01
The jetting dynamics of a gas bubble near a rigid wall in a non-Newtonian fluid are investigated using an axisymmetric simulation model. The bubble gas is assumed to be homogeneous, with density and pressure related through a polytropic equation of state. An Eulerian numerical description, based on a sharp interface capturing method for the shear-free bubble-liquid interface and an incompressible Navier-Stokes flow solver for generalized fluids, is developed specifically for this problem. Detailed simulations for a range of rheological parameters in the Carreau model show both the stabilizing and destabilizing non-Newtonian effects on the jet formation and impact. In general, for fixed driving pressure ratio, stand-off distance and reference zero-shear-rate viscosity, shear-thinning and shear-thickening promote and suppress jet formation and impact, respectively. For a sufficiently large high-shear-rate limit viscosity, the jet impact is completely suppressed. Thresholds are also determined for the Carreau power-index and material time constant. The dependence of these threshold rheological parameters on the non-dimensional driving pressure ratio and wall stand-off distance is similarly established. Implications for tissue injury in therapeutic ultrasound will be discussed.
Aspiration of human neutrophils: effects of shear thinning and cortical dissipation.
Drury, J L; Dembo, M
2001-12-01
It is generally accepted that the human neutrophil can be mechanically represented as a droplet of polymeric fluid enclosed by some sort of thin slippery viscoelastic cortex. Many questions remain however about the detailed rheology and chemistry of the interior fluid and the cortex. To address these quantitative issues, we have used a finite element method to simulate the dynamics of neutrophils during micropipet aspiration using various plausible assumptions. The results were then systematically compared with aspiration experiments conducted at eight different combinations of pipet size and pressure. Models in which the cytoplasm was represented by a simple Newtonian fluid (i.e., models without shear thinning) were grossly incapable of accounting for the effects of pressure on the general time scale of neutrophil aspiration. Likewise, models in which the cortex was purely elastic (i.e., models without surface viscosity) were unable to explain the effects of pipet size on the general aspiration rate. Such models also failed to explain the rapid acceleration of the aspiration rate during the final phase of aspiration nor could they account for the geometry of the neutrophil during various phases of aspiration. Thus, our results indicate that a minimal mechanical model of the neutrophil needs to incorporate both shear thinning and surface viscosity to remain valid over a reasonable range of conditions. At low shear rates, the surface dilatation viscosity of the neutrophil was found to be on the order of 100 poise-cm, whereas the viscosity of the interior cytoplasm was on the order of 1000 poise. Both the surface viscosity and the interior viscosity seem to decrease in a similar fashion when the shear rate exceeds approximately 0.05 s(-1). Unfortunately, even models with both surface viscosity and shear thinning studied are still not sufficient to fully explain all the features of neutrophil aspiration. In particular, the very high rate of aspiration during the
Shear thinning and shear thickening of a confined suspension of vesicles
Nait Ouhra, A.; Farutin, A.; Aouane, O.; Ez-Zahraouy, H.; Benyoussef, A.; Misbah, C.
2018-01-01
Widely regarded as an interesting model system for studying flow properties of blood, vesicles are closed membranes of phospholipids that mimic the cytoplasmic membranes of red blood cells. In this study we analyze the rheology of a suspension of vesicles in a confined geometry: the suspension, bound by two planar rigid walls on each side, is subject to a shear flow. Flow properties are then analyzed as a function of shear rate γ ˙, the concentration of the suspension ϕ , and the viscosity contrast λ =ηin/ηout , where ηin and ηout are the fluid viscosities of the inner and outer fluids, respectively. We find that the apparent (or effective viscosity) of the suspension exhibits both shear thinning (decreasing viscosity with shear rate) or shear thickening (increasing viscosity with shear rate) in the same concentration range. The shear thinning or thickening behaviors appear as subtle phenomena, dependant on viscosity contrast λ . We provide physical arguments on the origins of these behaviors.
Effect of shear-thinning behaviour on liquid-liquid plug flow in microchannels
Roumpea, Evangelia; Chinaud, Maxime; Weheliye, Weheliye Hashi; Angeli, Panagiota; Kahouadji, Lyes; Matar, Omar K.
2016-11-01
The present work investigates the dynamics of plug formation of shear-thinning solutions in a 200 μm microchannel using a two-colour micro-PIV system. Measurements, including phase-averaged velocity fields, have been conducted both at the T-junction inlet and the main channel to enhance understanding of non-Newtonian liquid-liquid flows. Two aqueous glycerol solutions containing xanthan gum are used as the non-Newtonian fluids while 5 cSt silicone oil is the Newtonian phase. The current experimental results revealed a pronounced impact of the xanthan gum (shear-thinning behaviour) on the flow pattern transition boundaries, and enhance the fluid flowrates where plug flow occurred. The addition of polymer resulted also in different hydrodynamic characteristics such as a bullet-shaped plug and an increased film thickness between the plug and the wall. In the present work, the technique allows to capture the velocity field of both phases simultaneously. Experimental results are compared with the numerical simulations provided by the code BLUE. Project funded under the UK Engineering and Physical Sciences Research Council (EPSRC) Programme Grant MEMPHIS.
Injectable shear-thinning nanoengineered hydrogels for stem cell delivery
DEFF Research Database (Denmark)
Thakur, Ashish; Jaiswal, Manish K.; Peak, Charles W.
2016-01-01
-thinning characteristics, and enhanced mechanical stiffness, elastomeric properties, and physiological stability. The shear-thinning characteristics of nanocomposite hydrogels are investigated for human mesenchymal stem cell (hMSC) delivery. The hMSCs showed high cell viability after injection and encapsulated cells......Injectable hydrogels are investigated for cell encapsulation and delivery as they can shield cells from high shear forces. One of the approaches to obtain injectable hydrogels is to reinforce polymeric networks with high aspect ratio nanoparticles such as two-dimensional (2D) nanomaterials. 2D...... showed a circular morphology. The proposed shear-thinning nanoengineered hydrogels can be used for cell delivery for cartilage tissue regeneration and 3D bioprinting....
Sojka, Paul E.; Rodrigues, Neil S.
2015-11-01
The current study investigates the drop characteristics of three Carboxymethylcellulose (CMC) sprays produced by the impingement of two liquid jets. The three water-based solutions used in this work (0.5 wt.-% CMC-7MF, 0.8 wt.-% CMC-7MF, and 1.4 wt.-% CMC-7MF) exhibited strong shear-thinning, non-Newtonian behavior - characterized by the Bird-Carreau rheological model. A generalized Bird-Carreau jet Reynolds number was used as the primary parameter to characterize the drop size and the drop velocity, which were measured using Phase Doppler Anemometry (PDA). PDA optical configuration enabled a drop size measurement range of approximately 2.3 to 116.2 μm. 50,000 drops were measured at each test condition to ensure statistical significance. The arithmetic mean diameter (D10) , Sauter mean diameter (D32) , and mass median diameter (MMD) were used as representative diameters to characterize drop size. The mean axial drop velocity Uz -mean along with its root-mean square Uz -rms were used to characterize drop velocity. Incredibly, measurements for all three CMC liquids and reference DI water sprays seemed to follow a single curve for D32 and MMD drop diameters in the high generalized Bird-Carreau jet Reynolds number range considered in this work (9.21E +03
Modelling the fluid mechanics of cilia and flagella in reproduction and development.
Montenegro-Johnson, Thomas D; Smith, Andrew A; Smith, David J; Loghin, Daniel; Blake, John R
2012-10-01
Cilia and flagella are actively bending slender organelles, performing functions such as motility, feeding and embryonic symmetry breaking. We review the mechanics of viscous-dominated microscale flow, including time-reversal symmetry, drag anisotropy of slender bodies, and wall effects. We focus on the fundamental force singularity, higher-order multipoles, and the method of images, providing physical insight and forming a basis for computational approaches. Two biological problems are then considered in more detail: 1) left-right symmetry breaking flow in the node, a microscopic structure in developing vertebrate embryos, and 2) motility of microswimmers through non-Newtonian fluids. Our model of the embryonic node reveals how particle transport associated with morphogenesis is modulated by the gradual emergence of cilium posterior tilt. Our model of swimming makes use of force distributions within a body-conforming finite-element framework, allowing the solution of nonlinear inertialess Carreau flow. We find that a three-sphere model swimmer and a model sperm are similarly affected by shear-thinning; in both cases swimming due to a prescribed beat is enhanced by shear-thinning, with optimal Deborah number around 0.8. The sperm exhibits an almost perfect linear relationship between velocity and the logarithm of the ratio of zero to infinite shear viscosity, with shear-thickening hindering cell progress.
Imaging the Microscopic Structure of Shear Thinning and Thickening Colloidal Suspensions
Cheng, X.
2011-09-01
The viscosity of colloidal suspensions varies with shear rate, an important effect encountered in many natural and industrial processes. Although this non-Newtonian behavior is believed to arise from the arrangement of suspended particles and their mutual interactions, microscopic particle dynamics are difficult to measure. By combining fast confocal microscopy with simultaneous force measurements, we systematically investigate a suspension\\'s structure as it transitions through regimes of different flow signatures. Our measurements of the microscopic single-particle dynamics show that shear thinning results from the decreased relative contribution of entropic forces and that shear thickening arises from particle clustering induced by hydrodynamic lubrication forces. This combination of techniques illustrates an approach that complements current methods for determining the microscopic origins of non-Newtonian flow behavior in complex fluids.
End Effects in Rotational Viscometry I. No-Slip Shear-Thinning Samples in the Z40 DIN Sensor.
Czech Academy of Sciences Publication Activity Database
Wein, Ondřej; Večeř, Marek; Havlica, Jaromír
2007-01-01
Roč. 46, 5 (2007) , s. 765-772 ISSN 0035-4511. [Annual Rheology Conference AERC 2006 /3./. Crete, 27.04.2006-29.04.2006] R&D Projects: GA ČR(CZ) GA104/04/0826; GA ČR GP104/06/P287; GA ČR GP104/05/P554 Institutional research plan: CEZ:AV0Z40720504 Keywords : rotational couette flow * shear-thinning fluids * end effects Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.110, year: 2007
Extrusion Bioprinting of Shear-Thinning Gelatin Methacryloyl Bioinks.
Liu, Wanjun; Heinrich, Marcel A; Zhou, Yixiao; Akpek, Ali; Hu, Ning; Liu, Xiao; Guan, Xiaofei; Zhong, Zhe; Jin, Xiangyu; Khademhosseini, Ali; Zhang, Yu Shrike
2017-06-01
Bioprinting is an emerging technique for the fabrication of 3D cell-laden constructs. However, the progress for generating a 3D complex physiological microenvironment has been hampered by a lack of advanced cell-responsive bioinks that enable bioprinting with high structural fidelity, particularly in the case of extrusion-based bioprinting. Herein, this paper reports a novel strategy to directly bioprint cell-laden gelatin methacryloyl (GelMA) constructs using bioinks of GelMA physical gels (GPGs) achieved through a simple cooling process. Attributed to their shear-thinning and self-healing properties, the GPG bioinks can retain the shape and form integral structures after deposition, allowing for subsequent UV crosslinking for permanent stabilization. This paper shows the structural fidelity by bioprinting various 3D structures that are typically challenging to fabricate using conventional bioinks under extrusion modes. Moreover, the use of the GPG bioinks enables direct bioprinting of highly porous and soft constructs at relatively low concentrations (down to 3%) of GelMA. It is also demonstrated that the bioprinted constructs not only permit cell survival but also enhance cell proliferation as well as spreading at lower concentrations of the GPG bioinks. It is believed that such a strategy of bioprinting will provide many opportunities in convenient fabrication of 3D cell-laden constructs for applications in tissue engineering, regenerative medicine, and pharmaceutical screening. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Kheyfets, Vitaly O; Kieweg, Sarah L
2013-06-01
HIV/AIDS is a growing global pandemic. A microbicide is a formulation of a pharmaceutical agent suspended in a delivery vehicle, and can be used by women to protect themselves against HIV infection during intercourse. We have developed a three-dimensional (3D) computational model of a shear-thinning power-law fluid spreading under the influence of gravity to represent the distribution of a microbicide gel over the vaginal epithelium. This model, accompanied by a new experimental methodology, is a step in developing a tool for optimizing a delivery vehicle's structure/function relationship for clinical application. We compare our model with experiments in order to identify critical considerations for simulating 3D free-surface flows of shear-thinning fluids. Here we found that neglecting lateral spreading, when modeling gravity-induced flow, resulted in up to 47% overestimation of the experimental axial spreading after 90 s. In contrast, the inclusion of lateral spreading in 3D computational models resulted in rms errors in axial spreading under 7%. In addition, the choice of the initial condition for shape in the numerical simulation influences the model's ability to describe early time spreading behavior. Finally, we present a parametric study and sensitivity analysis of the power-law parameters' influence on axial spreading, and to examine the impact of changing rheological properties as a result of dilution or formulation conditions. Both the shear-thinning index (n) and consistency (m) impacted the spreading length and deceleration of the moving front. The sensitivity analysis showed that gels with midrange m and n values (for the ranges in this study) would be most sensitive (over 8% changes in spreading length) to 10% changes (e.g., from dilution) in both rheological properties. This work is applicable to many industrial and geophysical thin-film flow applications of non-Newtonian fluids; in addition to biological applications in microbicide drug delivery.
Radiative flow of Carreau liquid in presence of Newtonian heating and chemical reaction
Hayat, T.; Ullah, Ikram; Ahmad, B.; Alsaedi, A.
Objective of this article is to investigate the magnetohydrodynamic (MHD) boundary layer stretched flow of Carreau fluid in the presence of Newtonian heating. Sheet is presumed permeable. Analysis is studied in the presence of chemical reaction and thermal radiation. Mathematical formulation is established by using the boundary layer approximations. The resultant nonlinear flow analysis is computed for the convergent solutions. Interval of convergence via numerical data and plots are obtained and verified. Impact of numerous pertinent variables on the velocity, temperature and concentration is outlined. Numerical data for surface drag coefficient, surface heat transfer (local Nusselt number) and mass transfer (local Sherwood number) is executed and inspected. Comparison of skin friction coefficient in limiting case is made for the verification of current derived solutions.
Directory of Open Access Journals (Sweden)
Muhammad Mubashir Bhatti
2016-05-01
Full Text Available In this article, entropy generation with radiation on non-Newtonian Carreau nanofluid towards a shrinking sheet is investigated numerically. The effects of magnetohydrodynamics (MHD are also taken into account. Firstly, the governing flow problem is simplified into ordinary differential equations from partial differential equations with the help of similarity variables. The solution of the resulting nonlinear differential equations is solved numerically with the help of the successive linearization method and Chebyshev spectral collocation method. The influence of all the emerging parameters is discussed with the help of graphs and tables. It is observed that the influence of magnetic field and fluid parameters oppose the flow. It is also analyzed that thermal radiation effects and the Prandtl number show opposite behavior on temperature profile. Furthermore, it is also observed that entropy profile increases for all the physical parameters.
Shear thinning behavior of monolayer liquid lubricant films measured by fiber wobbling method
International Nuclear Information System (INIS)
Hamamoto, Y; Itoh, S; Fukuzawa, K; Zhang, H
2010-01-01
It is essential to clarify mechanical properties of monolayer lubricant films coated on magnetic disks under shearing motion for designing future hard disk drives with ultra-low flying height. Many of previous researchers reported that strong shear rate dependence of viscoelasticity was one of the typical phenomena observed with molecularly thin liquid films. However, it has not been clarified whether or not perfluoropolyether (PFPE) lubricant films, which are used for the head-disk interface (HDI) lubrication, show shear thinning behavior under actual HDI conditions. In this study, we used the fiber wobbling method that can achieve both highly-sensitive shear force measurement and precise gap control and measured shear rate dependence of viscoelastic properties of monolayer PFPE films coated on the magnetic disk. Our experimental results showed that shear thinning does occur at high shear rate ranged from 10 2 to 10 6 s -1 .
Zhang, Meng; Liu, Lin
2018-06-01
To unravel the true nature of glass transition, broader insights into glass forming have been gained by examining the stress-driven glassy systems, where strong shear thinning, i.e. a reduced viscosity under increasing shear rate, is encountered. It is argued that arbitrarily small stress-driven shear rates would ‘melt’ the glass and erase any memory of its thermal history. In this work, we report a glass transition memorized by the enthalpy-entropy compensation in strongly shear-thinned supercooled metallic liquids, which coincides with the thermal glass transition in both the transition temperature and the activation Gibbs free energy. Our findings provide distinctive insights into both glass forming and shear thinning, and enrich current knowledge on the ubiquitous enthalpy-entropy compensation empirical law in condensed matter physics.
Hu, Wei; Xu, Qiang; Wang, Gonghui; Scaringi, Gianvito; Mcsaveney, Mauri; Hicher, Pierre-Yves
2017-11-01
We present results of ring shear frictional resistance for mudstone granules of different size obtained from a landslide shear zone. Little rate dependency of shear resistance was observed in sand-sized granules in any wet or dry test, while saturated gravel-sized granules exhibited significant and abrupt reversible rate-weakening (from μ = 0.6 to 0.05) at about 2 mm/s. Repeating resistance variations occurred also under constant shear displacement rate. Mudstone granules generate mud as they are crushed and softened. Shear-thinning and thixotropic behavior of the mud can explain the observed behavior: with the viscosity decreasing, the mud can flow through the coarser soil pores and migrate out from the shear zone. This brings new granules into contact which produces new mud. Thus, the process can start over. Similarities between experimental shear zones and those of some landslides in mudstone suggest that the observed behavior may play a role in some landslide kinematics.
Energy Technology Data Exchange (ETDEWEB)
Daugan, S.
2002-11-01
After drawing up a balance sheet of current knowledge of settling of particles and suspensions in Newtonian and non Newtonian fluids, we introduce the characterisation of the fluid-particles system and especially the shear-thinning behavior of Xanthan solutions. This experimental study is organised into two parts. First of all, we study the settling behavior of a few particles falling along their line of centres. The conditions for particles aggregation with respect to the rheological properties of the suspending fluid are systematically reported. To that extent, rheological relaxation experiments are performed. Once aggregated, the particles velocities are much more important that the velocity of a single one. We show that a simple model, based on the Newtonian case, allows to predict the position and the velocity of each particle with respect to the initial separation distance between them. The second part of this work is devoted to the study of the settling behavior of spherical and monodisperse particles suspensions according to the particles volume fraction, the polymer concentration of the suspending fluid and the geometry of the sedimenting cell. From a model giving the particle volume fraction as a function of the luminous intensity transmitted by the suspension, we show that three regimes of different kinetics occur. During the second regime, the particle volume fraction decreases exponentially with time and the observed phenomena are very fast. Finally, we study the spatial structuration of the suspension and we link it to the topography of the sediment obtained at the end of the sedimentation. (author)
Onset of shear thinning in glassy liquids: Shear-induced small reduction of effective density.
Furukawa, Akira
2017-01-01
We propose a simple mechanism for describing the onset of shear thinning in a high-density glassy liquid. In a shear flow, along the compression axis, the overlap between neighboring particles is more enhanced than that at equilibrium, meaning that the "effective" size is reduced along this axis. On the other hand, along the extension axis perpendicular to the compression axis, the average structural configurations are stretched, but it does not indicate the expansion of the "effective" size itself. This asymmetric shear flow effect for particles results in a small reduction of the "effective" density. Because, in glass-forming liquids, the structural relaxation time τ_{α} strongly depends on the density ρ, even a very small reduction of the effective density should lead to a significant decrease of the relaxation time under shear flow. We predict that the crossover shear rate from Newtonian to non-Newtonian flow behaviors is given by γ[over ̇]_{c}=[ρ(∂τ_{α}/∂ρ)]^{-1}, which can be much smaller than 1/τ_{α} near the glass transition point. It is shown that this prediction is consistent with the results of molecular dynamics simulations.
Sivashanmugam, A; Charoenlarp, Pornkawee; Deepthi, S; Rajendran, Arunkumar; Nair, Shantikumar V; Iseki, Sachiko; Jayakumar, R
2017-12-13
For craniofacial bone regeneration, shear-thinning injectable hydrogels are favored over conventional scaffolds because of their improved defect margin adaptability, easier handling, and ability to be injected manually into deeper tissues. The most accepted method, after autografting, is the use of recombinant human bone morphogenetic protein-2 (BMP-2); however, complications such as interindividual variations, edema, and poor cost-efficiency in supraphysiological doses have been reported. The endogenous synthesis of BMP-2 is desirable, and a molecule which induces this is fibroblast growth factor-18 (FGF-18) because it can upregulate the BMP-2 expression by supressing noggin. We developed a chitin-poly(lactide-co-glycolide) (PLGA) composite hydrogel by regeneration chemistry and then incorporated CaSO 4 and FGF-18 for this purpose. Rheologically, a 7-fold increase in the elastic modulus was observed in the CaSO 4 -incorporated chitin-PLGA hydrogels as compared to the chitin-PLGA hydrogel. Shear-thinning Herschel-Bulkley fluid nature was observed for both hydrogels. Chitin-PLGA/CaSO 4 gel showed sustained release of FGF-18. In vitro osteogenic differentiation showed an enhanced alkaline phosphatase (ALP) expression in the FGF-18-containing chitin-PLGA/CaSO 4 gel when compared to cells alone. Further, it was confirmed by studying the expression of osteogenic genes [RUNX2, ALP, BMP-2, osteocalcin (OCN), and osteopontin (OPN)], immunofluorescence staining of BMP-2, OCN, and OPN, and alizarin red S staining. Incorporation of FGF-18 in the hydrogel increased the endothelial cell migration. Further, the regeneration potential of the prepared hydrogels was tested in vivo, and longitudinal live animal μ-CT was performed. FGF-18-loaded chitin-PLGA/CaSO 4 showed early and almost complete bone healing in comparison with chitin-PLGA/CaSO 4 , chitin-PLGA/FGF-18, chitin-PLGA, and sham control systems, as confirmed by hematoxylin and eosin and osteoid tetrachrome stainings
Binous, Housam
2007-01-01
We study four non-Newtonian fluid mechanics problems using Mathematica[R]. Constitutive equations describing the behavior of power-law, Bingham and Carreau models are recalled. The velocity profile is obtained for the horizontal flow of power-law fluids in pipes and annuli. For the vertical laminar film flow of a Bingham fluid we determine the…
Directory of Open Access Journals (Sweden)
Imad Khan
Full Text Available Current work highlights the computational aspects of MHD Carreau nanofluid flow over an inclined stretching cylinder with convective boundary conditions and Joule heating. The mathematical modeling of physical problem yields nonlinear set of partial differential equations. A suitable scaling group of variables is employed on modeled equations to convert them into non-dimensional form. The integration scheme Runge-Kutta-Fehlberg on the behalf of shooting technique is utilized to solve attained set of equations. The interesting aspects of physical problem (linear momentum, energy and nanoparticles concentration are elaborated under the different parametric conditions through graphical and tabular manners. Additionally, the quantities (local skin friction coefficient, local Nusselt number and local Sherwood number which are responsible to dig out the physical phenomena in the vicinity of stretched surface are computed and delineated by varying controlling flow parameters. Keywords: MHD, Carreau nanofluid, Inclined stretching cylinder, Joule heating, Shooting technique
Philippe, A M; Baravian, C; Imperor-Clerc, M; De Silva, J; Paineau, E; Bihannic, I; Davidson, P; Meneau, F; Levitz, P; Michot, L J
2011-05-18
Aqueous suspensions of swelling clay minerals exhibit a rich and complex rheological behaviour. In particular, these repulsive systems display strong shear-thinning at very low volume fractions in both the isotropic and gel states. In this paper, we investigate the evolution with shear of the orientational distribution of aqueous clay suspensions by synchrotron-based rheo-SAXS experiments using a Couette device. Measurements in radial and tangential configurations were carried out for two swelling clay minerals of similar morphology and size, Wyoming montmorillonite and Idaho beidellite. The shear evolution of the small angle x-ray scattering (SAXS) patterns displays significantly different features for these two minerals. The detailed analysis of the angular dependence of the SAXS patterns in both directions provides the average Euler angles of the statistical effective particle in the shear plane. We show that for both samples, the average orientation is fully controlled by the local shear stress around the particle. We then apply an effective approach to take into account multiple hydrodynamic interactions in the system. Using such an approach, it is possible to calculate the evolution of viscosity as a function of shear rate from the knowledge of the average orientation of the particles. The viscosity thus recalculated almost perfectly matches the measured values as long as collective effects are not too important in the system.
International Nuclear Information System (INIS)
Philippe, A M; Baravian, C; Imperor-Clerc, M; De Silva, J; Davidson, P; Paineau, E; Bihannic, I; Michot, L J; Meneau, F; Levitz, P
2011-01-01
Aqueous suspensions of swelling clay minerals exhibit a rich and complex rheological behaviour. In particular, these repulsive systems display strong shear-thinning at very low volume fractions in both the isotropic and gel states. In this paper, we investigate the evolution with shear of the orientational distribution of aqueous clay suspensions by synchrotron-based rheo-SAXS experiments using a Couette device. Measurements in radial and tangential configurations were carried out for two swelling clay minerals of similar morphology and size, Wyoming montmorillonite and Idaho beidellite. The shear evolution of the small angle x-ray scattering (SAXS) patterns displays significantly different features for these two minerals. The detailed analysis of the angular dependence of the SAXS patterns in both directions provides the average Euler angles of the statistical effective particle in the shear plane. We show that for both samples, the average orientation is fully controlled by the local shear stress around the particle. We then apply an effective approach to take into account multiple hydrodynamic interactions in the system. Using such an approach, it is possible to calculate the evolution of viscosity as a function of shear rate from the knowledge of the average orientation of the particles. The viscosity thus recalculated almost perfectly matches the measured values as long as collective effects are not too important in the system.
Khan, Mair; Shahid, Amna; Malik, M. Y.; Salahuddin, T.
2018-03-01
Current analysis has been made to scrutinize the consequences of chemical response against magneto-hydrodynamic Carreau-Yasuda nanofluid flow induced by a non-linear stretching surface considering zero normal flux, slip and convective boundary conditions. Joule heating effect is also considered. Appropriate similarity approach is used to convert leading system of PDE's for Carreau-Yasuda nanofluid into nonlinear ODE's. Well known mathematical scheme namely shooting method is utilized to solve the system numerically. Physical parameters, namely Weissenberg number We , thermal slip parameter δ , thermophoresis number NT, non-linear stretching parameter n, magnetic field parameter M, velocity slip parameter k , Lewis number Le, Brownian motion parameter NB, Prandtl number Pr, Eckert number Ec and chemical reaction parameter γ upon temperature, velocity and concentration profiles are visualized through graphs and tables. Numerical influence of mass and heat transfer rates and friction factor are also represented in tabular as well as graphical form respectively. Skin friction coefficient reduces when Weissenberg number We is incremented. Rate of heat transfer enhances for large values of Brownian motion constraint NB. By increasing Lewis quantity Le rate of mass transfer declines.
Irfan, M.; Khan, M.; Khan, W. A.
Inspired by modern deeds of nanotechnology and nanoscience and their abundant applications in the field of science and engineering, we establish a mathematical relation for unsteady 3D forced convective flow of Carreau nanofluid over a bidirectional stretched surface. Heat transfer phenomena of Carreau nanofluid is inspected through the variable thermal conductivity and heat generation/absorption impact. Furthermore, this research paper presents a more convincing approach for heat and mass transfer phenomenon of nanoliquid by utilizing new mass flux condition. Practically, zero mass flux condition is more adequate because in this approach we assume nanoparticle amends itself accordingly on the boundaries. Now the features of Buongiorno's relation for Carreau nanofluid can be applied in a more efficient way. An appropriate transformation is vacant to alter the PDEs into ODEs and then tackled numerically by employing bvp4c scheme. The numerous consequence of scheming parameters on the Carreau nanoliquid velocity components, temperature and concentration fields are portrayed graphically and deliberated in detail. The numerical outcomes for local skin friction and the wall temperature gradient for nanoliquid are intended and vacant through tables. The outcomes conveyed here manifest that impact of Brownian motion parameter Nb on the rate of heat transfer for nanoliquids becomes negligible for the recently recommended revised relation. Addationally, for authentication of the present relation, the achieved results are distinguished with earlier research works in specific cases and marvelous agreement has been noted.
Khan, M.; Irfan, M.; Khan, W. A.
2017-12-01
Nanoliquids retain remarkable features that have fascinated various researchers owing to their utilization in nanoscience and nanotechnology. We will present a mathematical relation for 3D forced convective heat and mass transfer mechanism of a Carreau nanoliquid over a bidirectional stretched surface. Additionally, the features of heat source/sink and nonlinear thermal radiation are considered for the 3D Carreau nanoliquid. The governing nonlinear PDEs are established and altered into a set of nonlinear ODEs by utilizing a suitable conversion. A numerical approach, namely the bvp4c is adopted to resolve the resultant equations. The achieved outcomes are schemed and conferred in detail for somatic parameters. It is realized that amassed values of Brownian motion parameter Nb lead to enhance the temperature of the Carreau nanoliquid while quite conflicting behavior is being noticed for the concentration of the Carreau nanoliquid. Moreover, it is also noted that the influence of heat source δ > 0 is relatively antithetic to heat sink δ communication with these results.
Hayat, T.; Ahmed, Bilal; Alsaedi, A.; Abbasi, F. M.
2018-03-01
The present communication investigates flow of Carreau-Yasuda nanofluid in presence of mixed convection and Hall current. Effects of viscous dissipation, Ohmic heating and convective conditions are addressed. In addition zero nanoparticle mass flux condition is imposed. Wave frame analysis is carried out. Coupled differential systems after long wavelength and low Reynolds number are numerically solved. Effects of different parameters on velocity, temperature and concentration are studied. Heat and mass transfer rates are analyzed through tabular values. It is observed that concentration for thermophoresis and Brownian motion parameters has opposite effect. Further heat and mass transfer rates at the upper wall enhances significantly when Hartman number increases and reverse situation is noticed for Hall parameter.
Czech Academy of Sciences Publication Activity Database
Hundertmark-Zaušková, A.; Lukáčová-Medviďová, M.; Nečasová, Šárka
2016-01-01
Roč. 68, č. 1 (2016), s. 193-243 ISSN 0025-5645 R&D Projects: GA ČR(CZ) GAP201/11/1304 Institutional support: RVO:67985840 Keywords : non-Newtonian fluids * fluid-structure interaction * shear-thinning fluids Subject RIV: BA - General Mathematics Impact factor: 0.592, year: 2016 http://projecteuclid.org/euclid.jmsj/1453731541
Entropic lattice Boltzmann model for charged leaky dielectric multiphase fluids in electrified jets.
Lauricella, Marco; Melchionna, Simone; Montessori, Andrea; Pisignano, Dario; Pontrelli, Giuseppe; Succi, Sauro
2018-03-01
We present a lattice Boltzmann model for charged leaky dielectric multiphase fluids in the context of electrified jet simulations, which are of interest for a number of production technologies including electrospinning. The role of nonlinear rheology on the dynamics of electrified jets is considered by exploiting the Carreau model for pseudoplastic fluids. We report exploratory simulations of charged droplets at rest and under a constant electric field, and we provide results for charged jet formation under electrospinning conditions.
Hayat, Tasawar; Aziz, Arsalan; Muhammad, Taseer; Alsaedi, Ahmed
2018-06-01
Darcy-Forchheimer three dimensional flow of Carreau nanoliquid induced by a linearly stretchable surface with convective boundary condition has been analyzed. Buongiorno model has been employed to elaborate thermophoresis and Brownian diffusion effects. Zero nanoparticles mass flux and convective surface conditions are implemented at the boundary. The governing problems are nonlinear. Optimal homotopic procedure has been used to tackle the governing mathematical system. Graphical results clearly depict the outcome of temperature and concentration fields. Surface drag coefficients and local Nusselt number are also plotted and discussed.
Viscous-elastic dynamics of power-law fluids within an elastic cylinder
Boyko, Evgeniy; Bercovici, Moran; Gat, Amir D.
2017-07-01
In a wide range of applications, microfluidic channels are implemented in soft substrates. In such configurations, where fluidic inertia and compressibility are negligible, the propagation of fluids in channels is governed by a balance between fluid viscosity and elasticity of the surrounding solid. The viscous-elastic interactions between elastic substrates and non-Newtonian fluids are particularly of interest due to the dependence of viscosity on the state of the system. In this work, we study the fluid-structure interaction dynamics between an incompressible non-Newtonian fluid and a slender linearly elastic cylinder under the creeping flow regime. Considering power-law fluids and applying the thin shell approximation for the elastic cylinder, we obtain a nonhomogeneous p-Laplacian equation governing the viscous-elastic dynamics. We present exact solutions for the pressure and deformation fields for various initial and boundary conditions for both shear-thinning and shear-thickening fluids. We show that in contrast to Stokes' problem where a compactly supported front is obtained for shear-thickening fluids, here the role of viscosity is inversed and such fronts are obtained for shear-thinning fluids. Furthermore, we demonstrate that for the case of a step in inlet pressure, the propagation rate of the front has a tn/n +1 dependence on time (t ), suggesting the ability to indirectly measure the power-law index (n ) of shear-thinning liquids through measurements of elastic deformation.
Study of blood flow in several benchmark micro-channels using a two-fluid approach.
Wu, Wei-Tao; Yang, Fang; Antaki, James F; Aubry, Nadine; Massoudi, Mehrdad
2015-10-01
It is known that in a vessel whose characteristic dimension (e.g., its diameter) is in the range of 20 to 500 microns, blood behaves as a non-Newtonian fluid, exhibiting complex phenomena, such as shear-thinning, stress relaxation, and also multi-component behaviors, such as the Fahraeus effect, plasma-skimming, etc. For describing these non-Newtonian and multi-component characteristics of blood, using the framework of mixture theory, a two-fluid model is applied, where the plasma is treated as a Newtonian fluid and the red blood cells (RBCs) are treated as shear-thinning fluid. A computational fluid dynamic (CFD) simulation incorporating the constitutive model was implemented using OpenFOAM® in which benchmark problems including a sudden expansion and various driven slots and crevices were studied numerically. The numerical results exhibited good agreement with the experimental observations with respect to both the velocity field and the volume fraction distribution of RBCs.
The fluid dynamics of the chocolate fountain
International Nuclear Information System (INIS)
Townsend, Adam K; Wilson, Helen J
2016-01-01
We consider the fluid dynamics of the chocolate fountain. Molten chocolate is a mildly shear-thinning non-Newtonian fluid. Dividing the flow into three main domains—the pumped flow up the centre, the film flow over each dome, and the freely falling curtain flow between the domes—we generate a wide-ranging study of Newtonian and non-Newtonian fluid mechanics. The central pumped flow is a benchmark to elucidate the effects of shear-thinning. The dome flow can be modelled as a thin-film flow with the leading-order effects being a simple balance of gravity and viscosity. Finally, the curtain flow is analytically intractable but is related to the existing theory of water bells (both inviscid and viscous). In pipe flow, Newtonian fluids exhibit a parabolic velocity profile; shear-thinning makes the profile more blunted. In thin-film flow over the dome, gravitational and viscous effects balance and the dome shape is not important beyond the local slope. We find that the chocolate thins and slows down as it travels down the dome. Finally, in the curtain flow, we predict the shape of the falling sheet for an inviscid fluid, and compare this with the literature to predict the shape for a viscous fluid, having shown that viscous forces are too great to ignore. We also find that the primary effect driving the shape of the curtain (which falls inwards towards the axis of the fountain) is surface tension. We find that the three domains provide excellent introductions to non-Newtonian mechanics, the important mathematical technique of scaling, and how to manipulate existing data to make our own predictions. We also find that the topic generates interest among the public in our engagement work. (paper)
The fluid dynamics of the chocolate fountain
Townsend, Adam K.; Wilson, Helen J.
2016-01-01
We consider the fluid dynamics of the chocolate fountain. Molten chocolate is a mildly shear-thinning non-Newtonian fluid. Dividing the flow into three main domains—the pumped flow up the centre, the film flow over each dome, and the freely falling curtain flow between the domes—we generate a wide-ranging study of Newtonian and non-Newtonian fluid mechanics. The central pumped flow is a benchmark to elucidate the effects of shear-thinning. The dome flow can be modelled as a thin-film flow with the leading-order effects being a simple balance of gravity and viscosity. Finally, the curtain flow is analytically intractable but is related to the existing theory of water bells (both inviscid and viscous). In pipe flow, Newtonian fluids exhibit a parabolic velocity profile; shear-thinning makes the profile more blunted. In thin-film flow over the dome, gravitational and viscous effects balance and the dome shape is not important beyond the local slope. We find that the chocolate thins and slows down as it travels down the dome. Finally, in the curtain flow, we predict the shape of the falling sheet for an inviscid fluid, and compare this with the literature to predict the shape for a viscous fluid, having shown that viscous forces are too great to ignore. We also find that the primary effect driving the shape of the curtain (which falls inwards towards the axis of the fountain) is surface tension. We find that the three domains provide excellent introductions to non-Newtonian mechanics, the important mathematical technique of scaling, and how to manipulate existing data to make our own predictions. We also find that the topic generates interest among the public in our engagement work.
On Laminar Flow of Non-Newtonian Fluids in Porous Media
Fayed, Hassan E.
2015-10-20
Flow of generalized Newtonian fluids in porous media can be modeled as a bundle of capillary tubes or a pore-scale network. In general, both approaches rely on the solution of Hagen–Poiseuille equation using power law to estimate the variations in the fluid viscosity due to the applied shear rate. Despite the effectiveness and simplicity, power law tends to provide unrealistic values for the effective viscosity especially in the limits of zero and infinite shear rates. Here, instead of using power law, Carreau model (bubbles, drops, and particles in non-Newtonian fluids. Taylor & Francis Group, New York, 2007) is used to determine the effective viscosity as a function of the shear strain rate. Carreau model can predict accurately the variation in the viscosity at all shear rates and provide more accurate solution for the flow physics in a single pore. Using the results for a single pore, normalized Fanning friction coefficient has been calculated and plotted as a function of the newly defined Reynolds number based on pressure gradient. For laminar flow, the variation in the friction coefficient with Reynolds number has been plotted and scaled. It is observed that generalized Newtonian fluid flows show Newtonian nature up to a certain Reynolds number. At high Reynolds number, deviation from the Newtonian behavior is observed. The main contribution of this paper is to present a closed-form solution for the flow in a single pore using Carreau model, which allows for fast evaluation of the relationship between flux and pressure gradient in an arbitrary pore diameter. In this way, we believe that our development will open the perspectives for using Carreau models in pore-network simulations at low computational costs to obtain more accurate prediction for generalized Newtonian fluid flows in porous media.
On Laminar Flow of Non-Newtonian Fluids in Porous Media
Fayed, Hassan E.; Sheikh, Nadeem A.; Iliev, Oleg
2015-01-01
Flow of generalized Newtonian fluids in porous media can be modeled as a bundle of capillary tubes or a pore-scale network. In general, both approaches rely on the solution of Hagen–Poiseuille equation using power law to estimate the variations in the fluid viscosity due to the applied shear rate. Despite the effectiveness and simplicity, power law tends to provide unrealistic values for the effective viscosity especially in the limits of zero and infinite shear rates. Here, instead of using power law, Carreau model (bubbles, drops, and particles in non-Newtonian fluids. Taylor & Francis Group, New York, 2007) is used to determine the effective viscosity as a function of the shear strain rate. Carreau model can predict accurately the variation in the viscosity at all shear rates and provide more accurate solution for the flow physics in a single pore. Using the results for a single pore, normalized Fanning friction coefficient has been calculated and plotted as a function of the newly defined Reynolds number based on pressure gradient. For laminar flow, the variation in the friction coefficient with Reynolds number has been plotted and scaled. It is observed that generalized Newtonian fluid flows show Newtonian nature up to a certain Reynolds number. At high Reynolds number, deviation from the Newtonian behavior is observed. The main contribution of this paper is to present a closed-form solution for the flow in a single pore using Carreau model, which allows for fast evaluation of the relationship between flux and pressure gradient in an arbitrary pore diameter. In this way, we believe that our development will open the perspectives for using Carreau models in pore-network simulations at low computational costs to obtain more accurate prediction for generalized Newtonian fluid flows in porous media.
Garai, Ashesh; Nandi, Arun K
2008-04-01
The melt rheology of polyaniline (PANI)-dinonylnaphthalenedisulfonic acid (DNNDSA) gel nanocomposites (GNCs) with organically modified (modified with cetyl trimethylammonium bromide)-montmorillonite (om-MMT) clay has been studied for three different clay concentrations at the temperature range 120-160 degrees C. Field emission scanning electron microscopy (FE-SEM), wide angle X-ray scattering (WAXS), differential scanning calorimetry (DSC) and dc-conductivity data (approximately 10(-3) S/cm) indicate that the PANI-DNNDSA melt is in sol state and it is not de-doped at that condition. The WAXS data indicate that in GNC-1 sol clay tactoids are in exfoliated state but in the other sols they are in intercalated state. The zero shear viscosity (eta0), storage modulus (G') and loss modulus (G") increase than that of pure gel in the GNCs. The pure sol and the sols of gel nanocomposites (GNCs) exhibit Newtonian behavior for low shear rate (clay concentration and the power law index (n) decreases with increase in clay concentration in the GNCs indicating increased shear thinning for the clay addition. Thus the sols of om-clay nanocomposites of PANI-DNNDSA system are easily processible. The storage modulus (G') of GNC sols are higher than that of pure PANI-DNNDSA sol, GNC1 sol shows a maximum of 733% increase in storage modulus and the percent increase decreases with increase in temperature. Exfoliated nature of clay tactoids has been attributed for the above dramatic increase of G'. The PANI-DNNDSA sol nanocomposites behave as a pseudo-solid at higher frequency where G' and loss modulus (G") show a crossover point in the frequency sweep experiment at a fixed temperature. The crossover frequency decreases with increase in clay concentration and it increases with increase in temperature for GNC sols. The pseudo-solid behavior has been explained from jamming or network formation of clay tactoids under shear. A probable explanation of the two apparently contradictory phenomena
Equilibrium and nonequilibrium dynamics of soft sphere fluids.
Ding, Yajun; Mittal, Jeetain
2015-07-14
We use computer simulations to test the freezing-point scaling relationship between equilibrium transport coefficients (self-diffusivity, viscosity) and thermodynamic parameters for soft sphere fluids. The fluid particles interact via the inverse-power potential (IPP), and the particle softness is changed by modifying the exponent of the distance-dependent potential term. In the case of IPP fluids, density and temperature are not independent variables and can be combined to obtain a coupling parameter to define the thermodynamic state of the system. We find that the rescaled coupling parameter, based on its value at the freezing point, can approximately collapse the diffusivity and viscosity data for IPP fluids over a wide range of particle softness. Even though the collapse is far from perfect, the freezing-point scaling relationship provides a convenient and effective way to compare the structure and dynamics of fluid systems with different particle softness. We further show that an alternate scaling relationship based on two-body excess entropy can provide an almost perfect collapse of the diffusivity and viscosity data below the freezing transition. Next, we perform nonequilibrium molecular dynamics simulations to calculate the shear-dependent viscosity and to identify the distinct role of particle softness in underlying structural changes associated with rheological properties. Qualitatively, we find a similar shear-thinning behavior for IPP fluids with different particle softness, though softer particles exhibit stronger shear-thinning tendency. By investigating the distance and angle-dependent pair correlation functions in these systems, we find different structural features in the case of IPP fluids with hard-sphere like and softer particle interactions. Interestingly, shear-thinning in hard-sphere like fluids is accompanied by enhanced translational order, whereas softer fluids exhibit loss of order with shear. Our results provide a systematic evaluation
Paul, Nibedita; Hazarika, Samiran; Saha, Abhijit; Mohanta, Dambarudhar
2013-10-01
The present work reports on the spectroscopic and rheological properties of un-exposed and gamma (γ-) irradiated rare earth (RE) oxide nanoparticle-based ferrofluids (FFs). The FFs were produced by dispersing surfactant coated terbium (Tb3+)-doped gadolinium oxide (Gd2O3) nanoparticles in the ethanol medium and later on they were subjected to energetic γ-irradiation (1.25 MeV) at select doses (97 Gy and 2.635 kGy). The synthesized RE oxide nanoparticles were of ˜7 nm size and having a cubic crystal structure, as predicted from transmission electron microscopy and x-ray diffraction studies. Fourier transformed infra-red (FT-IR) spectra showed an adequate blue shift of the Gd-O vibrational stretching mode from a wavenumber value of ˜558 cm-1, for the un-irradiated sample to a value of ˜540 cm-1 corresponding to the irradiated sample (2.635 kGy). In contrast, photoluminescence spectra have revealed modification of defect states along with Tb3+ assisted radiative transitions. The rheology measurements have illustrated unusual shear thinning behavior of the FFs, with an apparently improved power index (s) value from 0.34 to 0.50, obtained for increasing γ-dose cases. The variation of the decay parameter with irradiation dose, as predicted from the nature of apparent viscosity curves, is attributed to the defect formation, role of impurity ions (Tb3+), and weakening of inter nanoparticle bonding. The unusual properties of the novel RE oxide based FFs may find scope in sealing and shielding elements in the radiation environment including accelerator and other related zones.
Engineering Fracking Fluids with Computer Simulation
Shaqfeh, Eric
2015-11-01
There are no comprehensive simulation-based tools for engineering the flows of viscoelastic fluid-particle suspensions in fully three-dimensional geometries. On the other hand, the need for such a tool in engineering applications is immense. Suspensions of rigid particles in viscoelastic fluids play key roles in many energy applications. For example, in oil drilling the ``drilling mud'' is a very viscous, viscoelastic fluid designed to shear-thin during drilling, but thicken at stoppage so that the ``cuttings'' can remain suspended. In a related application known as hydraulic fracturing suspensions of solids called ``proppant'' are used to prop open the fracture by pumping them into the well. It is well-known that particle flow and settling in a viscoelastic fluid can be quite different from that which is observed in Newtonian fluids. First, it is now well known that the ``fluid particle split'' at bifurcation cracks is controlled by fluid rheology in a manner that is not understood. Second, in Newtonian fluids, the presence of an imposed shear flow in the direction perpendicular to gravity (which we term a cross or orthogonal shear flow) has no effect on the settling of a spherical particle in Stokes flow (i.e. at vanishingly small Reynolds number). By contrast, in a non-Newtonian liquid, the complex rheological properties induce a nonlinear coupling between the sedimentation and shear flow. Recent experimental data have shown both the shear thinning and the elasticity of the suspending polymeric solutions significantly affects the fluid-particle split at bifurcations, as well as the settling rate of the solids. In the present work, we use the Immersed Boundary Method to develop computer simulations of viscoelastic flow in suspensions of spheres to study these problems. These simulations allow us to understand the detailed physical mechanisms for the remarkable physical behavior seen in practice, and actually suggest design rules for creating new fluid recipes.
Effect of non-Newtonian viscosity on the fluid-dynamic characteristics in stenotic vessels
Huh, Hyung Kyu; Ha, Hojin; Lee, Sang Joon
2015-08-01
Although blood is known to have shear-thinning and viscoelastic properties, the effects of such properties on the hemodynamic characteristics in various vascular environments are not fully understood yet. For a quantitative hemodynamic analysis, the refractive index of a transparent blood analogue needs to be matched with that of the flowing conduit in order to minimize the errors according to the distortion of the light. In this study, three refractive index-matched blood analogue fluids with different viscosities are prepared—one Newtonian and two non-Newtonian analogues—which correspond to healthy blood with 45 % hematocrit (i.e., normal non-Newtonian) and obese blood with higher viscosity (i.e., abnormal non-Newtonian). The effects of the non-Newtonian rheological properties of the blood analogues on the hemodynamic characteristics in the post-stenosis region of an axisymmetric stenosis model are experimentally investigated using particle image velocimetry velocity field measurement technique and pathline flow visualization. As a result, the centerline jet flow from the stenosis apex is suppressed by the shear-thinning feature of the blood analogues when the Reynolds number is smaller than 500. The lengths of the recirculation zone for abnormal and normal non-Newtonian blood analogues are 3.67 and 1.72 times shorter than that for the Newtonian analogue at Reynolds numbers smaller than 200. The Reynolds number of the transition from laminar to turbulent flow for all blood analogues increases as the shear-thinning feature increases, and the maximum wall shear stresses in non-Newtonian fluids are five times greater than those in Newtonian fluids. However, the shear-thinning effect on the hemodynamic characteristics is not significant at Reynolds numbers higher than 1000. The findings of this study on refractive index-matched non-Newtonian blood analogues can be utilized in other in vitro experiments, where non-Newtonian features dominantly affect the flow
Data on mixing of viscous fluids by helical screw impellers in cylindrical vessels
Directory of Open Access Journals (Sweden)
Houari Ameur
2016-09-01
Full Text Available In this article, the data assembled regarding the mixing of Newtonian and shear thinning fluids by screw impellers in a cylindrical tank is disclosed. The data summarizing some information on the efficiency of such impellers are obtained via 3D calculations of velocities and viscous dissipation in the whole vessel volume. The data presented herein may be useful for those who want to outline the mixing characteristics in terms of fluid circulation and power consumption for this kind of impellers, therefore, avoiding a great effort for achieving a high number of experiments. Keyword: Mixing, Helical screw agitator, Power consumption, Fluid circulation, Cylindrical tanks
1994-07-14
CHARACTERISTICS OF LOW MOLECULAR WEIGHT SHEAR-THINNING FLUIDS A. S. Pereira Departamento de Engenharia Quimica , Instituto Superior de Engenharia do Porto Rua...de S.Tom6. 4200 Porto CODEX. Portugal F. T. Pinho Departamento de Engenharia Mecinica e Gestio Industrial Faculdade de Engenharia , Rua dos Bragas. 4099...turbulence Investiga•:’o Cientifica- INIC. INEGI (lnstituto de Engenharia characteristics of the low molecular weight polymers are Mec~nica e Gestio
Hall effects on hydromagnetic flow of an Oldroyd 6-constant fluid between concentric cylinders
International Nuclear Information System (INIS)
Rana, M.A.; Siddiqui, A.M.; Qamar, Rashid
2009-01-01
The hydromagnetic flow of an electrically conducting, incompressible Oldroyd 6-constant fluid between two concentric cylinders is investigated. The flow is generated by moving inner cylinder and/or application of the constant pressure gradient. Two non-linear boundary value problems are solved numerically. The effects of material parameters, pressure gradient, magnetic field and Hall parameter on the velocity are studied. The graphical representation of velocity reveals that characteristics for shear thinning/shear thickening behaviour of a fluid is dependent upon the rheological properties
Hall effects on hydromagnetic flow of an Oldroyd 6-constant fluid between concentric cylinders
Energy Technology Data Exchange (ETDEWEB)
Rana, M.A. [Management Information System, PINSTECH, P.O. Nilore, Islamabad 44000 (Pakistan)], E-mail: mafzalrana@yahoo.com; Siddiqui, A.M. [Department of Mathematics, Pennsylvania State University, York Campus, York, PA 17403 (United States); Qamar, Rashid [Management Information System, PINSTECH, P.O. Nilore, Islamabad 44000 (Pakistan)
2009-01-15
The hydromagnetic flow of an electrically conducting, incompressible Oldroyd 6-constant fluid between two concentric cylinders is investigated. The flow is generated by moving inner cylinder and/or application of the constant pressure gradient. Two non-linear boundary value problems are solved numerically. The effects of material parameters, pressure gradient, magnetic field and Hall parameter on the velocity are studied. The graphical representation of velocity reveals that characteristics for shear thinning/shear thickening behaviour of a fluid is dependent upon the rheological properties.
Study of blood flow in several benchmark micro-channels using a two-fluid approach
Wu, Wei-Tao; Yang, Fang; Antaki, James F.; Aubry, Nadine; Massoudi, Mehrdad
2015-01-01
It is known that in a vessel whose characteristic dimension (e.g., its diameter) is in the range of 20 to 500 microns, blood behaves as a non-Newtonian fluid, exhibiting complex phenomena, such as shear-thinning, stress relaxation, and also multi-component behaviors, such as the Fahraeus effect, plasma-skimming, etc. For describing these non-Newtonian and multi-component characteristics of blood, using the framework of mixture theory, a two-fluid model is applied, where the plasma is treated ...
Experimental and computational fluid dynamics studies of mixing of complex oral health products
Cortada-Garcia, Marti; Migliozzi, Simona; Weheliye, Weheliye Hashi; Dore, Valentina; Mazzei, Luca; Angeli, Panagiota; ThAMes Multiphase Team
2017-11-01
Highly viscous non-Newtonian fluids are largely used in the manufacturing of specialized oral care products. Mixing often takes place in mechanically stirred vessels where the flow fields and mixing times depend on the geometric configuration and the fluid physical properties. In this research, we study the mixing performance of complex non-Newtonian fluids using Computational Fluid Dynamics models and validate them against experimental laser-based optical techniques. To this aim, we developed a scaled-down version of an industrial mixer. As test fluids, we used mixtures of glycerol and a Carbomer gel. The viscosities of the mixtures against shear rate at different temperatures and phase ratios were measured and found to be well described by the Carreau model. The numerical results were compared against experimental measurements of velocity fields from Particle Image Velocimetry (PIV) and concentration profiles from Planar Laser Induced Fluorescence (PLIF).
Study of blood flow in several benchmark micro-channels using a two-fluid approach
Wu, Wei-Tao; Yang, Fang; Antaki, James F.; Aubry, Nadine; Massoudi, Mehrdad
2015-01-01
It is known that in a vessel whose characteristic dimension (e.g., its diameter) is in the range of 20 to 500 microns, blood behaves as a non-Newtonian fluid, exhibiting complex phenomena, such as shear-thinning, stress relaxation, and also multi-component behaviors, such as the Fahraeus effect, plasma-skimming, etc. For describing these non-Newtonian and multi-component characteristics of blood, using the framework of mixture theory, a two-fluid model is applied, where the plasma is treated as a Newtonian fluid and the red blood cells (RBCs) are treated as shear-thinning fluid. A computational fluid dynamic (CFD) simulation incorporating the constitutive model was implemented using OpenFOAM® in which benchmark problems including a sudden expansion and various driven slots and crevices were studied numerically. The numerical results exhibited good agreement with the experimental observations with respect to both the velocity field and the volume fraction distribution of RBCs. PMID:26240438
Development of a Model Foamy Viscous Fluid
Directory of Open Access Journals (Sweden)
Vial C.
2013-08-01
Full Text Available The objective is to develop a model viscous foamy fluid, i.e. below the very wet limit, the rheological and stability properties of which can be tuned. First, the method used for the preparation of foamy fluids is detailed, including process and formulation. Then, experimental results highlight that stable foamy fluids with a monomodal bubble size distribution can be prepared with a void fraction between 25% and 50% (v/v. Their viscoelastic properties under flow and low-strain oscillatory conditions are shown to result from the interplay between the formulation of the continuous phase, void fraction and bubble size. Their apparent viscosity can be described using the Cross equation and zero-shear Newtonian viscosity may be predicted by a Mooney equation up to a void fraction about 40%. The Cox-Merz and the Laun’s rules apply when the capillary number Ca is lower than 0.1. The upper limit of the zero-shear plateau region decreases when void fraction increases or bubble size decreases. In the shear-thinning region, shear stress varies with Ca1/2, as in wet foams with immobile surfaces. Finally, foamy fluids can be sheared up to Ca about 0.1 without impairing their microstructure. Their stability at rest achieves several hours and increases with void fraction due to compact packing constraints. These constitute, therefore, versatile model fluids to investigate the behaviour of foamy fluids below the very wet limit in process conditions.
The interaction of two spheres in a simple-shear flow of complex fluids
Firouznia, Mohammadhossein; Metzger, Bloen; Ovarlez, Guillaume; Hormozi, Sarah
2017-11-01
We study the interaction of two small freely-moving spheres in a linear flow field of Newtonian, shear thinning and yield stress fluids. We perform a series of experiments over a range of shear rates as well as different shear histories using an original apparatus and with the aid of conventional rheometry, Particle Image Velocimetry and Particle Tracking Velocimetry. Showing that the non-Newtonian nature of the suspending fluid strongly affects the shape of particle trajectories and the irreversibility. An important point is that non-Newtonian effects can be varied and unusual. Depending on the shear rate, nonideal shear thinning and yield stress suspending fluids might show elasticity that needs to be taken into account. The flow field around one particle is studied in different fluids when subjected to shear. Then using these results to explain the two particle interactions in a simple-shear flow we show how particle-particle contact and non-Newtonian behaviors result in relative trajectories with fore-aft asymmetry. Well-resolved velocity and stress fields around the particles are presented here. Finally, we discuss how the relative particle trajectories may affect the microstructure of complex suspensions and consequently the bulk rheology. NSF (Grant No. CBET-1554044-CAREER).
Spray Formation of Herschel-Bulkley Fluids using Impinging Jets
Rodrigues, Neil; Gao, Jian; Chen, Jun; Sojka, Paul E.
2015-11-01
The impinging jet spray formation of two non-Newtonian, shear-thinning, Herschel-Bulkley fluids was investigated in this work. The water-based gelled solutions used were 1.0 wt.-% agar and 1.0 wt.-% kappa carrageenan. A rotational rheometer and a capillary viscometer were used to measure the strain-rate dependency of viscosity and the Herschel-Bulkley Extended (HBE) rheological model was used to characterize the shear-thinning behavior. A generalized HBE jet Reynolds number Rej , gen - HBE was used as the primary parameter to characterize the spray formation. A like-on-like impinging jet doublet was used to produce atomization. Shadowgraphs were captured in the plane of the sheet formed by the two jets using a CCD camera with an Nd:YAG laser beam providing the back-illumination. Typical behavior for impinging jet atomization using Newtonian liquids was not generally observed due to the non-Newtonian, viscous properties of the agar and kappa carrageenan gels. Instead various spray patterns were observed depending on Rej , gen - HBE. Spray characteristics of maximum instability wavelength and sheet breakup length were extracted from the shadowgraphs. Multi-University Research Initiative Grant Number W911NF-08-1-0171.
Substitute fluid examinations for liquid manure
Directory of Open Access Journals (Sweden)
Schrader Kevin
2017-01-01
Full Text Available For the farming industry it is essential to use liquid manure as natural fertilizer. Through new agricultural regulation 2015 in Germany the industry must develop new liquid manure spreader systems because the ammonia and methane emission are limited. In a research project the University of Applied Sciences Zwickau and some other industry partners will develop such a new innovative liquid manure spreader. The new liquid manure spreader should use pulsating air to distribute the liquid manure exactly. The pulsating air, which flows through the pipelines, should be analysed at a test station. For examinations at this test station it is important to find another substitute fluid because liquid manure smells strong, is not transparent and is also not homogeneous enough for scientific investigations. Furthermore it is important to ensure that the substitute fluid is, like liquid manure, a non-Newtonian fluid. The substitute fluid must be a shear-thinning substance - this means the viscosity decrease at higher shear rate. Many different samples like soap-water-farragoes, jelly-water-farragoes, agar-water-farragoes, soap-ethanol-farragoes and more are, for the project, examined in regard of their physical properties to find the best substitute fluid. The samples are examined at the rotational viscometer for viscosity at various shear rates and then compared with the viscosity values of liquid manure.
Substitute fluid examinations for liquid manure
Schrader, Kevin; Riedel, Marco; Eichert, Helmut
For the farming industry it is essential to use liquid manure as natural fertilizer. Through new agricultural regulation 2015 in Germany the industry must develop new liquid manure spreader systems because the ammonia and methane emission are limited. In a research project the University of Applied Sciences Zwickau and some other industry partners will develop such a new innovative liquid manure spreader. The new liquid manure spreader should use pulsating air to distribute the liquid manure exactly. The pulsating air, which flows through the pipelines, should be analysed at a test station. For examinations at this test station it is important to find another substitute fluid because liquid manure smells strong, is not transparent and is also not homogeneous enough for scientific investigations. Furthermore it is important to ensure that the substitute fluid is, like liquid manure, a non-Newtonian fluid. The substitute fluid must be a shear-thinning substance - this means the viscosity decrease at higher shear rate. Many different samples like soap-water-farragoes, jelly-water-farragoes, agar-water-farragoes, soap-ethanol-farragoes and more are, for the project, examined in regard of their physical properties to find the best substitute fluid. The samples are examined at the rotational viscometer for viscosity at various shear rates and then compared with the viscosity values of liquid manure.
Dynamic characteristics of Non Newtonian fluid Squeeze film damper
Palaksha, C. P.; Shivaprakash, S.; Jagadish, H. P.
2016-09-01
The fluids which do not follow linear relationship between rate of strain and shear stress are termed as non-Newtonian fluid. The non-Newtonian fluids are usually categorized as those in which shear stress depends on the rates of shear only, fluids for which relation between shear stress and rate of shear depends on time and the visco inelastic fluids which possess both elastic and viscous properties. It is quite difficult to provide a single constitutive relation that can be used to define a non-Newtonian fluid due to a great diversity found in its physical structure. Non-Newtonian fluids can present a complex rheological behaviour involving shear-thinning, viscoelastic or thixotropic effects. The rheological characterization of complex fluids is an important issue in many areas. The paper analyses the damping and stiffness characteristics of non-Newtonian fluids (waxy crude oil) used in squeeze film dampers using the available literature for viscosity characterization. Damping and stiffness characteristic will be evaluated as a function of shear strain rate, temperature and percentage wax concentration etc.
Unconfined Unsteady Laminar Flow of a Power-Law Fluid across a Square Cylinder
Directory of Open Access Journals (Sweden)
Asterios Pantokratoras
2016-11-01
Full Text Available The flow of a non-Newtonian, power-law fluid, directed normally to a horizontal cylinder with square cross-section (two-dimensional flow is considered in the present paper. The problem is investigated numerically with a very large calculation domain in order that the flow could be considered unconfined. The investigation covers the power-law index from 0.1 up to 2 and the Reynolds number ranges from 60 to 160. Over this range of Reynolds numbers the flow is unsteady. It is found that the drag coefficient and the Strouhal number are higher in a confined flow compared to those of an unconfined flow. In addition some flow characteristics are lost in a confined flow. Complete results for the drag coefficient and Strouhal number in the entire shear-thinning and shear-thickening region have been produced. In shear-thinning fluids chaotic structures exist which diminish at higher values of power-law index. This study represents the first investigation of unsteady, non-Newtonian power-law flow past a square cylinder in an unconfined field.
Impact of induced magnetic field on synovial fluid with peristaltic flow in an asymmetric channel
Afsar Khan, Ambreen; Farooq, Arfa; Vafai, Kambiz
2018-01-01
In this paper, we have worked for the impact of induced magnetic field on peristaltic motion of a non-Newtonian, incompressible, synovial fluid in an asymmetric channel. We have solved the problem for two models, Model-1 which behaves as shear thinning fluid and Model-2 which behaves as shear thickening fluid. The problem is solved by using modified Adomian Decomposition method. It has seen that two models behave quite opposite to each other for some parameters. The impact of various parameters on u, dp/dx, Δp and induced magnetic field bx have been studied graphically. The significant findings of this study is that the size of the trapped bolus and the pressure gradient increases by increasing M for both models.
Electro-osmosis of non-Newtonian fluids in porous media using lattice Poisson-Boltzmann method.
Chen, Simeng; He, Xinting; Bertola, Volfango; Wang, Moran
2014-12-15
Electro-osmosis in porous media has many important applications in various areas such as oil and gas exploitation and biomedical detection. Very often, fluids relevant to these applications are non-Newtonian because of the shear-rate dependent viscosity. The purpose of this study was to investigate the behaviors and physical mechanism of electro-osmosis of non-Newtonian fluids in porous media. Model porous microstructures (granular, fibrous, and network) were created by a random generation-growth method. The nonlinear governing equations of electro-kinetic transport for a power-law fluid were solved by the lattice Poisson-Boltzmann method (LPBM). The model results indicate that: (i) the electro-osmosis of non-Newtonian fluids exhibits distinct nonlinear behaviors compared to that of Newtonian fluids; (ii) when the bulk ion concentration or zeta potential is high enough, shear-thinning fluids exhibit higher electro-osmotic permeability, while shear-thickening fluids lead to the higher electro-osmotic permeability for very low bulk ion concentration or zeta potential; (iii) the effect of the porous medium structure depends significantly on the constitutive parameters: for fluids with large constitutive coefficients strongly dependent on the power-law index, the network structure shows the highest electro-osmotic permeability while the granular structure exhibits the lowest permeability on the entire range of power law indices considered; when the dependence of the constitutive coefficient on the power law index is weaker, different behaviors can be observed especially in case of strong shear thinning. Copyright © 2014 Elsevier Inc. All rights reserved.
Directory of Open Access Journals (Sweden)
M. Rahimi-Gorji
2015-06-01
Full Text Available An analytical investigation is applied for unsteady motion of a rigid spherical particle in a quiescent shear-thinning power-law fluid. The results were compared with those obtained from Collocation Method (CM and the established Numerical Method (Fourth order Runge–Kutta scheme. It was shown that CM gave accurate results. Collocation Method (CM and Numerical Method are used to solve the present problem. We obtained that the CM which was used to solve such nonlinear differential equation with fractional power is simpler and more accurate than series method such as HPM which was used in some previous works by others but the new method named Akbari-Ganji’s Method (AGM is an accurate and simple method which is slower than CM for solving such problems. The terminal settling velocity—that is the velocity at which the net forces on a falling particle eliminate—for three different spherical particles (made of plastic, glass and steel and three flow behavior index n, in three sets of power-law non-Newtonian fluids was investigated, based on polynomial solution (CM. Analytical results obtained indicated that the time of reaching the terminal velocity in a falling procedure is significantly increased with growing of the particle size that validated with Numerical Method. Further, with approaching flow behavior to Newtonian behavior from shear-thinning properties of flow (n → 1, the transient time to achieving the terminal settling velocity is decreased.
Sui, Jize; Zhao, Peng; Cheng, Zhengdong; Zheng, Liancun; Zhang, Xinxin
2017-02-01
The rheological and heat-conduction constitutive models of micropolar fluids (MFs), which are important non-Newtonian fluids, have been, until now, characterized by simple linear expressions, and as a consequence, the non-Newtonian performance of such fluids could not be effectively captured. Here, we establish the novel nonlinear constitutive models of a micropolar fluid and apply them to boundary layer flow and heat transfer problems. The nonlinear power law function of angular velocity is represented in the new models by employing generalized "n-diffusion theory," which has successfully described the characteristics of non-Newtonian fluids, such as shear-thinning and shear-thickening fluids. These novel models may offer a new approach to the theoretical understanding of shear-thinning behavior and anomalous heat transfer caused by the collective micro-rotation effects in a MF with shear flow according to recent experiments. The nonlinear similarity equations with a power law form are derived and the approximate analytical solutions are obtained by the homotopy analysis method, which is in good agreement with the numerical solutions. The results indicate that non-Newtonian behaviors involving a MF depend substantially on the power exponent n and the modified material parameter K 0 introduced by us. Furthermore, the relations of the engineering interest parameters, including local boundary layer thickness, local skin friction, and Nusselt number are found to be fitted by a quadratic polynomial to n with high precision, which enables the extraction of the rapid predictions from a complex nonlinear boundary-layer transport system.
Optimum fluid design for drilling and cementing a well drilled with coil tubing technology
Energy Technology Data Exchange (ETDEWEB)
Swendsen, O.; Saasen, A.; Vassoy, B. [Statoil (Norway); Skogen, E.; Mackin, F.; Normann, S. H.
1998-12-31
The strategy, design and drilling fluid and cementing operations in the first two wells drilled with coil tubing technology in the Gullfaks field in the Tampen Spur Area of the Norwegian sector of the North Sea are discussed. The drilling fluid use was a solids-free potassium formate/polymer brine-based fluid with a density of 1,50-1.56 g/cc, with flow properties characterized by very low fluid loss due to high extensional viscosity, a low viscosity at all shear rates, and a low degree of shear-thinning. The low viscous drilling fluid is considered to have been the major contributing factor in achieving excellent hole cleaning, no differential sticking, successful setting of cement kick-off plugs, problem-free running of the liner, and excellent zonal isolation when cementing the liner. These experiences led the authors to conclude that it is possible to formulate a brine-based solids-free drilling fluid with low viscosity and fluid loss properties for most formation pressure regimes, and that such a drilling fluid is well suited to drilling highly deviated slim hole wells where hole cleaning and differential sticking present special challenges. 12 refs., 2 tabs., 3 figs.
Polymer Drilling Fluid with Micron-Grade Cenosphere for Deep Coal Seam
Directory of Open Access Journals (Sweden)
Peng Xu
2015-01-01
Full Text Available Traditional shallow coal seam uses clean water, solid-free system, and foam system as drilling fluid, while they are not suitable for deep coal seam drilling due to mismatching density, insufficient bearing capacity, and poor reservoir protection effect. According to the existing problems of drilling fluid, micron-grade cenosphere with high bearing capacity and ultralow true density is selected as density regulator; it, together with polymer “XC + CMC” and some other auxiliary agents, is jointly used to build micron-grade polymer drilling fluid with cenosphere which is suitable for deep coal seam. Basic performance test shows that the drilling fluid has good rheological property, low filtration loss, good density adjustability, shear thinning, and thixotropy; besides, drilling fluid flow is in line with the power law rheological model. Compared with traditional drilling fluid, dispersion stability basically does not change within 26 h; settlement stability evaluated with two methods only shows a small amount of change; permeability recovery rate evaluated with Qinshui Basin deep coal seam core exceeds 80%. Polymer drilling fluid with cenosphere provides a new thought to solve the problem of drilling fluid density and pressure for deep coal seam drilling and also effectively improves the performance of reservoir protection ability.
Universal rescaling of flow curves for yield-stress fluids close to jamming
Dinkgreve, M.; Paredes, J.; Michels, M. A. J.; Bonn, D.
2015-07-01
The experimental flow curves of four different yield-stress fluids with different interparticle interactions are studied near the jamming concentration. By appropriate scaling with the distance to jamming all rheology data can be collapsed onto master curves below and above jamming that meet in the shear-thinning regime and satisfy the Herschel-Bulkley and Cross equations, respectively. In spite of differing interactions in the different systems, master curves characterized by universal scaling exponents are found for the four systems. A two-state microscopic theory of heterogeneous dynamics is presented to rationalize the observed transition from Herschel-Bulkley to Cross behavior and to connect the rheological exponents to microscopic exponents for the divergence of the length and time scales of the heterogeneous dynamics. The experimental data and the microscopic theory are compared with much of the available literature data for yield-stress systems.
Xie, Lei; Choi, Young-Tai; Liao, Chang-Rong; Wereley, Norman M.
2015-05-01
A key requirement for the commercialization of various magnetorheological fluid (MRF)-based applications is sedimentation stability. In this study, a high viscosity linear polysiloxane (HVLP), which has been used for shock absorbers in heavy equipment, is proposed as a new carrier fluid in highly stable MRFs. The HVLP is known to be a thixotropic (i.e., shear thinning) fluid that shows very high viscosity at very low shear rate and low viscosity at higher shear rate. In this study, using the shear rheometer, the significant thixotropic behavior of the HVLP was experimentally confirmed. In addition, a HVLP carrier fluid-based MRF (HVLP MRF) with 26 vol. % was synthesized and its sedimentation characteristics were experimentally investigated. But, because of the opacity of the HVLP MRF, no mudline can be visually observed. Hence, a vertical axis inductance monitoring system (VAIMS) applied to a circular column of fluid was used to evaluate sedimentation behavior by correlating measured inductance with the volume fraction of dispersed particles (i.e., Fe). Using the VAIMS, Fe concentration (i.e., volume fraction) was monitored for 28 days with a measurement taken every four days, as well as one measurement after 96 days to characterize long-term sedimentation stability. Finally, the concentration of the HVLP MRF as a function of the depth in the column and time, as well as the concentration change versus the depth in the column, are presented and compared with those of a commercially available MRF (i.e., Lord MRF-126CD).
Nonisothermal flow of a non-Newtonian fluid with viscous heating between two parallel plates
International Nuclear Information System (INIS)
Imal, M.; Pinarbasi, A.
2004-01-01
In this study the pressure gradient-flow rate relationship for steady-state nonisothermal pressure-driven flow of a non-Newtonian fluid in a channel is investigated including the effect of viscous heating is taken into account. The viscosity of the fluid depends on both temperature and shear-rate. Exponential dependence of viscosity on temperature is modelled through Arrhenius law. Non-Newtonian behaviour of the fluid is modelled according to the Carreau rheological equation, which reflects the characteristics of most polymers adequately with an exponential temperature dependence of viscosity. Flow governing motion and energy balance equations are coupled and solution of this non-linear boundary value problem is found iteratively using a pseudo spectral method based on Chebyshev polynomials. The effect of activation energy parameter and Brinkman number, as well as the power-law index and material time constant on the flow is studied. It is found that while the pressure gradient-flow rate graph is monotonic for certain ranges of flow controlling parameters, there is a large jump in the graph under certain values of these parameters.(1 table and 5 figures are included.)
Contracting bubbles in Hele-Shaw cells with a power-law fluid
International Nuclear Information System (INIS)
McCue, Scott W; King, John R
2011-01-01
The problem of bubble contraction in a Hele-Shaw cell is studied for the case in which the surrounding fluid is of power-law type. A small perturbation of the radially symmetric problem is first considered, focussing on the behaviour just before the bubble vanishes, it being found that for shear-thinning fluids the radially symmetric solution is stable, while for shear-thickening fluids the aspect ratio of the bubble boundary increases. The borderline (Newtonian) case considered previously is neutrally stable, the bubble boundary becoming elliptic in shape with the eccentricity of the ellipse depending on the initial data. Further light is shed on the bubble contraction problem by considering a long thin Hele-Shaw cell: for early times the leading-order behaviour is one-dimensional in this limit; however, as the bubble contracts its evolution is ultimately determined by the solution of a Wiener–Hopf problem, the transition between the long thin limit and the extinction limit in which the bubble vanishes being described by what is in effect a similarity solution of the second kind. This same solution describes the generic (slit-like) extinction behaviour for shear-thickening fluids, the interface profiles that generalize the ellipses that characterize the Newtonian case being constructed by the Wiener–Hopf calculation
A Numerical Study of Mesh Adaptivity in Multiphase Flows with Non-Newtonian Fluids
Percival, James; Pavlidis, Dimitrios; Xie, Zhihua; Alberini, Federico; Simmons, Mark; Pain, Christopher; Matar, Omar
2014-11-01
We present an investigation into the computational efficiency benefits of dynamic mesh adaptivity in the numerical simulation of transient multiphase fluid flow problems involving Non-Newtonian fluids. Such fluids appear in a range of industrial applications, from printing inks to toothpastes and introduce new challenges for mesh adaptivity due to the additional ``memory'' of viscoelastic fluids. Nevertheless, the multiscale nature of these flows implies huge potential benefits for a successful implementation. The study is performed using the open source package Fluidity, which couples an unstructured mesh control volume finite element solver for the multiphase Navier-Stokes equations to a dynamic anisotropic mesh adaptivity algorithm, based on estimated solution interpolation error criteria, and conservative mesh-to-mesh interpolation routine. The code is applied to problems involving rheologies ranging from simple Newtonian to shear-thinning to viscoelastic materials and verified against experimental data for various industrial and microfluidic flows. This work was undertaken as part of the EPSRC MEMPHIS programme grant EP/K003976/1.
International Nuclear Information System (INIS)
Li, Si-Ning; Zhang, Hong-Na; Li, Xiao-Bin; Li, Qian; Li, Feng-Chen; Qian, Shizhi; Joo, Sang Woo
2017-01-01
Highlights: • Heat transfer performance of non-Newtonian fluid flow in a MHS is studied. • Pseudo-plastic fluid flow can clearly promote the heat transfer efficiency in MMC. • Heat transfer enhancement is attributed to the emergence of secondary flow. • The heat transfer uniformity can also be improved by pseudo-plastic fluid flow. - Abstract: As the miniaturization and integration become the leading trend of the micro-electro-mechanical systems, it is of great significance to improve the microscaled heat transfer performance. This paper presents a three-dimensional (3D) numerical simulation on the flow characteristics and heat transfer performance of non-Newtonian fluid flow in a manifold microchannel (MMC) heat sink and traditional microchannel (TMC) heat sink. The non-Newtonian fluid was described by the power-law model. The analyses concentrated on the non-Newtonian fluid effect on the heat transfer performance, including the heat transfer efficiency and uniformity of temperature distribution, as well as the influence of inlet/outlet configurations on fluid flow and heat transfer. Comparing with Newtonian fluid flow, pseudo-plastic fluid could reduce the drag resistance in both MMC and TMC, while the dilatant fluid brought in quite larger drag resistance. For the heat transfer performance, the introduction of pseudo-plastic fluid flow greatly improved the heat transfer efficiency owing to the generation of secondary flow due to the shear-thinning property. Besides, the temperature distribution in MMC was more uniform by using pseudo-plastic fluid. Moreover, the inlet/outlet configuration was also important for the design and arrangement of microchannel heat sinks, since the present work showed that the maximum temperature was prone to locating in the corners near the inlet and outlet. This work provides guidance for optimal design of small-scale heat transfer devices in many cooling applications, such as biomedical chips, electronic systems, and
Fluctuations of wormlike micelle fluids in capillary flow
Salipante, Paul; Meek, Stephen; Hudson, Steven; Polymers; Complex Fluids Group Team
2017-11-01
We investigate the effect of entrance geometry on the flow stability of wormlike micelles solutions in capillary flow. These solutions exhibit strong shear thinning behavior resulting from micelle breakage and have been observed to undergo large flow rate fluctuations. We investigate these fluctuations using simultaneous measurements of flow rate and pressure drop across a capillary, and we adjust entrance geometry. With a tapered constriction, we observe large persistent fluctuations above a critical flow rate, characterized by rapid decreases in the pressure drop with corresponding increase in flow rate followed by a period of recovery where pressure increases and flow rate decreases. Flow field observations in the tapered entrance show large flow circulations. An abrupt contraction produces smaller transient fluidized jets forming upstream of the constriction and the magnitude of the fluctuations are significantly diminished. The effect of fluid properties is studied by comparing the magnitude and timescales of the fluctuations for surfactant systems with different relaxation times. The onset of fluctuations is compared to a criterion for the onset of elastic instabilities and the magnitude is compared to estimates for changes in channel resistance. NIST on a Chip.
Drazin, Philip
1987-01-01
Outlines the contents of Volume II of "Principia" by Sir Isaac Newton. Reviews the contributions of subsequent scientists to the physics of fluid dynamics. Discusses the treatment of fluid mechanics in physics curricula. Highlights a few of the problems of modern research in fluid dynamics. Shows that problems still remain. (CW)
International Nuclear Information System (INIS)
Cantrell, K.J.; Kaplan, D.I.; Gilmore, T.J.
1997-01-01
Previous work has demonstrated the feasibility of injecting suspensions of micron-size zero-valent (FeO) particles into porous media as a method to emplace a permeable reactive zone. Further studies were conducted to evaluate the effects of several shearthinning fluids on enhancing the injectability of micron-size FeO particles into porous media. In contrast to Newtonian fluids, whose viscosities are constant with shear rate, certain non-Newtonian fluids are shearthinning, that is, the viscosity of these fluids decreases with increasing shear rate. The primary benefit of using these fluids for this application is that they increase the viscosity of the aqueous phase without adversely decreasing the hydraulic conductivity. A suspension formulated with a shearthinning fluid will maintain a relatively high viscosity in solution near the FeO particles (where the shear stress is low) relative to locations near the surfaces of the porous media, where the shear stress is high. The increased viscosity decreases the rate of gravitational settling of the dense FeO colloids (7.6 9/cm3) while maintaining a relatively high hydraulic conductivity that permits pumping the colloid suspensions into porous media at greater flowrates and distances. Aqueous solutions of three polymers at different concentrations were investigated. It was determined that, the use of shear thinning fluids greatly increases the injectability of the colloidal FeO suspensions in porous media
Undulatory swimming in viscoelastic fluids under geometric confinement: experiments with C. elegans
Gagnon, David; Shih, Jerry; Arratia, Paulo
2017-11-01
Many natural biological processes, such as bacteria moving through vesicles in the circulatory system and spermatozoa swimming through millimeter-scale fallopian tubes, require low Reynolds number swimmers to move between two fluid-solid interfaces. Furthermore, these biological systems typically involve non-Newtonian fluids (e.g. blood and mucus), which can be shear-thinning, viscoelastic, or both. Using the model biological organism C. elegans, we introduce two far-field no-slip boundary conditions in the beating plane by observing swimming through thin channels in viscosified Newtonian and viscoelastic fluids. Using image processing and particle tracking velocimetry techniques, we measure both the swimming kinematics and the resulting flow fields as a function of decreasing channel width. As this width approaches the characteristic transverse length scale of the nematode's swimming gate, we observe (i) swimming speed decreases with increasing De, (ii) this decrease in speed can be non-monotonic with decreasing channel width at a given De, and (iii) the change in nematode kinematics appears to be associated with a structural change in the flow field around the swimmer quantified using the flow type parameter.
Bhusal, Prabhat; Rahiri, Jamie Lee; Sua, Bruce; McDonald, Jessica E; Bansal, Mahima; Hanning, Sara; Sharma, Manisha; Chandramouli, Kaushik; Harrison, Jeff; Procter, Georgina; Andrews, Gavin; Jones, David S; Hill, Andrew G; Svirskis, Darren
2018-06-01
An understanding of biological fluids at the site of administration is important to predict the fate of drug delivery systems in vivo. Little is known about peritoneal fluid; therefore, we have investigated this biological fluid and compared it to phosphate-buffered saline, a synthetic media commonly used for in vitro evaluation of intraperitoneal drug delivery systems. Human peritoneal fluid samples were analysed for electrolyte, protein and lipid levels. In addition, physicochemical properties were measured alongside rheological parameters. Significant inter-patient variations were observed with regard to pH (p < 0.001), buffer capacity (p < 0.05), osmolality (p < 0.001) and surface tension (p < 0.05). All the investigated physicochemical properties of peritoneal fluid differed from phosphate-buffered saline (p < 0.001). Rheological examination of peritoneal fluid demonstrated non-Newtonian shear thinning behaviour and predominantly exhibited the characteristics of an entangled network. Inter-patient and inter-day variability in the viscosity of peritoneal fluid was observed. The solubility of the local anaesthetic lidocaine in peritoneal fluid was significantly higher (p < 0.05) when compared to phosphate-buffered saline. Interestingly, the dissolution rate of lidocaine was not significantly different between the synthetic and biological media. Importantly, and with relevance to intraperitoneal drug delivery systems, the sustained release of lidocaine from a thermosensitive gel formulation occurred at a significantly faster rate into peritoneal fluid. Collectively, these data demonstrate the variation between commonly used synthetic media and human peritoneal fluid. The differences in drug release rates observed illustrate the need for bio-relevant media, which ultimately would improve in vitro-in vivo correlation.
Ionic liquid nanotribology: stiction suppression and surface induced shear thinning.
Asencio, Rubén Álvarez; Cranston, Emily D; Atkin, Rob; Rutland, Mark W
2012-07-03
The friction and adhesion between pairs of materials (silica, alumina, and polytetrafluoroethylene) have been studied and interpreted in terms of the long-ranged interactions present. In ambient laboratory air, the interactions are dominated by van der Waals attraction and strong adhesion leading to significant frictional forces. In the presence of the ionic liquid (IL) ethylammonium nitrate (EAN) the van der Waals interaction is suppressed and the attractive/adhesive interactions which lead to "stiction" are removed, resulting in an at least a 10-fold reduction in the friction force at large applied loads. The friction coefficient for each system was determined; coefficients obtained in air were significantly larger than those obtained in the presence of EAN (which ranged between 0.1 and 0.25), and variation in the friction coefficients between systems was correlated with changes in surface roughness. As the viscosity of ILs can be relatively high, which has implications for the lubricating properties, the hydrodynamic forces between the surfaces have therefore also been studied. The linear increase in repulsive force with speed, expected from hydrodynamic interactions, is clearly observed, and these forces further inhibit the potential for stiction. Remarkably, the viscosity extracted from the data is dramatically reduced compared to the bulk value, indicative of a surface ordering effect which significantly reduces viscous losses.
Extrusion Bioprinting of Shear-Thinning Gelatin Methacryloyl Bioinks
Liu, Wanjun; Heinrich, Marcel A.; Zhou, Yixiao; Akpek, Ali; Hu, Ning; Liu, Xiao; Guan, Xiaofei; Zhong, Zhe; Jin, Xiangyu; Khademhosseini, Ali; Zhang, Yu Shrike
Bioprinting is an emerging technique for the fabrication of 3D cell-laden constructs. However, the progress for generating a 3D complex physiological microenvironment has been hampered by a lack of advanced cell-responsive bioinks that enable bioprinting with high structural fidelity, particularly
International Nuclear Information System (INIS)
Anon.
1991-01-01
Fluids engineering has played an important role in many applications, from ancient flood control to the design of high-speed compact turbomachinery. New applications of fluids engineering, such as in high-technology materials processing, biotechnology, and advanced combustion systems, have kept up unwaining interest in the subject. More accurate and sophisticated computational and measurement techniques are also constantly being developed and refined. On a more fundamental level, nonlinear dynamics and chaotic behavior of fluid flow are no longer an intellectual curiosity and fluid engineers are increasingly interested in finding practical applications for these emerging sciences. Applications of fluid technology to new areas, as well as the need to improve the design and to enhance the flexibility and reliability of flow-related machines and devices will continue to spur interest in fluids engineering. The objectives of the present seminar were: to exchange current information on arts, science, and technology of fluids engineering; to promote scientific cooperation between the fluids engineering communities of both nations, and to provide an opportunity for the participants and their colleagues to explore possible joint research programs in topics of high priority and mutual interest to both countries. The Seminar provided an excellent forum for reviewing the current state and future needs of fluids engineering for the two nations. With the Seminar ear-marking the first formal scientific exchange between Korea and the United States in the area of fluids engineering, the scope was deliberately left broad and general
Energy Technology Data Exchange (ETDEWEB)
Mirzadzhanzade, A Kh; Dedusanko, G Ya; Dinaburg, L S; Markov, Yu M; Rasizade, Ya N; Rozov, V N; Sherstnev, N M
1979-08-30
A drilling fluid is suggested for separating the drilling and plugging fluids which contains as the base increased solution of polyacrylamide and additive. In order to increase the viscoelastic properties of the liquid with simultaneous decrease in the periods of its fabrication, the solution contains as an additive dry bentonite clay. In cases of the use of a buffer fluid under conditions of negative temperatures, it is necessary to add to it table salt or ethylene glycol.
International Nuclear Information System (INIS)
Kan, K.K.
1983-01-01
The relationship of nuclear internal flow and collective inertia, the difference of this flow from that of a classical fluid, and the approach of this flow to rigid flow in independent-particle model rotation are elucidated by reviewing the theory of Schroedinger fluid and its implications for collective vibration and rotation. (author)
Bernard, Peter S
2015-01-01
This book presents a focused, readable account of the principal physical and mathematical ideas at the heart of fluid dynamics. Graduate students in engineering, applied math, and physics who are taking their first graduate course in fluids will find this book invaluable in providing the background in physics and mathematics necessary to pursue advanced study. The book includes a detailed derivation of the Navier-Stokes and energy equations, followed by many examples of their use in studying the dynamics of fluid flows. Modern tensor analysis is used to simplify the mathematical derivations, thus allowing a clearer view of the physics. Peter Bernard also covers the motivation behind many fundamental concepts such as Bernoulli's equation and the stream function. Many exercises are designed with a view toward using MATLAB or its equivalent to simplify and extend the analysis of fluid motion including developing flow simulations based on techniques described in the book.
Stenger, M. B.; Hargens, A. R.; Dulchavsky, S. A.; Arbeille, P.; Danielson, R. W.; Ebert, D. J.; Garcia, K. M.; Johnston, S. L.; Laurie, S. S.; Lee, S. M. C.;
2017-01-01
Introduction. NASA's Human Research Program is focused on addressing health risks associated with long-duration missions on the International Space Station (ISS) and future exploration-class missions beyond low Earth orbit. Visual acuity changes observed after short-duration missions were largely transient, but now more than 50 percent of ISS astronauts have experienced more profound, chronic changes with objective structural findings such as optic disc edema, globe flattening and choroidal folds. These structural and functional changes are referred to as the visual impairment and intracranial pressure (VIIP) syndrome. Development of VIIP symptoms may be related to elevated intracranial pressure (ICP) secondary to spaceflight-induced cephalad fluid shifts, but this hypothesis has not been tested. The purpose of this study is to characterize fluid distribution and compartmentalization associated with long-duration spaceflight and to determine if a relation exists with vision changes and other elements of the VIIP syndrome. We also seek to determine whether the magnitude of fluid shifts during spaceflight, as well as any VIIP-related effects of those shifts, are predicted by the crewmember's pre-flight status and responses to acute hemodynamic manipulations, specifically posture changes and lower body negative pressure. Methods. We will examine a variety of physiologic variables in 10 long-duration ISS crewmembers using the test conditions and timeline presented in the figure below. Measures include: (1) fluid compartmentalization (total body water by D2O, extracellular fluid by NaBr, intracellular fluid by calculation, plasma volume by CO rebreathe, interstitial fluid by calculation); (2) forehead/eyelids, tibia, and calcaneus tissue thickness (by ultrasound); (3) vascular dimensions by ultrasound (jugular veins, cerebral and carotid arteries, vertebral arteries and veins, portal vein); (4) vascular dynamics by MRI (head/neck blood flow, cerebrospinal fluid
Simulating single-phase and two-phase non-Newtonian fluid flow of a digital rock scanned at high resolution
Tembely, Moussa; Alsumaiti, Ali M.; Jouini, Mohamed S.; Rahimov, Khurshed; Dolatabadi, Ali
2017-11-01
Most of the digital rock physics (DRP) simulations focus on Newtonian fluids and overlook the detailed description of rock-fluid interaction. A better understanding of multiphase non-Newtonian fluid flow at pore-scale is crucial for optimizing enhanced oil recovery (EOR). The Darcy scale properties of reservoir rocks such as the capillary pressure curves and the relative permeability are controlled by the pore-scale behavior of the multiphase flow. In the present work, a volume of fluid (VOF) method coupled with an adaptive meshing technique is used to perform the pore-scale simulation on a 3D X-ray micro-tomography (CT) images of rock samples. The numerical model is based on the resolution of the Navier-Stokes equations along with a phase fraction equation incorporating the dynamics contact model. The simulations of a single phase flow for the absolute permeability showed a good agreement with the literature benchmark. Subsequently, the code is used to simulate a two-phase flow consisting of a polymer solution, displaying a shear-thinning power law viscosity. The simulations enable to access the impact of the consistency factor (K), the behavior index (n), along with the two contact angles (advancing and receding) on the relative permeability.
International Nuclear Information System (INIS)
Granger, R.A.
1985-01-01
This text offers the most comprehensive approach available to fluid mechanics. The author takes great care to insure a physical understanding of concepts grounded in applied mathematics. The presentation of theory is followed by engineering applications, helping students develop problem-solving skills from the perspective of a professional engineer. Extensive use of detailed examples reinforces the understanding of theoretical concepts
Fluid dynamics of dilatant fluid
DEFF Research Database (Denmark)
Nakanishi, Hiizu; Nagahiro, Shin-ichiro; Mitarai, Namiko
2012-01-01
of the state variable, we demonstrate that the model can describe basic features of the dilatant fluid such as the stress-shear rate curve that represents discontinuous severe shear thickening, hysteresis upon changing shear rate, and instantaneous hardening upon external impact. An analysis of the model...
Directory of Open Access Journals (Sweden)
M. H. Yazdi
2014-01-01
Full Text Available In the present study, the first and second law analyses of power-law non-Newtonian flow over embedded open parallel microchannels within micropatterned permeable continuous moving surface are examined at prescribed surface temperature. A similarity transformation is used to reduce the governing equations to a set of nonlinear ordinary differential equations. The dimensionless entropy generation number is formulated by an integral of the local rate of entropy generation along the width of the surface based on an equal number of microchannels and no-slip gaps interspersed between those microchannels. The velocity, the temperature, the velocity gradient, and the temperature gradient adjacent to the wall are substituted into this equation resulting from the momentum and energy equations obtained numerically by Dormand-Prince pair and shooting method. Finally, the entropy generation numbers, as well as the Bejan number, are evaluated. It is noted that the presence of the shear thinning (pseudoplastic fluids creates entropy along the surface, with an opposite effect resulting from shear thickening (dilatant fluids.
Secondary flow in a curved artery model with Newtonian and non-Newtonian blood-analog fluids
Najjari, Mohammad Reza; Plesniak, Michael W.
2016-11-01
Steady and pulsatile flows of Newtonian and non-Newtonian fluids through a 180°-curved pipe were investigated using particle image velocimetry (PIV). The experiment was inspired by physiological pulsatile flow through large curved arteries, with a carotid artery flow rate imposed. Sodium iodide (NaI) and sodium thiocyanate (NaSCN) were added to the working fluids to match the refractive index (RI) of the test section to eliminate optical distortion. Rheological measurements revealed that adding NaI or NaSCN changes the viscoelastic properties of non-Newtonian solutions and reduces their shear-thinning property. Measured centerline velocity profiles in the upstream straight pipe agreed well with an analytical solution. In the pulsatile case, secondary flow structures, i.e. deformed-Dean, Dean, Wall and Lyne vortices, were observed in various cross sections along the curved pipe. Vortical structures at each cross section were detected using the d2 vortex identification method. Circulation analysis was performed on each vortex separately during the systolic deceleration phase, and showed that vortices split and rejoin. Secondary flow structures in steady flows were found to be morphologically similar to those in pulsatile flows for sufficiently high Dean number. supported by the George Washington University Center for Biomimetics and Bioinspired Engineering.
Ruban, Anatoly I
This is the first book in a four-part series designed to give a comprehensive and coherent description of Fluid Dynamics, starting with chapters on classical theory suitable for an introductory undergraduate lecture course, and then progressing through more advanced material up to the level of modern research in the field. The present Part 1 consists of four chapters. Chapter 1 begins with a discussion of Continuum Hypothesis, which is followed by an introduction to macroscopic functions, the velocity vector, pressure, density, and enthalpy. We then analyse the forces acting inside a fluid, and deduce the Navier-Stokes equations for incompressible and compressible fluids in Cartesian and curvilinear coordinates. In Chapter 2 we study the properties of a number of flows that are presented by the so-called exact solutions of the Navier-Stokes equations, including the Couette flow between two parallel plates, Hagen-Poiseuille flow through a pipe, and Karman flow above an infinite rotating disk. Chapter 3 is d...
Stochastic characteristics and Second Law violations of atomic fluids in Couette flow
Raghavan, Bharath V.; Karimi, Pouyan; Ostoja-Starzewski, Martin
2018-04-01
Using Non-equilibrium Molecular Dynamics (NEMD) simulations, we study the statistical properties of an atomic fluid undergoing planar Couette flow, in which particles interact via a Lennard-Jones potential. We draw a connection between local density contrast and temporal fluctuations in the shear stress, which arise naturally through the equivalence between the dissipation function and entropy production according to the fluctuation theorem. We focus on the shear stress and the spatio-temporal density fluctuations and study the autocorrelations and spectral densities of the shear stress. The bispectral density of the shear stress is used to measure the degree of departure from a Gaussian model and the degree of nonlinearity induced in the system owing to the applied strain rate. More evidence is provided by the probability density function of the shear stress. We use the Information Theory to account for the departure from Gaussian statistics and to develop a more general probability distribution function that captures this broad range of effects. By accounting for negative shear stress increments, we show how this distribution preserves the violations of the Second Law of Thermodynamics observed in planar Couette flow of atomic fluids, and also how it captures the non-Gaussian nature of the system by allowing for non-zero higher moments. We also demonstrate how the temperature affects the band-width of the shear-stress and how the density affects its Power Spectral Density, thus determining the conditions under which the shear-stress acts is a narrow-band or wide-band random process. We show that changes in the statistical characteristics of the parameters of interest occur at a critical strain rate at which an ordering transition occurs in the fluid causing shear thinning and affecting its stability. A critical strain rate of this kind is also predicted by the Loose-Hess stability criterion.
Fernandez, C. A.; Jung, H. B.; Shao, H.; Bonneville, A.; Heldebrant, D.; Hoyt, D.; Zhong, L.; Holladay, J.
2014-12-01
Cost-effective yet safe creation of high-permeability reservoirs inside deep crystalline bedrock is the primary challenge for the viability of enhanced geothermal systems and unconventional oil/gas recovery. Current reservoir stimulation processes utilize brute force (hydraulic pressures in the order of hundreds of bar) to create/propagate fractures in the bedrock. Such stimulation processes entail substantial economic costs ($3.3 million per reservoir as of 2011). Furthermore, the environmental impacts of reservoir stimulation are only recently being determined. Widespread concerns about the environmental contamination have resulted in a number of regulations for fracturing fluids advocating for greener fracturing processes. To reduce the costs and environmental impact of reservoir stimulation, we developed an environmentally friendly and recyclable hydraulic fracturing fluid that undergoes a controlled and large volume expansion with a simultaneous increase in viscosity triggered by CO2 at temperatures relevant for reservoir stimulation in Enhanced Geothermal System (EGS). The volume expansion, which will specifically occurs at EGS depths of interest, generates an exceptionally large mechanical stress in fracture networks of highly impermeable rock propagating fractures at effective stress an order of magnitude lower than current technology. This paper will concentrate on the presentation of this CO2-triggered expanding hydrogel formed from diluted aqueous solutions of polyallylamine (PAA). Aqueous PAA-CO2 mixtures also show significantly higher viscosities than conventional rheology modifiers at similar pressures and temperatures due to the cross-linking reaction of PAA with CO2, which was demonstrated by chemical speciation studies using in situ HP-HT 13C MAS-NMR. In addtion, PAA shows shear-thinning behavior, a critical advantage for the use of this fluid system in EGS reservoir stimulation. The high pressure/temperature experiments and their results as well
International Nuclear Information System (INIS)
Paraschivoiu, I.; Prud'homme, M.; Robillard, L.; Vasseur, P.
2003-01-01
This book constitutes at the same time theoretical and practical base relating to the phenomena associated with fluid mechanics. The concept of continuum is at the base of the approach developed in this work. The general advance proceeds of simple balances of forces as into hydrostatic to more complex situations or inertias, the internal stresses and the constraints of Reynolds are taken into account. This advance is not only theoretical but contains many applications in the form of solved problems, each chapter ending in a series of suggested problems. The major part of the applications relates to the incompressible flows
International Nuclear Information System (INIS)
Kreider, J.F.
1985-01-01
This book is an introduction on fluid mechanics incorporating computer applications. Topics covered are as follows: brief history; what is a fluid; two classes of fluids: liquids and gases; the continuum model of a fluid; methods of analyzing fluid flows; important characteristics of fluids; fundamentals and equations of motion; fluid statics; dimensional analysis and the similarity principle; laminar internal flows; ideal flow; external laminar and channel flows; turbulent flow; compressible flow; fluid flow measurements
International Nuclear Information System (INIS)
Graney, K.; Chu, J.; Lin, P.C.
2002-01-01
Full text: A 78-year old male in end stage renal failure (ESRF) with a background of NIDDM retinopathy, nephropathy, and undergoing continuous ambulatory peritoneal dialysis (CAPD) presented with anorexia, clinically unwell, decreased mobility and right scrotal swelling. There was no difficulty during CAPD exchange except there was a positive fluid balance Peritoneal dialysates remained clear A CAPD peritoneal study was requested. 100Mbq 99mTc Sulphur Colloid was injected into a standard dialysate bag containing dialysate. Anterior dynamic images were acquired over the abdomen pelvis while the dialysate was infused Static images with anatomical markers were performed 20 mins post infusion, before and after patient ambulation and then after drainage. The study demonstrated communication between the peritoneal cavity and the right scrotal sac. Patient underwent right inguinal herniaplasty with a marlex mesh. A repeat CAPD flow study was performed as follow up and no abnormal connection between the peritoneal cavity and the right scrotal sac was demonstrated post operatively. This case study shows that CAPD flow studies can be undertaken as a simple, minimally invasive method to evaluate abnormal peritoneal fluid flow dynamics in patients undergoing CAPD, and have an impact on dialysis management. Copyright (2002) The Australian and New Zealand Society of Nuclear Medicine Inc
DEFF Research Database (Denmark)
RezaNejad Gatabi, Javad; Forouzbakhsh, Farshid; Ebrahimi Darkhaneh, Hadi
2010-01-01
The Auxiliary Fluid Flow meter is proposed to measure the fluid flow of any kind in both pipes and open channels. In this kind of flow measurement, the flow of an auxiliary fluid is measured Instead of direct measurement of the main fluid flow. The auxiliary fluid is injected into the main fluid ...
Energy Technology Data Exchange (ETDEWEB)
Kerbel, G.D.
1981-01-20
A study is made of a scale model in three dimensions of a guiding center plasma within the purview of gyroelastic (also known as finite gyroradius-near theta pinch) magnetohydrodynamics. The (nonlinear) system sustains a particular symmetry called isorrhopy which permits the decoupling of fluid modes from drift modes. Isorrhopic equilibria are analyzed within the framework of geometrical optics resulting in (local) dispersion relations and ray constants. A general scheme is developed to evolve an arbitrary linear perturbation of a screwpinch equilibrium as an invertible integral transform (over the complete set of generalized eigenfunctions defined naturally by the equilibrium). Details of the structure of the function space and the associated spectra are elucidated. Features of the (global) dispersion relation owing to the presence of gyroelastic stabilization are revealed. An energy principle is developed to study the stability of the tubular screwpinch.
International Nuclear Information System (INIS)
Kerbel, G.D.
1981-01-01
A study is made of a scale model in three dimensions of a guiding center plasma within the purview of gyroelastic (also known as finite gyroradius-near theta pinch) magnetohydrodynamics. The (nonlinear) system sustains a particular symmetry called isorrhopy which permits the decoupling of fluid modes from drift modes. Isorrhopic equilibria are analyzed within the framework of geometrical optics resulting in (local) dispersion relations and ray constants. A general scheme is developed to evolve an arbitrary linear perturbation of a screwpinch equilibrium as an invertible integral transform (over the complete set of generalized eigenfunctions defined naturally by the equilibrium). Details of the structure of the function space and the associated spectra are elucidated. Features of the (global) dispersion relation owing to the presence of gyroelastic stabilization are revealed. An energy principle is developed to study the stability of the tubular screwpinch
The Correlated Dynamics of Micron-Scale Cantilevers in a Viscous Fluid
Robbins, Brian A.
A number of microcantilever systems of fundamental importance are explored using theoretical and numerical methods to quantify and provide physical insights into the dynamics of experimentally accessible systems that include a variety of configurations and viscous fluids. It is first shown that the correlated dynamics of both a laterally and vertically offset cantilever pair can be accurately predicted by numerical simulations. This is verified by comparing the correlated dynamics yielded by numerical simulations with experimental measurement. It is also demonstrated that in order to obtain these accurate predictions, geometric details of the cantilever must be included in the numerical simulation to directly reflect the experimental cantilever. A microrheology technique that utilizes the fluctuation-dissipation theorem is proposed. It is shown that by including the frequency dependence of the fluid damping, improvements in accuracy of the predictions of the rheological properties of the surrounding fluid are observed over current techniques. The amplitude spectrum of a 2-D cantilever in a power-law fluid is studied. The resulting amplitude spectrum yielded a curve similar to an overdamped system. It is observed that the amplitude and noise spectrum yield the same qualitative response for a 2-D cantilever in a shear-thinning, power-law fluid. The correlated dynamics of a tethered vertically offset cantilever pair is investigated. It is shown that for a range of stiffness ratios, which is the ratio of the spring constant of the tethering relative to the cantilever spring constant, the change in the correlated dynamics of a Hookean spring tethered cantilever pair can be seen in the presence of fluid coupling. The dynamics of a spring-mass tethered, vertically offset cantilever pair is qualitatively studied by simplifying the model to an array of springs and masses. The resulting study found that the correlated dynamics of the displacement of mass of the tethered
Directory of Open Access Journals (Sweden)
Payam Hooshmand
2017-03-01
Full Text Available Numerical investigation of the effects of magnetic field strength, thermal radiation, Joule heating, and viscous heating on a forced convective flow of a non-Newtonian, incompressible power law fluid in an axisymmetric stretching sheet with variable temperature wall is accomplished. The power law shear thinning viscosity-shear rate model for the anisotropic solutions and the Rosseland approximation for the thermal radiation through a highly absorbing medium are considered. The temperature dependent heat sources, Joule heating, and viscous heating are considered as the source terms in the energy balance. The non-dimensional boundary layer equations are solved numerically in terms of similarity variable. A parameter study on the Nusselt number, viscous components of entropy generation, and thermal components of entropy generation in fluid is performed as a function of thermal radiation parameter (0 to 2, Brinkman number (0 to 10, Prandtl number (0 to 10, Hartmann number (0 to 1, power law index (0 to 1, and heat source coefficient (0 to 0.1.
Joint fluid analysis; Joint fluid aspiration ... El-Gabalawy HS. Synovial fluid analysis, synovial biopsy, and synovial pathology. In: Firestein GS, Budd RC, Gabriel SE, McInnes IB, O'Dell JR, eds. Kelly's Textbook of ...
Self lubricating fluid bearings
International Nuclear Information System (INIS)
Kapich, D.D.
1980-01-01
The invention concerns self lubricating fluid bearings, which are used in a shaft sealed system extending two regions. These regions contain fluids, which have to be isolated. A first seal is fluid tight for the first region between the carter shaft and the shaft. The second seal is fluid tight between the carter and the shaft, it communicates with the second region. The first fluid region is the environment surrounding the shaft carter. The second fluid region is a part of a nuclear reactor which contains the cooling fluid. The shaft is conceived to drive a reactor circulating and cooling fluid [fr
Kleinstreuer, Clement
2018-01-01
Modern Fluid Dynamics, Second Edition provides up-to-date coverage of intermediate and advanced fluids topics. The text emphasizes fundamentals and applications, supported by worked examples and case studies. Scale analysis, non-Newtonian fluid flow, surface coating, convection heat transfer, lubrication, fluid-particle dynamics, microfluidics, entropy generation, and fluid-structure interactions are among the topics covered. Part A presents fluids principles, and prepares readers for the applications of fluid dynamics covered in Part B, which includes computer simulations and project writing. A review of the engineering math needed for fluid dynamics is included in an appendix.
Prediction of blood pressure and blood flow in stenosed renal arteries using CFD
Jhunjhunwala, Pooja; Padole, P. M.; Thombre, S. B.; Sane, Atul
2018-04-01
In the present work an attempt is made to develop a diagnostive tool for renal artery stenosis (RAS) which is inexpensive and in-vitro. To analyse the effects of increase in the degree of severity of stenosis on hypertension and blood flow, haemodynamic parameters are studied by performing numerical simulations. A total of 16 stenosed models with varying degree of stenosis severity from 0-97.11% are assessed numerically. Blood is modelled as a shear-thinning, non-Newtonian fluid using the Carreau model. Computational Fluid Dynamics (CFD) analysis is carried out to compute the values of flow parameters like maximum velocity and maximum pressure attained by blood due to stenosis under pulsatile flow. These values are further used to compute the increase in blood pressure and decrease in available blood flow to kidney. The computed available blood flow and secondary hypertension for varying extent of stenosis are mapped by curve fitting technique using MATLAB and a mathematical model is developed. Based on these mathematical models, a quantification tool is developed for tentative prediction of probable availability of blood flow to the kidney and severity of stenosis if secondary hypertension is known.
Biasetti, Jacopo; Hussain, Fazle; Gasser, T Christian
2011-10-07
Abdominal aortic aneurysms (AAAs) are frequently characterized by the development of an intra-luminal thrombus (ILT), which is known to have multiple biochemical and biomechanical implications. Development of the ILT is not well understood, and shear-stress-triggered activation of platelets could be the first step in its evolution. Vortical structures (VSs) in the flow affect platelet dynamics, which motivated the present study of a possible correlation between VS and ILT formation in AAAs. VSs educed by the λ(2)-method using computational fluid dynamics simulations of the backward-facing step problem, normal aorta, fusiform AAA and saccular AAA were investigated. Patient-specific luminal geometries were reconstructed from computed tomography scans, and Newtonian and Carreau-Yasuda models were used to capture salient rheological features of blood flow. Particularly in complex flow domains, results depended on the constitutive model. VSs developed all along the normal aorta, showing that a clear correlation between VSs and high wall shear stress (WSS) existed, and that VSs started to break up during late systole. In contrast, in the fusiform AAA, large VSs developed at sites of tortuous geometry and high WSS, occupying the entire lumen, and lasting over the entire cardiac cycle. Downward motion of VSs in the AAA was in the range of a few centimetres per cardiac cycle, and with a VS burst at that location, the release (from VSs) of shear-stress-activated platelets and their deposition to the wall was within the lower part of the diseased artery, i.e. where the thickest ILT layer is typically observed. In the saccular AAA, only one VS was found near the healthy portion of the aorta, while in the aneurysmatic bulge, no VSs occurred. We present a fluid-dynamics-motivated mechanism for platelet activation, convection and deposition in AAAs that has the potential of improving our current understanding of the pathophysiology of fluid-driven ILT growth.
Fluid mechanics in fluids at rest.
Brenner, Howard
2012-07-01
Using readily available experimental thermophoretic particle-velocity data it is shown, contrary to current teachings, that for the case of compressible flows independent dye- and particle-tracer velocity measurements of the local fluid velocity at a point in a flowing fluid do not generally result in the same fluid velocity measure. Rather, tracer-velocity equality holds only for incompressible flows. For compressible fluids, each type of tracer is shown to monitor a fundamentally different fluid velocity, with (i) a dye (or any other such molecular-tagging scheme) measuring the fluid's mass velocity v appearing in the continuity equation and (ii) a small, physicochemically and thermally inert, macroscopic (i.e., non-Brownian), solid particle measuring the fluid's volume velocity v(v). The term "compressibility" as used here includes not only pressure effects on density, but also temperature effects thereon. (For example, owing to a liquid's generally nonzero isobaric coefficient of thermal expansion, nonisothermal liquid flows are to be regarded as compressible despite the general perception of liquids as being incompressible.) Recognition of the fact that two independent fluid velocities, mass- and volume-based, are formally required to model continuum fluid behavior impacts on the foundations of contemporary (monovelocity) fluid mechanics. Included therein are the Navier-Stokes-Fourier equations, which are now seen to apply only to incompressible fluids (a fact well-known, empirically, to experimental gas kineticists). The findings of a difference in tracer velocities heralds the introduction into fluid mechanics of a general bipartite theory of fluid mechanics, bivelocity hydrodynamics [Brenner, Int. J. Eng. Sci. 54, 67 (2012)], differing from conventional hydrodynamics in situations entailing compressible flows and reducing to conventional hydrodynamics when the flow is incompressible, while being applicable to both liquids and gases.
Reduced abrasion drilling fluid
2010-01-01
A reduced abrasion drilling fluid system and method of drilling a borehole by circulating the reduced abrasion drilling fluid through the borehole is disclosed. The reduced abrasion drilling fluid comprises a drilling fluid, a first additive and a weighting agent, wherein the weighting agent has a
Reduced abrasion drilling fluid
2012-01-01
A reduced abrasion drilling fluid system and method of drilling a borehole by circulating the reduced abrasion drilling fluid through the borehole is disclosed. The reduced abrasion drilling fluid comprises a drilling fluid, a first additive and a weighting agent, wherein the weighting agent has a
International Nuclear Information System (INIS)
Farquhar, N.G.; Schwab, J.A.
1977-01-01
A system of heat exchangers is disclosed for cooling process fluids. The system is particularly applicable to cooling steam generator blowdown fluid in a nuclear plant prior to chemical purification of the fluid in which it minimizes the potential of boiling of the plant cooling water which cools the blowdown fluid
FOREWORD Fluid Mechanics and Fluid Power (FMFP)
Indian Academy of Sciences (India)
This section of the Special Issue carries selected articles from the Fluid Mechanics and Fluid. Power Conference held during 12–14 December 2013 at the National Institute of Technology,. Hamirpur (HP). The section includes three review articles and nine original research articles. These were selected on the basis of their ...
Shinbrot, Marvin
2012-01-01
Readable and user-friendly, this high-level introduction explores the derivation of the equations of fluid motion from statistical mechanics, classical theory, and a portion of the modern mathematical theory of viscous, incompressible fluids. 1973 edition.
... Plasma Free Metanephrines Platelet Count Platelet Function Tests Pleural Fluid Analysis PML-RARA Porphyrin Tests Potassium Prealbumin ... is being tested? Synovial fluid is a thick liquid that acts as a lubricant for the body's ...
Van Dam, Jeremy Daniel; Turnquist, Norman Arnold; Raminosoa, Tsarafidy; Shah, Manoj Ramprasad; Shen, Xiaochun
2015-09-29
An electric machine is presented. The electric machine includes a hollow rotor; and a stator disposed within the hollow rotor, the stator defining a flow channel. The hollow rotor includes a first end portion defining a fluid inlet, a second end portion defining a fluid outlet; the fluid inlet, the fluid outlet, and the flow channel of the stator being configured to allow passage of a fluid from the fluid inlet to the fluid outlet via the flow channel; and wherein the hollow rotor is characterized by a largest cross-sectional area of hollow rotor, and wherein the flow channel is characterized by a smallest cross-sectional area of the flow channel, wherein the smallest cross-sectional area of the flow channel is at least about 25% of the largest cross-sectional area of the hollow rotor. An electric fluid pump and a power generation system are also presented.
... Alternative Names Culture - CSF; Spinal fluid culture; CSF culture Images Pneumococci organism References Karcher DS, McPherson RA. Cerebrospinal, synovial, serous body fluids, and alternative specimens. In: McPherson RA, Pincus ...
Cerebrospinal fluid leak (image)
... brain and spinal cord by acting like a liquid cushion. The fluid allows the organs to be buoyant protecting them from blows or other trauma. Inside the skull the cerebrospinal fluid is contained by the dura which covers ...
International Nuclear Information System (INIS)
Myeong, Hyeon Guk
1999-06-01
This book deals with computational fluid dynamics with basic and history of numerical fluid dynamics, introduction of finite volume method using one-dimensional heat conduction equation, solution of two-dimensional heat conduction equation, solution of Navier-Stokes equation, fluid with heat transport, turbulent flow and turbulent model, Navier-Stokes solution by generalized coordinate system such as coordinate conversion, conversion of basic equation, program and example of calculation, application of abnormal problem and high speed solution of numerical fluid dynamics.
Indian Academy of Sciences (India)
librium of a vertical slice fluid (Figure Id) of height H and again using the fact .... same fluid having the same shape and same volume as the body. This fluid volume .... example, can be caused by the heating of air near the ground by the sun ...
Fernandes, Nikhil; Dallas, Panagiotis; Rodriguez, Robert; Bourlinos, Athanasios B.; Georgakilas, Vasilios; Giannelis, Emmanuel P.
2010-01-01
®). The ionic fluid was compared to a control synthesized by mixing the partially protonated form (sodium form) of the fullerols with the same oligomeric amine in the same ratio as in the ionic fluids (20 wt% fullerol). In the fullerol fluid the ionic bonding
Michell, S J
2013-01-01
Fluid and Particle Mechanics provides information pertinent to hydraulics or fluid mechanics. This book discusses the properties and behavior of liquids and gases in motion and at rest. Organized into nine chapters, this book begins with an overview of the science of fluid mechanics that is subdivided accordingly into two main branches, namely, fluid statics and fluid dynamics. This text then examines the flowmeter devices used for the measurement of flow of liquids and gases. Other chapters consider the principle of resistance in open channel flow, which is based on improper application of th
Fluid inclusion geothermometry
Cunningham, C.G.
1977-01-01
Fluid inclusions trapped within crystals either during growth or at a later time provide many clues to the histories of rocks and ores. Estimates of fluid-inclusion homogenization temperature and density can be obtained using a petrographic microscope with thin sections, and they can be refined using heating and freezing stages. Fluid inclusion studies, used in conjunction with paragenetic studies, can provide direct data on the time and space variations of parameters such as temperature, pressure, density, and composition of fluids in geologic environments. Changes in these parameters directly affect the fugacity, composition, and pH of fluids, thus directly influencing localization of ore metals. ?? 1977 Ferdinand Enke Verlag Stuttgart.
Fluid Mechanics and Fluid Power (FMFP)
Indian Academy of Sciences (India)
Amitabh Bhattacharya
of renewable energy (e.g., via wind, hydrokinetic generators), creating low-cost healthcare ... multiphase flow, turbulence, bio-fluid dynamics, atmospheric flows, microfluidic flows, and ... study the challenging problem of entry of solids in water.
Rheo-NMR - how nuclear magnetic resonance is providing new insight regarding complex fluid rheology
International Nuclear Information System (INIS)
Callaghan, P.T.
2000-01-01
Over the past five decades, NMR has revolutionised chemistry, and has found widespread application in condensed matter physics, in molecular biology, in medicine and in food technology. Most recently NMR has made a significant impact in chemical engineering, where it is being extensively used for the non-invasive study of dispersion and flow in porous media. One of the most recent applications of NMR in materials science concerns its use in the study of the mechanical properties of complex fluids. This particular aspect of NMR has been extensively developed in research carried out at Massey University in New Zealand. In this short article, some of the ideas behind this work and the applications which have resulted, will be described. These examples provide a glimpse of possible applications of Nuclear Magnetic Resonance to the study of complex fluid rheology. While this is a very new field of research in which only a handful of groups presently participate, the potential exists for a substantial increase in Rheo-NMR research activity. Systems studied to date include polymer melts and semi-dilute solutions, thermotropic and lyotropic liquid crystals and liquid crystalline polymers, micellar solutions, food materials and colloidal suspensions. Rheo-NMR suffers in a number of respects by comparison with optical methods. It is expensive, it is difficult to use, it suffers from poor signal-to-noise ratios and the effective interpretation of spectra often depends on familiarity with the nuclear spin Hamiltonian and the associated effects of spin dynamics. Nonetheless NMR offers some unique advantages, including the ability to work with opaque materials, the ability to combine velocimetry with localised spectroscopy, and the ability to access a wide range of molecular properties relating to organisation, orientation and dynamics. Rheo-NMR has been able to provide a direct window on a variety of behaviours, including slip, shear-thinning, shear banding, yield stress
Fernandes, Nikhil; Dallas, Panagiotis; Rodriguez, Robert; Bourlinos, Athanasios B.; Georgakilas, Vasilios; Giannelis, Emmanuel P.
2010-09-01
We report for the first time an ionic fluid based on hydroxylated fullerenes (fullerols). The ionic fluid was synthesized by neutralizing the fully protonated fullerol with an amine terminated polyethylene/polypropylene oxide oligomer (Jeffamine®). The ionic fluid was compared to a control synthesized by mixing the partially protonated form (sodium form) of the fullerols with the same oligomeric amine in the same ratio as in the ionic fluids (20 wt% fullerol). In the fullerol fluid the ionic bonding significantly perturbs the thermal transitions and melting/crystallization behavior of the amine. In contrast, both the normalized heat of fusion and crystallization of the amine in the control are similar to those of the neat amine consistent with a physical mixture of the fullerols/amine with minimal interactions. In addition to differences in thermal behavior, the fullerol ionic fluid exhibits a complex viscoelastic behavior intermediate between the neat Jeffamine® (liquid-like) and the control (solid-like).
Angel, S.M.
1987-02-27
Particular gases or liquids are detected with a fiber optic element having a cladding or coating of a material which absorbs the fluid or fluids and which exhibits a change of an optical property, such as index of refraction, light transmissiveness or fluoresence emission, for example, in response to absorption of the fluid. The fluid is sensed by directing light into the fiber optic element and detecting changes in the light, such as exit angle changes for example, that result from the changed optical property of the coating material. The fluid detector may be used for such purposes as sensing toxic or explosive gases in the atmosphere, measuring ground water contamination or monitoring fluid flows in industrial processes, among other uses. 10 figs.
Angel, S. Michael
1989-01-01
Particular gases or liquids are detected with a fiber optic element (11, 11a to 11j) having a cladding or coating of a material (23, 23a to 23j) which absorbs the fluid or fluids and which exhibits a change of an optical property, such as index of refraction, light transmissiveness or fluoresence emission, for example, in response to absorption of the fluid. The fluid is sensed by directing light into the fiber optic element and detecting changes in the light, such as exit angle changes for example, that result from the changed optical property of the coating material. The fluid detector (24, 24a to 24j) may be used for such purposes as sensing toxic or explosive gases in the atmosphere, measuring ground water contamination or monitoring fluid flows in industrial processes, among other uses.
Metalworking and machining fluids
Erdemir, Ali; Sykora, Frank; Dorbeck, Mark
2010-10-12
Improved boron-based metal working and machining fluids. Boric acid and boron-based additives that, when mixed with certain carrier fluids, such as water, cellulose and/or cellulose derivatives, polyhydric alcohol, polyalkylene glycol, polyvinyl alcohol, starch, dextrin, in solid and/or solvated forms result in improved metalworking and machining of metallic work pieces. Fluids manufactured with boric acid or boron-based additives effectively reduce friction, prevent galling and severe wear problems on cutting and forming tools.
International Nuclear Information System (INIS)
Bradley, J.S.
1984-01-01
Toxic liquid waste, eg liquid radioactive waste, is disposed of by locating a sub-surface stratum which, before removal of any fluid, has a fluid pressure in the pores thereof which is less than the hydrostatic pressure which is normal for a stratum at that depth in the chosen area, and then feeding the toxic liquid into the stratum at a rate such that the fluid pressure in the stratum never exceeds the said normal hydrostatic pressure. (author)
Fiszdon, W
1965-01-01
Fluid Dynamics Transactions, Volume 2 compiles 46 papers on fluid dynamics, a subdiscipline of fluid mechanics that deals with fluid flow. The topics discussed in this book include developments in interference theory for aeronautical applications; diffusion from sources in a turbulent boundary layer; unsteady motion of a finite wing span in a compressible medium; and wall pressure covariance and comparison with experiment. The certain classes of non-stationary axially symmetric flows in magneto-gas-dynamics; description of the phenomenon of secondary flows in curved channels by means of co
Electrorheological fluids and methods
Green, Peter F.; McIntyre, Ernest C.
2015-06-02
Electrorheological fluids and methods include changes in liquid-like materials that can flow like milk and subsequently form solid-like structures under applied electric fields; e.g., about 1 kV/mm. Such fluids can be used in various ways as smart suspensions, including uses in automotive, defense, and civil engineering applications. Electrorheological fluids and methods include one or more polar molecule substituted polyhedral silsesquioxanes (e.g., sulfonated polyhedral silsesquioxanes) and one or more oils (e.g., silicone oil), where the fluid can be subjected to an electric field.
International Nuclear Information System (INIS)
Anon.
1986-01-01
Plasma and fluid physics includes the fields of fusion research and space investigation. This book discusses the most important advances in these areas over the past decade and recommends a stronger commitment to basic research in plasma and fluid physics. The book recommends that plasma and fluid physics be included in physics curriculums because of their increasing importance in energy and defense. The book also lists recent accomplishments in the fields of general plasma physics, fusion plasma confinement and heating, space and astrophysical plasmas, and fluid physics and lists research opportunities in these areas. A funding summary explains how research monies are allocated and suggests ways to improve their effectiveness
Shivamoggi, Bhimsen K
1998-01-01
"Although there are many texts and monographs on fluid dynamics, I do not know of any which is as comprehensive as the present book. It surveys nearly the entire field of classical fluid dynamics in an advanced, compact, and clear manner, and discusses the various conceptual and analytical models of fluid flow." - Foundations of Physics on the first edition. Theoretical Fluid Dynamics functions equally well as a graduate-level text and a professional reference. Steering a middle course between the empiricism of engineering and the abstractions of pure mathematics, the author focuses
Space Station fluid management logistics
Dominick, Sam M.
1990-01-01
Viewgraphs and discussion on space station fluid management logistics are presented. Topics covered include: fluid management logistics - issues for Space Station Freedom evolution; current fluid logistics approach; evolution of Space Station Freedom fluid resupply; launch vehicle evolution; ELV logistics system approach; logistics carrier configuration; expendable fluid/propellant carrier description; fluid carrier design concept; logistics carrier orbital operations; carrier operations at space station; summary/status of orbital fluid transfer techniques; Soviet progress tanker system; and Soviet propellant resupply system observations.
Compressible generalized Newtonian fluids
Czech Academy of Sciences Publication Activity Database
Málek, Josef; Rajagopal, K.R.
2010-01-01
Roč. 61, č. 6 (2010), s. 1097-1110 ISSN 0044-2275 Institutional research plan: CEZ:AV0Z20760514 Keywords : power law fluid * uniform temperature * compressible fluid Subject RIV: BJ - Thermodynamics Impact factor: 1.290, year: 2010
... into the space around the lungs, called the pleural space. As fluid drains into a collection bottle, you may cough a bit. This is because your lung re-expands to fill the space where fluid had been. This sensation lasts for a few hours after the test.
Culture - peritoneal fluid ... sent to the laboratory for Gram stain and culture. The sample is checked to see if bacteria ... The peritoneal fluid culture may be negative, even if you have ... diagnosis of peritonitis is based on other factors, in addition ...
DEFF Research Database (Denmark)
Gromov, Pavel; Gromova, Irina; Olsen, Charlotta J.
2013-01-01
Tumor interstitial fluid (TIF) is a proximal fluid that, in addition to the set of blood soluble phase-borne proteins, holds a subset of aberrantly externalized components, mainly proteins, released by tumor cells and tumor microenvironment through various mechanisms, which include classical...
International Nuclear Information System (INIS)
Rankin, J.
1980-01-01
A fluid control valve is described in which it is not necessary to insert a hand or a tool into the housing to remove the valve seat. Such a valve is particularly suitable for the control of radioactive fluids since maintenance by remote control is possible. (UK)
Collyer, A. A.
1973-01-01
Discusses theories underlying Newtonian and non-Newtonian fluids by explaining flow curves exhibited by plastic, shear-thining, and shear-thickening fluids and Bingham plastic materials. Indicates that the exact mechanism governing shear-thickening behaviors is a problem of further study. (CC)
Relativistic thermodynamics of fluids
International Nuclear Information System (INIS)
Souriau, J.-M.
1977-05-01
The relativistic covariant definition of a statistical equilibrium, applied to a perfect gas, involves a 'temperature four-vector', whose direction is the mean velocity of the fluid, and whose length is the reciprocal temperature. The hypothesis of this 'temperature four-vector' being a relevant variable for the description of the dissipative motions of a simple fluid is discussed. The kinematics is defined by using a vector field and measuring the number of molecules. Such a dissipative fluid is subject to motions involving null entropy generation; the 'temperature four-vector' is then a Killing vector; the equations of motion can be completely integrated. Perfect fluids can be studied by this way and the classical results of Lichnerowicz are obtained. In weakly dissipative motions two viscosity coefficient appear together with the heat conductibility coefficient. Two other coefficients perharps measurable on real fluids. Phase transitions and shock waves are described with using the model [fr
Garcia, A.R.; Johnston, R.G.; Martinez, R.K.
1999-05-25
A fluid sampling tool is described for sampling fluid from a container. The tool has a fluid collecting portion which is drilled into the container wall, thereby affixing it to the wall. The tool may have a fluid extracting section which withdraws fluid collected by the fluid collecting section. The fluid collecting section has a fluted shank with an end configured to drill a hole into a container wall. The shank has a threaded portion for tapping the borehole. The shank is threadably engaged to a cylindrical housing having an inner axial passageway sealed at one end by a septum. A flexible member having a cylindrical portion and a bulbous portion is provided. The housing can be slid into an inner axial passageway in the cylindrical portion and sealed to the flexible member. The bulbous portion has an outer lip defining an opening. The housing is clamped into the chuck of a drill, the lip of the bulbous section is pressed against a container wall until the shank touches the wall, and the user operates the drill. Wall shavings (kerf) are confined in a chamber formed in the bulbous section as it folds when the shank advances inside the container. After sufficient advancement of the shank, an o-ring makes a seal with the container wall. 6 figs.
International Nuclear Information System (INIS)
Truckenbrodt, E.
1980-01-01
The second volume contains the chapter 4 to 6. Whereas chapter 1 deals with the introduction into the mechanics of fluids and chapter 2 with the fundamental laws of fluid and thermal fluid dynamics, in chapter 3 elementary flow phenomena in fluids with constant density are treated. Chapter 4 directly continues chapter 3 and describes elementary flow phenomena in fluids with varying density. Fluid statics again is treated as a special case. If compared with the first edition the treatment of unsteady laminar flow and of pipe flow for a fluid with varying density were subject to a substantial extension. In chapter 5 rotation-free and rotating potential flows are presented together. By this means it is achieved to explain the behaviour of the multidimensional fictionless flow in closed form. A subchapter describes some related problems of potential theory like the flow along a free streamline and seepage flow through a porous medium. The boundary layer flows in chapter 6 are concerned with the flow and temperature boundary layer in laminar and turbulent flows at a fired wall. In it differential and integral methods are applied of subchapter reports on boundary layer flows without a fixed boundary, occurring e.g. in an open jet and in a wake flow. The problems of intermittence and of the Coanda effect are briefly mentioned. (orig./MH)
Garcia, Anthony R.; Johnston, Roger G.; Martinez, Ronald K.
1999-05-25
A fluid sampling tool for sampling fluid from a container. The tool has a fluid collecting portion which is drilled into the container wall, thereby affixing it to the wall. The tool may have a fluid extracting section which withdraws fluid collected by the fluid collecting section. The fluid collecting section has a fluted shank with an end configured to drill a hole into a container wall. The shank has a threaded portion for tapping the borehole. The shank is threadably engaged to a cylindrical housing having an inner axial passageway sealed at one end by a septum. A flexible member having a cylindrical portion and a bulbous portion is provided. The housing can be slid into an inner axial passageway in the cylindrical portion and sealed to the flexible member. The bulbous portion has an outer lip defining an opening. The housing is clamped into the chuck of a drill, the lip of the bulbous section is pressed against a container wall until the shank touches the wall, and the user operates the drill. Wall shavings (kerf) are confined in a chamber formed in the bulbous section as it folds when the shank advances inside the container. After sufficient advancement of the shank, an o-ring makes a seal with the container wall.
FRACTURING FLUID CHARACTERIZATION FACILITY
Energy Technology Data Exchange (ETDEWEB)
Subhash Shah
2000-08-01
Hydraulic fracturing technology has been successfully applied for well stimulation of low and high permeability reservoirs for numerous years. Treatment optimization and improved economics have always been the key to the success and it is more so when the reservoirs under consideration are marginal. Fluids are widely used for the stimulation of wells. The Fracturing Fluid Characterization Facility (FFCF) has been established to provide the accurate prediction of the behavior of complex fracturing fluids under downhole conditions. The primary focus of the facility is to provide valuable insight into the various mechanisms that govern the flow of fracturing fluids and slurries through hydraulically created fractures. During the time between September 30, 1992, and March 31, 2000, the research efforts were devoted to the areas of fluid rheology, proppant transport, proppant flowback, dynamic fluid loss, perforation pressure losses, and frictional pressure losses. In this regard, a unique above-the-ground fracture simulator was designed and constructed at the FFCF, labeled ''The High Pressure Simulator'' (HPS). The FFCF is now available to industry for characterizing and understanding the behavior of complex fluid systems. To better reflect and encompass the broad spectrum of the petroleum industry, the FFCF now operates under a new name of ''The Well Construction Technology Center'' (WCTC). This report documents the summary of the activities performed during 1992-2000 at the FFCF.
Thermodynamics of Fluid Polyamorphism
Directory of Open Access Journals (Sweden)
Mikhail A. Anisimov
2018-01-01
Full Text Available Fluid polyamorphism is the existence of different condensed amorphous states in a single-component fluid. It is either found or predicted, usually at extreme conditions, for a broad group of very different substances, including helium, carbon, silicon, phosphorous, sulfur, tellurium, cerium, hydrogen, and tin tetraiodide. This phenomenon is also hypothesized for metastable and deeply supercooled water, presumably located a few degrees below the experimental limit of homogeneous ice formation. We present a generic phenomenological approach to describe polyamorphism in a single-component fluid, which is completely independent of the molecular origin of the phenomenon. We show that fluid polyamorphism may occur either in the presence or in the absence of fluid phase separation depending on the symmetry of the order parameter. In the latter case, it is associated with a second-order transition, such as in liquid helium or liquid sulfur. To specify the phenomenology, we consider a fluid with thermodynamic equilibrium between two distinct interconvertible states or molecular structures. A fundamental signature of this concept is the identification of the equilibrium fraction of molecules involved in each of these alternative states. However, the existence of the alternative structures may result in polyamorphic fluid phase separation only if mixing of these structures is not ideal. The two-state thermodynamics unifies all the debated scenarios of fluid polyamorphism in different areas of condensed-matter physics, with or without phase separation, and even goes beyond the phenomenon of polyamorphism by generically describing the anomalous properties of fluids exhibiting interconversion of alternative molecular states.
Faber, T. E.
1995-08-01
This textbook provides an accessible and comprehensive account of fluid dynamics that emphasizes fundamental physical principles and stresses connections with other branches of physics. Beginning with a basic introduction, the book goes on to cover many topics not typically treated in texts, such as compressible flow and shock waves, sound attenuation and bulk viscosity, solitary waves and ship waves, thermal convection, instabilities, turbulence, and the behavior of anisotropic, non-Newtonian and quantum fluids. Undergraduate or graduate students in physics or engineering who are taking courses in fluid dynamics will find this book invaluable.
International Nuclear Information System (INIS)
Jang, Byeong Ju
1984-01-01
This book is made up of 5 chapters. They are fluid mechanics, fluid machines, Industrial thermodynamics, steam boiler and steam turbine. It introduces hydrostatics, basic theory of fluid movement and law of momentum. It also deals with centrifugal pump, axial flow pump, general hydraulic turbine, and all phenomena happening in the pump. It covers the law of thermodynamics, perfect gas, properties of steam, and flow of gas and steam and water tube boiler. Lastly it explains basic format, theory, loss and performance as well as principle part of steam turbine.
The non-monotonic shear-thinning flow of two strongly cohesive concentrated suspensions
Buscall, Richard; Kusuma, Tiara E.; Stickland, Anthony D.; Rubasingha, Sayuri; Scales, Peter J.; Teo, Hui-En; Worrall, Graham L.
2014-01-01
The behaviour in simple shear of two concentrated and strongly cohesive mineral suspensions showing highly non-monotonic flow curves is described. Two rheometric test modes were employed, controlled stress and controlled shear-rate. In controlled stress mode the materials showed runaway flow above a yield stress, which, for one of the suspensions, varied substantially in value and seemingly at random from one run to the next, such that the up flow-curve appeared to be quite irreproducible. Th...
... tests Chest x-ray CT (computerized tomography, or advanced imaging) scan EKG (electrocardiogram, or heart tracing) Fluids ... Stanton BF, St. Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics . 20th ed. Philadelphia, PA: Elsevier; ...
COUPLED CHEMOTAXIS FLUID MODEL
LORZ, ALEXANDER
2010-01-01
We consider a model system for the collective behavior of oxygen-driven swimming bacteria in an aquatic fluid. In certain parameter regimes, such suspensions of bacteria feature large-scale convection patterns as a result of the hydrodynamic
Brenner, Howard
2011-12-01
This paper presents a unified theory of phoretic phenomena in single-component fluids. Simple formulas are given for the phoretic velocities of small inert force-free non-Brownian particles migrating through otherwise quiescent single-component gases and liquids and animated by a gradient in the fluid's temperature (thermophoresis), pressure (barophoresis), density (pycnophoresis), or any combination thereof. The ansatz builds upon a recent paper [Phys. Rev. E 84, 046309 (2011)] concerned with slip of the fluid's mass velocity at solid surfaces--that is, with phenomena arising from violations of the classical no-slip fluid-mechanical boundary condition. Experimental and other data are cited in support of the phoretic model developed herein.
... Get Tested? To help diagnose the cause of peritonitis, an inflammation of the membrane lining the abdomen, ... fever and your healthcare practitioner suspects you have peritonitis or ascites Sample Required? A peritoneal fluid sample ...
International Nuclear Information System (INIS)
Rion, Jacky.
1982-01-01
Fluid flow control system featuring a series of grids placed perpendicular to the fluid flow direction, characterized by the fact that it is formed of a stack of identical and continuous grids, each of which consists of identical meshes forming a flat lattice. The said meshes are offset from one grid to the next. This system applies in particular to flow control of the coolant flowing at the foot of an assembly of a liquid metal cooled nuclear reactor [fr
Amniotic fluid inflammatory cytokines
DEFF Research Database (Denmark)
Abdallah, Morsi; Larsen, Nanna; Grove, Jakob
2013-01-01
The aim of the study was to analyze cytokine profiles in amniotic fluid (AF) samples of children developing autism spectrum disorders (ASD) and controls, adjusting for maternal autoimmune disorders and maternal infections during pregnancy.......The aim of the study was to analyze cytokine profiles in amniotic fluid (AF) samples of children developing autism spectrum disorders (ASD) and controls, adjusting for maternal autoimmune disorders and maternal infections during pregnancy....
[Diagnosis: synovial fluid analysis].
Gallo Vallejo, Francisco Javier; Giner Ruiz, Vicente
2014-01-01
Synovial fluid analysis in rheumatological diseases allows a more accurate diagnosis in some entities, mainly infectious and microcrystalline arthritis. Examination of synovial fluid in patients with osteoarthritis is useful if a differential diagnosis will be performed with other processes and to distinguish between inflammatory and non-inflammatory forms. Joint aspiration is a diagnostic and sometimes therapeutic procedure that is available to primary care physicians. Copyright © 2014 Elsevier España, S.L. All rights reserved.
Immunotherapy With Magentorheologic Fluids
2011-08-01
anti-tumor effects are weakened by removal of the tumor antigen pool (i.e. surgery) or use of cytoreductive and immunosuppressive therapies (i.e...particles were injected as magneto -rheological fluid (MRF) into an orthotopic primary breast cancer and followed by application of a magnetic field to...SUBJECT TERMS MRF: Magneto -rehological fluid iron particles, IT: immunotherapy, necrotic death, DCs: dendritic cells, cytokines, chemokines
Supercritical fluid chromatography
Vigdergauz, M. S.; Lobachev, A. L.; Lobacheva, I. V.; Platonov, I. A.
1992-03-01
The characteristic features of supercritical fluid chromatography (SCFC) are examined and there is a brief historical note concerning the development of the method. Information concerning the use of supercritical fluid chromatography in the analysis of objects of different nature is presented in the form of a table. The roles of the mobile and stationary phases in the separation process and the characteristic features of the apparatus and of the use of the method in physicochemical research are discussed. The bibliography includes 364 references.
Fernandes, Nikhil
2010-01-01
We report for the first time an ionic fluid based on hydroxylated fullerenes (fullerols). The ionic fluid was synthesized by neutralizing the fully protonated fullerol with an amine terminated polyethylene/polypropylene oxide oligomer (Jeffamine®). The ionic fluid was compared to a control synthesized by mixing the partially protonated form (sodium form) of the fullerols with the same oligomeric amine in the same ratio as in the ionic fluids (20 wt% fullerol). In the fullerol fluid the ionic bonding significantly perturbs the thermal transitions and melting/crystallization behavior of the amine. In contrast, both the normalized heat of fusion and crystallization of the amine in the control are similar to those of the neat amine consistent with a physical mixture of the fullerols/amine with minimal interactions. In addition to differences in thermal behavior, the fullerol ionic fluid exhibits a complex viscoelastic behavior intermediate between the neat Jeffamine® (liquid-like) and the control (solid-like). © 2010 The Royal Society of Chemistry.
Thermostating highly confined fluids.
Bernardi, Stefano; Todd, B D; Searles, Debra J
2010-06-28
In this work we show how different use of thermostating devices and modeling of walls influence the mechanical and dynamical properties of confined nanofluids. We consider a two dimensional fluid undergoing Couette flow using nonequilibrium molecular dynamics simulations. Because the system is highly inhomogeneous, the density shows strong fluctuations across the channel. We compare the dynamics produced by applying a thermostating device directly to the fluid with that obtained when the wall is thermostated, considering also the effects of using rigid walls. This comparison involves an analysis of the chaoticity of the fluid and evaluation of mechanical properties across the channel. We look at two thermostating devices with either rigid or vibrating atomic walls and compare them with a system only thermostated by conduction through vibrating atomic walls. Sensitive changes are observed in the xy component of the pressure tensor, streaming velocity, and density across the pore and the Lyapunov localization of the fluid. We also find that the fluid slip can be significantly reduced by rigid walls. Our results suggest caution in interpreting the results of systems in which fluid atoms are thermostated and/or wall atoms are constrained to be rigid, such as, for example, water inside carbon nanotubes.
Viscous Flow with Large Fluid-Fluid Interface Displacement
DEFF Research Database (Denmark)
Rasmussen, Henrik Koblitz; Hassager, Ole; Saasen, Arild
1998-01-01
The arbitrary Lagrange-Euler (ALE) kinematic description has been implemented in a 3D transient finite element program to simulate multiple fluid flows with fluid-fluid interface or surface displacements. The description of fluid interfaces includes variable interfacial tension, and the formulation...... is useful in the simulation of low and intermediate Reynolds number viscous flow. The displacement of two immiscible Newtonian fluids in a vertical (concentric and eccentric) annulus and a (vertical and inclined)tube is simulated....
Two-phase cooling fluids; Les fluides frigoporteurs diphasiques
Energy Technology Data Exchange (ETDEWEB)
Lallemand, A. [Institut National des Sciences Appliquees (INSA), 69 - Lyon (France)
1997-12-31
In the framework of the diminution of heat transfer fluid consumption, the concept of indirect refrigerating circuits, using cooling intermediate fluids, is reviewed and the fluids that are currently used in these systems are described. Two-phase cooling fluids advantages over single-phase fluids are presented with their thermophysical characteristics: solid fraction, two-phase mixture enthalpy, thermal and rheological properties, determination of heat and mass transfer characteristics, and cold storage through ice slurry
Boiler using combustible fluid
Baumgartner, H.; Meier, J.G.
1974-07-03
A fluid fuel boiler is described comprising a combustion chamber, a cover on the combustion chamber having an opening for introducing a combustion-supporting gaseous fluid through said openings, means to impart rotation to the gaseous fluid about an axis of the combustion chamber, a burner for introducing a fluid fuel into the chamber mixed with the gaseous fluid for combustion thereof, the cover having a generally frustro-conical configuration diverging from the opening toward the interior of the chamber at an angle of between 15/sup 0/ and 55/sup 0/; means defining said combustion chamber having means defining a plurality of axial hot gas flow paths from a downstream portion of the combustion chamber to flow hot gases into an upstream portion of the combustion chamber, and means for diverting some of the hot gas flow along paths in a direction circumferentially of the combustion chamber, with the latter paths being immersed in the water flow path thereby to improve heat transfer and terminating in a gas outlet, the combustion chamber comprising at least one modular element, joined axially to the frustro-conical cover and coaxial therewith. The modular element comprises an inner ring and means of defining the circumferential, radial, and spiral flow paths of the hot gases.
Directory of Open Access Journals (Sweden)
Kiranpreet Kaur
2016-01-01
Full Text Available Amniotic fluid embolism (AFE is one of the catastrophic complications of pregnancy in which amniotic fluid, fetal cells, hair, or other debris enters into the maternal pulmonary circulation, causing cardiovascular collapse. Etiology largely remains unknown, but may occur in healthy women during labour, during cesarean section, after abnormal vaginal delivery, or during the second trimester of pregnancy. It may also occur up to 48 hours post-delivery. It can also occur during abortion, after abdominal trauma, and during amnio-infusion. The pathophysiology of AFE is not completely understood. Possible historical cause is that any breach of the barrier between maternal blood and amniotic fluid forces the entry of amniotic fluid into the systemic circulation and results in a physical obstruction of the pulmonary circulation. The presenting signs and symptoms of AFE involve many organ systems. Clinical signs and symptoms are acute dyspnea, cough, hypotension, cyanosis, fetal bradycardia, encephalopathy, acute pulmonary hypertension, coagulopathy etc. Besides basic investigations lung scan, serum tryptase levels, serum levels of C3 and C4 complements, zinc coproporphyrin, serum sialyl Tn etc are helpful in establishing the diagnosis. Treatment is mainly supportive, but exchange transfusion, extracorporeal membrane oxygenation, and uterine artery embolization have been tried from time to time. The maternal prognosis after amniotic fluid embolism is very poor though infant survival rate is around 70%.
Fluid structure coupling algorithm
International Nuclear Information System (INIS)
McMaster, W.H.; Gong, E.Y.; Landram, C.S.; Quinones, D.F.
1980-01-01
A fluid-structure-interaction algorithm has been developed and incorporated into the two-dimensional code PELE-IC. This code combines an Eulerian incompressible fluid algorithm with a Lagrangian finite element shell algorithm and incorporates the treatment of complex free surfaces. The fluid structure and coupling algorithms have been verified by the calculation of solved problems from the literature and from air and steam blowdown experiments. The code has been used to calculate loads and structural response from air blowdown and the oscillatory condensation of steam bubbles in water suppression pools typical of boiling water reactors. The techniques developed have been extended to three dimensions and implemented in the computer code PELE-3D
Saintillan, David
2018-01-01
An active fluid denotes a viscous suspension of particles, cells, or macromolecules able to convert chemical energy into mechanical work by generating stresses on the microscale. By virtue of this internal energy conversion, these systems display unusual macroscopic rheological signatures, including a curious transition to an apparent superfluid-like state where internal activity exactly compensates viscous dissipation. These behaviors are unlike those of classical complex fluids and result from the coupling of particle configurations with both externally applied flows and internally generated fluid disturbances. Focusing on the well-studied example of a suspension of microswimmers, this review summarizes recent experiments, models, and simulations in this area and highlights the critical role played by the rheological response of these active materials in a multitude of phenomena, from the enhanced transport of passive suspended objects to the emergence of spontaneous flows and collective motion.
Gray, Harold E.; McLaurin, Felder M.; Ortiz, Monico; Huth, William A.
1996-01-01
A device or system for monitoring for the presence of leaks from a hazardous fluid is disclosed which uses two electrodes immersed in deionized water. A gas is passed through an enclosed space in which a hazardous fluid is contained. Any fumes, vapors, etc. escaping from the containment of the hazardous fluid in the enclosed space are entrained in the gas passing through the enclosed space and transported to a closed vessel containing deionized water and two electrodes partially immersed in the deionized water. The electrodes are connected in series with a power source and a signal, whereby when a sufficient number of ions enter the water from the gas being bubbled through it (indicative of a leak), the water will begin to conduct, thereby allowing current to flow through the water from one electrode to the other electrode to complete the circuit and activate the signal.
International Nuclear Information System (INIS)
Sator, N.
2003-01-01
This article concerns the correspondence between thermodynamics and the morphology of simple fluids in terms of clusters. Definitions of clusters providing a geometric interpretation of the liquid-gas phase transition are reviewed with an eye to establishing their physical relevance. The author emphasizes their main features and basic hypotheses, and shows how these definitions lead to a recent approach based on self-bound clusters. Although theoretical, this tutorial review is also addressed to readers interested in experimental aspects of clustering in simple fluids
Basniev, Kaplan S; Chilingar, George V 0
2012-01-01
The mechanics of fluid flow is a fundamental engineering discipline explaining both natural phenomena and human-induced processes, and a thorough understanding of it is central to the operations of the oil and gas industry. This book, written by some of the world's best-known and respected petroleum engineers, covers the concepts, theories, and applications of the mechanics of fluid flow for the veteran engineer working in the field and the student, alike. It is a must-have for any engineer working in the oil and gas industry.
Supercritical fluid analytical methods
International Nuclear Information System (INIS)
Smith, R.D.; Kalinoski, H.T.; Wright, B.W.; Udseth, H.R.
1988-01-01
Supercritical fluids are providing the basis for new and improved methods across a range of analytical technologies. New methods are being developed to allow the detection and measurement of compounds that are incompatible with conventional analytical methodologies. Characterization of process and effluent streams for synfuel plants requires instruments capable of detecting and measuring high-molecular-weight compounds, polar compounds, or other materials that are generally difficult to analyze. The purpose of this program is to develop and apply new supercritical fluid techniques for extraction, separation, and analysis. These new technologies will be applied to previously intractable synfuel process materials and to complex mixtures resulting from their interaction with environmental and biological systems
Sliding friction in the hydrodynamic lubrication regime for a power-law fluid
International Nuclear Information System (INIS)
Warren, P B
2017-01-01
A scaling analysis is undertaken for the load balance in sliding friction in the hydrodynamic lubrication regime, with a particular emphasis on power-law shear-thinning typical of a structured liquid. It is argued that the shear-thinning regime is mechanically unstable if the power-law index n < 1/2, where n is the exponent that relates the shear stress to the shear rate. Consequently the Stribeck (friction) curve should be discontinuous, with possible hysteresis. Further analysis suggests that normal stress and flow transience (stress overshoot) do not destroy this basic picture, although they may provide stabilising mechanisms at higher shear rates. Extensional viscosity is also expected to be insignificant unless the Trouton ratio is large. A possible application to shear thickening in non-Brownian particulate suspensions is indicated. (paper)
Energy Technology Data Exchange (ETDEWEB)
Oostrom, Mart; Wietsma, Thomas W.; Covert, Matthew A.; Vermeul, Vince R.
2005-12-22
At the Hanford Site, an extensive In Situ Redox Manipulation (ISRM) permeable reactive barrier was installed to prevent chromate from reaching the Columbia River. However, chromium has been detected in several wells, indicating a premature loss of the reductive capacity in the aquifer. One possible cause for premature chromate breakthrough is associated with the presence of high-permeability zones in the aquifer. In these zones, groundwater moves relatively fast and is able to oxidize iron more rapidly. There is also a possibility that the high-permeability flow paths are deficient in reducing equivalents (e.g. reactive iron), required for barrier performance. One way enhancement of the current barrier reductive capacity can be achieved is by the addition of micron-scale zero-valent iron to the high-permeability zones within the aquifer. The potential emplacement of zero-valent iron (Fe0) into high-permeability Hanford sediments (Ringold Unit E gravels) using shear-thinning fluids containing polymers was investigated in three-dimensional wedge-shaped aquifer models. Polymers were used to create a suspension viscous enough to keep the Fe0 in solution for extended time periods to improve colloid movement into the porous media without causing a permanent detrimental decrease in hydraulic conductivity. Porous media were packed in the wedge-shaped flow cell to create either a heterogeneous layered system with a high-permeability zone in between two low-permeability zones or a high-permeability channel surrounded by low-permeability materials. The injection flow rate, polymer type, polymer concentration, and injected pore volumes were determined based on preliminary short- and long-column experiments.
Incompressible ionized fluid mixtures
Czech Academy of Sciences Publication Activity Database
Roubíček, Tomáš
2006-01-01
Roč. 17, č. 7 (2006), s. 493-509 ISSN 0935-1175 Institutional research plan: CEZ:AV0Z10750506 Keywords : chemically reacting fluids * Navier-Stokes * Nernst-Planck * Possion equation s * heat equation s Subject RIV: BA - General Mathematics Impact factor: 0.954, year: 2006
Relativistic viscoelastic fluid mechanics
International Nuclear Information System (INIS)
Fukuma, Masafumi; Sakatani, Yuho
2011-01-01
A detailed study is carried out for the relativistic theory of viscoelasticity which was recently constructed on the basis of Onsager's linear nonequilibrium thermodynamics. After rederiving the theory using a local argument with the entropy current, we show that this theory universally reduces to the standard relativistic Navier-Stokes fluid mechanics in the long time limit. Since effects of elasticity are taken into account, the dynamics at short time scales is modified from that given by the Navier-Stokes equations, so that acausal problems intrinsic to relativistic Navier-Stokes fluids are significantly remedied. We in particular show that the wave equations for the propagation of disturbance around a hydrostatic equilibrium in Minkowski space-time become symmetric hyperbolic for some range of parameters, so that the model is free of acausality problems. This observation suggests that the relativistic viscoelastic model with such parameters can be regarded as a causal completion of relativistic Navier-Stokes fluid mechanics. By adjusting parameters to various values, this theory can treat a wide variety of materials including elastic materials, Maxwell materials, Kelvin-Voigt materials, and (a nonlinearly generalized version of) simplified Israel-Stewart fluids, and thus we expect the theory to be the most universal description of single-component relativistic continuum materials. We also show that the presence of strains and the corresponding change in temperature are naturally unified through the Tolman law in a generally covariant description of continuum mechanics.
Relativistic viscoelastic fluid mechanics.
Fukuma, Masafumi; Sakatani, Yuho
2011-08-01
A detailed study is carried out for the relativistic theory of viscoelasticity which was recently constructed on the basis of Onsager's linear nonequilibrium thermodynamics. After rederiving the theory using a local argument with the entropy current, we show that this theory universally reduces to the standard relativistic Navier-Stokes fluid mechanics in the long time limit. Since effects of elasticity are taken into account, the dynamics at short time scales is modified from that given by the Navier-Stokes equations, so that acausal problems intrinsic to relativistic Navier-Stokes fluids are significantly remedied. We in particular show that the wave equations for the propagation of disturbance around a hydrostatic equilibrium in Minkowski space-time become symmetric hyperbolic for some range of parameters, so that the model is free of acausality problems. This observation suggests that the relativistic viscoelastic model with such parameters can be regarded as a causal completion of relativistic Navier-Stokes fluid mechanics. By adjusting parameters to various values, this theory can treat a wide variety of materials including elastic materials, Maxwell materials, Kelvin-Voigt materials, and (a nonlinearly generalized version of) simplified Israel-Stewart fluids, and thus we expect the theory to be the most universal description of single-component relativistic continuum materials. We also show that the presence of strains and the corresponding change in temperature are naturally unified through the Tolman law in a generally covariant description of continuum mechanics.
Cryogenic Fluid Management Facility
Eberhardt, R. N.; Bailey, W. J.
1985-01-01
The Cryogenic Fluid Management Facility is a reusable test bed which is designed to be carried within the Shuttle cargo bay to investigate the systems and technologies associated with the efficient management of cryogens in space. Cryogenic fluid management consists of the systems and technologies for: (1) liquid storage and supply, including capillary acquisition/expulsion systems which provide single-phase liquid to the user system, (2) both passive and active thermal control systems, and (3) fluid transfer/resupply systems, including transfer lines and receiver tanks. The facility contains a storage and supply tank, a transfer line and a receiver tank, configured to provide low-g verification of fluid and thermal models of cryogenic storage and transfer processes. The facility will provide design data and criteria for future subcritical cryogenic storage and transfer system applications, such as Space Station life support, attitude control, power and fuel depot supply, resupply tankers, external tank (ET) propellant scavenging, and ground-based and space-based orbit transfer vehicles (OTV).
Touret, J.L.R.
2001-01-01
Basic principles for the study of fluid inclusions in metamorphic rocks are reviewed and illustrated. A major problem relates to the number of inclusions, possibly formed on a wide range of P-T conditions, having also suffered, in most cases, extensive changes after initial trapping. The
Subudhi, Sudhakar; Sreenivas, K. R.; Arakeri, Jaywant H.
2013-01-01
This work is concerned with the removal of unwanted fluid through the source-sink pair. The source consists of fluid issuing out of a nozzle in the form of a jet and the sink is a pipe that is kept some distance from the source pipe. Of concern is the percentage of source fluid sucked through the sink. The experiments have been carried in a large glass water tank. The source nozzle diameter is 6 mm and the sink pipe diameter is either 10 or 20 mm. The horizontal and vertical separations and angles between these source and sink pipes are adjustable. The flow was visualized using KMnO4 dye, planer laser induced fluorescence and particle streak photographs. To obtain the effectiveness (that is percentage of source fluid entering the sink pipe), titration method is used. The velocity profiles with and without the sink were obtained using particle image velocimetry. The sink flow rate to obtain a certain effectiveness increase dramatically with lateral separation. The sink diameter and the angle between source and the sink axes don't influence effectiveness as much as the lateral separation.
Continuous feedback fluid queues
Scheinhardt, Willem R.W.; van Foreest, N.D.; Mandjes, M.R.H.
2003-01-01
We investigate a fluid buffer which is modulated by a stochastic background process, while the momentary behavior of the background process depends on the current buffer level in a continuous way. Loosely speaking the feedback is such that the background process behaves `as a Markov process' with
Editorial Special Issue on Fluid Mechanics and Fluid Power (FMFP ...
Indian Academy of Sciences (India)
This special issue of Sadhana contains selected papers from two conferences related to fluid mechanics held in India recently, Fluid Mechanics and Fluid Power conference at NIT, Hamirpur, and an International Union of Theoretical ... A simple, well thought out, flow visualization experiment or a computation can sometimes ...
Microgravity Fluids for Biology, Workshop
Griffin, DeVon; Kohl, Fred; Massa, Gioia D.; Motil, Brian; Parsons-Wingerter, Patricia; Quincy, Charles; Sato, Kevin; Singh, Bhim; Smith, Jeffrey D.; Wheeler, Raymond M.
2013-01-01
Microgravity Fluids for Biology represents an intersection of biology and fluid physics that present exciting research challenges to the Space Life and Physical Sciences Division. Solving and managing the transport processes and fluid mechanics in physiological and biological systems and processes are essential for future space exploration and colonization of space by humans. Adequate understanding of the underlying fluid physics and transport mechanisms will provide new, necessary insights and technologies for analyzing and designing biological systems critical to NASAs mission. To enable this mission, the fluid physics discipline needs to work to enhance the understanding of the influence of gravity on the scales and types of fluids (i.e., non-Newtonian) important to biology and life sciences. In turn, biomimetic, bio-inspired and synthetic biology applications based on physiology and biology can enrich the fluid mechanics and transport phenomena capabilities of the microgravity fluid physics community.
Compressible Fluid Suspension Performance Testing
National Research Council Canada - National Science Library
Hoogterp, Francis
2003-01-01
... compressible fluid suspension system that was designed and installed on the vehicle by DTI. The purpose of the tests was to evaluate the possible performance benefits of the compressible fluid suspension system...
International Nuclear Information System (INIS)
Shen, M.C.; Ebel, D.
1987-01-01
In this paper some new results concerning magnetohydrodynamic (MHD) equations with the Hall current (HC) term in the Ohm's law are presented. For the cylindrical pinch of a compressible HC fluid, it is found that for large time and long wave length the solution to the governing equations exhibits the behavior of solitons as in the case of an ideal MHD model. In some special cases, the HC model appears to be better posed. An open question is whether a simple toroidal equilibrium of an HC fluid with resistivity and viscosity exists. The answer to this question is affirmative if the prescribed velocity on the boundary has a small norm. Furthermore, the equilibrium is also linearly and nonlinearly stable
COUPLED CHEMOTAXIS FLUID MODEL
LORZ, ALEXANDER
2010-06-01
We consider a model system for the collective behavior of oxygen-driven swimming bacteria in an aquatic fluid. In certain parameter regimes, such suspensions of bacteria feature large-scale convection patterns as a result of the hydrodynamic interaction between bacteria. The presented model consist of a parabolicparabolic chemotaxis system for the oxygen concentration and the bacteria density coupled to an incompressible Stokes equation for the fluid driven by a gravitational force of the heavier bacteria. We show local existence of weak solutions in a bounded domain in d, d = 2, 3 with no-flux boundary condition and in 2 in the case of inhomogeneous Dirichlet conditions for the oxygen. © 2010 World Scientific Publishing Company.
Fluid dynamics an introduction
Rieutord, Michel
2015-01-01
This book is dedicated to readers who want to learn fluid dynamics from the beginning. It assumes a basic level of mathematics knowledge that would correspond to that of most second-year undergraduate physics students and examines fluid dynamics from a physicist’s perspective. As such, the examples used primarily come from our environment on Earth and, where possible, from astrophysics. The text is arranged in a progressive and educational format, aimed at leading readers from the simplest basics to more complex matters like turbulence and magnetohydrodynamics. Exercises at the end of each chapter help readers to test their understanding of the subject (solutions are provided at the end of the book), and a special chapter is devoted to introducing selected aspects of mathematics that beginners may not be familiar with, so as to make the book self-contained.
Electrorheologic fluids; Fluidos electroreologicos
Energy Technology Data Exchange (ETDEWEB)
Rejon G, Leonardo; Lopez G, Francisco; Montoya T, Gerardo [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Manero B, Octavio [Instituto de Investigaciones en Materiales, UNAM.(Mexico)
2003-07-01
The present article has as an objective to offer a review of the research work made in the Instituto de Investigaciones Electricas (IIE) on the study of the electrorheologic fluids whose flow properties can abruptly change in the presence of an electric field when this is induced by a direct current. The electrorheologic fluids have their main application in the manufacture of self-controlling damping systems. [Spanish] El presente articulo tiene por objetivo ofrecer una resena de los trabajos de investigacion realizados en el Instituto de Investigaciones Electricas (IIE) sobre el estudio de los fluidos electroreologicos cuyas propiedades de flujo pueden cambiar abruptamente en presencia de un campo electrico cuando este es inducido por una corriente directa. Los fluidos electroreologicos tienen su principal aplicacion en la fabricacion de sistemas de amortiguamiento autocontrolables.
Fürthauer, S; Strempel, M; Grill, S W; Jülicher, F
2012-09-01
Active processes in biological systems often exhibit chiral asymmetries. Examples are the chirality of cytoskeletal filaments which interact with motor proteins, the chirality of the beat of cilia and flagella as well as the helical trajectories of many biological microswimmers. Here, we derive constitutive material equations for active fluids which account for the effects of active chiral processes. We identify active contributions to the antisymmetric part of the stress as well as active angular momentum fluxes. We discuss four types of elementary chiral motors and their effects on a surrounding fluid. We show that large-scale chiral flows can result from the collective behavior of such motors even in cases where isolated motors do not create a hydrodynamic far field.
Personalised fluid resuscitation in the ICU: still a fluid concept?
van Haren, Frank
2017-12-28
The administration of intravenous fluid to critically ill patients is one of the most common, but also one of the most fiercely debated, interventions in intensive care medicine. Even though many thousands of patients have been enrolled in large trials of alternative fluid strategies, consensus remains elusive and practice is widely variable. Critically ill patients are significantly heterogeneous, making a one size fits all approach unlikely to be successful.New data from basic, animal, and clinical research suggest that fluid resuscitation could be associated with significant harm. There are several important limitations and concerns regarding fluid bolus therapy as it is currently being used in clinical practice. These include, but are not limited to: the lack of an agreed definition; limited and short-lived physiological effects; no evidence of an effect on relevant patient outcomes; and the potential to contribute to fluid overload, specifically when fluid responsiveness is not assessed and when targets and safety limits are not used.Fluid administration in critically ill patients requires clinicians to integrate abnormal physiological parameters into a clinical decision-making model that also incorporates the likely diagnosis and the likely risk or benefit in the specific patient's context. Personalised fluid resuscitation requires careful attention to the mnemonic CIT TAIT: context, indication, targets, timing, amount of fluid, infusion strategy, and type of fluid.The research agenda should focus on experimental and clinical studies to: improve our understanding of the physiological effects of fluid infusion, e.g. on the glycocalyx; evaluate new types of fluids; evaluate novel fluid minimisation protocols; study the effects of a no-fluid strategy for selected patients and scenarios; and compare fluid therapy with other interventions. The adaptive platform trial design may provide us with the tools to evaluate these types of interventions in the intrinsically
Handbook of hydraulic fluid technology
Totten, George E
2011-01-01
""The Handbook of Hydraulic Fluid Technology"" serves as the foremost resource for designing hydraulic systems and for selecting hydraulic fluids used in engineering applications. Featuring new illustrations, data tables, as well as practical examples, this second edition is updated with essential information on the latest hydraulic fluids and testing methods. The detailed text facilitates unparalleled understanding of the total hydraulic system, including important hardware, fluid properties, and hydraulic lubricants. Written by worldwide experts, the book also offers a rigorous overview of h
Recording fluid currents by holography
Heflinger, L. O.; Wuerker, R. F.
1980-01-01
Convection in fluids can be studied with aid of holographic apparatus that reveals three-dimensional motion of liquid. Apparatus eliminates images of fixed particles such as dust on windows and lenses, which might mask behavior of moving fluid particles. Holographic apparatus was developed for experiments on fluid convection cells under zero gravity. Principle is adaptable to study of fluid processes-for example, electrochemical plating and combustion in automotive engines.
International Nuclear Information System (INIS)
Ottino, J.M.
1989-01-01
What do the eruption of Krakatau, the manufacture of puff pastry and the brightness of stars have in common? Each involves some aspect of mixing. Mixing also plays a critical role in modern technology. Chemical engineers rely on mixing to ensure that substances react properly, to produce polymer blends that exhibit unique properties and to disperse drag-reducing agents in pipelines. Yet in spite of its of its ubiquity in nature and industry, mixing is only imperfectly under-stood. Indeed, investigators cannot even settle on a common terminology: mixing is often referred to as stirring by oceanographers and geophysicists, as blending by polymer engineers and as agitation by process engineers. Regardless of what the process is called, there is little doubt that it is exceedingly complex and is found in a great variety of systems. In constructing a theory of fluid mixing, for example, one has to take into account fluids that can be miscible or partially miscible and reactive or inert, and flows that are slow and orderly or very fast and turbulent. It is therefore not surprising that no single theory can explain all aspect of mixing in fluids and that straightforward computations usually fail to capture all the important details. Still, both physical experiments and computer simulations can provide insight into the mixing process. Over the past several years the authors and his colleague have taken both approaches in an effort to increase understanding of various aspect of the process-particularly of mixing involving slow flows and viscous fluids such as oils
Abdominal cerebrospinal fluid pseudocyst
International Nuclear Information System (INIS)
Pathi, Ramon; Sage, Michael; Slavotinek, John; Hanieh, Ahmad
2004-01-01
A case of an abdominal cerebrospinal fluid (CSF) pseudocyst in a patient with a ventriculoperitoneal shunt is reported to illustrate this known but rare complication. In the setting of a VP shunt, the frequency of abdominal CSF pseudocyst formation is approximately 3.2%, often being precipitated by a recent inflammatory or infective process or recent surgery. Larger pseudocysts tend to be sterile, whereas smaller pseudocysts are more often infected. Ultrasound and CTeach have characteristic findings Copyright (2004) Blackwell Publishing Asia Pty Ltd
International Nuclear Information System (INIS)
Miller, F. M.
1985-01-01
Apparatus for sensing the electrical conductivity of fluid which can be used to detonate an electro explosive device for operating a release mechanism for uncoupling a parachute canopy from its load upon landing in water. An operating network connected to an ignition capacitor and to a conductivity sensing circuit and connected in controlling relation to a semiconductor switch has a voltage independent portion which controls the time at which the semiconductor switch is closed to define a discharge path to detonate the electro explosive device independent of the rate of voltage rise on the ignition capacitor. The operating network also has a voltage dependent portion which when a voltage of predetermined magnitude is developed on the conductivity sensing circuit in response to fluid not having the predetermined condition of conductivity, the voltage dependent portion closes the semiconductor switch to define the discharge path when the energy level is insufficient to detonate the electro explosive device. A regulated current source is connected in relation to the conductivity sensing circuit and to the electrodes thereof in a manner placing the circuit voltage across the electrodes when the conductivity of the fluid is below a predetermined magnitude so that the sensing circuit does not respond thereto and placing the circuit voltage across the sensing circuit when the conductivity of the fluid is greater than a predetermined magnitude. The apparatus is operated from a battery, and the electrodes are of dissimilar metals so selected and connected relative to the polarity portions of the circuit to maximize utilization of the battery output voltage
International Nuclear Information System (INIS)
Lee, A.S.
1978-01-01
A method and apparatus are described for measuring the pressure of a fluid having characteristics that make it unsuitable for connection directly to a pressure gauge. The method is particularly suitable for the periodic measurement of the pressure of a supply of liquid Na to Na-lubricated bearings of pumps for pumping Na from a reservoir to the bearing via a filter, the reservoir being contained in a closed vessel containing an inert blanket gas, such as Ar, above the Na. (UK)
Perspectives in Fluid Dynamics
Batchelor, G. K.; Moffatt, H. K.; Worster, M. G.
2002-12-01
With applications ranging from modelling the environment to automotive design and physiology to astrophysics, conventional textbooks cannot hope to give students much information on what topics in fluid dynamics are currently being researched, or how to choose between them. This book rectifies matters. It consists of eleven chapters that introduce and review different branches of the subject for graduate-level courses, or for specialists seeking introductions to other areas. Hb ISBN (2001): 0-521-78061-6
Fluid circulation control device
International Nuclear Information System (INIS)
Benard, Henri; Henocque, Jean.
1982-01-01
Horizontal fluid circulation control device, of the type having a pivoting flap. This device is intended for being fitted in the pipes of hydraulic installation, particularly in a bleed and venting system of a nuclear power station shifting radioactive or contaminated liquids. The characteristic of this device is the cut-out at the top of the flap to allow the air contained in the pipes to flow freely [fr
International Nuclear Information System (INIS)
Brasch, D.J.
1986-01-01
Chemical and mineral engineering students require texts which give guidance to problem solving to complement their main theoretical texts. This book has a broad coverage of the fluid flow problems which these students may encounter. The fundamental concepts and the application of the behaviour of liquids and gases in unit operation are dealt with. The book is intended to give numerical practice; development of theory is undertaken only when elaboration of treatments available in theoretical texts is absolutely necessary
Pedlosky, Joseph
1982-01-01
The content of this book is based, largely, on the core curriculum in geophys ical fluid dynamics which land my colleagues in the Department of Geophysical Sciences at The University of Chicago have taught for the past decade. Our purpose in developing a core curriculum was to provide to advanced undergraduates and entering graduate students a coherent and systematic introduction to the theory of geophysical fluid dynamics. The curriculum and the outline of this book were devised to form a sequence of courses of roughly one and a half academic years (five academic quarters) in length. The goal of the sequence is to help the student rapidly advance to the point where independent study and research are practical expectations. It quickly became apparent that several topics (e. g. , some aspects of potential theory) usually thought of as forming the foundations of a fluid-dynamics curriculum were merely classical rather than essential and could be, however sadly, dispensed with for our purposes. At the same tim...
Ogilvie, Gordon I.
2016-06-01
> These lecture notes and example problems are based on a course given at the University of Cambridge in Part III of the Mathematical Tripos. Fluid dynamics is involved in a very wide range of astrophysical phenomena, such as the formation and internal dynamics of stars and giant planets, the workings of jets and accretion discs around stars and black holes and the dynamics of the expanding Universe. Effects that can be important in astrophysical fluids include compressibility, self-gravitation and the dynamical influence of the magnetic field that is `frozen in' to a highly conducting plasma. The basic models introduced and applied in this course are Newtonian gas dynamics and magnetohydrodynamics (MHD) for an ideal compressible fluid. The mathematical structure of the governing equations and the associated conservation laws are explored in some detail because of their importance for both analytical and numerical methods of solution, as well as for physical interpretation. Linear and nonlinear waves, including shocks and other discontinuities, are discussed. The spherical blast wave resulting from a supernova, and involving a strong shock, is a classic problem that can be solved analytically. Steady solutions with spherical or axial symmetry reveal the physics of winds and jets from stars and discs. The linearized equations determine the oscillation modes of astrophysical bodies, as well as their stability and their response to tidal forcing.
Downhole Fluid Analyzer Development
Energy Technology Data Exchange (ETDEWEB)
Bill Turner
2006-11-28
A novel fiber optic downhole fluid analyzer has been developed for operation in production wells. This device will allow real-time determination of the oil, gas and water fractions of fluids from different zones in a multizone or multilateral completion environment. The device uses near infrared spectroscopy and induced fluorescence measurement to unambiguously determine the oil, water and gas concentrations at all but the highest water cuts. The only downhole components of the system are the fiber optic cable and windows. All of the active components--light sources, sensors, detection electronics and software--will be located at the surface, and will be able to operate multiple downhole probes. Laboratory testing has demonstrated that the sensor can accurately determine oil, water and gas fractions with a less than 5 percent standard error. Once installed in an intelligent completion, this sensor will give the operating company timely information about the fluids arising from various zones or multilaterals in a complex completion pattern, allowing informed decisions to be made on controlling production. The research and development tasks are discussed along with a market analysis.
Microfluidics with fluid walls.
Walsh, Edmond J; Feuerborn, Alexander; Wheeler, James H R; Tan, Ann Na; Durham, William M; Foster, Kevin R; Cook, Peter R
2017-10-10
Microfluidics has great potential, but the complexity of fabricating and operating devices has limited its use. Here we describe a method - Freestyle Fluidics - that overcomes many key limitations. In this method, liquids are confined by fluid (not solid) walls. Aqueous circuits with any 2D shape are printed in seconds on plastic or glass Petri dishes; then, interfacial forces pin liquids to substrates, and overlaying an immiscible liquid prevents evaporation. Confining fluid walls are pliant and resilient; they self-heal when liquids are pipetted through them. We drive flow through a wide range of circuits passively by manipulating surface tension and hydrostatic pressure, and actively using external pumps. Finally, we validate the technology with two challenging applications - triggering an inflammatory response in human cells and chemotaxis in bacterial biofilms. This approach provides a powerful and versatile alternative to traditional microfluidics.The complexity of fabricating and operating microfluidic devices limits their use. Walsh et al. describe a method in which circuits are printed as quickly and simply as writing with a pen, and liquids in them are confined by fluid instead of solid walls.
Pedlosky, Joseph
1979-01-01
The content of this book is based, largely, on the core curriculum in geophys ical fluid dynamics which I and my colleagues in the Department of Geophysical Sciences at The University of Chicago have taught for the past decade. Our purpose in developing a core curriculum was to provide to advanced undergraduates and entering graduate students a coherent and systematic introduction to the theory of geophysical fluid dynamics. The curriculum and the outline of this book were devised to form a sequence of courses of roughly one and a half academic years (five academic quarters) in length. The goal of the sequence is to help the student rapidly advance to the point where independent study and research are practical expectations. It quickly became apparent that several topics (e. g. , some aspects of potential theory) usually thought of as forming the foundations of a fluid-dynamics curriculum were merely classical rather than essential and could be, however sadly, dispensed with for our purposes. At the same ti...
International Nuclear Information System (INIS)
Mihalas, D.; Weaver, R.
1982-01-01
The purpose of this paper is to give an overview of the role of radiation in the transport of energy and momentum in a combined matter-radiation fluid. The transport equation for a moving radiating fluid is presented in both a fully Eulerian and a fully Lagrangian formulation, along with conservation equations describing the dynamics of the fluid. Special attention is paid to the problem of deriving equations that are mutually consistent in each frame, and between frames, to 0(v/c). A detailed analysis is made to show that in situations of broad interest, terms that are formally of 0(v/c) actually dominate the solution, demonstrating that it is essential (1) to pay scrupulous attention to the question of the frame dependence in formulating the equations, and (2) to solve the equations to 0(v/c) in quite general circumstances. These points are illustrated in the context of the nonequilibrium radiation diffusion limit, and a sketch of how the Lagrangian equations are to be solved is presented
Fluid transport due to nonlinear fluid-structure interaction
DEFF Research Database (Denmark)
Jensen, Jakob Søndergaard
1997-01-01
This work considers nonlinear fluid-structure interaction for a vibrating pipe containing fluid. Transverse pipe vibrations will force the fluid to move relative to the pipe creating unidirectional fluid flow towards the pipe end. The fluid flow induced affects the damping and the stiffness...... of the pipe. The behavior of the system in response to lateral resonant base excitation is analysed numerically and by the use of a perturbation method (multiple scales). Exciting the pipe in the fundamental mode of vibration seems to be most effective for transferring energy from the shaker to the fluid......, whereas higher modes of vibration can be used to transport fluid with pipe vibrations of smaller amplitude. The effect of the nonlinear geometrical terms is analysed and these terms are shown to affect the response for higher modes of vibration. Experimental investigations show good agreement...
Supercritical fluid reverse micelle separation
Fulton, J.L.; Smith, R.D.
1993-11-30
A method of separating solute material from a polar fluid in a first polar fluid phase is provided. The method comprises combining a polar fluid, a second fluid that is a gas at standard temperature and pressure and has a critical density, and a surfactant. The solute material is dissolved in the polar fluid to define the first polar fluid phase. The combined polar and second fluids, surfactant, and solute material dissolved in the polar fluid is maintained under near critical or supercritical temperature and pressure conditions such that the density of the second fluid exceeds the critical density thereof. In this way, a reverse micelle system defining a reverse micelle solvent is formed which comprises a continuous phase in the second fluid and a plurality of reverse micelles dispersed in the continuous phase. The solute material is dissolved in the polar fluid and is in chemical equilibrium with the reverse micelles. The first polar fluid phase and the continuous phase are immiscible. The reverse micelles each comprise a dynamic aggregate of surfactant molecules surrounding a core of the polar fluid. The reverse micelle solvent has a polar fluid-to-surfactant molar ratio W, which can vary over a range having a maximum ratio W[sub o] that determines the maximum size of the reverse micelles. The maximum ratio W[sub o] of the reverse micelle solvent is then varied, and the solute material from the first polar fluid phase is transported into the reverse micelles in the continuous phase at an extraction efficiency determined by the critical or supercritical conditions. 27 figures.
Heat transfer fluids containing nanoparticles
Singh, Dileep; Routbort, Jules; Routbort, A.J.; Yu, Wenhua; Timofeeva, Elena; Smith, David S.; France, David M.
2016-05-17
A nanofluid of a base heat transfer fluid and a plurality of ceramic nanoparticles suspended throughout the base heat transfer fluid applicable to commercial and industrial heat transfer applications. The nanofluid is stable, non-reactive and exhibits enhanced heat transfer properties relative to the base heat transfer fluid, with only minimal increases in pumping power required relative to the base heat transfer fluid. In a particular embodiment, the plurality of ceramic nanoparticles comprise silicon carbide and the base heat transfer fluid comprises water and water and ethylene glycol mixtures.
Hazards of organic working fluids
International Nuclear Information System (INIS)
Silberstein, S.
1977-08-01
We present several brief reviews on working fluids proposed for use in organic Rankine and bi-phase bottoming cycles. There are several general problems with many organic working fluids: flammability, toxicity, and a tendency to leak through seals. Besides, two of the proposed working fluids are to be used at temperatures above the manufacturer's maximum recommended temperature, and one is to be used in a way different from its customary usage. It may, in some cases, be more profitable to first seek alternative working fluids before committing large amounts of time and money to research projects on unsafe working fluids
Magnetic power piston fluid compressor
Gasser, Max G. (Inventor)
1994-01-01
A compressor with no moving parts in the traditional sense having a housing having an inlet end allowing a low pressure fluid to enter and an outlet end allowing a high pressure fluid to exit is described. Within the compressor housing is at least one compression stage to increase the pressure of the fluid within the housing. The compression stage has a quantity of magnetic powder within the housing, is supported by a screen that allows passage of the fluid, and a coil for selectively providing a magnetic field across the magnetic powder such that when the magnetic field is not present the individual particles of the powder are separated allowing the fluid to flow through the powder and when the magnetic field is present the individual particles of the powder pack together causing the powder mass to expand preventing the fluid from flowing through the powder and causing a pressure pulse to compress the fluid.
Energy Technology Data Exchange (ETDEWEB)
Prikryl, J; Kotyza, R; Krulikovsky, J; Mjartan, V; Valisova, I
1981-09-15
Composition of cleaning fluid emulsion are presented for drilling small diameter wells in clay soils, at high drill bit rotation velocity. The emulsions have lubricating properties and the abilty to improve stability of the drilled soil. The given fluids have a high fatty acid content with 12-24 carbon atoms in a single molecule, with a predominance of resinous acids 1-5% in mass, and having been emulsified in water or clay suspension without additives, or in a clay suspension with high-molecular polymer additives (glycobate cellulose compounds and/or polysaccharides, and/or their derivatives) in an amount of 0.1-3% per mass; thinning agents - huminite or lignite compounds in the amount of 0.01 to 0.5% in mass; weighting material - barite or lime 0.01 to 50% per mass; medium stabilizers - organic poly-electrolyte with polyacrylate in the amount of 0.05 to 2% in mass, or alkaline chloride/alkaline-ground metals 1-10% per mass. A cleaning emulsion fluid was prepared in the laboratory according to the given method. Add 3 kg tall oil to a solution of 1 kg K/sub 2/CO/sub 3/ per 100 l of water. Dynamic viscosity was equal to 1.4 x 10-/sup 3/ Pa/s. When drilling in compacted clay soils, when the emulsions require improved stability, it is necessary to add the maximum amount of tall oil whose molecules are absorbed by the clay soil and increase its durability.
Essential Computational Fluid Dynamics
Zikanov, Oleg
2011-01-01
This book serves as a complete and self-contained introduction to the principles of Computational Fluid Dynamic (CFD) analysis. It is deliberately short (at approximately 300 pages) and can be used as a text for the first part of the course of applied CFD followed by a software tutorial. The main objectives of this non-traditional format are: 1) To introduce and explain, using simple examples where possible, the principles and methods of CFD analysis and to demystify the `black box’ of a CFD software tool, and 2) To provide a basic understanding of how CFD problems are set and
Transport Coefficients of Fluids
Eu, Byung Chan
2006-01-01
Until recently the formal statistical mechanical approach offered no practicable method for computing the transport coefficients of liquids, and so most practitioners had to resort to empirical fitting formulas. This has now changed, as demonstrated in this innovative monograph. The author presents and applies new methods based on statistical mechanics for calculating the transport coefficients of simple and complex liquids over wide ranges of density and temperature. These molecular theories enable the transport coefficients to be calculated in terms of equilibrium thermodynamic properties, and the results are shown to account satisfactorily for experimental observations, including even the non-Newtonian behavior of fluids far from equilibrium.
Electrochemistry in supercritical fluids
Branch, Jack A.; Bartlett, Philip N.
2015-01-01
A wide range of supercritical fluids (SCFs) have been studied as solvents for electrochemistry with carbon dioxide and hydrofluorocarbons (HFCs) being the most extensively studied. Recent advances have shown that it is possible to get well-resolved voltammetry in SCFs by suitable choice of the conditions and the electrolyte. In this review, we discuss the voltammetry obtained in these systems, studies of the double-layer capacitance, work on the electrodeposition of metals into high aspect ratio nanopores and the use of metallocenes as redox probes and standards in both supercritical carbon dioxide–acetonitrile and supercritical HFCs. PMID:26574527
Acoustic concentration of particles in fluid flow
Ward, Michael D.; Kaduchak, Gregory
2010-11-23
An apparatus for acoustic concentration of particles in a fluid flow includes a substantially acoustically transparent membrane and a vibration generator that define a fluid flow path therebetween. The fluid flow path is in fluid communication with a fluid source and a fluid outlet and the vibration generator is disposed adjacent the fluid flow path and is capable of producing an acoustic field in the fluid flow path. The acoustic field produces at least one pressure minima in the fluid flow path at a predetermined location within the fluid flow path and forces predetermined particles in the fluid flow path to the at least one pressure minima.
Acoustic concentration of particles in fluid flow
Ward, Michael W.; Kaduchak, Gregory
2017-08-15
Disclosed herein is a acoustic concentration of particles in a fluid flow that includes a substantially acoustically transparent membrane and a vibration generator that define a fluid flow path therebetween. The fluid flow path is in fluid communication with a fluid source and a fluid outlet and the vibration generator is disposed adjacent the fluid flow path and is capable of producing an acoustic field in the fluid flow path. The acoustic field produces at least one pressure minima in the fluid flow path at a predetermined location within the fluid flow path and forces predetermined particles in the fluid flow path to the at least one pressure minima.
Barati Farimani, Amir; Gomes, Joseph; Pande, Vijay
2017-11-01
We have developed a new data-driven model paradigm for the rapid inference and solution of the constitutive equations of fluid mechanic by deep learning models. Using generative adversarial networks (GAN), we train models for the direct generation of solutions to steady state heat conduction and incompressible fluid flow without knowledge of the underlying governing equations. Rather than using artificial neural networks to approximate the solution of the constitutive equations, GANs can directly generate the solutions to these equations conditional upon an arbitrary set of boundary conditions. Both models predict temperature, velocity and pressure fields with great test accuracy (>99.5%). The application of our framework for inferring and generating the solutions of partial differential equations can be applied to any physical phenomena and can be used to learn directly from experiments where the underlying physical model is complex or unknown. We also have shown that our framework can be used to couple multiple physics simultaneously, making it amenable to tackle multi-physics problems.
Fay, James A.; Sonwalkar, Nishikant
1996-05-01
This CD-ROM is designed to accompany James Fay's Introduction to Fluid Mechanics. An enhanced hypermedia version of the textbook, it offers a number of ways to explore the fluid mechanics domain. These include a complete hypertext version of the original book, physical-experiment video clips, excerpts from external references, audio annotations, colored graphics, review questions, and progressive hints for solving problems. Throughout, the authors provide expert guidance in navigating the typed links so that students do not get lost in the learning process. System requirements: Macintosh with 68030 or greater processor and with at least 16 Mb of RAM. Operating System 6.0.4 or later for 680x0 processor and System 7.1.2 or later for Power-PC. CD-ROM drive with 256- color capability. Preferred display 14 inches or above (SuperVGA with 1 megabyte of VRAM). Additional system font software: Computer Modern postscript fonts (CM/PS Screen Fonts, CMBSY10, and CMTT10) and Adobe Type Manager (ATM 3.0 or later). James A. Fay is Professor Emeritus and Senior Lecturer in the Department of Mechanical Engineering at MIT.
Grimshaw, RHJ
2007-01-01
After the initial observation by John Scott Russell of a solitary wave in a canal, his insightful laboratory experiments and the subsequent theoretical work of Boussinesq, Rayleigh and Korteweg and de Vries, interest in solitary waves in fluids lapsed until the mid 1960's with the seminal paper of Zabusky and Kruskal describing the discovery of the soliton. This was followed by the rapid development of the theory of solitons and integrable systems. At the same time came the realization that solitary waves occur naturally in many physical systems, and play a fundamental role in many circumstances. The aim of this text is to describe the role that soliton theory plays in fluids in several contexts. After an historical introduction, the book is divided five chapters covering the basic theory of the Korteweg-de Vries equation, and the subsequent application to free-surface solitary waves in water to internal solitary waves in the coastal ocean and the atmospheric boundary layer, solitary waves in rotating flows, ...
Hama, Brian; Mahajan, Gautam; Kothapalli, Chandrasekhar
2017-08-01
Exogenous delivery of cartilage extract is being explored as a promising candidate for knee arthritis treatment as it biomimics native cartilage tissue characteristics. In this study, we report on the rheological characterization of aqueous suspensions constituted from a powdered form of unhydrolyzed chicken sternum extract. The effect of particle size (as-received vs. milled), suspension fluid (water vs. PBS), and temperature (37°C vs. 4°C), on the viscoelastic properties of the sternum extract based particulate suspensions were evaluated. Results showed that these suspensions exhibit shear-thinning characteristics as shear rate (γ̇) increases, while viscosity (η), storage (G'), and loss (G″) moduli of the suspensions increased with increasing particulate loading (ϕ: 2.5-10wt%). Reducing the as-received particle size by milling decreased G', G, and η of the suspensions and increased the influence of ϕ on these properties, possibly due to improved particle packing. Replacing water with PBS had no significant effect on the rheological properties, but temperature reduction from 37°C to 4°C increased G', G", and η of the suspensions and lowered the impact of powder loading on viscoelastic properties. The suspension's time-dependent response was typical of viscoelastic materials, characterized by an asymptotical approach to a final stress (stress relaxation) or strain (creep). Results were fit to a power-law model for creep, a general relaxation model for exponential decay in stress, Carreau-Yasuda models for flow curves, and a two-parameter Liu model to identify the maximum powder loading (ϕ m ). Among the various forces involved in particle-particle interactions within these suspensions, electrostatic forces appeared to dominate the most. Such characterization of the viscoelastic nature of these suspensions would help in formulating stable injectable cartilage extract based therapeutics for in vivo applications. Copyright © 2017 Elsevier Ltd. All
Fluid mechanics fundamentals and applications
Cengel, Yunus
2013-01-01
Cengel and Cimbala's Fluid Mechanics Fundamentals and Applications, communicates directly with tomorrow's engineers in a simple yet precise manner. The text covers the basic principles and equations of fluid mechanics in the context of numerous and diverse real-world engineering examples. The text helps students develop an intuitive understanding of fluid mechanics by emphasizing the physics, using figures, numerous photographs and visual aids to reinforce the physics. The highly visual approach enhances the learning of Fluid mechanics by students. This text distinguishes itself from others by the way the material is presented - in a progressive order from simple to more difficult, building each chapter upon foundations laid down in previous chapters. In this way, even the traditionally challenging aspects of fluid mechanics can be learned effectively. McGraw-Hill is also proud to offer ConnectPlus powered by Maple with the third edition of Cengel/Cimbabla, Fluid Mechanics. This innovative and powerful new sy...
Ecotoxicological testing of performance fluids
International Nuclear Information System (INIS)
Kallqvist, T.
1990-05-01
The report deals with a project comprising the testing of drilling fluids concerning ecotoxicology, biological degradation, and toxicity. Two types of drilling fluids were tested for toxic effects on marine algae and biological degradability. A fluid based on mineral oil was readily degradable (98% DOC removal in 28 days) while an ether based oil degraded more slowly (56% DOC removal in 28 days). The toxicity of both fluids was tested after emulsification of the oils in water and separating the oil and water phase after equilibration. The EC 50 values obtained with this approach were 8.15 g/l for the oil based fluid and 116 g/l for the ether fluid. 9 figs., 8 tabs
Fluids in crustal deformation: Fluid flow, fluid-rock interactions, rheology, melting and resources
Lacombe, Olivier; Rolland, Yann
2016-11-01
Fluids exert a first-order control on the structural, petrological and rheological evolution of the continental crust. Fluids interact with rocks from the earliest stages of sedimentation and diagenesis in basins until these rocks are deformed and/or buried and metamorphosed in orogens, then possibly exhumed. Fluid-rock interactions lead to the evolution of rock physical properties and rock strength. Fractures and faults are preferred pathways for fluids, and in turn physical and chemical interactions between fluid flow and tectonic structures, such as fault zones, strongly influence the mechanical behaviour of the crust at different space and time scales. Fluid (over)pressure is associated with a variety of geological phenomena, such as seismic cycle in various P-T conditions, hydrofracturing (including formation of sub-horizontal, bedding-parallel veins), fault (re)activation or gravitational sliding of rocks, among others. Fluid (over)pressure is a governing factor for the evolution of permeability and porosity of rocks and controls the generation, maturation and migration of economic fluids like hydrocarbons or ore forming hydrothermal fluids, and is therefore a key parameter in reservoir studies and basin modeling. Fluids may also help the crust partially melt, and in turn the resulting melt may dramatically change the rheology of the crust.
Supercritical fluids processing: emerging opportunities
International Nuclear Information System (INIS)
Kovaly, K.A.
1985-01-01
This publication on the emerging opportunities of supercritical fluids processing reveals the latest research findings and development trends in this field. These findings and development trends are highlighted, and the results of applications of technology to the business of supercritical fluids are reported. Applications of supercritical fluids to chemical intermediates, environmental applications, chemical reactions, food and biochemistry processing, and fuels processing are discussed in some detail
Palazzi, Elisa; Fraedrich, Klaus
2016-01-01
This volume provides an overview of the fluid aspects of the climate system, focusing on basic aspects as well as recent research developments. It will bring together contributions from diverse fields of the physical, mathematical and engineering sciences. The volume will be useful to doctorate students, postdocs and researchers working on different aspects of atmospheric, oceanic and environmental fluid dynamics. It will also be of interest to researchers interested in quantitatively understanding how fluid dynamics can be applied to the climate system, and to climate scientists willing to gain a deeper insight into the fluid mechanics underlying climate processes.
CISM Course on Rotating Fluids
1992-01-01
The volume presents a comprehensive overview of rotation effects on fluid behavior, emphasizing non-linear processes. The subject is introduced by giving a range of examples of rotating fluids encountered in geophysics and engineering. This is then followed by a discussion of the relevant scales and parameters of rotating flow, and an introduction to geostrophic balance and vorticity concepts. There are few books on rotating fluids and this volume is, therefore, a welcome addition. It is the first volume which contains a unified view of turbulence in rotating fluids, instability and vortex dynamics. Some aspects of wave motions covered here are not found elsewhere.
Cerebral spinal fluid (CSF) collection
... Ventricular puncture; Lumbar puncture; Cisternal puncture; Cerebrospinal fluid culture ... the meaning of your specific test results. The examples above show the common measurements for results for ...
Cerebrospinal fluid cisternography
International Nuclear Information System (INIS)
Sandler, M.P.; Price, A.C.; Partain, C.L.; James, A.E.; Runge, V.M.
1988-01-01
The evaluation of CSF dynamics has been discussed utilizing nuclear medicine, computed tomography, and magnetic resonance imaging. Cerebrospinal fluid leaks are readily diagnosed by both CT and nuclear scintigraphy. The major advantage of CT is the exact anatomic localization of the site of CSF leakage. Contrast toxicity, as well as complex and costly technology, often limit the wide applicability of CT in the diagnosis of CSF leaks. Nuclear scintigraphy, on the other hand, offers nonexact localization of CSF leaks, but is often more readily available than Ct. Magnetic resonance resolution is presently insufficient for diagnosis of CSF leaks. The anatomic diagnosis of hydrocephalus is more readily established with CT and MRI as compared to nuclear scintigraphy. However, none of the imaging modalities discussed are clearly superior in differentiating communicating from obstructive hydrocephalus. Nuclear scintigraphy remains the imaging modality of choice in the quantitative evaluation of CSF shunts and their patency
International Nuclear Information System (INIS)
Salesi, G.
1995-07-01
Starting from the Pauli current the decomposition of the non-relativistic local velocity has been obtained in two parts (in the ordinary tensorial language): one parallel and the other orthogonal to the impulse. The former is recognized to be the classical part, that is, the center-of-mass (CM) velocity, and the latter the quantum one, that is, the velocity of the motion in the CM frame (namely, the internal spin motion or Zitterbewegung). Inserting this complete, composite expression of the velocity into the kinetic energy term of the classical non-relativistic (i.e. Newtonian) Lagrangian, the author straightforwardly get the appearance of the so called quantum potential associates as it is known, to the Madelung fluid. In such a way, the quantum mechanical behaviour of particles appears to be strictly correlated to the existence of spin and Zitterbewegung
Improved Fluid Perturbation Theory: Equation of state for Fluid Xenon
Li, Qiong; Liu, Hai-Feng; Zhang, Gong-Mu; Zhao, Yan-Hong; Tian, Ming-Feng; Song, Hai-Feng
2016-01-01
The traditional fluid perturbation theory is improved by taking electronic excitations and ionizations into account, in the framework of average ion spheres. It is applied to calculate the equation of state for fluid Xenon, which turns out in good agreement with the available shock data.
Editorial Special Issue on Fluid Mechanics and Fluid Power (FMFP ...
Indian Academy of Sciences (India)
a shark is more efficient than a propeller; the notoriously complicated and nonlinear Navier–. Stokes equations governing fluid motion provide fertile ground for research to both applied and pure mathematicians. There is the phenomenon of turbulence in fluid flows. A statement in 1932, attributed to Horace Lamb, author of ...
statistical fluid theory for associating fluids containing alternating ...
Indian Academy of Sciences (India)
Statistical associating fluid theory of homonuclear dimerized chain fluids and homonuclear ... The proposed models account for the appropriate .... where gHNM(1,1) is the expression for the contact value of the correlation func- tion of two ...
Thermophysical properties of supercritical fluids and fluid mixtures
International Nuclear Information System (INIS)
Sengers, J.V.
1989-08-01
The purpose of the research is to extend the theory of critical phenomena in fluids and fluid mixtures to obtain scientifically based equations that include the crossover from the asymptotic singular behavior of the thermophysical properties close to the critical point to the regular behavior of these properties far away from the critical point
Fluid Creep and Over-resuscitation.
Saffle, Jeffrey R
2016-10-01
Fluid creep is the term applied to a burn resuscitation, which requires more fluid than predicted by standard formulas. Fluid creep is common today and is linked to several serious edema-related complications. Increased fluid requirements may accompany the appropriate resuscitation of massive injuries but dangerous fluid creep is also caused by overly permissive fluid infusion and the lack of colloid supplementation. Several strategies for recognizing and treating fluid creep are presented. Copyright © 2016 Elsevier Inc. All rights reserved.
Materials processing using supercritical fluids
Directory of Open Access Journals (Sweden)
Orlović Aleksandar M.
2005-01-01
Full Text Available One of the most interesting areas of supercritical fluids applications is the processing of novel materials. These new materials are designed to meet specific requirements and to make possible new applications in Pharmaceuticals design, heterogeneous catalysis, micro- and nano-particles with unique structures, special insulating materials, super capacitors and other special technical materials. Two distinct possibilities to apply supercritical fluids in processing of materials: synthesis of materials in supercritical fluid environment and/or further processing of already obtained materials with the help of supercritical fluids. By adjusting synthesis parameters the properties of supercritical fluids can be significantly altered which further results in the materials with different structures. Unique materials can be also obtained by conducting synthesis in quite specific environments like reversed micelles. This paper is mainly devoted to processing of previously synthesized materials which are further processed using supercritical fluids. Several new methods have been developed to produce micro- and nano-particles with the use of supercritical fluids. The following methods: rapid expansion of supercritical solutions (RESS supercritical anti-solvent (SAS, materials synthesis under supercritical conditions and encapsulation and coating using supercritical fluids were recently developed.
Fluid simulation for computer graphics
Bridson, Robert
2008-01-01
Animating fluids like water, smoke, and fire using physics-based simulation is increasingly important in visual effects, in particular in movies, like The Day After Tomorrow, and in computer games. This book provides a practical introduction to fluid simulation for graphics. The focus is on animating fully three-dimensional incompressible flow, from understanding the math and the algorithms to the actual implementation.
Fluid jet electric discharge source
Bender, Howard A [Ripon, CA
2006-04-25
A fluid jet or filament source and a pair of coaxial high voltage electrodes, in combination, comprise an electrical discharge system to produce radiation and, in particular, EUV radiation. The fluid jet source is composed of at least two serially connected reservoirs, a first reservoir into which a fluid, that can be either a liquid or a gas, can be fed at some pressure higher than atmospheric and a second reservoir maintained at a lower pressure than the first. The fluid is allowed to expand through an aperture into a high vacuum region between a pair of coaxial electrodes. This second expansion produces a narrow well-directed fluid jet whose size is dependent on the size and configuration of the apertures and the pressure used in the reservoir. At some time during the flow of the fluid filament, a high voltage pulse is applied to the electrodes to excite the fluid to form a plasma which provides the desired radiation; the wavelength of the radiation being determined by the composition of the fluid.
Introduction to mathematical fluid dynamics
Meyer, Richard E
2010-01-01
An introduction to the behavior of liquids and gases, this volume provides excellent coverage of kinematics, momentum principle, Newtonian fluid, rotating fluids, compressibility, and more. It is geared toward advanced undergraduate and graduate students of mathematics and general science, and it requires a background in calculus and vector analysis. 1971 edition.
Supercritical fluids in ionic liquids
Kroon, M.C.; Peters, C.J.; Plechkova, N.V.; Seddon, K.R.
2014-01-01
Ionic liquids and supercritical fluids are both alternative environmentally benign solvents, but their properties are very different. Ionic liquids are non-volatile but often considered highly polar compounds, whereas supercritical fluids are non-polar but highly volatile compounds. The combination
Fluid diversion in oil recovery
International Nuclear Information System (INIS)
Nimir, Hassan B.
1999-01-01
In any oil recovery process, large scale heterogeneities, such as fractures, channels, or high-permeability streaks, can cause early break through of injected fluid which will reduce oil recovery efficiency. In waterflooding, enhanced oil recovery, and acidizing operations, this problem is particularly acute because of the cost of the injected fluid. On the other hand coping with excess water production is always a challenging task for field operators. The cost of handling and disposing produced water can significantly shorten the economic production life of an oil well. The hydrostatic pressure created by high fluid levels in a well (water coning) is also detrimental to oil production. In this paper, the concept of fluid diversion is explained. Different methods that are suggested to divert the fluid into the oil-bearing-zones are briefly discussed, to show their advantages and disadvantages. Methods of reducing water production in production well are also discussed. (Author)
Revisiting the Landau fluid closure.
Hunana, P.; Zank, G. P.; Webb, G. M.; Adhikari, L.
2017-12-01
Advanced fluid models that are much closer to the full kinetic description than the usual magnetohydrodynamic description are a very useful tool for studying astrophysical plasmas and for interpreting solar wind observational data. The development of advanced fluid models that contain certain kinetic effects is complicated and has attracted much attention over the past years. Here we focus on fluid models that incorporate the simplest possible forms of Landau damping, derived from linear kinetic theory expanded about a leading-order (gyrotropic) bi-Maxwellian distribution function f_0, under the approximation that the perturbed distribution function f_1 is gyrotropic as well. Specifically, we focus on various Pade approximants to the usual plasma response function (and to the plasma dispersion function) and examine possibilities that lead to a closure of the linear kinetic hierarchy of fluid moments. We present re-examination of the simplest Landau fluid closures.
Fluid migration studies in salt
International Nuclear Information System (INIS)
Shefelbine, H.C.; Raines, G.E.
1980-01-01
This discussion will be limited to the migration of water trapped in the rock salt under the influence of the heat field produced by nuclear waste. This is of concern because hypotheticl scenarios have been advanced in which this fluid movement allows radionuclides to escape to the biosphere. While portions of these scenarios are supported by observation, none of the complete scenarios has been demonstrated. The objectives of the present fluid migration studies are two-fold: 1. determine the character of the trapped fluid in terms of quantity, habitat and chemical constituents; and 2. define the mechanisms that cause the fluid to migrate toward heat sources. Based on the observations to date, fluid migration will not have a major impact on repository integrity. However, the above objectives will be pursued until the impacts, if any, can be quantified
Performance Testing of Cutting Fluids
DEFF Research Database (Denmark)
Belluco, Walter
The importance of cutting fluid performance testing has increased with documentation requirements of new cutting fluid formulations based on more sustainable products, as well as cutting with minimum quantity of lubrication and dry cutting. Two sub-problems have to be solved: i) which machining...... tests feature repeatability, reproducibility and sensitivity to cutting fluids, and ii) to what extent results of one test ensure relevance to a wider set of machining situations. The present work is aimed at assessing the range of validity of the different testing methods, investigating correlation...... within the whole range of operations, materials, cutting fluids, operating conditions, etc. Cutting fluid performance was evaluated in turning, drilling, reaming and tapping, and with respect to tool life, cutting forces, chip formation and product quality (dimensional accuracy and surface integrity...
Heating production fluids in a wellbore
Orrego, Yamila; Jankowski, Todd A.
2016-07-12
A method for heating a production fluid in a wellbore. The method can include heating, using a packer fluid, a working fluid flowing through a first medium disposed in a first section of the wellbore, where the first medium transfers heat from the packer fluid to the working fluid. The method can also include circulating the working fluid into a second section of the wellbore through a second medium, where the second medium transfers heat from the working fluid to the production fluid. The method can further include returning the working fluid to the first section of the wellbore through the first medium.
Energy Technology Data Exchange (ETDEWEB)
Michael C. Adams; Greg Nash
2004-03-01
Geothermal water must be injected back into the reservoir after it has been used for power production. Injection is critical in maximizing the power production and lifetime of the reservoir. To use injectate effectively the direction and velocity of the injected water must be known or inferred. This information can be obtained by using chemical tracers to track the subsurface flow paths of the injected fluid. Tracers are chemical compounds that are added to the water as it is injected back into the reservoir. The hot production water is monitored for the presence of this tracer using the most sensitive analytic methods that are economically feasible. The amount and concentration pattern of the tracer revealed by this monitoring can be used to evaluate how effective the injection strategy is. However, the tracers must have properties that suite the environment that they will be used in. This requires careful consideration and testing of the tracer properties. In previous and parallel investigations we have developed tracers that are suitable from tracing liquid water. In this investigation, we developed tracers that can be used for steam and mixed water/steam environments. This work will improve the efficiency of injection management in geothermal fields, lowering the cost of energy production and increasing the power output of these systems.
Energy Technology Data Exchange (ETDEWEB)
Kajdas, C.; Dominiak, M.; Kozinski, R.; Misterkiewicz, B.; Polowniak, J.; Szczepaniak, S.
1982-06-30
The cutting fluid (SOZh) contains 0.5 to 10 percent vegetable or animal fats, selectively sulfurized in the presence of a catalyst (Kt): 0.1 to 10 percent chlorinated C2O to C3O paraffins, which contain 10 to 50 percent Chlorine in a molecule, and 0.001 to 0.5 percent dialkyldithiocarbamic or alkylen-bis-(dithiocarbamic) acids or their salts or derivatives of the form (R(R')NC(S)SRn'', (CH2)n(NHC(S)S)2R'' or R(R')NC(S)SnC(S)(R)R', where R and R' are alkyl or cycloalkyl of the C1 to C6 fractions, R'' is Hydrogen, a metal, or aliphatic or heterocyclic amine, n = 2 to 6 and 0.001 to 0.3 percent of heterocyclic mercaptanes or disulfides of the cited formula, where A is Nitrogen or Sulfur, and up to 100 percent petroleum oil with a kinematic viscosity of 5 to 50 square millimeters per second at 323K.
Multidomain multiphase fluid mechanics
International Nuclear Information System (INIS)
Sha, W.T.; Soo, S.L.
1976-10-01
A set of multiphase field equations--conversion of mass, momentum and energy--based on multiphase mechanics is developed. Multiphase mechanics applies to mixtures of phases which are separated by interfaces and are mutually exclusive. Based on the multiphase mechanics formulation, additional terms appear in the field equations when the physical size of the dispersed phase (bubble or droplet) is many times larger than the inter-molecular spacing. These terms are the inertial coupling due to virtual mass and the additional viscous coupling due to unsteadiness of the flow field. The multiphase formulation given here takes into account the discreteness of particles of dispersed phases and, at the same time, the necessity of the distributive representation of field variables via space-time averaging when handling a large number of particles. The provision for multidomain transition further permits us to treat dispersed phases which are large compared to the characteristic dimension of the flow system via interdomain relations. The multidomain multiphase approach provides a framework for us to model the various flow regimes. Because some of the transport parameters associated with the system equations are not well known at the present time, an idealized two-domain two-phase solution approach is proposed as a first step. Finally, comparisons are made between the field equations formulated based on the multidomain-multiphase fluid mechanics and the pertinent existing models, and their relative significances are discussed. The desirability of consistent approximation and simplifications possible for dilute suspensions are discussed
Computational fluid dynamic applications
Energy Technology Data Exchange (ETDEWEB)
Chang, S.-L.; Lottes, S. A.; Zhou, C. Q.
2000-04-03
The rapid advancement of computational capability including speed and memory size has prompted the wide use of computational fluid dynamics (CFD) codes to simulate complex flow systems. CFD simulations are used to study the operating problems encountered in system, to evaluate the impacts of operation/design parameters on the performance of a system, and to investigate novel design concepts. CFD codes are generally developed based on the conservation laws of mass, momentum, and energy that govern the characteristics of a flow. The governing equations are simplified and discretized for a selected computational grid system. Numerical methods are selected to simplify and calculate approximate flow properties. For turbulent, reacting, and multiphase flow systems the complex processes relating to these aspects of the flow, i.e., turbulent diffusion, combustion kinetics, interfacial drag and heat and mass transfer, etc., are described in mathematical models, based on a combination of fundamental physics and empirical data, that are incorporated into the code. CFD simulation has been applied to a large variety of practical and industrial scale flow systems.
Non-Newtonian Hele-Shaw Flow and the Saffman-Taylor Instability
International Nuclear Information System (INIS)
Kondic, L.; Shelley, M.J.; Palffy-Muhoray, P.
1998-01-01
We explore the Saffman-Taylor instability of a gas bubble expanding into a shear thinning liquid in a radial Hele-Shaw cell. Using Darcy close-quote s law generalized for non-Newtonian fluids, we perform simulations of the full dynamical problem. The simulations show that shear thinning significantly influences the developing interfacial patterns. Shear thinning can suppress tip splitting, and produce fingers which oscillate during growth and shed side branches. Emergent length scales show reasonable agreement with a general linear stability analysis. copyright 1998 The American Physical Society
Noncommutative geometry and fluid dynamics
International Nuclear Information System (INIS)
Das, Praloy; Ghosh, Subir
2016-01-01
In the present paper we have developed a Non-Commutative (NC) generalization of perfect fluid model from first principles, in a Hamiltonian framework. The noncommutativity is introduced at the Lagrangian (particle) coordinate space brackets and the induced NC fluid bracket algebra for the Eulerian (fluid) field variables is derived. Together with a Hamiltonian this NC algebra generates the generalized fluid dynamics that satisfies exact local conservation laws for mass and energy, thereby maintaining mass and energy conservation. However, nontrivial NC correction terms appear in the charge and energy fluxes. Other non-relativistic spacetime symmetries of the NC fluid are also discussed in detail. This constitutes the study of kinematics and dynamics of NC fluid. In the second part we construct an extension of the Friedmann-Robertson-Walker (FRW) cosmological model based on the NC fluid dynamics presented here. We outline the way in which NC effects generate cosmological perturbations bringing about anisotropy and inhomogeneity in the model. We also derive a NC extended Friedmann equation. (orig.)
Noncommutative geometry and fluid dynamics
Energy Technology Data Exchange (ETDEWEB)
Das, Praloy; Ghosh, Subir [Indian Statistical Institute, Physics and Applied Mathematics Unit, Kolkata (India)
2016-11-15
In the present paper we have developed a Non-Commutative (NC) generalization of perfect fluid model from first principles, in a Hamiltonian framework. The noncommutativity is introduced at the Lagrangian (particle) coordinate space brackets and the induced NC fluid bracket algebra for the Eulerian (fluid) field variables is derived. Together with a Hamiltonian this NC algebra generates the generalized fluid dynamics that satisfies exact local conservation laws for mass and energy, thereby maintaining mass and energy conservation. However, nontrivial NC correction terms appear in the charge and energy fluxes. Other non-relativistic spacetime symmetries of the NC fluid are also discussed in detail. This constitutes the study of kinematics and dynamics of NC fluid. In the second part we construct an extension of the Friedmann-Robertson-Walker (FRW) cosmological model based on the NC fluid dynamics presented here. We outline the way in which NC effects generate cosmological perturbations bringing about anisotropy and inhomogeneity in the model. We also derive a NC extended Friedmann equation. (orig.)
Quantum field theory of fluids.
Gripaios, Ben; Sutherland, Dave
2015-02-20
The quantum theory of fields is largely based on studying perturbations around noninteracting, or free, field theories, which correspond to a collection of quantum-mechanical harmonic oscillators. The quantum theory of an ordinary fluid is "freer", in the sense that the noninteracting theory also contains an infinite collection of quantum-mechanical free particles, corresponding to vortex modes. By computing a variety of correlation functions at tree and loop level, we give evidence that a quantum perfect fluid can be consistently formulated as a low-energy, effective field theory. We speculate that the quantum behavior is radically different from both classical fluids and quantum fields.
Wave Interactions and Fluid Flows
Craik, Alex D. D.
1988-07-01
This up-to-date and comprehensive account of theory and experiment on wave-interaction phenomena covers fluids both at rest and in their shear flows. It includes, on the one hand, water waves, internal waves, and their evolution, interaction, and associated wave-driven means flow and, on the other hand, phenomena on nonlinear hydrodynamic stability, especially those leading to the onset of turbulence. This study provide a particularly valuable bridge between these two similar, yet different, classes of phenomena. It will be of value to oceanographers, meteorologists, and those working in fluid mechanics, atmospheric and planetary physics, plasma physics, aeronautics, and geophysical and astrophysical fluid dynamics.
Fluid intelligence: A brief history.
Kent, Phillip
2017-01-01
The concept of fluid and crystallized intelligence was introduced to the psychological community approximately 75 years ago by Raymond B. Cattell, and it continues to be an area of active research and controversy. The purpose of this paper is to provide a brief overview of the origin of the concept, early efforts to define intelligence and uses of intelligence tests to address pressing social issues, and the ongoing controversies associated with fluid intelligence and the structure of intelligence. The putative neuropsychological underpinnings and neurological substrates of fluid intelligence are discussed.
Advances in Environmental Fluid Mechanics
Mihailovic, Dragutin T
2010-01-01
Environmental fluid mechanics (EFM) is the scientific study of transport, dispersion and transformation processes in natural fluid flows on our planet Earth, from the microscale to the planetary scale. This book brings together scientists and engineers working in research institutions, universities and academia, who engage in the study of theoretical, modeling, measuring and software aspects in environmental fluid mechanics. It provides a forum for the participants, and exchanges new ideas and expertise through the presentations of up-to-date and recent overall achievements in this field.
Molecular thermodynamics of nonideal fluids
Lee, Lloyd L
2013-01-01
Molecular Thermodynamics of Nonideal Fluids serves as an introductory presentation for engineers to the concepts and principles behind and the advances in molecular thermodynamics of nonideal fluids. The book covers related topics such as the laws of thermodynamics; entropy; its ensembles; the different properties of the ideal gas; and the structure of liquids. Also covered in the book are topics such as integral equation theories; theories for polar fluids; solution thermodynamics; and molecular dynamics. The text is recommended for engineers who would like to be familiarized with the concept
Spinning fluids in general relativity
Ray, J. R.; Smalley, L. L.
1982-01-01
General relativity field equations are employed to examine a continuous medium with internal spin. A variational principle formerly applied in the special relativity case is extended to the general relativity case, using a tetrad to express the spin density and the four-velocity of the fluid. An energy-momentum tensor is subsequently defined for a spinning fluid. The equations of motion of the fluid are suggested to be useful in analytical studies of galaxies, for anisotropic Bianchi universes, and for turbulent eddies.
Superconfinement tailors fluid flow at microscales.
Setu, Siti Aminah; Dullens, Roel P A; Herná ndez-Machado, Aurora; Pagonabarraga, Ignacio; Aarts, Dirk G A L; Ledesma-Aguilar, Rodrigo
2015-01-01
Understanding fluid dynamics under extreme confinement, where device and intrinsic fluid length scales become comparable, is essential to successfully develop the coming generations of fluidic devices. Here we report measurements of advancing fluid
Extension of Generalized Fluid System Simulation Program's Fluid Property Database
Patel, Kishan
2011-01-01
This internship focused on the development of additional capabilities for the General Fluid Systems Simulation Program (GFSSP). GFSSP is a thermo-fluid code used to evaluate system performance by a finite volume-based network analysis method. The program was developed primarily to analyze the complex internal flow of propulsion systems and is capable of solving many problems related to thermodynamics and fluid mechanics. GFSSP is integrated with thermodynamic programs that provide fluid properties for sub-cooled, superheated, and saturation states. For fluids that are not included in the thermodynamic property program, look-up property tables can be provided. The look-up property tables of the current release version can only handle sub-cooled and superheated states. The primary purpose of the internship was to extend the look-up tables to handle saturated states. This involves a) generation of a property table using REFPROP, a thermodynamic property program that is widely used, and b) modifications of the Fortran source code to read in an additional property table containing saturation data for both saturated liquid and saturated vapor states. Also, a method was implemented to calculate the thermodynamic properties of user-fluids within the saturation region, given values of pressure and enthalpy. These additions required new code to be written, and older code had to be adjusted to accommodate the new capabilities. Ultimately, the changes will lead to the incorporation of this new capability in future versions of GFSSP. This paper describes the development and validation of the new capability.
Standardization of Thermo-Fluid Modeling in Modelica.Fluid
Energy Technology Data Exchange (ETDEWEB)
Franke, Rudiger; Casella, Francesco; Sielemann, Michael; Proelss, Katrin; Otter, Martin; Wetter, Michael
2009-09-01
This article discusses the Modelica.Fluid library that has been included in the Modelica Standard Library 3.1. Modelica.Fluid provides interfaces and basic components for the device-oriented modeling of onedimensional thermo-fluid flow in networks containing vessels, pipes, fluid machines, valves and fittings. A unique feature of Modelica.Fluid is that the component equations and the media models as well as pressure loss and heat transfer correlations are decoupled from each other. All components are implemented such that they can be used for media from the Modelica.Media library. This means that an incompressible or compressible medium, a single or a multiple substance medium with one or more phases might be used with one and the same model as long as the modeling assumptions made hold. Furthermore, trace substances are supported. Modeling assumptions can be configured globally in an outer System object. This covers in particular the initialization, uni- or bi-directional flow, and dynamic or steady-state formulation of mass, energy, and momentum balance. All assumptions can be locally refined for every component. While Modelica.Fluid contains a reasonable set of component models, the goal of the library is not to provide a comprehensive set of models, but rather to provide interfaces and best practices for the treatment of issues such as connector design and implementation of energy, mass and momentum balances. Applications from various domains are presented.
The Variety of Fluid Dynamics.
Barnes, Francis; And Others
1980-01-01
Discusses three research topics which are concerned with eminently practical problems and deal at the same time with fundamental fluid dynamical problems. These research topics come from the general areas of chemical and biological engineering, geophysics, and pure mathematics. (HM)
Blanks, Robert F.
1979-01-01
A humanistic approach to teaching fluid mechanics is described which minimizes lecturing, increases professor-student interaction, uses group and individual problem solving sessions, and allows for student response. (BB)
Electrokinetic effects and fluid permeability
International Nuclear Information System (INIS)
Berryman, J.G.
2003-01-01
Fluid permeability of porous media depends mainly on connectivity of the pore space and two physical parameters: porosity and a pertinent length-scale parameter. Electrical imaging methods typically establish connectivity and directly measure electrical conductivity, which can then often be related to porosity by Archie's law. When electrical phase measurements are made in addition to the amplitude measurements, information about the pertinent length scale can then be obtained. Since fluid permeability controls the ability to flush unwanted fluid contaminants from the subsurface, inexpensive maps of permeability could improve planning strategies for remediation efforts. Detailed knowledge of fluid permeability is also important for oil field exploitation, where knowledge of permeability distribution in three dimensions is a common requirement for petroleum reservoir simulation and analysis, as well as for estimates on the economics of recovery
Thermodynamic properties of cryogenic fluids
Leachman, Jacob; Lemmon, Eric; Penoncello, Steven
2017-01-01
This update to a classic reference text provides practising engineers and scientists with accurate thermophysical property data for cryogenic fluids. The equations for fifteen important cryogenic fluids are presented in a basic format, accompanied by pressure-enthalpy and temperature-entropy charts and tables of thermodynamic properties. It begins with a chapter introducing the thermodynamic relations and functional forms for equations of state, and goes on to describe the requirements for thermodynamic property formulations, needed for the complete definition of the thermodynamic properties of a fluid. The core of the book comprises extensive data tables and charts for the most commonly-encountered cryogenic fluids. This new edition sees significant updates to the data presented for air, argon, carbon monoxide, deuterium, ethane, helium, hydrogen, krypton, nitrogen and xenon. The book supports and complements NIST’s REFPROP - an interactive database and tool for the calculation of thermodynamic propertie...
Mixed Fluid Conditions: Capillary Phenomena
Santamarina, Carlos; Sun, Zhonghao
2017-01-01
Mixed fluid phenomena in porous media have profound implications on soil-atmosphere interaction, energy geotechnology, environmental engineering and infrastructure design. Surface tension varies with pressure, temperature, solute concentration
Heart failure - fluids and diuretics
... this page: //medlineplus.gov/ency/patientinstructions/000112.htm Heart failure - fluids and diuretics To use the sharing features ... to Expect at Home When you have heart failure, your heart does not pump out enough blood. This causes ...
Growth kinetics in multicomponent fluids
International Nuclear Information System (INIS)
Chen, S.; Lookman, T.
1995-01-01
The hydrodynamic effects on the late-stage kinetics in spinodal decomposition of multicomponent fluids are examined using a lattice Boltzmann scheme with stochastic fluctuations in the fluid and at the interface. In two dimensions, the three- and four-component immiscible fluid mixture (with a 1024 2 lattice) behaves like an off-critical binary fluid with an estimated domain growth of t 0.4 +/= 0.03 rather than t 1/3 as previously estimated, showing the significant influence of hydrodynamics. In three dimensions (with a 256 3 lattice), we estimate the growth as t 0.96 +/= 0.05 for both critical and off-critical quenches, in agreement with phenomenological theory
Mesoscopic model for binary fluids
Echeverria, C.; Tucci, K.; Alvarez-Llamoza, O.; Orozco-Guillén, E. E.; Morales, M.; Cosenza, M. G.
2017-10-01
We propose a model for studying binary fluids based on the mesoscopic molecular simulation technique known as multiparticle collision, where the space and state variables are continuous, and time is discrete. We include a repulsion rule to simulate segregation processes that does not require calculation of the interaction forces between particles, so binary fluids can be described on a mesoscopic scale. The model is conceptually simple and computationally efficient; it maintains Galilean invariance and conserves the mass and energy in the system at the micro- and macro-scale, whereas momentum is conserved globally. For a wide range of temperatures and densities, the model yields results in good agreement with the known properties of binary fluids, such as the density profile, interface width, phase separation, and phase growth. We also apply the model to the study of binary fluids in crowded environments with consistent results.
Inverted emulsion drilling fluid
Energy Technology Data Exchange (ETDEWEB)
Ana, I; Astanei, E; Mireanu, G; Orosz, M; Popescu, F; Vasile, I
1979-07-28
The subject of the invention is the method of obtaining inverted drilling fluid which is required during stripping of a productive bed and ending of a well where difficulties develop during drilling of the argillaceous rock. Example: in a reservoir with capacity 30 m/sup 3/, 10 m/sup 3/ of diesel fuel are added. A total of 1000 kg of emulsifier are added to the diesel fuel consisting of: 85 mass% of a mixture of sodium and potassium salts of fatty acids, residues of fatty acids or naphthene acids with high molecular weight taken in proportion of 10:90; 5 mass% of a mixture of polymers with hydrophilic-hydrophobic properties obtained by mixing 75 mass% of polyethylene oxide with molecular weight 10,000 and 25 mass% of propylene oxide with molecular weight 15,000, and 10 mass% of salt on alkaline earth metal (preferably calcium chloride). The mixture is mixed into complete dissolving. Then 1200 kg of filtering accelerator are added obtained from concentrated sulfuric acid serving for sulfur oxidation, asphalt substance with softening temperature 85-104/sup 0/C and fatty acids C/sub 10/-C/sub 20/ taken in a proportion of 23.70 and 7 mass% The mixture obtained in this manner is neutralized by adding calcium hydroxide and equal quantities of alumina and activated bentonite clay in a concentration of 1-10 mass%, more preferably 5 mass% in relation to the initial mixture. The obtained mass is mixed until complete dispersion, after which 200 kg of organophilic clay are added obtained from bentonite of the type montmorillonite of sodium by processing with derivate obtained from amine of the type of the quaternary base of ammonium salt, and agent of hydrophobization of the type of fatty alcohols, fatty acids, nonion surfactants of the block-polymer type. After complete dispersion of the organophilic clay, 100 kg of stabilizer of emulsion of the surfactant type was added with molecular weight of 250010,000, more preferably 5000, in concentration of 0.1-5.0 mass%, more
Variable flexure-based fluid filter
Brown, Steve B.; Colston, Jr., Billy W.; Marshall, Graham; Wolcott, Duane
2007-03-13
An apparatus and method for filtering particles from a fluid comprises a fluid inlet, a fluid outlet, a variable size passage between the fluid inlet and the fluid outlet, and means for adjusting the size of the variable size passage for filtering the particles from the fluid. An inlet fluid flow stream is introduced to a fixture with a variable size passage. The size of the variable size passage is set so that the fluid passes through the variable size passage but the particles do not pass through the variable size passage.
Observation of Droplet Size Oscillations in a Two-Phase Fluid under Shear Flow
Courbin, Laurent; Panizza, Pascal; Salmon, Jean-Baptiste
2004-01-01
Experimental observations of droplet size sustained oscillations are reported in a two-phase flow between a lamellar and a sponge phase. Under shear flow, this system presents two different steady states made of monodisperse multilamellar droplets, separated by a shear-thinning transition. At low and high shear rates, the droplet size results from a balance between surface tension and viscous stress, whereas for intermediate shear rates it becomes a periodic function of time. A possible mechanism for such kinds of oscillations is discussed.
Cosmology with moving bimetric fluids
Energy Technology Data Exchange (ETDEWEB)
García-García, Carlos; Maroto, Antonio L.; Martín-Moruno, Prado, E-mail: cargar08@ucm.es, E-mail: maroto@ucm.es, E-mail: pradomm@ucm.es [Departamento de Física Teórica I, Universidad Complutense de Madrid, E-28040 Madrid (Spain)
2016-12-01
We study cosmological implications of bigravity and massive gravity solutions with non-simultaneously diagonal metrics by considering the generalized Gordon and Kerr-Schild ansatzes. The scenario that we obtain is equivalent to that of General Relativity with additional non-comoving perfect fluids. We show that the most general ghost-free bimetric theory generates three kinds of effective fluids whose equations of state are fixed by a function of the ansatz. Different choices of such function allow to reproduce the behaviour of different dark fluids. In particular, the Gordon ansatz is suitable for the description of various kinds of slowly-moving fluids, whereas the Kerr-Schild one is shown to describe a null dark energy component. The motion of those dark fluids with respect to the CMB is shown to generate, in turn, a relative motion of baryonic matter with respect to radition which contributes to the CMB anisotropies. CMB dipole observations are able to set stringent limits on the dark sector described by the effective bimetric fluid.
International Nuclear Information System (INIS)
Yilmaz, C.; Akkas, N.
1979-01-01
In previous studies a fluid element is incorporated in the widely used general purpose finite element program SAPIV. This type of problem is of interest in the design of nuclear components involving geometric complexities and nonlinearities. The elasticity matrix of a general-purpose finite element program is modified in such a way that it becomes possible to idealize fluid as a structural finite element with zero shear modulus and a given bulk modules. Using the modified version of SAPIV, several solid-fluid interactions problems are solved. The numerical solutions are compared with the available analytical solutions. They are shown to be in reasonable aggrement. It is also shown that by solving an exterior-fluid interaction problem, the pressure wave propagation in the acoustic medium can be solved with the same approach. In this study, two of the problem not studied in the previous work will be presented. These problems are namely the effects of the link elements used at solid-fluid interfaces and of the concentrated loads on the response of the fluid medium. Truss elements are used as the link elements. After these investigations, it is decided that general purpose finite element programs with slight modifications can be used in the safety analysis of nuclear reactor plants. By this procedure it is possible to handle two-dimensional plane strain and tridimensional axisymmetric problems of this type. (orig.)
Thermophysical properties of supercritical fluids and fluid mixtures
International Nuclear Information System (INIS)
Sengers, J.V.
1991-07-01
This research is concerned with the development of a quantitative scientific description of the thermodynamic and transport properties of supercritical and subcritical fluids and fluid mixtures. It is known that the thermophysical properties of fluids and fluid mixtures asymptotically close to the critical point satisfy scaling laws with universal critical exponents and universal scaling functions. However, the range of validity of these asymptotic scaling laws is quite small. As a consequence, the impact of the modern theory of critical phenomena on chemical engineering has been limited. On the other hand, an a priori estimate of the range of temperatures and densities, where critical fluctuations become significant, can be made on the basis of the so-called Ginzburg criterion. A recent analysis of this criterion suggests that this range is actually quite large and for a fluid like carbon dioxide can easily extend to 100 degrees or so above the critical temperature. Hence, the use of traditional engineering equations like cubic equations is not scientifically justified in a very wide range of temperatures and densities around the critical point. We have therefore embarked on a scientific approach to deal with the global effects of critical fluctuations on the thermophysical properties of fluids and fluid mixtures. For this purpose it is not sufficient to consider the asymptotic critical fluctuations but we need to deal also with the nonasymptotic critical fluctuations. The goal is to develop scientifically based questions that account for the crossover of the thermophysical properties from their asymptotic singular behavior in the near vicinity of the critical point to their regular behavior very far away from the critical point
Insertable fluid flow passage bridgepiece and method
Jones, Daniel O.
2000-01-01
A fluid flow passage bridgepiece for insertion into an open-face fluid flow channel of a fluid flow plate is provided. The bridgepiece provides a sealed passage from a columnar fluid flow manifold to the flow channel, thereby preventing undesirable leakage into and out of the columnar fluid flow manifold. When deployed in the various fluid flow plates that are used in a Proton Exchange Membrane (PEM) fuel cell, bridgepieces of this invention prevent mixing of reactant gases, leakage of coolant or humidification water, and occlusion of the fluid flow channel by gasket material. The invention also provides a fluid flow plate assembly including an insertable bridgepiece, a fluid flow plate adapted for use with an insertable bridgepiece, and a method of manufacturing a fluid flow plate with an insertable fluid flow passage bridgepiece.
Turbine lubrication fluid varnish mitigation
Energy Technology Data Exchange (ETDEWEB)
Farooq, Khalid [Pall Corporation, Port Washington, NY (United States)
2010-04-15
Varnish deposits on internal surfaces in turbine lube systems result in a number of adverse operational issues, especially the restriction and sticking of the moving parts of servo- or directional control valves, resulting in their malfunction. The lubrication fluid has limited solvency for the varnish-forming material, hence a typical turbine will have the majority of this material as deposits and a relatively small portion as suspension in the fluid phase, in quasi-equilibrium with the deposits. The lube system needs to be cleaned by removing the suspended varnish-forming material from the fluid phase, which allows the deposits to re-entrain into the fluid phase, until the majority of the transferable deposits are removed and the fluid carries no significant amount of the material to have any adverse effect. The methods used for the removal of varnish from turbine lube systems include chemical cleaning/flushing, electrostatic charge induced agglomeration/retention, and the adsorption of the varnish suspended in the oil on an adsorbent medium. The paper discusses an absorption-based removal method that utilizes a fibrous medium that has pronounced affinity for the removal and retention of the varnish-forming material from the fluid as well as the deposits from surfaces that are in quasi-equilibrium with the varnish precursors in the fluid. The filtration medium is a composite, made with cellulose bonded by specially formulated, temperature-cured resins. The absorptive medium exhibits high structural and chemical integrity and has been thoroughly tested on operating turbines, showing reduction in varnish levels from the critical range to below normal range in a relatively short time. The experience with the utilization of the absorptive medium in laboratory tests and in two operating turbines is presented. (orig.)
Fluid Mechanics An Introduction to the Theory of Fluid Flows
Durst, Franz
2008-01-01
Advancements of fluid flow measuring techniques and of computational methods have led to new ways to treat laminar and turbulent flows. These methods are extensively used these days in research and engineering practise. This also requires new ways to teach the subject to students at higher educational institutions in an introductory manner. The book provides the knowledge to students in engineering and natural science needed to enter fluid mechanics applications in various fields. Analytical treatments are provided, based on the Navier-Stokes equations. Introductions are also given into numerical and experimental methods applied to flows. The main benefit the reader will derive from the book is a sound introduction into all aspects of fluid mechanics covering all relevant subfields.
Fluid Behavior and Fluid-Solid Interactions in Nanoporous Media
Xu, H.
2015-12-01
Although shale oil/gas production in the US has increased exponentially, the low energy recovery is a daunting problem needed to be solved for its sustainability and continued growth, especially in light of the recent oil/gas price decline. This is apparently related to the small porosity (a few to a few hundred nm) and low permeability (10-16-10-20 m2) of tight shale formations. The fundamental question lies in the anomalous behavior of fluids in nanopores due to confinement effects, which, however, remains poorly understood. In this study, we combined experimental characterization and observations, particularly using small-angle neutron scattering (SANS), with pore-scale modeling using lattice Boltzmann method (LBM), to examine the fluid behavior and fluid-solid interactions in nanopores at reservoir conditions. Experimentally, we characterized the compositions and microstructures of a shale sample from Wolfcamp, Texas, using a variety of analytical techniques. Our analyses reveal that the shale sample is made of organic-matter (OM)-lean and OM-rich layers that exhibit different chemical and mineral compositions, and microstructural characteristics. Using the hydrostatic pressure system and gas-mixing setup we developed, in-situ SANS measurements were conducted at pressures up to 20 kpsi on shale samples imbibed with water or water-methane solutions. The obtained results indicate that capillary effect plays a significant role in fluid-nanopore interactions and the associated changes in nanopore structures vary with pore size and pressure. Computationally, we performed LBM modeling to simulate the flow behavior of methane in kerogen nanoporous structure. The correction factor, which is the ratio of apparent permeability to intrinsic permeability, was calculated. Our results show that the correction factor is always greater than one (non-continuum/non-Darcy effects) and increases with decreasing nanopore size, intrinsic permeability and pressure. Hence, the
Pitch-catch only ultrasonic fluid densitometer
Greenwood, M.S.; Harris, R.V.
1999-03-23
The present invention is an ultrasonic fluid densitometer that uses a material wedge and pitch-catch only ultrasonic transducers for transmitting and receiving ultrasonic signals internally reflected within the material wedge. Density of a fluid is determined by immersing the wedge into the fluid and measuring reflection of ultrasound at the wedge-fluid interface. 6 figs.
Fluid observers and tilting cosmology
International Nuclear Information System (INIS)
Coley, A A; Hervik, S; Lim, W C
2006-01-01
We study perfect fluid cosmological models with a constant equation of state parameter γ in which there are two naturally defined timelike congruences, a geometrically defined geodesic congruence and a non-geodesic fluid congruence. We establish an appropriate set of boost formulae relating the physical variables, and consequently the observed quantities, in the two frames. We study expanding spatially homogeneous tilted perfect fluid models, with an emphasis on future evolution with extreme tilt. We show that for ultra-radiative equations of state (i.e. γ > 4/3), generically the tilt becomes extreme at late times and the fluid observers will reach infinite expansion within a finite proper time and experience a singularity similar to that of the big rip. In addition, we show that for sub-radiative equations of state (i.e. γ < 4/3), the tilt can become extreme at late times and give rise to an effective quintessential equation of state. To establish the connection with phantom cosmology and quintessence, we calculate the effective equation of state in the models under consideration and we determine the future asymptotic behaviour of the tilting models in the fluid frame variables using the boost formulae. We also discuss spatially inhomogeneous models and tilting spatially homogeneous models with a cosmological constant
Anthropometric changes and fluid shifts
Thornton, W. E.; Hoffler, G. W.; Rummel, J. A.
1974-01-01
Several observations of body size, shape, posture, and configuration were made to document changes resulting from direct effects of weightlessness during the Skylab 4 mission. After the crewmen were placed in orbit, a number of anatomical and anthropometric changes occurred including a straightening of the thoracolumbar spine, a general decrease in truncal girth, and an increase in height. By the time of the earliest in-flight measurement on mission day 3, all crewmen had lost more than two liters of extravascular fluid from the calf and thigh. The puffy facies, the bird legs effect, the engorgement of upper body veins, and the reduced volume of lower body veins were all documented with photographs. Center-of-mass measurements confirmed a fluid shift cephalad. This shift remained throughout the mission until recovery, when a sharp reversal occurred; a major portion of the reversal was completed in a few hours. The anatomical changes are of considerable scientific interest and of import to the human factors design engineer, but the shifts of blood and extravascular fluid are of more consequence. It is hypothesized that the driving force for the fluid shift is the intrinsic and unopposed lower limb elasticity that forces venous blood and then other fluid cephalad.
Ultrasonic techniques for fluids characterization
Povey, Malcolm J W
1997-01-01
This book is a comprehensive and practical guide to the use of ultrasonic techniques for the characterization of fluids. Focusing on ultrasonic velocimetry, the author covers the basic topics and techniques necessaryfor successful ultrasound measurements on emulsions, dispersions, multiphase media, and viscoelastic/viscoplastic materials. Advanced techniques such as scattering, particle sizing, and automation are also presented. As a handbook for industrial and scientific use, Ultrasonic Techniques for Fluids Characterization is an indispensable guide to chemists and chemical engineers using ultrasound for research or process monitoring in the chemical, food processing, pharmaceutical, cosmetic, biotechnology,and fuels industries. Key Features * Appeals to anyone using ultrasound to study fluids * Provides the first detailed description of the ultrasound profiling technique for dispersions * Describes new techniques for measuring phase transitions and nucleation, such as water/ice and oil/fat * Presents the l...
Spinodal decomposition in fluid mixtures
International Nuclear Information System (INIS)
Kawasaki, Kyozi; Koga, Tsuyoshi
1993-01-01
We study the late stage dynamics of spinodal decomposition in binary fluids by the computer simulation of the time-dependent Ginzburg-Landau equation. We obtain a temporary linear growth law of the characteristic length of domains in the late stage. This growth law has been observed in many real experiments of binary fluids and indicates that the domain growth proceeds by the flow caused by the surface tension of interfaces. We also find that the dynamical scaling law is satisfied in this hydrodynamic domain growth region. By comparing the scaling functions for fluids with that for the case without hydrodynamic effects, we find that the scaling functions for the two systems are different. (author)
Fluid Mechanics and Homeland Security
Settles, Gary S.
2006-01-01
Homeland security involves many applications of fluid mechanics and offers many opportunities for research and development. This review explores a wide selection of fluids topics in counterterrorism and suggests future directions. Broad topics range from preparedness and deterrence of impending terrorist attacks to detection, response, and recovery. Specific topics include aircraft hardening, blast mitigation, sensors and sampling, explosive detection, microfluidics and labs-on-a-chip, chemical plume dispersal in urban settings, and building ventilation. Also discussed are vapor plumes and standoff detection, nonlethal weapons, airborne disease spread, personal protective equipment, and decontamination. Involvement in these applications requires fluid dynamicists to think across the traditional boundaries of the field and to work with related disciplines, especially chemistry, biology, aerosol science, and atmospheric science.
Fluid-structure-coupling algorithm
International Nuclear Information System (INIS)
McMaster, W.H.; Gong, E.Y.; Landram, C.S.; Quinones, D.F.
1980-01-01
A fluid-structure-interaction algorithm has been developed and incorporated into the two dimensional code PELE-IC. This code combines an Eulerian incompressible fluid algorithm with a Lagrangian finite element shell algorithm and incorporates the treatment of complex free surfaces. The fluid structure, and coupling algorithms have been verified by the calculation of solved problems from the literature and from air and steam blowdown experiments. The code has been used to calculate loads and structural response from air blowdown and the oscillatory condensation of steam bubbles in water suppression pools typical of boiling water reactors. The techniques developed here have been extended to three dimensions and implemented in the computer code PELE-3D
Rotational superradiance in fluid laboratories
Cardoso, Vitor; Richartz, Mauricio; Weinfurtner, Silke
2016-01-01
Rotational superradiance has been predicted theoretically decades ago, and is the chief responsible for a number of important effects and phenomenology in black hole physics. However, rotational superradiance has never been observed experimentally. Here, with the aim of probing superradiance in the lab, we investigate the behaviour of sound and surface waves in fluids resting in a circular basin at the center of which a rotating cylinder is placed. We show that with a suitable choice for the material of the cylinder, surface and sound waves are amplified. By confining the superradiant modes near the rotating cylinder, an instability sets in. Our findings are experimentally testable in existing fluid laboratories and hence offer experimental exploration and comparison of dynamical instabilities arising from rapidly rotating boundary layers in astrophysical as well as in fluid dynamical systems.
Coulombic Fluids Bulk and Interfaces
Freyland, Werner
2011-01-01
Ionic liquids have attracted considerable interest in recent years. In this book the bulk and interfacial physico-chemical characteristics of various fluid systems dominated by Coulomb interactions are treated which includes molten salts, ionic liquids as well as metal-molten salt mixtures and expanded fluid metals. Of particular interest is the comparison of the different systems. Topics in the bulk phase concern the microscopic structure, the phase behaviour and critical phenomena, and the metal-nonmetal transition. Interfacial phenomena include wetting transitions, electrowetting, surface freezing, and the electrified ionic liquid/ electrode interface. With regard to the latter 2D and 3D electrochemical phase formation of metals and semi-conductors on the nanometer scale is described for a number of selected examples. The basic concepts and various experimental methods are introduced making the book suitable for both graduate students and researchers interested in Coulombic fluids.
Edge Fracture in Complex Fluids.
Hemingway, Ewan J; Kusumaatmaja, Halim; Fielding, Suzanne M
2017-07-14
We study theoretically the edge fracture instability in sheared complex fluids, by means of linear stability analysis and direct nonlinear simulations. We derive an exact analytical expression for the onset of edge fracture in terms of the shear-rate derivative of the fluid's second normal stress difference, the shear-rate derivative of the shear stress, the jump in shear stress across the interface between the fluid and the outside medium (usually air), the surface tension of that interface, and the rheometer gap size. We provide a full mechanistic understanding of the edge fracture instability, carefully validated against our simulations. These findings, which are robust with respect to choice of rheological constitutive model, also suggest a possible route to mitigating edge fracture, potentially allowing experimentalists to achieve and accurately measure flows stronger than hitherto possible.
Fluid-solid contact vessel having fluid distributors therein
Jones, Jr., John B.
1980-09-09
Rectangularly-shaped fluid distributors for large diameter, vertical vessels include reinforcers for high heat operation, vertical sides with gas distributing orifices and overhanging, sloped roofs. Devices are provided for cleaning the orifices from a buildup of solid deposits resulting from the reactions in the vessel.
Nonlinear rheology of complex fluid-fluid interfaces
Sagis, L.M.C.; Fischer, P.
2014-01-01
Fluid–fluid interfaces stabilized by proteins, protein aggregates, polymers, or colloidal particles, tend to have a complex microstructure. Their response to an applied deformation is often highly nonlinear, even at small deformation (rates). The nonlinearity of the response is a result of changes
CT findings of a unicameral calcaneal bone cyst containing a fluid-fluid level.
Gallagher, Thomas A; Lim-Dunham, Jennifer E; Vade, Aruna
2007-03-01
Calcaneal unicameral bone cysts often contain fluid, but rarely contain fluid-fluid levels. We present a case focusing on the CT findings of a large calcaneal bone cyst with a fluid-fluid level and a review of the literature.
Relativistic fluid theories - Self organization
International Nuclear Information System (INIS)
Mahajan, S.M.; Hazeltine, R.D.; Yoshida, Z.
2003-01-01
Developments in two distinct but related subjects are reviewed: 1) Formulation and investigation of closed fluid theories which transcend the limitations of standard magnetohydrodynamics (MHD), in particular, theories which are valid in the long mean free path limit and in which pressure anisotropy, heat flow, and arbitrarily strong sheared flows are treated consistently, and 2) Exploitation of the two-fluid theories to derive new plasma configurations in which the flow-field is a co-determinant of the overall dynamics; some of these states belong to the category of self-organized relaxed states. Physical processes which may provide a route to self-organization and complexity are also explored. (author)
Microbial Metabolism in Serpentinite Fluids
Crespo-Medina, M.; Brazelton, W. J.; Twing, K. I.; Kubo, M.; Hoehler, T. M.; Schrenk, M. O.
2013-12-01
Serpentinization is the process in which ultramafic rocks, characteristic of the upper mantle, react with water liberating mantle carbon and reducing power to potenially support chemosynthetic microbial communities. These communities may be important mediators of carbon and energy exchange between the deep Earth and the surface biosphere. Our work focuses on the Coast Range Ophiolite Microbial Observatory (CROMO) in Northern California where subsurface fluids are accessible through a series of wells. Preliminary analyses indicate that the highly basic fluids (pH 9-12) have low microbial diversity, but there is limited knowledge about the metabolic capabilities of these communties. Metagenomic data from similar serpentine environments [1] have identified Betaproteobacteria belonging to the order Burkholderiales and Gram-positive bacteria from the order Clostridiales as key components of the serpentine microbiome. In an effort to better characterize the microbial community, metabolism, and geochemistry at CROMO, fluids from two representative wells (N08B and CSWold) were sampled during recent field campaigns. Geochemical characterization of the fluids includes measurements of dissolved gases (H2, CO, CH4), dissolved inorganic and organic carbon, volatile fatty acids, and nutrients. The wells selected can be differentiated in that N08B had higher pH (10-11), lower dissolved oxygen, and cell counts ranging from 105-106 cells mL-1 of fluid, with an abundance of the betaproteobacterium Hydrogenophaga. In contrast, fluids from CSWold have slightly lower pH (9-9.5), DO, and conductivity, as well as higher TDN and TDP. CSWold fluid is also characterized for having lower cell counts (~103 cells mL-1) and an abundance of Dethiobacter, a taxon within the phylum Clostridiales. Microcosm experiments were conducted with the purpose of monitoring carbon fixation, methanotrophy and metabolism of small organic compounds, such as acetate and formate, while tracing changes in fluid
Capillary waves of compressible fluids
International Nuclear Information System (INIS)
Falk, Kerstin; Mecke, Klaus
2011-01-01
The interplay of thermal noise and molecular forces is responsible for surprising features of liquids on sub-micrometer lengths-in particular at interfaces. Not only does the surface tension depend on the size of an applied distortion and nanoscopic thin liquid films dewet faster than would be expected from hydrodynamics, but also the dispersion relation of capillary waves differ at the nanoscale from the familiar macroscopic behavior. Starting with the stochastic Navier-Stokes equation we study the coupling of capillary waves to acoustic surface waves which is possible in compressible fluids. We find propagating 'acoustic-capillary waves' at nanometer wavelengths where in incompressible fluids capillary waves are overdamped.
Analysis of giant electrorheological fluids.
Seo, Youngwook P; Seo, Yongsok
2013-07-15
The yield stress dependence on electric field strength for giant electrorheological (GER) fluids over the full range of electric fields was examined using Seo's scaling function which incorporated both the polarization and the conductivity models. If a proper scaling was applied to the yield stress data to collapse them onto a single curve, the Seo's scaling function could correctly fit the yield stress behavior of GER suspensions, even at very high electric field strengths. The model predictions were also compared with recently proposed Choi et al.'s model to allow a consideration of the universal framework of ER fluids. Copyright © 2013 Elsevier Inc. All rights reserved.
Fluid behavior in microgravity environment
Hung, R. J.; Lee, C. C.; Tsao, Y. D.
1990-01-01
The instability of liquid and gas interface can be induced by the presence of longitudinal and lateral accelerations, vehicle vibration, and rotational fields of spacecraft in a microgravity environment. In a spacecraft design, the requirements of settled propellant are different for tank pressurization, engine restart, venting, or propellent transfer. In this paper, the dynamical behavior of liquid propellant, fluid reorientation, and propellent resettling have been carried out through the execution of a CRAY X-MP super computer to simulate fluid management in a microgravity environment. Characteristics of slosh waves excited by the restoring force field of gravity jitters have also been investigated.
Interfacial instabilities in vibrated fluids
Porter, Jeff; Laverón-Simavilla, Ana; Tinao Perez-Miravete, Ignacio; Fernandez Fraile, Jose Javier
2016-07-01
Vibrations induce a range of different interfacial phenomena in fluid systems depending on the frequency and orientation of the forcing. With gravity, (large) interfaces are approximately flat and there is a qualitative difference between vertical and horizontal forcing. Sufficient vertical forcing produces subharmonic standing waves (Faraday waves) that extend over the whole interface. Horizontal forcing can excite both localized and extended interfacial phenomena. The vibrating solid boundaries act as wavemakers to excite traveling waves (or sloshing modes at low frequencies) but they also drive evanescent bulk modes whose oscillatory pressure gradient can parametrically excite subharmonic surface waves like cross-waves. Depending on the magnitude of the damping and the aspect ratio of the container, these locally generated surfaces waves may interact in the interior resulting in temporal modulation and other complex dynamics. In the case where the interface separates two fluids of different density in, for example, a rectangular container, the mass transfer due to vertical motion near the endwalls requires a counterflow in the interior region that can lead to a Kelvin-Helmholtz type instability and a ``frozen wave" pattern. In microgravity, the dominance of surface forces favors non-flat equilibrium configurations and the distinction between vertical and horizontal applied forcing can be lost. Hysteresis and multiplicity of solutions are more common, especially in non-wetting systems where disconnected (partial) volumes of fluid can be established. Furthermore, the vibrational field contributes a dynamic pressure term that competes with surface tension to select the (time averaged) shape of the surface. These new (quasi-static) surface configurations, known as vibroequilibria, can differ substantially from the hydrostatic state. There is a tendency for the interface to orient perpendicular to the vibrational axis and, in some cases, a bulge or cavity is induced
Fluid mechanics problems and solutions
Spurk, Joseph H
1997-01-01
his collection of over 200 detailed worked exercises adds to and complements the textbook Fluid Mechanics by the same author, and illustrates the teaching material through examples. In the exercises the fundamental concepts of Fluid Mechanics are applied to obtaining the solution of diverse concrete problems, and in doing this the student's skill in the mathematical modeling of practical problems is developed. In addition, 30 challenging questions without detailed solutions have been included, and while lecturers will find these questions suitable for examinations and tests, the student himself can use them to check his understanding of the subject.
Piezooptic behavior of certain fluids
International Nuclear Information System (INIS)
Weiss, J.D.
1985-01-01
In this paper we present an analysis of pressure--volume data for certain optical fluids, which characterizes them by two parameters: their bulk moduli and the pressure derivative of their bulk moduli, both evaluated at zero pressure. We then relate their refractive-index changes to density and pressure using this analysis and the Lorentz-Lorenz equation with a density-dependent polarizability. An example of the use of such fluids in a fiber-optic pressure gauge being developed at Sandia is also discussed
Indian Academy of Sciences (India)
makes fluid flows so rich, so complex - some times so highly ordered ..... to other frequencies, which again can grow in amplitude before they also eventually decay again. On the ..... think of it as a slice of flow issuing towards this sheet of paper.
Free Falling in Stratified Fluids
Lam, Try; Vincent, Lionel; Kanso, Eva
2017-11-01
Leaves falling in air and discs falling in water are examples of unsteady descents due to complex interaction between gravitational and aerodynamic forces. Understanding these descent modes is relevant to many branches of engineering and science such as estimating the behavior of re-entry space vehicles to studying biomechanics of seed dispersion. For regularly shaped objects falling in homogenous fluids, the motion is relatively well understood. However, less is known about how density stratification of the fluid medium affects the falling behavior. Here, we experimentally investigate the descent of discs in both pure water and in stable linearly stratified fluids for Froude numbers Fr 1 and Reynolds numbers Re between 1000 -2000. We found that stable stratification (1) enhances the radial dispersion of the disc at landing, (2) increases the descent time, (3) decreases the inclination (or nutation) angle, and (4) decreases the fluttering amplitude while falling. We conclude by commenting on how the corresponding information can be used as a predictive model for objects free falling in stratified fluids.
Computational Fluid Dynamics in Ventilation
DEFF Research Database (Denmark)
Nielsen, Peter V.; Allard, Francis; Awbi, Hazim B.
2008-01-01
Computational Fluid Dynamics in Ventilation Design is a new title in the is a new title in the REHVA guidebook series. The guidebook is written for people who need to use and discuss results based on CFD predictions, and it gives insight into the subject for those who are not used to work with CFD...
Fluid mechanics of heart valves.
Yoganathan, Ajit P; He, Zhaoming; Casey Jones, S
2004-01-01
Valvular heart disease is a life-threatening disease that afflicts millions of people worldwide and leads to approximately 250,000 valve repairs and/or replacements each year. Malfunction of a native valve impairs its efficient fluid mechanic/hemodynamic performance. Artificial heart valves have been used since 1960 to replace diseased native valves and have saved millions of lives. Unfortunately, despite four decades of use, these devices are less than ideal and lead to many complications. Many of these complications/problems are directly related to the fluid mechanics associated with the various mechanical and bioprosthetic valve designs. This review focuses on the state-of-the-art experimental and computational fluid mechanics of native and prosthetic heart valves in current clinical use. The fluid dynamic performance characteristics of caged-ball, tilting-disc, bileaflet mechanical valves and porcine and pericardial stented and nonstented bioprostheic valves are reviewed. Other issues related to heart valve performance, such as biomaterials, solid mechanics, tissue mechanics, and durability, are not addressed in this review.
Intraoperative fluid therapy in neonates
African Journals Online (AJOL)
Differences from adults and children in physiology and anatomy of neonates inform our ... is based on energy expenditure indexed to bodyweight.2 Energy ... fragile and poorly keratinised.5 ... neonates means that very conservative fluid regimes in neonates ..... I make an estimation of insensible loss from the skin, viscera,.
Protein profiling of cerebrospinal fluid
DEFF Research Database (Denmark)
Simonsen, Anja H
2012-01-01
The cerebrospinal fluid (CSF) perfuses the brain and spinal cord. CSF contains proteins and peptides important for brain physiology and potentially also relevant for brain pathology. Hence, CSF is the perfect source to search for new biomarkers to improve diagnosis of neurological diseases as well...
Fundamentals of Geophysical Fluid Dynamics
McWilliams, James C.
2006-07-01
Earth's atmosphere and oceans exhibit complex patterns of fluid motion over a vast range of space and time scales. These patterns combine to establish the climate in response to solar radiation that is inhomogeneously absorbed by the materials comprising air, water, and land. Spontaneous, energetic variability arises from instabilities in the planetary-scale circulations, appearing in many different forms such as waves, jets, vortices, boundary layers, and turbulence. Geophysical fluid dynamics (GFD) is the science of all these types of fluid motion. This textbook is a concise and accessible introduction to GFD for intermediate to advanced students of the physics, chemistry, and/or biology of Earth's fluid environment. The book was developed from the author's many years of teaching a first-year graduate course at the University of California, Los Angeles. Readers are expected to be familiar with physics and mathematics at the level of general dynamics (mechanics) and partial differential equations. Covers the essential GFD required for atmospheric science and oceanography courses Mathematically rigorous, concise coverage of basic theory and applications to both oceans and atmospheres Author is a world expert; this book is based on the course he has taught for many years Exercises are included, with solutions available to instructors from solutions@cambridge.org
Fluid Mechanics of Fish Swimming
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 1. Fluid Mechanics of Fish Swimming - Lift-based Propulsion. Jaywant H Arakeri. General Article Volume 14 Issue 1 January 2009 pp 32-46. Fulltext. Click here to view fulltext PDF. Permanent link:
Essential Fluid Dynamics for Scientists
Braithwaite, Jonathan
2017-12-01
The book is an introduction to the subject of fluid mechanics, essential for students and researchers in many branches of science. It illustrates its fundamental principles with a variety of examples drawn mainly from astrophysics and geophysics as well as from everyday experience. Prior familiarity with basic thermodynamics and vector calculus is assumed.
Fluid Power, Rate Training Manual.
Bureau of Naval Personnel, Washington, DC.
Fundamentals of hydraulics and pneumatics are presented in this manual, prepared for regular navy and naval reserve personnel who are seeking advancement to Petty Officer Third Class. The history of applications of compressed fluids is described in connection with physical principles. Selection of types of liquids and gases is discussed with a…
Geometrical approach to fluid models
International Nuclear Information System (INIS)
Kuvshinov, B.N.; Schep, T.J.
1997-01-01
Differential geometry based upon the Cartan calculus of differential forms is applied to investigate invariant properties of equations that describe the motion of continuous media. The main feature of this approach is that physical quantities are treated as geometrical objects. The geometrical notion of invariance is introduced in terms of Lie derivatives and a general procedure for the construction of local and integral fluid invariants is presented. The solutions of the equations for invariant fields can be written in terms of Lagrange variables. A generalization of the Hamiltonian formalism for finite-dimensional systems to continuous media is proposed. Analogously to finite-dimensional systems, Hamiltonian fluids are introduced as systems that annihilate an exact two-form. It is shown that Euler and ideal, charged fluids satisfy this local definition of a Hamiltonian structure. A new class of scalar invariants of Hamiltonian fluids is constructed that generalizes the invariants that are related with gauge transformations and with symmetries (Noether). copyright 1997 American Institute of Physics
Fluid queues and regular variation
Boxma, O.J.
1996-01-01
This paper considers a fluid queueing system, fed by N independent sources that alternate between silence and activity periods. We assume that the distribution of the activity periods of one or more sources is a regularly varying function of index ¿. We show that its fat tail gives rise to an even
Fluid queues and regular variation
O.J. Boxma (Onno)
1996-01-01
textabstractThis paper considers a fluid queueing system, fed by $N$ independent sources that alternate between silence and activity periods. We assume that the distribution of the activity periods of one or more sources is a regularly varying function of index $zeta$. We show that its fat tail
Installations having pressurised fluid circuits
International Nuclear Information System (INIS)
Rigg, S.; Grant, J.
1977-01-01
Reference is made to nuclear installations having pressurised coolant flow circuits. Breaches in such circuits may quickly result in much damage to the plant. Devices such as non-return valves, orifice plates, and automatically operated shut-off valves have been provided to prevent or reduce fluid flow through a breached pipe line, but such devices have several disadvantages; they may present large restrictions to normal flow of coolant, and may depend on the operation of ancillary equipment, with consequent delay in bringing them into operation in an emergency. Other expedients that have been adopted to prevent or reduce reverse flow through an upstream breach comprise various forms of hydraulic counter flow brakes. The arrangement described has at least one variable fluid brake comprising a fluidic device connected into a duct in the pressurised circuit, the device having an inlet, an outlet, a vortex chamber between the inlet and outlet, a control jet for introducing fluid into the vortex chamber, connections communicating the inlet and the outlet into one part of the circuit and the control jet into another region at a complementary pressure so that, in the event of a breach in the circuit in one region, fluid passes from the other region to enter the vortex chamber to stimulate pressure to create a flow restricting vortex in the chamber that reduces flow through the breach. The system finds particular application to stream generating pressure tube reactors, such as the steam generating heavy water reactor at UKAEA, Winfrith. (U.K.)
Mixed Fluid Conditions: Capillary Phenomena
Santamarina, Carlos
2017-07-06
Mixed fluid phenomena in porous media have profound implications on soil-atmosphere interaction, energy geotechnology, environmental engineering and infrastructure design. Surface tension varies with pressure, temperature, solute concentration, and surfactant concentration; on the other hand, the contact angle responds to interfacial tensions, surface topography, invasion velocity, and chemical interactions. Interfaces are not isolated but interact through the fluid pressure and respond to external fields. Jumps, snap-offs and percolating wetting liquids along edges and crevices are ubiquitous in real, non-cylindrical porous networks. Pore- and macroscale instabilities together with pore structure variability-and-correlation favor fluid trapping and hinder recovery efficiency. The saturation-pressure characteristic curve is affected by the saturation-history, flow-rate, the mechanical response of the porous medium, and time-dependent reactive and diffusive processes; in addition, there are salient differences between unsaturation by internal gas nucleation and gas invasion. Capillary forces add to other skeletal forces in the porous medium and can generate open-mode discontinuities when the capillary entry pressure is high relative to the effective stress. Time emerges as an important variable in mixed-fluid conditions and common quasi-static analyses may fail to capture the system response.
Dissecting spontaneous cerebrospinal fluid collection.
Champagne, Pierre-Olivier; Decarie, Jean-Claude; Crevier, Louis; Weil, Alexander G
2018-04-01
Hydrocephalus is a common condition in the pediatric population known to have many causes and presentation patterns. We report from the analysis of 2 cases the existence of a new complication of pediatric hydrocephalus. Naming this entity "dissecting intraparenchymal cerebrospinal fluid collection", we advance a hypothesis regarding its pathophysiology and discuss its clinical implications and management. Copyright © 2018 Elsevier Ltd. All rights reserved.
Heat Transfer in Complex Fluids
Energy Technology Data Exchange (ETDEWEB)
Mehrdad Massoudi
2012-01-01
Amongst the most important constitutive relations in Mechanics, when characterizing the behavior of complex materials, one can identify the stress tensor T, the heat flux vector q (related to heat conduction) and the radiant heating (related to the radiation term in the energy equation). Of course, the expression 'complex materials' is not new. In fact, at least since the publication of the paper by Rivlin & Ericksen (1955), who discussed fluids of complexity (Truesdell & Noll, 1992), to the recently published books (Deshpande et al., 2010), the term complex fluids refers in general to fluid-like materials whose response, namely the stress tensor, is 'non-linear' in some fashion. This non-linearity can manifest itself in variety of forms such as memory effects, yield stress, creep or relaxation, normal-stress differences, etc. The emphasis in this chapter, while focusing on the constitutive modeling of complex fluids, is on granular materials (such as coal) and non-linear fluids (such as coal-slurries). One of the main areas of interest in energy related processes, such as power plants, atomization, alternative fuels, etc., is the use of slurries, specifically coal-water or coal-oil slurries, as the primary fuel. Some studies indicate that the viscosity of coal-water mixtures depends not only on the volume fraction of solids, and the mean size and the size distribution of the coal, but also on the shear rate, since the slurry behaves as shear-rate dependent fluid. There are also studies which indicate that preheating the fuel results in better performance, and as a result of such heating, the viscosity changes. Constitutive modeling of these non-linear fluids, commonly referred to as non-Newtonian fluids, has received much attention. Most of the naturally occurring and synthetic fluids are non-linear fluids, for example, polymer melts, suspensions, blood, coal-water slurries, drilling fluids, mud, etc. It should be noted that sometimes these
Instrumentation, measurements, and experiments in fluids
Rathakrishnan, E
2007-01-01
NEED AND OBJECTIVE OF EXPERIMENTAL STUDY Some Fluid Mechanics MeasurementsMeasurement SystemsSome of the Important Quantities Associated with FluidFlow MeasurementsFUNDAMENTALS OF FLUID MECHANICSProperties of FluidsThermodynamic PropertiesSurface TensionAnalysis of Fluid FlowBasic and Subsidiary Laws for Continuous MediaKinematics of Fluid FlowStreamlinesPotential FlowViscous FlowsGas DynamicsWIND TUNNELSLow-Speed Wind TunnelsPower Losses in a Wind TunnelHigh-Speed Wind TunnelsHypersonic TunnelsInstrume
On the efficiency of a fluid-fluid centrifugal separation
International Nuclear Information System (INIS)
Apazidis, N.
1984-05-01
Efficiency of a separation process of two immiscible incompressible fluids of different densities occuring under the influence of a combined centrifugal and gravitational force field is investigated. The analysis is based on the set of equations for a rotating two-phase flow of a mixture as presented by Greenspan (1983). The geometry of the separation process is considered and the total flow of the separated phases evaluated. (author)
Fundamental Issues of Nano-fluid Behavior
International Nuclear Information System (INIS)
Williams, Wesley C.
2006-01-01
This paper will elucidate some of the behaviors of nano-fluids other than the abnormal conductivity enhancement, which are of importance to the experimental and engineering use of nano-fluids. Nano-fluid is the common name of any sol colloid involving nano-scale (less than 100 nm) sized particles dispersed within a base fluid. It has been shown previously that the dispersion of nano-particulate metallic oxides into water can increase thermal conductivity up to 30-40% over that of the base fluid and anomalously more than the mere weighed average of the colloid. There is a great potential for the use of nano-fluids as a way to enhance fluid/thermal energy transfer systems. Due to the recentness of nano-fluid science, there are still many issues which have not been fully investigated. This paper should act as a primer for the basic understanding of nano-fluid behavior. Particle size and colloid stability are of key importance to the functionality of nano-fluids. The pH and concentration/loading of nano-fluids can alter the size of the nano-particles and also the stability of the fluids. It will be shown through experiment and colloid theory the importance of these parameters. Furthermore, most of the existing literature uses volume percentage as the measure of particle loading, which can often be misleading. There will be discussion of this and other misleading ideas in nano-fluid science. (author)
Aqueous cutting fluid for machining fissionable materials
Duerksen, Walter K.; Googin, John M.; Napier, Jr., Bradley
1984-01-01
The present invention is directed to a cutting fluid for machining fissionable material. The cutting fluid is formed of glycol, water and boron compound in an adequate concentration for effective neutron attenuation so as to inhibit criticality incidents during machining.
Generating perfect fluid spheres in general relativity
Boonserm, Petarpa; Visser, Matt; Weinfurtner, Silke
2005-06-01
Ever since Karl Schwarzschild’s 1916 discovery of the spacetime geometry describing the interior of a particular idealized general relativistic star—a static spherically symmetric blob of fluid with position-independent density—the general relativity community has continued to devote considerable time and energy to understanding the general-relativistic static perfect fluid sphere. Over the last 90 years a tangle of specific perfect fluid spheres has been discovered, with most of these specific examples seemingly independent from each other. To bring some order to this collection, in this article we develop several new transformation theorems that map perfect fluid spheres into perfect fluid spheres. These transformation theorems sometimes lead to unexpected connections between previously known perfect fluid spheres, sometimes lead to new previously unknown perfect fluid spheres, and in general can be used to develop a systematic way of classifying the set of all perfect fluid spheres.
Generating perfect fluid spheres in general relativity
International Nuclear Information System (INIS)
Boonserm, Petarpa; Visser, Matt; Weinfurtner, Silke
2005-01-01
Ever since Karl Schwarzschild's 1916 discovery of the spacetime geometry describing the interior of a particular idealized general relativistic star--a static spherically symmetric blob of fluid with position-independent density--the general relativity community has continued to devote considerable time and energy to understanding the general-relativistic static perfect fluid sphere. Over the last 90 years a tangle of specific perfect fluid spheres has been discovered, with most of these specific examples seemingly independent from each other. To bring some order to this collection, in this article we develop several new transformation theorems that map perfect fluid spheres into perfect fluid spheres. These transformation theorems sometimes lead to unexpected connections between previously known perfect fluid spheres, sometimes lead to new previously unknown perfect fluid spheres, and in general can be used to develop a systematic way of classifying the set of all perfect fluid spheres
Mixing and Processing of Complex Biological Fluids
National Research Council Canada - National Science Library
Liepmann, Dorian
2003-01-01
... of microfluidic control on the makeup and molecular structure of biological fluids. For this project, we focused on two critical fluids that are biologically significant and that are of critical importance to DoD...
Noncommuting fields and non-Abelian fluids
International Nuclear Information System (INIS)
Jackiw, R.
2004-01-01
The original ideas about noncommuting coordinates are recalled. The connection between U(1) gauge fields defined on noncommuting coordinates and fluid mechanics is explained. Non-Abelian fluid mechanics is described
CRITICALITY CURVES FOR PLUTONIUM HYDRAULIC FLUID MIXTURES
International Nuclear Information System (INIS)
WITTEKIND WD
2007-01-01
This Calculation Note performs and documents MCNP criticality calculations for plutonium (100% 239 Pu) hydraulic fluid mixtures. Spherical geometry was used for these generalized criticality safety calculations and three geometries of neutron reflection are: (sm b ullet)bare, (sm b ullet)1 inch of hydraulic fluid, or (sm b ullet)12 inches of hydraulic fluid. This document shows the critical volume and critical mass for various concentrations of plutonium in hydraulic fluid. Between 1 and 2 gallons of hydraulic fluid were discovered in the bottom of HA-23S. This HA-23S hydraulic fluid was reported by engineering to be Fyrquel 220. The hydraulic fluid in GLovebox HA-23S is Fyrquel 220 which contains phosphorus. Critical spherical geometry in air is calculated with 0 in., 1 in., or 12 inches hydraulic fluid reflection
Coulomb interactions in charged fluids.
Vernizzi, Graziano; Guerrero-García, Guillermo Iván; de la Cruz, Monica Olvera
2011-07-01
The use of Ewald summation schemes for calculating long-range Coulomb interactions, originally applied to ionic crystalline solids, is a very common practice in molecular simulations of charged fluids at present. Such a choice imposes an artificial periodicity which is generally absent in the liquid state. In this paper we propose a simple analytical O(N(2)) method which is based on Gauss's law for computing exactly the Coulomb interaction between charged particles in a simulation box, when it is averaged over all possible orientations of a surrounding infinite lattice. This method mitigates the periodicity typical of crystalline systems and it is suitable for numerical studies of ionic liquids, charged molecular fluids, and colloidal systems with Monte Carlo and molecular dynamics simulations.
Finite element computational fluid mechanics
International Nuclear Information System (INIS)
Baker, A.J.
1983-01-01
This book analyzes finite element theory as applied to computational fluid mechanics. It includes a chapter on using the heat conduction equation to expose the essence of finite element theory, including higher-order accuracy and convergence in a common knowledge framework. Another chapter generalizes the algorithm to extend application to the nonlinearity of the Navier-Stokes equations. Other chapters are concerned with the analysis of a specific fluids mechanics problem class, including theory and applications. Some of the topics covered include finite element theory for linear mechanics; potential flow; weighted residuals/galerkin finite element theory; inviscid and convection dominated flows; boundary layers; parabolic three-dimensional flows; and viscous and rotational flows
Filtering reducer of flushing fluid
Energy Technology Data Exchange (ETDEWEB)
Secu, P; Apostu, M; Basarabescu, T; Popescu, F
1981-02-28
This is a patent of a filtering reducer of flushing fluid on a water base with low content of solid particles used at temperatures of roughly 200/sup 0/C. With the use of the proposed filtering reducer, there is no excessive increase in viscosity and gelatinization of the flushing fluids without restriction in the quantity of reducer needed to guarantee the required filtering. There is a possibility of recovering the polyalkylphenol vat residues obtained in the production of nonyl phenol. It is possible to reduce the time of treatment and dissolving of the product; there is no danger of plugging of the productive oil beds. The process of hydration of clay is excluded.
Relativistic fluid dynamics with spin
Florkowski, Wojciech; Friman, Bengt; Jaiswal, Amaresh; Speranza, Enrico
2018-04-01
Using the conservation laws for charge, energy, momentum, and angular momentum, we derive hydrodynamic equations for the charge density, local temperature, and fluid velocity, as well as for the polarization tensor, starting from local equilibrium distribution functions for particles and antiparticles with spin 1/2. The resulting set of differential equations extends the standard picture of perfect-fluid hydrodynamics with a conserved entropy current in a minimal way. This framework can be used in space-time analyses of the evolution of spin and polarization in various physical systems including high-energy nuclear collisions. We demonstrate that a stationary vortex, which exhibits vorticity-spin alignment, corresponds to a special solution of the spin-hydrodynamical equations.
Lipidomics by Supercritical Fluid Chromatography
Directory of Open Access Journals (Sweden)
Laurent Laboureur
2015-06-01
Full Text Available This review enlightens the role of supercritical fluid chromatography (SFC in the field of lipid analysis. SFC has been popular in the late 1980s and 1990s before almost disappearing due to the commercial success of liquid chromatography (LC. It is only 20 years later that a regain of interest appeared when new commercial instruments were introduced. As SFC is fully compatible with the injection of extracts in pure organic solvent, this technique is perfectly suitable for lipid analysis and can be coupled with either highly universal (UV or evaporative light scattering or highly specific (mass spectrometry detection methods. A short history of the use of supercritical fluids as mobile phase for the separation oflipids will be introduced first. Then, the advantages and drawbacks of SFC are discussed for each class of lipids (fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, sterols, prenols, polyketides defined by the LIPID MAPS consortium.
Lipidomics by Supercritical Fluid Chromatography
Laboureur, Laurent; Ollero, Mario; Touboul, David
2015-01-01
This review enlightens the role of supercritical fluid chromatography (SFC) in the field of lipid analysis. SFC has been popular in the late 1980s and 1990s before almost disappearing due to the commercial success of liquid chromatography (LC). It is only 20 years later that a regain of interest appeared when new commercial instruments were introduced. As SFC is fully compatible with the injection of extracts in pure organic solvent, this technique is perfectly suitable for lipid analysis and can be coupled with either highly universal (UV or evaporative light scattering) or highly specific (mass spectrometry) detection methods. A short history of the use of supercritical fluids as mobile phase for the separation oflipids will be introduced first. Then, the advantages and drawbacks of SFC are discussed for each class of lipids (fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, sterols, prenols, polyketides) defined by the LIPID MAPS consortium. PMID:26090714
Solving problems in fluid mechanics. Vol. 1
International Nuclear Information System (INIS)
Douglas, J.F.
1986-01-01
Fluid mechanics is that part of applied mechanics concerned with the statics and dynamics of liquids and gases. The presentation is in a pedagogically sound question-and-answer format, which includes many worked examples preceding the exercises. This book which assumes only an elementary knowledge of mathematics and mechanics, offers a clear exposition of topics including hydrostatics, fluid pressure and the stability of floating bodies, fluid motion, flow measurement, pipelines, open channel flow, and fluid friction
Fluid dynamics theoretical and computational approaches
Warsi, ZUA
2005-01-01
Important Nomenclature Kinematics of Fluid Motion Introduction to Continuum Motion Fluid Particles Inertial Coordinate Frames Motion of a Continuum The Time Derivatives Velocity and Acceleration Steady and Nonsteady Flow Trajectories of Fluid Particles and Streamlines Material Volume and Surface Relation between Elemental Volumes Kinematic Formulas of Euler and Reynolds Control Volume and Surface Kinematics of Deformation Kinematics of Vorticity and Circulation References Problems The Conservation Laws and the Kinetics of Flow Fluid Density and the Conservation of Mass Prin
Fluid Annotations in a Open World
DEFF Research Database (Denmark)
Zellweger, Polle Trescott; Bouvin, Niels Olof; Jehøj, Henning
2001-01-01
Fluid Documents use animated typographical changes to provide a novel and appealing user experience for hypertext browsing and for viewing document annotations in context. This paper describes an effort to broaden the utility of Fluid Documents by using the open hypermedia Arakne Environment to l...... to layer fluid annotations and links on top of abitrary HTML pages on the World Wide Web. Changes to both Fluid Documents and Arakne are required....
Fluid management in space construction
Snyder, Howard
1989-01-01
The low-g fluids management group with the Center for Space Construction is engaged in active research on the following topics: gauging; venting; controlling contamination; sloshing; transfer; acquisition; and two-phase flow. Our basic understanding of each of these topics at present is inadequate to design space structures optimally. A brief report is presented on each topic showing the present status, recent accomplishings by our group and our plans for future research. Reports are presented in graphic and outline form.
Computational modelling in fluid mechanics
International Nuclear Information System (INIS)
Hauguel, A.
1985-01-01
The modelling of the greatest part of environmental or industrial flow problems gives very similar types of equations. The considerable increase in computing capacity over the last ten years consequently allowed numerical models of growing complexity to be processed. The varied group of computer codes presented are now a complementary tool of experimental facilities to achieve studies in the field of fluid mechanics. Several codes applied in the nuclear field (reactors, cooling towers, exchangers, plumes...) are presented among others [fr
Simulation of cerebrospinal fluid transport
Czech Academy of Sciences Publication Activity Database
Otáhal, Jakub; Štěpáník, Z.; Kaczmarská, A.; Maršík, František; Brož, Z.; Otáhal, S.
2007-01-01
Roč. 38, 11-12 (2007), s. 802-809 ISSN 0965-9978 Grant - others:GA UK(CZ) 112/2005; GA UK(CZ) 114/2005; GA ČR(CZ) GA106/03/0958 Program:GA Institutional research plan: CEZ:AV0Z50110509; CEZ:AV0Z20760514 Keywords : cerebrospinal fluid * pulsation * mathematical modeling Subject RIV: BO - Biophysics Impact factor: 0.529, year: 2007
Supercritical fluid regeneration of adsorbents
Defilippi, R. P.; Robey, R. J.
1983-05-01
The results of a program to perform studies supercritical (fluid) carbon dioxide (SCF CO2) regeneration of adsorbents, using samples of industrial wastewaters from manufacturing pesticides and synthetic solution, and to estimate the economics of the specific wastewater treatment regenerations, based on test data are given. Processing costs for regenerating granular activated carbon GAC) for treating industrial wastewaters depend on stream properties and regeneration throughput.
Fluid mechanics of environmental interfaces
Gualtieri, Carlo
2008-01-01
Fluid Mechanics of Environmental Interfaces describes the concept of the environmental interface, defined as a surface between two either abiotic or biotic systems. These are in relative motion and exchange mass, heat and momentum through biophysical and/or chemical processes. These processes are fluctuating temporally and spatially.The book will be of interest to graduate students, PhD students as well as researchers in environmental sciences, civil engineering and environmental engineering, (geo)physics and applied mathematics.
Multiple Sclerosis Cerebrospinal Fluid Biomarkers
Directory of Open Access Journals (Sweden)
Gavin Giovannoni
2006-01-01
Full Text Available Cerebrospinal fluid (CSF is the body fluid closest to the pathology of multiple sclerosis (MS. For many candidate biomarkers CSF is the only fluid that can be investigated. Several factors need to be standardized when sampling CSF for biomarker research: time/volume of CSF collection, sample processing/storage, and the temporal relationship of sampling to clinical or MRI markers of disease activity. Assays used for biomarker detection must be validated so as to optimize the power of the studies. A formal method for establishing whether or not a particular biomarker can be used as a surrogate end-point needs to be adopted. This process is similar to that used in clinical trials, where the reporting of studies has to be done in a standardized way with sufficient detail to permit a critical review of the study and to enable others to reproduce the study design. A commitment must be made to report negative studies so as to prevent publication bias. Pre-defined consensus criteria need to be developed for MS-related prognostic biomarkers. Currently no candidate biomarker is suitable as a surrogate end-point. Bulk biomarkers of the neurodegenerative process such as glial fibrillary acidic protein (GFAP and neurofilaments (NF have advantages over intermittent inflammatory markers.
Finite approximations in fluid mechanics
International Nuclear Information System (INIS)
Hirschel, E.H.
1986-01-01
This book contains twenty papers on work which was conducted between 1983 and 1985 in the Priority Research Program ''Finite Approximations in Fluid Mechanics'' of the German Research Society (Deutsche Forschungsgemeinschaft). Scientists from numerical mathematics, fluid mechanics, and aerodynamics present their research on boundary-element methods, factorization methods, higher-order panel methods, multigrid methods for elliptical and parabolic problems, two-step schemes for the Euler equations, etc. Applications are made to channel flows, gas dynamical problems, large eddy simulation of turbulence, non-Newtonian flow, turbomachine flow, zonal solutions for viscous flow problems, etc. The contents include: multigrid methods for problems from fluid dynamics, development of a 2D-Transonic Potential Flow Solver; a boundary element spectral method for nonstationary viscous flows in 3 dimensions; navier-stokes computations of two-dimensional laminar flows in a channel with a backward facing step; calculations and experimental investigations of the laminar unsteady flow in a pipe expansion; calculation of the flow-field caused by shock wave and deflagration interaction; a multi-level discretization and solution method for potential flow problems in three dimensions; solutions of the conservation equations with the approximate factorization method; inviscid and viscous flow through rotating meridional contours; zonal solutions for viscous flow problems
Consistency argued students of fluid
Viyanti; Cari; Suparmi; Winarti; Slamet Budiarti, Indah; Handika, Jeffry; Widyastuti, Fatma
2017-01-01
Problem solving for physics concepts through consistency arguments can improve thinking skills of students and it is an important thing in science. The study aims to assess the consistency of the material Fluid student argmentation. The population of this study are College students PGRI Madiun, UIN Sunan Kalijaga Yogyakarta and Lampung University. Samples using cluster random sampling, 145 samples obtained by the number of students. The study used a descriptive survey method. Data obtained through multiple-choice test and interview reasoned. Problem fluid modified from [9] and [1]. The results of the study gained an average consistency argmentation for the right consistency, consistency is wrong, and inconsistent respectively 4.85%; 29.93%; and 65.23%. Data from the study have an impact on the lack of understanding of the fluid material which is ideally in full consistency argued affect the expansion of understanding of the concept. The results of the study as a reference in making improvements in future studies is to obtain a positive change in the consistency of argumentations.
Pleural fluid exchange in rabbits.
Stashenko, Gregg J; Robichaux, Amy; Lee, Y C Gary; Sanders, Jonathan R; Roselli, Robert J; Light, Richard W
2007-07-01
The study was designed to better characterize pleural fluid absorption in rabbits with the following two objectives: to determine the relative absorption of saline versus high-protein solutions, and to identify the relative rates of absorption of dextran molecules of varying sizes. Twenty New Zealand white rabbits received a 12-mL intrapleural injection of saline solution and a 10% protein solution on opposite sides, each solution containing dextran molecules with varying MWs. At sacrifice at 1, 4, 8, 18 and 24 h, the volume of pleural fluid and the concentrations of the dextran molecules were determined. Saline was absorbed faster than the high-protein fluid (P higher than those in the protein solution at all times after injection (P = 0.005; P higher-MW dextrans were cleared more slowly than the lower-MW dextrans in a continuously graded manner. Saline was absorbed faster than a solution with a high protein content. There was a continuous spectrum in the rate of absorption of the dextran molecules, with the larger molecules being absorbed more slowly.
Transient flows of a Burgers' fluid
International Nuclear Information System (INIS)
Khan, M.
2005-12-01
An analysis is performed to develop the analytical solutions for some unsteady magnetohydrodynamic (MHD) flows of a Burgers' fluid between two plates. A uniform magnetic field is applied transversely to the fluid motion. The exact solutions are given for three problems. Results for the velocity fields are discussed and compared with the flows of Oldroyd-B, Maxwell, second grade and Newtonian fluids. (author)
Self-lubricating fluid bearing assembly
International Nuclear Information System (INIS)
Kapich, D.D.
1981-01-01
A sealed self-lubricating fluid bearing assembly is described for circulating fluid in the form of a gas coolant in a nuclear reactor, the power for the circulator being provided by a shaft located within the primary containment vessel. In such a system the reactor coolant is isolated from the fluid region at the far end of the drive shaft. (U.K.)
Optimal composition of fluid-replacement beverages.
Baker, Lindsay B; Jeukendrup, Asker E
2014-04-01
The objective of this article is to provide a review of the fundamental aspects of body fluid balance and the physiological consequences of water imbalances, as well as discuss considerations for the optimal composition of a fluid replacement beverage across a broad range of applications. Early pioneering research involving fluid replacement in persons suffering from diarrheal disease and in military, occupational, and athlete populations incurring exercise- and/or heat-induced sweat losses has provided much of the insight regarding basic principles on beverage palatability, voluntary fluid intake, fluid absorption, and fluid retention. We review this work and also discuss more recent advances in the understanding of fluid replacement as it applies to various populations (military, athletes, occupational, men, women, children, and older adults) and situations (pathophysiological factors, spaceflight, bed rest, long plane flights, heat stress, altitude/cold exposure, and recreational exercise). We discuss how beverage carbohydrate and electrolytes impact fluid replacement. We also discuss nutrients and compounds that are often included in fluid-replacement beverages to augment physiological functions unrelated to hydration, such as the provision of energy. The optimal composition of a fluid-replacement beverage depends upon the source of the fluid loss, whether from sweat, urine, respiration, or diarrhea/vomiting. It is also apparent that the optimal fluid-replacement beverage is one that is customized according to specific physiological needs, environmental conditions, desired benefits, and individual characteristics and taste preferences.
EXPERIMENTAL STUDY OF MAGNETIC FLUID SEAL
Directory of Open Access Journals (Sweden)
V. G. Bashtovoi
2006-01-01
Full Text Available Dependences of critical pressure drop, being held by magnetic fluid seal, on time in a static state and shaft rotation velocity in dynamics have been experimentally determined. The significant influence of particles’ redistribution in magnetic fluid on static parameters of magnetic fluid seal has been established.
Markov-modulated and feedback fluid queues
Scheinhardt, Willem R.W.
1998-01-01
In the last twenty years the field of Markov-modulated fluid queues has received considerable attention. In these models a fluid reservoir receives and/or releases fluid at rates which depend on the actual state of a background Markov chain. In the first chapter of this thesis we give a short
21 CFR 886.4275 - Intraocular fluid.
2010-04-01
... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4275 Intraocular fluid. (a) Identification. An intraocular fluid is a device consisting of a nongaseous fluid intended to be introduced into the eye to aid... section 515 of the act is required before this device may be commercially distributed. See § 886.3. ...
Fluid injection and induced seismicity
Kendall, Michael; Verdon, James
2016-04-01
The link between fluid injection, or extraction, and induced seismicity has been observed in reservoirs for many decades. In fact spatial mapping of low magnitude events is routinely used to estimate a stimulated reservoir volume. However, the link between subsurface fluid injection and larger felt seismicity is less clear and has attracted recent interest with a dramatic increase in earthquakes associated with the disposal of oilfield waste fluids. In a few cases, hydraulic fracturing has also been linked to induced seismicity. Much can be learned from past case-studies of induced seismicity so that we can better understand the risks posed. Here we examine 12 case examples and consider in particular controls on maximum event size, lateral event distributions, and event depths. Our results suggest that injection volume is a better control on maximum magnitude than past, natural seismicity in a region. This might, however, simply reflect the lack of baseline monitoring and/or long-term seismic records in certain regions. To address this in the UK, the British Geological Survey is leading the deployment of monitoring arrays in prospective shale gas areas in Lancashire and Yorkshire. In most cases, seismicity is generally located in close vicinity to the injection site. However, in some cases, the nearest events are up to 5km from the injection point. This gives an indication of the minimum radius of influence of such fluid injection projects. The most distant events are never more than 20km from the injection point, perhaps implying a maximum radius of influence. Some events are located in the target reservoir, but most occur below the injection depth. In fact, most events lie in the crystalline basement underlying the sedimentary rocks. This suggests that induced seismicity may not pose a leakage risk for fluid migration back to the surface, as it does not impact caprock integrity. A useful application for microseismic data is to try and forecast induced seismicity
Selected topics of fluid mechanics
Kindsvater, Carl E.
1958-01-01
The fundamental equations of fluid mechanics are specific expressions of the principles of motion which are ascribed to Isaac Newton. Thus, the equations which form the framework of applied fluid mechanics or hydraulics are, in addition to the equation of continuity, the Newtonian equations of energy and momentum. These basic relationships are also the foundations of river hydraulics. The fundamental equations are developed in this report with sufficient rigor to support critical examinations of their applicability to most problems met by hydraulic engineers of the Water Resources Division of the United States Geological Survey. Physical concepts are emphasized, and mathematical procedures are the simplest consistent with the specific requirements of the derivations. In lieu of numerical examples, analogies, and alternative procedures, this treatment stresses a brief methodical exposition of the essential principles. An important objective of this report is to prepare the user to read the literature of the science. Thus, it begins With a basic vocabulary of technical symbols, terms, and concepts. Throughout, emphasis is placed on the language of modern fluid mechanics as it pertains to hydraulic engineering. The basic differential and integral equations of simple fluid motion are derived, and these equations are, in turn, used to describe the essential characteristics of hydrostatics and piezometry. The one-dimensional equations of continuity and motion are defined and are used to derive the general discharge equation. The flow net is described as a means of demonstrating significant characteristics of two-dimensional irrotational flow patterns. A typical flow net is examined in detail. The influence of fluid viscosity is described as an obstacle to the derivation of general, integral equations of motion. It is observed that the part played by viscosity is one which is usually dependent on experimental evaluation. It follows that the dimensionless ratios known as
Hydrodynamic bearing lubricated with magnetic fluids
International Nuclear Information System (INIS)
Urreta, H; Leicht, Z; Sanchez, A; Agirre, A; Kuzhir, P; Magnac, G
2009-01-01
This paper summarizes the work carried out in the development of hydrodynamic lubricated journal bearings with magnetic fluids. Two different fluids have been analyzed, one ferrofluid from FERROTEC APG s10n and one magnetorheological fluid from LORD Corp., MRF122-2ED. Theoretical analysis has been carried out with numerical solutions of Reynolds equation, based on apparent viscosity modulation for ferrofluid and Bingham model for MR fluid. To validate this model, one test bench has been designed, manufactured and set up, where preliminary results shown in this paper demonstrate that magnetic fluids can be used to develop active journal bearings.
Euler's fluid equations: Optimal control vs optimization
International Nuclear Information System (INIS)
Holm, Darryl D.
2009-01-01
An optimization method used in image-processing (metamorphosis) is found to imply Euler's equations for incompressible flow of an inviscid fluid, without requiring that the Lagrangian particle labels exactly follow the flow lines of the Eulerian velocity vector field. Thus, an optimal control problem and an optimization problem for incompressible ideal fluid flow both yield the same Euler fluid equations, although their Lagrangian parcel dynamics are different. This is a result of the gauge freedom in the definition of the fluid pressure for an incompressible flow, in combination with the symmetry of fluid dynamics under relabeling of their Lagrangian coordinates. Similar ideas are also illustrated for SO(N) rigid body motion.
Fluid mechanics. 5. enlarged ed.
International Nuclear Information System (INIS)
Kalide, W.
1980-01-01
Originally written for students in the field of engineering, this book may also be of use in the engineering practice. The subject is presented with a view to practice. Fundamental theorems of fluid mechanics are presented without going too much into theory. The chapter on supersonic flow has been extended in the fifth edition as this is a field of great importance in engineering. The new chapter on gas dynamics takes account of these processes in turbine and compressure construction and aeronautical engineering. There is an appendix with material data, characteristic values, flow resistance coefficients, diagrams and two tables with rated pressure loss values for pipeline flow. (orig./GL)
Compact heat exchanger for fluids
International Nuclear Information System (INIS)
Marchal, P.A.H.
1975-01-01
The invention concerns a welded heat exchanger with two or more fluids which can be used counter current. The principle of the apparatus allows the use of rolled welded concentric metal strips as well as spiral rolled metal strips. The ring sheets are kept apart either by their rigidity due to the cylindrical shape or by deformations in the sheets themselves or yet again by spacers or chequered and/or perforated sheets forming for instance corrugated spacers, the end sheet being thick enough to take the pressure strain [fr
Scattering methods in complex fluids
Chen, Sow-Hsin
2015-01-01
Summarising recent research on the physics of complex liquids, this in-depth analysis examines the topic of complex liquids from a modern perspective, addressing experimental, computational and theoretical aspects of the field. Selecting only the most interesting contemporary developments in this rich field of research, the authors present multiple examples including aggregation, gel formation and glass transition, in systems undergoing percolation, at criticality, or in supercooled states. Connecting experiments and simulation with key theoretical principles, and covering numerous systems including micelles, micro-emulsions, biological systems, and cement pastes, this unique text is an invaluable resource for graduate students and researchers looking to explore and understand the expanding field of complex fluids.
Experimental Approach to Teaching Fluids
Stern, Catalina
2015-11-01
For the last 15 years we have promoted experimental work even in the theoretical courses. Fluids appear in the Physics curriculum of the National University of Mexico in two courses: Collective Phenomena in their sophomore year and Continuum Mechanics in their senior year. In both, students are asked for a final project. Surprisingly, at least 85% choose an experimental subject even though this means working extra hours every week. Some of the experiments were shown in this congress two years ago. This time we present some new results and the methodology we use in the classroom. I acknowledge support from the Physics Department, Facultad de Ciencias, UNAM.
Scintigraphy of the cerebrospinal fluid
International Nuclear Information System (INIS)
Touya, E.; Perillo, W.; Paez, A.; Osorio, A.; Ferrando, R.; Lago, G.; Garcia Guelfi, A.; Ferrari, M.
1977-01-01
Eight years of experience in scintigraphy of cerebrospinal fluid (CSF) with 113 Insup(m)-colloid is reported. Two hundred cases are discussed. On the basis of the clinical diagnosis, the cases are divided into five groups: (1) spinal cord compression; (2) hydrocephalus of the adult and child; (3) control of extracranial CSF shunts; (4) CSF fistula; and (5) brain tumour. It is concluded that the radiopharmaceutical used has no limitations except in the study of the hydrocephalus of the adult. For those services remote from the production centres, it is a convenient option for CSF scintigraphy. (author)
Sensors for Fluid Leak Detection
Directory of Open Access Journals (Sweden)
Gonzalo Pajares Martinsanz
2015-02-01
Full Text Available Fluid leak detection represents a problem that has attracted the interest of researchers, but not exclusively because in industries and services leaks are frequently common. Indeed, in water or gas supplies, chemical or thermal plants, sea-lines or cooling/heating systems leakage rates can cause important economic losses and sometimes, what it is more relevant, environmental pollution with human, animal or plant lives at risk. This last issue has led to increased national and international regulations with different degrees of severity regarding environmental conservation.[...
Complex fluids modeling and algorithms
Saramito, Pierre
2016-01-01
This book presents a comprehensive overview of the modeling of complex fluids, including many common substances, such as toothpaste, hair gel, mayonnaise, liquid foam, cement and blood, which cannot be described by Navier-Stokes equations. It also offers an up-to-date mathematical and numerical analysis of the corresponding equations, as well as several practical numerical algorithms and software solutions for the approximation of the solutions. It discusses industrial (molten plastics, forming process), geophysical (mud flows, volcanic lava, glaciers and snow avalanches), and biological (blood flows, tissues) modeling applications. This book is a valuable resource for undergraduate students and researchers in applied mathematics, mechanical engineering and physics.
Immersible solar heater for fluids
Kronberg, James W.
1995-01-01
An immersible solar heater comprising a light-absorbing panel attached to a frame for absorbing heat energy from the light and transferring the absorbed heat energy directly to the fluid in which the heater is immersed. The heater can be used to heat a swimming pool, for example, and is held in position and at a preselected angle by a system of floats, weights and tethers so that the panel can operate efficiently. A skid can be used in one embodiment to prevent lateral movement of the heater along the bottom of the pool. Alternative embodiments include different arrangements of the weights, floats and tethers and methods for making the heater.
Self diffusion in isotopic fluid
International Nuclear Information System (INIS)
Tankeshwar, K.
1991-01-01
Expressions for the second and fourth frequency sum rules of the velocity auto-correlation function have been obtained for an isotopic fluid. These expressions and Mori memory function formalism have been used to study the influence of the particle mass and mole fraction on the self diffusion coefficient. Our results confirm the weak mass dependence of the self diffusion. The influence of the mole fraction of the light particles on the self diffusion constant has been found to increase for the larger particle mass. (author). 17 refs, 1 fig., 2 tabs
Supercritical fluid extraction of uranium
International Nuclear Information System (INIS)
Kumar, Pradeep
2017-01-01
Uranium being strategic material, its separation and purification is of utmost importance in nuclear industry, for which solvent extraction is being employed. During solvent extraction significant quantity of radioactive liquid waste gets generated which is of environmental concern. In recent decades supercritical fluid extraction (SFE) has emerged as promising alternative to solvent extraction owing to its inherent advantage of reduction in liquid waste generation and simplification of process. In this paper a brief overview of research work carried out so far on SFE of uranium by BARC has been given
Parallel plasma fluid turbulence calculations
International Nuclear Information System (INIS)
Leboeuf, J.N.; Carreras, B.A.; Charlton, L.A.; Drake, J.B.; Lynch, V.E.; Newman, D.E.; Sidikman, K.L.; Spong, D.A.
1994-01-01
The study of plasma turbulence and transport is a complex problem of critical importance for fusion-relevant plasmas. To this day, the fluid treatment of plasma dynamics is the best approach to realistic physics at the high resolution required for certain experimentally relevant calculations. Core and edge turbulence in a magnetic fusion device have been modeled using state-of-the-art, nonlinear, three-dimensional, initial-value fluid and gyrofluid codes. Parallel implementation of these models on diverse platforms--vector parallel (National Energy Research Supercomputer Center's CRAY Y-MP C90), massively parallel (Intel Paragon XP/S 35), and serial parallel (clusters of high-performance workstations using the Parallel Virtual Machine protocol)--offers a variety of paths to high resolution and significant improvements in real-time efficiency, each with its own advantages. The largest and most efficient calculations have been performed at the 200 Mword memory limit on the C90 in dedicated mode, where an overlap of 12 to 13 out of a maximum of 16 processors has been achieved with a gyrofluid model of core fluctuations. The richness of the physics captured by these calculations is commensurate with the increased resolution and efficiency and is limited only by the ingenuity brought to the analysis of the massive amounts of data generated
Semiclassical statistical mechanics of fluids
International Nuclear Information System (INIS)
Singh, Y.; Sinha, S.K.
1981-01-01
The problem of calculating the equilibrium properties of fluids in the semiclassical limit when the quantum effects are small is studied. Particle distribution functions and thermodynamic quantities are defined in terms of the Slater sum and methods for evaluating the Slater sum are discussed. It is shown that the expansion method employing the usual Wigner-Kirkwood or Hemmer-Jancovici series is not suitable to treat the properties of the condensed state. Using the grand canonical ensemble and functional differentiation technique we develop cluster expansion series of the Helmholtz free energy and pair correlation functions. Using topological reduction we transform these series to more compact form involving a renormalized potential or a renormalized Mayer function. Then the convergence of the two series is improved by an optimal choice of the renormalized potential or the Mayer function. Integral equation theories are derived and used to devise perturbation methods. An application of these methods to the calculation of the virial coefficients, thermodynamic properties and the pair correlation function for model fluids is discussed. (orig.)
Phase transitions of quadrupolar fluids
International Nuclear Information System (INIS)
OShea, S.F.; Dubey, G.S.; Rasaiah, J.C.
1997-01-01
Gibbs ensemble simulations are reported for Lennard-Jones particles with embedded quadrupoles of strength Q * =Q/(εσ 5 ) 1/2 =2.0 where ε and σ are the Lennard-Jones parameters. Calculations revealing the effect of the dispersive forces on the liquid endash vapor coexistence were carried out by scaling the attractive r -6 term in the Lennard-Jones pair potential by a factor λ ranging from 0 to 1. Liquid endash vapor coexistence is observed for all values of λ including λ=0 for Q * =2.0, unlike the corresponding dipolar fluid studied by van Leeuwen and Smit et al. [Phys. Rev. Lett. 71, 3991 (1993)] which showed no phase transition below λ=0.35 when the reduced dipole moment μ * =2.0. The simulation data are analyzed to estimate the critical properties of the quadrupolar fluid and their dependence on the strength λ of the dispersive force. The critical temperature and pressure show a clear quadratic dependence on λ, while the density is less confidently identified as being linear in λ. The compressibility is roughly linear in λ. copyright 1997 American Institute of Physics
Fluid structure interaction with sloshing
International Nuclear Information System (INIS)
Belytschko, T.B.; Liu, W.K.
1983-01-01
In this paper, three different formulations for fluid-structure interaction with sloshing are discussed. When the surface displacements are large, the problems are nonlinear, and Arbitrary Lagrangian Eulerian (ALE) methods and direct time integration are most appropriate. Explicit direct time integration has the disadvantage of a limited time-step whereas implicit method has the disadvantage of nonconvergence and high computational cost. A mixed time method which employs E-mE (explicit-multiple explicit) integration for obtaining the velocity and free surface displacement and I-mI (implicit-multiple implicit) integration for obtaining the pressure is described. An iterative solution procedure is used to enhance the efficiency of the implicit solution procedure as well as to reduce the computer storage. For linear problems, the surface wave effects can be approximated by a perturbation method on the body force term if the surface displacements are small. Furthermore, if the fluid can be idealized as inviscid, incompressible and irrotational, the pressure, velocity, and free surface displacement variables can be eliminated via a velocity potential formulation. (orig.)
Dissipative fluid mechanics of nuclei
International Nuclear Information System (INIS)
Morgenstern, B.
1987-11-01
With the aim to describe nucleus-nucleus collisions at low energies in the present thesis for the first time dissipative fluid dynamics for large-amplitude nuclear motion have been formulated. Thereby the collective dynamics are described in a scaling approximation in which the wave function of the system is distorted by a vortex-free velocity field. For infintely extended nuclear matter this scaling of the wave functions leads to a deformation of the Fermi sphere. Two-body collisions destroy the collective deformation of the Fermi sphere and yield so the dissipative contribution of the motion. Equations of motion for a finite set of collective variables and a field equation for the collective velocity potential in the limit of infinitely many degrees of freedom were developed. In the elastic limit oscillations around the equilibrium position are described. For small collective amplitudes and vortex-free velocity fields the integrodifferential equation for the velocity potential in the elastic limit could be transformed to the divergence of the field equation of fluid dynamics. In the dissipative limit an equation results which is similar to the Navier-Stokes equation and transforms to the divergence of the Navier-Stokes equation for vortex-free fields. It was shown that generally the dynamics of the many-body system is described by non-Markovian equations. (orig./HSI) [de
Computational methods for fluid dynamics
Ferziger, Joel H
2002-01-01
In its 3rd revised and extended edition the book offers an overview of the techniques used to solve problems in fluid mechanics on computers and describes in detail those most often used in practice. Included are advanced methods in computational fluid dynamics, like direct and large-eddy simulation of turbulence, multigrid methods, parallel computing, moving grids, structured, block-structured and unstructured boundary-fitted grids, free surface flows. The 3rd edition contains a new section dealing with grid quality and an extended description of discretization methods. The book shows common roots and basic principles for many different methods. The book also contains a great deal of practical advice for code developers and users, it is designed to be equally useful to beginners and experts. The issues of numerical accuracy, estimation and reduction of numerical errors are dealt with in detail, with many examples. A full-feature user-friendly demo-version of a commercial CFD software has been added, which ca...
Volumetric velocimetry for fluid flows
Discetti, Stefano; Coletti, Filippo
2018-04-01
In recent years, several techniques have been introduced that are capable of extracting 3D three-component velocity fields in fluid flows. Fast-paced developments in both hardware and processing algorithms have generated a diverse set of methods, with a growing range of applications in flow diagnostics. This has been further enriched by the increasingly marked trend of hybridization, in which the differences between techniques are fading. In this review, we carry out a survey of the prominent methods, including optical techniques and approaches based on medical imaging. An overview of each is given with an example of an application from the literature, while focusing on their respective strengths and challenges. A framework for the evaluation of velocimetry performance in terms of dynamic spatial range is discussed, along with technological trends and emerging strategies to exploit 3D data. While critical challenges still exist, these observations highlight how volumetric techniques are transforming experimental fluid mechanics, and that the possibilities they offer have just begun to be explored.
Cerebrospinal fluid endorphins in schizophrenia
International Nuclear Information System (INIS)
Rimon, R.; Terenius, L.; Kampman, R.
1980-01-01
Opioid-receptor-active material, endorphins, has been measured in cerebrospinal fluid samples obtained from schizophrenics. A chromatographic procedure isolated the Fraction I endorphin which was quantitated in a receptorassay. At least two cerebrospinal fluid samples were obtained from each patient, at day 0 with no medication and at days 30 and 60 after medication with fluphenazine under standardized conditions. Three series of patients were included: acute schizophrenics (n=11); re-entry schizophrenics (n=7) who have previously been treated with neuroleptics but were readmitted to hospital usually as a consequence of stopped medication, and chronic schizophrenics (n=9) who had been without neuroleptics for at least 2 weeks prior to day 0. At day 0, 6/9 acute cases, 4/6 of re-entry and 2/9 chronic cases had endorphin levels above the range of healthy volunteers. The levels in chronic cases were significantly lower than those in acute cases. Treatment with neuroleptics significantly lowered the endorphin levels in acute cases. These results confirm and extend previous observations. (author)
Nanoparticle Assemblies at Fluid Interfaces
Energy Technology Data Exchange (ETDEWEB)
Russell, Thomas P. [Univ. of Massachusetts, Amherst, MA (United States). Dept. of Polymer Science and Engineering
2015-03-10
A systematic study of the structure and dynamics of nanoparticles (NP) and NP-surfactants was performed. The ligands attached to both the NPs and NP-surfactants dictate the manner in which the nanoscopic materials assemble at fluid interfaces. Studies have shown that a single layer of the nanoscpic materials form at the interface to reduce the interactions between the two immiscible fluids. The shape of the NP is, also, important, where for spherical particles, a disordered, liquid-like monolayer forms, and, for nanorods, ordered domains at the interface is found and, if the monolayers are compressed, the orientation of the nanorods with respect to the interface can change. By associating end-functionalized polymers to the NPs assembled at the interface, NP-surfactants are formed that increase the energetic gain in segregating each NP at the interface which allows the NP-surfactants to jam at the interface when compressed. This has opened the possibility of structuring the two liquids by freezing in shape changes of the liquids.
Fluid discrimination based on rock physics templates
International Nuclear Information System (INIS)
Liu, Qian; Yin, Xingyao; Li, Chao
2015-01-01
Reservoir fluid discrimination is an indispensable part of seismic exploration. Reliable fluid discrimination helps to decrease the risk of exploration and to increase the success ratio of drilling. There are many kinds of fluid indicators that are used in fluid discriminations, most of which are single indicators. But single indicators do not always work well under complicated reservoir conditions. Therefore, combined fluid indicators are needed to increase accuracies of discriminations. In this paper, we have proposed an alternative strategy for the combination of fluid indicators. An alternative fluid indicator, the rock physics template-based indicator (RPTI) has been derived to combine the advantages of two single indicators. The RPTI is more sensitive to the contents of fluid than traditional indicators. The combination is implemented based on the characteristic of the fluid trend in the rock physics template, which means few subjective factors are involved. We also propose an inversion method to assure the accuracy of the RPTI input data. The RPTI profile is an intuitionistic interpretation of fluid content. Real data tests demonstrate the applicability and validity. (paper)
Biodegradability of unused lubricating brake fluids in fresh and ...
African Journals Online (AJOL)
The biodegradability of four unused lubricating brake fluids (Total brake fluid, Allied brake fluid, Oando brake fluid and Ate brake fluid) was carried out in fresh and marine water obtained from Isiokpo stream and Bonny river of the Niger Delta, South South Nigeria. Biodegradability, of the brake fluids were obtained after a 56 ...
Fluid-fluid level on MR image: significance in Musculoskeletal diseases
Energy Technology Data Exchange (ETDEWEB)
Chung, Hye Won; Lee, Kyung Won [Seoul Naitonal University, Seoul (Korea, Republic of). Coll. of Medicine; Song, Chi Sung [Seoul City Boramae Hospital, Seoul (Korea, Republic of); Han, Sang Wook; Kang, Heung Sik [Seoul Naitonal University, Seoul (Korea, Republic of). Coll. of Medicine
1998-01-01
To evaluate the frequency, number and signal intensity of fluid-fluid levels of musculoskeletal diseases on MR images, and to determine the usefulness of this information for the differentiation of musculoskeletal diseases. MR images revealed fluid-fluid levels in the following diseases : giant cell tumor(6), telangiectatic osteosarcoma(4), aneurysmal bone cyst(3), synovial sarcoma(3), chondroblastoma(2), soft tissue tuberculous abscess(2), hematoma(2), hemangioma (1), neurilemmoma(1), metastasis(1), malignant fibrous histiocytoma(1), bursitis(1), pyogenic abscess(1), and epidermoid inclusion cyst(1). Fourteen benign tumors and ten malignant, three abscesses, and the epidermoid inclusion cyst showed only one fluid-fluid level in a unilocular cyst. On T1-weighted images, the signal intensities of fluid varied, but on T2-weighted images, superior layers were in most cases more hyperintense than inferior layers. Because fluid-fluid layers are a nonspecific finding, it is difficult to specifically diagnose each disease according to the number of fluid-fluid levels or signal intensity of fluid. In spite of the nonspecificity of fluid-fluid levels, they were frequently seen in cases of giant cell tumor, telangiectatic osteosarcoma, aneurysmal bone cycle, and synovial sarcoma. Nontumorous diseases such abscesses and hematomas also demonstrated this finding. (author). 11 refs., 1 tab., 4 figs.
Fluid-fluid level on MR image: significance in Musculoskeletal diseases
International Nuclear Information System (INIS)
Chung, Hye Won; Lee, Kyung Won; Han, Sang Wook; Kang, Heung Sik
1998-01-01
To evaluate the frequency, number and signal intensity of fluid-fluid levels of musculoskeletal diseases on MR images, and to determine the usefulness of this information for the differentiation of musculoskeletal diseases. MR images revealed fluid-fluid levels in the following diseases : giant cell tumor(6), telangiectatic osteosarcoma(4), aneurysmal bone cyst(3), synovial sarcoma(3), chondroblastoma(2), soft tissue tuberculous abscess(2), hematoma(2), hemangioma (1), neurilemmoma(1), metastasis(1), malignant fibrous histiocytoma(1), bursitis(1), pyogenic abscess(1), and epidermoid inclusion cyst(1). Fourteen benign tumors and ten malignant, three abscesses, and the epidermoid inclusion cyst showed only one fluid-fluid level in a unilocular cyst. On T1-weighted images, the signal intensities of fluid varied, but on T2-weighted images, superior layers were in most cases more hyperintense than inferior layers. Because fluid-fluid layers are a nonspecific finding, it is difficult to specifically diagnose each disease according to the number of fluid-fluid levels or signal intensity of fluid. In spite of the nonspecificity of fluid-fluid levels, they were frequently seen in cases of giant cell tumor, telangiectatic osteosarcoma, aneurysmal bone cycle, and synovial sarcoma. Nontumorous diseases such abscesses and hematomas also demonstrated this finding. (author). 11 refs., 1 tab., 4 figs
[Arterial pressure curve and fluid status].
Pestel, G; Fukui, K
2009-04-01
Fluid optimization is a major contributor to improved outcome in patients. Unfortunately, anesthesiologists are often in doubt whether an additional fluid bolus will improve the hemodynamics of the patient or not as excess fluid may even jeopardize the condition. This article discusses physiological concepts of liberal versus restrictive fluid management followed by a discussion on the respective capabilities of various monitors to predict fluid responsiveness. The parameter difference in pulse pressure (dPP), derived from heart-lung interaction in mechanically ventilated patients is discussed in detail. The dPP cutoff value of 13% to predict fluid responsiveness is presented together with several assessment techniques of dPP. Finally, confounding variables on dPP measurements, such as ventilation parameters, pneumoperitoneum and use of norepinephrine are also mentioned.
Fluid control structures in microfluidic devices
Mathies, Richard A.; Grover, William H.; Skelley, Alison; Lagally, Eric; Liu, Chung N.
2017-05-09
Methods and apparatus for implementing microfluidic analysis devices are provided. A monolithic elastomer membrane associated with an integrated pneumatic manifold allows the placement and actuation of a variety of fluid control structures, such as structures for pumping, isolating, mixing, routing, merging, splitting, preparing, and storing volumes of fluid. The fluid control structures can be used to implement a variety of sample introduction, preparation, processing, and storage techniques.
Relativistic charged fluids: hydrodynamic and kinetic approaches
International Nuclear Information System (INIS)
Debbasch, F.; Bonnaud, G.
1991-10-01
This report gives a rigorous and consistent hydrodynamic and kinetic description of a charged fluid and the basis equations, in a relativistic context. This study should lead to a reliable model, as much analytical as numerical, of relativistic plasmas which will appear in the interaction of a strong laser field with a plasma. For simplicity, we limited our study to a perfect fluid or, in other words, we disregarded the energy dissipation processes inside the fluid [fr
Proceedings of industrial applications of fluid mechanics
International Nuclear Information System (INIS)
Sherif, S.A.; Morrow, T.B.; Marshall, L.R.; Dalton, C.
1990-01-01
The is the fourth Forum on Industrial Applications of Fluid Mechanics sponsored by the Fluid Mechanics Committee of the ASME Fluids Engineering Division. The Forum objective is to promote the discussion and interchange of current information on developing and state-of-the-art applications of fluid mechanics technology. The program is organized as a technical forum to encourage the presentation of new ideas, especially those which may be so innovative that a conservative review process might delay their dissemination to the fluids engineering community. Four sessions and a total of 17 papers are scheduled for this program. Three of the four sessions were devoted to contributed papers, while the fourth is a panel discussion with three invited presentations. All papers were reviewed editorially to assure that they are related to the forum theme The papers were not evaluated technically, and therefore carry no endorsement from the Fluid Mechanics Committee or the Fluids Engineering Division with regard to peer evaluation. The forum presentations will focus on specific applications of fluid mechanics technology. Lively discussion of the papers is encouraged at the forum. The Fluid Mechanics Committee plans to sponsor a forum with an industrial applications theme each year at the ASME Winter Annual Meeting. In 1991, the scope of the forum will be enlarged to include the topic of textile applications of fluid mechanics, and another panel session featuring speakers with industrial experience in different areas of fluid mechanics applications. In future years, it is anticipated that the forum will solicit papers from other areas where fluid mechanics technology is applied
Rheological properties of PHPA polymer support fluids
Lam, Carlos; Martin, P J; Jefferis, S A
2015-01-01
Synthetic polymer fluids are becoming a popular replacement for bentonite slurries to support excavations for deep foundation elements. However, the rheological properties of the polymer fluids used in excavation support have not been studied in detail, and there is currently confusion about the choice of mathematical models for this type of fluid. To advance the current state of knowledge, a laboratory study has been performed to investigate the steady-shear viscosity and transient viscoelas...
Studies of complexity in fluid systems
Energy Technology Data Exchange (ETDEWEB)
Nagel, Sidney R.
2000-06-12
This is the final report of Grant DE-FG02-92ER25119, ''Studies of Complexity in Fluids'', we have investigated turbulence, flow in granular materials, singularities in evolution of fluid surfaces and selective withdrawal fluid flows. We have studied numerical methods for dealing with complex phenomena, and done simulations on the formation of river networks. We have also studied contact-line deposition that occurs in a drying drop.
4-H NFPA Fluid Power Challenge
Bonnett, Erika D
2016-01-01
The 4-H NFPA Fluid Power Challenge partnered Purdue Polytechnic Institute and Indiana 4-H with the National Fluid Power Association and Center for Compact and Efficient Fluid Power to provide teams of Indiana youth in 6-8th grades with opportunity to learn about hydraulics, engineering design, and other STEM skills. This created an opportunity to give youth a learning experience with STEM through hands-on, experiential learning activities. Youth experienced a one day workshop in which they wo...
Gas powered fluid gun with recoil mitigation
Grubelich, Mark C; Yonas, Gerold
2013-11-12
A gas powered fluid gun for propelling a stream or slug of a fluid at high velocity toward a target. Recoil mitigation is provided that reduces or eliminates the associated recoil forces, with minimal or no backwash. By launching a quantity of water in the opposite direction, net momentum forces are reduced or eliminated. Examples of recoil mitigation devices include a cone for making a conical fluid sheet, a device forming multiple impinging streams of fluid, a cavitating venturi, one or more spinning vanes, or an annular tangential entry/exit.
Relativistic fluids in spherically symmetric space
International Nuclear Information System (INIS)
Dipankar, R.
1977-12-01
Some of McVittie and Wiltshire's (1977) solutions of Walker's (1935) isotropy conditions for relativistic perfect fluid spheres are generalized. Solutions are spherically symmetric and conformally flat
Effects of drilling fluids on marine organisms
International Nuclear Information System (INIS)
Parrish, P.R.; Duke, T.W.
1990-01-01
This paper reports on drilling fluids, also called drilling muds, which are essential to drilling processes in the exploration and production of oil and gas from the U.S. Outer Continental Shelf (OCS). These fluids are usually discharged from drilling platforms into surrounding waters of the OCS and are regulated by the U.S. Environmental Protection Agency (EPA). In a program carried out by the EPA Environmental research Laboratory at Gulf Breeze, Florida, diverse marine species as well as microbiotic and macrobiotic communities were studied. Drilling fluids were toxic to marine organisms in certain concentrations and exposure regimes. Furthermore, the fluids adversely affected the benthos physically by burying them or by altering the substrates. Toxicity of the drilling-fluid components, used drilling fluids from active Gulf of Mexico sites, and laboratory-prepared drilling fluids varied considerably. for example 96-h LC 50 s were from 25 μ liter -1 to > 1500 μl liter -1 for clams, larval lobsters, mysids, and grass shrimp. In most instances, mortality was significantly (α = 0.05) correlated with the diesel-oil content of the fluids collected from the Gulf of Mexico. Data and model simulations suggest a rapid dilution of drilling fluids released into OCS waters, resulting in concentrations below the acute-effect concentration for the water column organisms tested
Fundamental trends in fluid-structure interaction
Galdi, Giovanni P
2010-01-01
The interaction of a fluid with a solid body is a widespread phenomenon in nature, occurring at different scales and different applied disciplines. Interestingly enough, even though the mathematical theory of the motion of bodies in a liquid is one of the oldest and most classical problems in fluid mechanics, mathematicians have, only very recently, become interested in a systematic study of the basic problems related to fluid-structure interaction, from both analytical and numerical viewpoints. ""Fundamental Trends in Fluid-Structure Interaction"" is a unique collection of important papers wr
Predicting and measuring fluid responsiveness with echocardiography
Directory of Open Access Journals (Sweden)
Ashley Miller
2016-06-01
Full Text Available Echocardiography is ideally suited to guide fluid resuscitation in critically ill patients. It can be used to assess fluid responsiveness by looking at the left ventricle, aortic outflow, inferior vena cava and right ventricle. Static measurements and dynamic variables based on heart–lung interactions all combine to predict and measure fluid responsiveness and assess response to intravenous fluid esuscitation. Thorough knowledge of these variables, the physiology behind them and the pitfalls in their use allows the echocardiographer to confidently assess these patients and in combination with clinical judgement manage them appropriately.
Advances in fluid modeling and turbulence measurements
International Nuclear Information System (INIS)
Wada, Akira; Ninokata, Hisashi; Tanaka, Nobukazu
2002-01-01
The context of this book consists of four fields: Environmental Fluid Mechanics; Industrial Fluid Mechanics; Fundamentals of Fluid Mechanics; and Turbulence Measurements. Environmental Fluid Mechanics includes free surface flows in channels, rivers, seas, and estuaries. It also discusses wind engineering issues, ocean circulation model and dispersion problems in atmospheric, water and ground water environments. In Industrial Fluid Mechanics, fluid phenomena in energy exchanges, modeling of turbulent two- or multi-phase flows, swirling flows, flows in combustors, variable density flows and reacting flows, flows in turbo-machines, pumps and piping systems, and fluid-structure interaction are discussed. In Fundamentals of Fluid Mechanics, progress in modeling turbulent flows and heat/mass transfers, computational fluid dynamics/numerical techniques, parallel computing algorithms, applications of chaos/fractal theory in turbulence are reported. In Turbulence Measurements, experimental studies of turbulent flows, experimental and post-processing techniques, quantitative and qualitative flow visualization techniques are discussed. Separate abstracts were presented for 15 of the papers in this issue. The remaining 89 were considered outside the subject scope of INIS. (J.P.N.)
An introduction to Computational Fluid Dynamics
DEFF Research Database (Denmark)
Sørensen, Lars Schiøtt
1999-01-01
CFD is the shortname for Computational Fluid Dynamics and is a numerical method by means of which we can analyze systems containing fluids. For instance systems dealing with heat flow or smoke control systems acting when a fire occur in a building.......CFD is the shortname for Computational Fluid Dynamics and is a numerical method by means of which we can analyze systems containing fluids. For instance systems dealing with heat flow or smoke control systems acting when a fire occur in a building....
Introduction to thermo-fluids systems design
Garcia McDonald, André
2012-01-01
A fully comprehensive guide to thermal systems design covering fluid dynamics, thermodynamics, heat transfer and thermodynamic power cycles Bridging the gap between the fundamental concepts of fluid mechanics, heat transfer and thermodynamics, and the practical design of thermo-fluids components and systems, this textbook focuses on the design of internal fluid flow systems, coiled heat exchangers and performance analysis of power plant systems. The topics are arranged so that each builds upon the previous chapter to convey to the reader that topics are not stand-alone i
Krekelberg, William P; Siderius, Daniel W; Shen, Vincent K; Truskett, Thomas M; Errington, Jeffrey R
2017-08-03
Using molecular simulations, we investigate how the range of fluid-fluid (adsorbate-adsorbate) interactions and the strength of fluid-solid (adsorbate-adsorbent) interactions impact the strong connection between distinct adsorptive regimes and distinct self-diffusivity regimes reported in [Krekelberg, W. P.; Siderius, D. W.; Shen, V. K.; Truskett, T. M.; Errington, J. R. Langmuir 2013 , 29 , 14527-14535]. Although increasing the fluid-fluid interaction range changes both the thermodynamics and the dynamic properties of adsorbed fluids, the previously reported connection between adsorptive filling regimes and self-diffusivity regimes remains. Increasing the fluid-fluid interaction range leads to enhanced layering and decreased self-diffusivity in the multilayer-formation regime but has little effect on the properties within film-formation and pore-filling regimes. We also find that weakly attractive adsorbents, which do not display distinct multilayer formation, are hard-sphere-like at super- and subcritical temperatures. In this case, the self-diffusivity of the confined and bulk fluid has a nearly identical scaling-relationship with effective density.
Topology of helical fluid flow
DEFF Research Database (Denmark)
Andersen, Morten; Brøns, Morten
2014-01-01
function for the topology of the streamline pattern in incompressible flows. On this basis, we perform a comprehensive study of the topology of the flow field generated by a helical vortex filament in an ideal fluid. The classical expression for the stream function obtained by Hardin (Hardin, J. C. 1982...... the zeroes of a single real function of one variable, and we show that three different flow topologies can occur, depending on a single dimensionless parameter. By including the self-induced velocity on the vortex filament by a localised induction approximation, the stream function is slightly modified...... and an extra parameter is introduced. In this setting two new flow topologies arise, but not more than two critical points occur for any combination of parameters....
Principles of computational fluid dynamics
Wesseling, Pieter
2001-01-01
The book is aimed at graduate students, researchers, engineers and physicists involved in flow computations. An up-to-date account is given of the present state-of-the-art of numerical methods employed in computational fluid dynamics. The underlying numerical principles are treated with a fair amount of detail, using elementary mathematical analysis. Attention is given to difficulties arising from geometric complexity of the flow domain and of nonuniform structured boundary-fitted grids. Uniform accuracy and efficiency for singular perturbation problems is studied, pointing the way to accurate computation of flows at high Reynolds number. Much attention is given to stability analysis, and useful stability conditions are provided, some of them new, for many numerical schemes used in practice. Unified methods for compressible and incompressible flows are discussed. Numerical analysis of the shallow-water equations is included. The theory of hyperbolic conservation laws is treated. Godunov's order barrier and ho...
Cerebrospinal fluid flow. Pt. 3
International Nuclear Information System (INIS)
Schroth, G.; Klose, U.
1992-01-01
Cardiac- and respiration-related movements of the cerebrospinal fluid (CSF) were investigated by MRI in 71 patients. In most patients with arteriosclerotic occlusive vascular disease CSF pulsations are normal. Decreased pulsatile flow is detectable in those with arteriovenous malformations, intracranial air and following lumbar puncture and withdrawal of CSF. Increased pulsatile flow in the cerebral aqueduct was found in 2 patients with large aneurysms, idiopathic communicating syringomyelia and in most cases of normal pressure hydrocephalus (NPH). CSF flow in the cervical spinal canal is, however, reduced or normal in NPH, indicating reduction of the unfolding ability of the surface of the brain and/or inhibition of rapid CSF movements in the subrachnoid space over its convexity. (orig.)
Mechanics of solids and fluids
International Nuclear Information System (INIS)
Ziegler, F.
1991-01-01
This book is a comprehensive treatise on the mechanics of solids and fluids, with a significant application to structural mechanics. In reading through the text, I can not help being impressed with Dr. Ziegler's command of both historical and contemporary developments of theoretical and applied mechanics. The book is a unique volume which contains information not easily found throughout the related literature. The book opens with a fundamental consideration of the kinematics of particle motion, followed by those of rigid body and deformable medium .In the latter case, both small and finite deformation have been presented concisely, paving the way for the constitutive description given later in the book. In both chapters one and two, the author has provided sufficient applications of the theoretical principles introduced. Such a connection between theory and appication is a common theme throughout every chapter, and is quite an attractive feature of the book
Barenghi, Carlo
2016-01-01
The aim of this primer is to cover the essential theoretical information, quickly and concisely, in order to enable senior undergraduate and beginning graduate students to tackle projects in topical research areas of quantum fluids, for example, solitons, vortices and collective modes. The selection of the material, both regarding the content and level of presentation, draws on the authors analysis of the success of relevant research projects with newcomers to the field, as well as of the students feedback from many taught and self-study courses on the subject matter. Starting with a brief historical overview, this text covers particle statistics, weakly interacting condensates and their dynamics and finally superfluid helium and quantum turbulence. At the end of each chapter (apart from the first) there will be some exercises. Detailed solutions can be made available to instructors upon request to the authors. .
Apparatus for filtering radioactive fluids
International Nuclear Information System (INIS)
Gischel, E.H.
1975-01-01
Apparatus is provided for filtering radioactive particles from the cooling and/or auxiliary process water of a nuclear reactor, or nuclear fuel processing plant, or other installations wherein radioactive fluid systems are known to exist. The apparatus affords disposal of the captured particles in a manner which minimizes the exposure of operating personnel to radioactivity. The apparatus comprises a housing adapted to contain a removable filter cartridge assembly, a valve normally closing the lower end of the housing, an upwardly-open shipping cask located below the valve, and an elongated operating rod assembly projecting upwardly from the filter cartridge assembly and through the upper end of the housing to enable a workman to dismount the filter cartridge assembly from its housing and to lower the filter cartridge assembly through the valve and into the cask from a remote location above the housing. (U.S.)
Daly, B J
1990-05-01
John S. is a 72-year-old patriarch of a large, extended family. He underwent a mitral and aortic valve replacement, followed by a complicated postoperative course. His recovery was complicated by hemodynamic instability, several cardiac arrests, acute renal failure, and sepsis. He has been in the ICU for 14 weeks and has been unable to wean from mechanical ventilation. After many conferences between the patient's family and the ICU staff, a decision was made to remove ventilator support. This was done 3 days ago. John's condition seems stable now, but it is clear that he will not regain his former state of health. He is very debilitated, may require chronic dialysis, and has suffered some anoxic brain damage during his arrests. The nursing and medical staff are now faced with the question of further withdrawal of treatment and are considering whether or not to discontinue his parenteral nutrition and all IV fluids.
Directory of Open Access Journals (Sweden)
Pezelj-Ribarić Sonja
2015-12-01
Full Text Available Saliva is a readily available oral fluid with many functions, from digestion, maintenance of oral tissues' integrity, to caries prevention. Changes regarding its secretion may be divided into qualitative and quantitative: both of them are a consequence of certain conditions/diseases (e.g. internal factors or nutrients/drugs ingested (e.g. external factors. During the last 15 years, technological advances gave a significant momentum to utilization of saliva as a diagnostic tool. Analysis of saliva, just like the blood analysis, has two main objectives: to identify the subjects suffering from a certain disorder, and to follow the development and progress of therapy. This paper provides an overview of possibilities for the use of saliva for diagnostic purposes and gives specific examples of some clinical investigations, with the final aim to stimulate the use of this noninvasive means for the health care promotion.
Fluid mechanics of Windkessel effect.
Mei, C C; Zhang, J; Jing, H X
2018-01-08
We describe a mechanistic model of Windkessel phenomenon based on the linear dynamics of fluid-structure interactions. The phenomenon has its origin in an old-fashioned fire-fighting equipment where an air chamber serves to transform the intermittent influx from a pump to a more steady stream out of the hose. A similar mechanism exists in the cardiovascular system where blood injected intermittantly from the heart becomes rather smooth after passing through an elastic aorta. In existing haeodynamics literature, this mechanism is explained on the basis of electric circuit analogy with empirical impedances. We present a mechanistic theory based on the principles of fluid/structure interactions. Using a simple one-dimensional model, wave motion in the elastic aorta is coupled to the viscous flow in the rigid peripheral artery. Explicit formulas are derived that exhibit the role of material properties such as the blood density, viscosity, wall elasticity, and radii and lengths of the vessels. The current two-element model in haemodynamics is shown to be the limit of short aorta and low injection frequency and the impedance coefficients are derived theoretically. Numerical results for different aorta lengths and radii are discussed to demonstrate their effects on the time variations of blood pressure, wall shear stress, and discharge. Graphical Abstract A mechanistic analysis of Windkessel Effect is described which confirms theoretically the well-known feature that intermittent influx becomes continuous outflow. The theory depends only on the density and viscosity of the blood, the elasticity and dimensions of the vessel. Empirical impedence parameters are avoided.
Fluid Mechanics of Urban Environments
Fernando, Harindra J.
2008-11-01
The rapid urbanization of the Earth has led to highly populated cities that act as concentrated centers of anthropogenic stressors on the natural environment. The degradation of environmental quality due to such stressors, in turn, greatly impacts human behavior. Anthropogenic stressors largely originate as a result of coupling between man-made urban elements (i.e., networks of engineering and socio-economic infrastructures) and the environment, for which surrounding fluid motions play a key role. In recent years, research efforts have been directed at the understanding and modeling of fluid motions in urban areas, infrastructure dynamics and interactions thereof, with the hope of identifying environmental impacts of urbanization and complex outcomes (or ``emergent properties'') of nominally simple interactions between infrastructures and environment. Such consequences play an important role in determining the ``resilience'' of cities under anthropogenic stressors, defined as maintaining the structure and essential functions of an urbanity without regime shifts. Holistic integrated models that meld the dynamics of infrastructures and environment as well as ``quality of life'' attributes are becoming powerful decision-making tools with regard to sustainability of urban areas (continuance or even enhancement of socio-economic activities in harmony with the environment). The rudimentary forms of integrated models are beginning to take shape, augmented by comprehensive field studies and advanced measurement platforms to validate them. This presentation deals with the challenges of modeling urban atmosphere, subject to anthropogenic forcing. An important emergent property, the Urban Heat Island, and its role in determining resilience and sustainability of cities will be discussed based on the prediction of a coupled model.
Relativistic thermodynamics of Fluids. l
International Nuclear Information System (INIS)
Havas, P.; Swenson, R.J.
1979-01-01
In 1953, Stueckelberg and Wanders derived the basic laws of relativistic linear nonequilibrium thermodynamics for chemically reacting fluids from the relativistic local conservation laws for energy-momentum and the local laws of production of substances and of nonnegative entropy production by the requirement that the corresponding currents (assumed to depend linearly on the derivatives of the state variables) should not be independent. Generalizing their method, we determine the most general allowed form of the energy-momentum tensor T/sup alphabeta/ and of the corresponding rate of entropy production under the same restriction on the currents. The problem of expressing this rate in terms of thermodynamic forces and fluxes is discussed in detail; it is shown that the number of independent forces is not uniquely determined by the theory, and seven possibilities are explored. A number of possible new cross effects are found, all of which persist in the Newtonian (low-velocity) limit. The treatment of chemical reactions is incorporated into the formalism in a consistent manner, resulting in a derivation of the law for rate of production, and in relating this law to transport processes differently than suggested previously. The Newtonian limit is discussed in detail to establish the physical interpretation of the various terms of T/sup alphabeta/. In this limit, the interpretation hinges on that of the velocity field characterizing the fluid. If it is identified with the average matter velocity following from a consideration of the number densities, the usual local conservation laws of Newtonian nonequilibrium thermodynamics are obtained, including that of mass. However, a slightly different identification allows conversion of mass into energy even in this limit, and thus a macroscopic treatment of nuclear or elementary particle reactions. The relation of our results to previous work is discussed in some detail
Energy Technology Data Exchange (ETDEWEB)
Yu, Hong; Cui, Jian Ling; Cui, Sheng Jie; Sun, Ying Cal; Cui, Feng Zhen [Dept. of Radiology, The Third Hospital of Hebei Medical University, Hebei Province Biomechanical Key Laborary of Orthopedics, Shijiazhuang, Hebei (China)
2014-12-15
To analyze different fluid-fluid level features between benign and malignant bone tumors on magnetic resonance imaging (MRI). This study was approved by the hospital ethics committee. We retrospectively analyzed 47 patients diagnosed with benign (n = 29) or malignant (n = 18) bone tumors demonstrated by biopsy/surgical resection and who showed the intratumoral fluid-fluid level on pre-surgical MRI. The maximum length of the largest fluid-fluid level and the ratio of the maximum length of the largest fluid-fluid level to the maximum length of a bone tumor in the sagittal plane were investigated for use in distinguishing benign from malignant tumors using the Mann-Whitney U-test and a receiver operating characteristic (ROC) analysis. Fluid-fluid level was categorized by quantity (multiple vs. single fluid-fluid level) and by T1-weighted image signal pattern (high/low, low/high, and undifferentiated), and the findings were compared between the benign and malignant groups using the chi2 test. The ratio of the maximum length of the largest fluid-fluid level to the maximum length of bone tumors in the sagittal plane that allowed statistically significant differentiation between benign and malignant bone tumors had an area under the ROC curve of 0.758 (95% confidence interval, 0.616-0.899). A cutoff value of 41.5% (higher value suggests a benign tumor) had sensitivity of 73% and specificity of 83%. The ratio of the maximum length of the largest fluid-fluid level to the maximum length of a bone tumor in the sagittal plane may be useful to differentiate benign from malignant bone tumors.
International Nuclear Information System (INIS)
Yu, Hong; Cui, Jian Ling; Cui, Sheng Jie; Sun, Ying Cal; Cui, Feng Zhen
2014-01-01
To analyze different fluid-fluid level features between benign and malignant bone tumors on magnetic resonance imaging (MRI). This study was approved by the hospital ethics committee. We retrospectively analyzed 47 patients diagnosed with benign (n = 29) or malignant (n = 18) bone tumors demonstrated by biopsy/surgical resection and who showed the intratumoral fluid-fluid level on pre-surgical MRI. The maximum length of the largest fluid-fluid level and the ratio of the maximum length of the largest fluid-fluid level to the maximum length of a bone tumor in the sagittal plane were investigated for use in distinguishing benign from malignant tumors using the Mann-Whitney U-test and a receiver operating characteristic (ROC) analysis. Fluid-fluid level was categorized by quantity (multiple vs. single fluid-fluid level) and by T1-weighted image signal pattern (high/low, low/high, and undifferentiated), and the findings were compared between the benign and malignant groups using the chi2 test. The ratio of the maximum length of the largest fluid-fluid level to the maximum length of bone tumors in the sagittal plane that allowed statistically significant differentiation between benign and malignant bone tumors had an area under the ROC curve of 0.758 (95% confidence interval, 0.616-0.899). A cutoff value of 41.5% (higher value suggests a benign tumor) had sensitivity of 73% and specificity of 83%. The ratio of the maximum length of the largest fluid-fluid level to the maximum length of a bone tumor in the sagittal plane may be useful to differentiate benign from malignant bone tumors.
Numerical Modeling of Fluid-Structure Interaction with Rheologically Complex Fluids
Chen, Xingyuan
2014-01-01
In the present work the interaction between rheologically complex fluids and elastic solids is studied by means of numerical modeling. The investigated complex fluids are non-Newtonian viscoelastic fluids. The fluid-structure interaction (FSI) of this kind is frequently encountered in injection molding, food processing, pharmaceutical engineering and biomedicine. The investigation via experiments is costly, difficult or in some cases, even impossible. Therefore, research is increasingly aided...
Injection dynamics of gelled propellants
Yoon, Changjin
Gel propellants have been recognized as attractive candidates for future propulsion systems due to the reduced tendency to spill and the energy advantages over solid propellants. One of strong benefits emphasized in gel propellant applications is a throttling capability, but the accurate flow control is more complicated and difficult than with conventional Newtonian propellants because of the unique rheological behaviors of gels. This study is a computational effort directed to enhance understanding of the injector internal flow characteristics for gel propellants under rocket injection conditions. In simulations, the emphasized rheology is a shear-thinning which represents a viscosity decrease with increasing a shear rate. It is described by a generalized Newtonian fluid constitutive equation and Carreau-Yasuda model. Using this rheological model, two injection schemes are considered in the present study: axially-fed and cross-fed injection for single-element and multi-element impinging injectors, respectively. An axisymmetric model is developed to describe the axially-fed injector flows and fully three-dimensional model is utilized to simulate cross-fed injector flows. Under axially-fed injection conditions investigated, three distinct modes, an unsteady, steady, and hydraulic flip mode, are observed and mapped in terms of Reynolds number and orifice design. In an unsteady mode, quasi-periodic oscillations occur near the inlet lip leading mass pulsations and viscosity fluctuations at the orifice exit. This dynamic behavior is characterized using a time-averaged discharge coefficient, oscillation magnitude and frequency by a parametric study with respect to an orifice design, Reynolds number and rheology. As a result, orifice exit flows for gel propellants appear to be significantly influenced by a viscous damping and flow resistance due to a shear thinning behavior and these are observed in each factors considered. Under conditions driven by a manifold crossflow
Fluid dynamic effects on precision cleaning with supercritical fluids
Energy Technology Data Exchange (ETDEWEB)
Phelps, M.R.; Hogan, M.O.; Silva, L.J.
1994-06-01
Pacific Northwest Laboratory staff have assembled a small supercritical fluids parts cleaning test stand to characterize how system dynamics affect the efficacy of precision cleaning with supercritical carbon dioxide. A soiled stainless steel coupon, loaded into a ``Berty`` autoclave, was used to investigate how changes in system turbulence and solvent temperature influenced the removal of test dopants. A pulsed laser beam through a fiber optic was used to investigate real-time contaminant removal. Test data show that cleaning efficiency is a function of system agitation, solvent density, and temperature. These data also show that high levels of cleaning efficiency can generally be achieved with high levels of system agitation at relatively low solvent densities and temperatures. Agitation levels, temperatures, and densities needed for optimal cleaning are largely contaminant dependent. Using proper system conditions, the levels of cleanliness achieved with supercritical carbon dioxide compare favorably with conventional precision cleaning methods. Additional research is currently being conducted to generalize the relationship between cleaning performance and parameters such as contaminant solubilities, mass transfer rates, and solvent agitation. These correlations can be used to optimize cleaning performance, system design, and time and energy consumption for particular parts cleaning applications.
Fluid dynamics of bubbly flows
International Nuclear Information System (INIS)
Ziegenhein, Thomas
2016-01-01
Bubbly flows can be found in many applications in chemical, biological and power engineering. Reliable simulation tools of such flows that allow the design of new processes and optimization of existing one are therefore highly desirable. CFD-simulations applying the multi-fluid approach are very promising to provide such a design tool for complete facilities. In the multi-fluid approach, however, closure models have to be formulated to model the interaction between the continuous and dispersed phase. Due to the complex nature of bubbly flows, different phenomena have to be taken into account and for every phenomenon different closure models exist. Therefore, reliable predictions of unknown bubbly flows are not yet possible with the multi-fluid approach. A strategy to overcome this problem is to define a baseline model in which the closure models including the model constants are fixed so that the limitations of the modeling can be evaluated by validating it on different experiments. Afterwards, the shortcomings are identified so that the baseline model can be stepwise improved without losing the validity for the already validated cases. This development of a baseline model is done in the present work by validating the baseline model developed at the Helmholtz-Zentrum Dresden-Rossendorf mainly basing on experimental data for bubbly pipe flows to bubble columns, bubble plumes and air-lift reactors that are relevant in chemical and biological engineering applications. In the present work, a large variety of such setups is used for validation. The buoyancy driven bubbly flows showed thereby a transient behavior on the scale of the facility. Since such large scales are characterized by the geometry of the facility, turbulence models cannot describe them. Therefore, the transient simulation of bubbly flows with two equation models based on the unsteady Reynolds-averaged Navier-Stokes equations is investigated. In combination with the before mentioned baseline model these
Fluid dynamics of bubbly flows
Energy Technology Data Exchange (ETDEWEB)
Ziegenhein, Thomas
2016-07-08
Bubbly flows can be found in many applications in chemical, biological and power engineering. Reliable simulation tools of such flows that allow the design of new processes and optimization of existing one are therefore highly desirable. CFD-simulations applying the multi-fluid approach are very promising to provide such a design tool for complete facilities. In the multi-fluid approach, however, closure models have to be formulated to model the interaction between the continuous and dispersed phase. Due to the complex nature of bubbly flows, different phenomena have to be taken into account and for every phenomenon different closure models exist. Therefore, reliable predictions of unknown bubbly flows are not yet possible with the multi-fluid approach. A strategy to overcome this problem is to define a baseline model in which the closure models including the model constants are fixed so that the limitations of the modeling can be evaluated by validating it on different experiments. Afterwards, the shortcomings are identified so that the baseline model can be stepwise improved without losing the validity for the already validated cases. This development of a baseline model is done in the present work by validating the baseline model developed at the Helmholtz-Zentrum Dresden-Rossendorf mainly basing on experimental data for bubbly pipe flows to bubble columns, bubble plumes and air-lift reactors that are relevant in chemical and biological engineering applications. In the present work, a large variety of such setups is used for validation. The buoyancy driven bubbly flows showed thereby a transient behavior on the scale of the facility. Since such large scales are characterized by the geometry of the facility, turbulence models cannot describe them. Therefore, the transient simulation of bubbly flows with two equation models based on the unsteady Reynolds-averaged Navier-Stokes equations is investigated. In combination with the before mentioned baseline model these
International Nuclear Information System (INIS)
Caldarelli, Marco M.; Dias, Oscar J.C.; Emparan, Roberto; Klemm, Dietmar
2009-01-01
The old suggestive observation that black holes often resemble lumps of fluid has recently been taken beyond the level of an analogy to a precise duality. We investigate aspects of this duality, and in particular clarify the relation between area minimization of the fluid vs. area maximization of the black hole horizon, and the connection between surface tension and curvature of the fluid, and surface gravity of the black hole. We also argue that the Rayleigh-Plateau instability in a fluid tube is the holographic dual of the Gregory-Laflamme instability of a black string. Associated with this fluid instability there is a rich variety of phases of fluid solutions that we study in detail, including in particular the effects of rotation. We compare them against the known results for asymptotically flat black holes finding remarkable agreement. Furthermore, we use our fluid results to discuss the unknown features of the gravitational system. Finally, we make some observations that suggest that asymptotically flat black holes may admit a fluid description in the limit of large number of dimensions.
Adrenal hormones in human follicular fluid.
Jimena, P; Castilla, J A; Peran, F; Ramirez, J P; Vergara, F; Molina, R; Vergara, F; Herruzo, A
1992-11-01
Considerable evidence indicates that adrenal hormones may affect gonadal function. To assess the role of some adrenal hormones in human follicular fluid and their relationship with the ability of the oocyte to be fertilized and then to cleave in vitro, cortisol and dehydroepiandrosterone sulfate were measured in follicular fluid obtained at the time of oocyte recovery for in vitro fertilization from cycles stimulated by clomiphene citrate, human menopausal gonadotropin and human chorionic gonadotropin. Thirty-six follicular fluid containing mature oocyte-corona-cumulus complexes and free of visible blood contamination were included in this study. There was no significant difference in follicular fluid dehydroepiandrosterone sulfate concentration between follicles with oocytes which did or did not fertilize (5.1 +/- 1.1 vs 5.8 +/- 2.0 mumol/l). However, follicular fluid from follicles whose oocytes were not fertilized had levels of cortisol significantly higher than those in follicular fluid from follicles containing successfully fertilized oocytes (406.0 +/- 75.9 vs 339.2 +/- 37.0 nmol/l; p < 0.005). No significant correlations were found between rates of embryo cleavage and cortisol and dehydroepiandrosterone levels in follicular fluid. We conclude that cortisol levels in follicular fluid may provide an index of fertilization outcome, at least in stimulated cycles by clomiphene citrate, human menopausal gonadotropin and human chorionic gonadotropin.
NASA Ames Fluid Mechanics Laboratory research briefs
Davis, Sanford (Editor)
1994-01-01
The Ames Fluid Mechanics Laboratory research program is presented in a series of research briefs. Nineteen projects covering aeronautical fluid mechanics and related areas are discussed and augmented with the publication and presentation output of the Branch for the period 1990-1993.
Supercritical fluids technology. Pt. 1 General topics
International Nuclear Information System (INIS)
Marongiu, B.; De Giorgi, M. R.; Porcedda, S.; Cadoni, E.
1998-01-01
Supercritical fluids technology is among the emerging 'clean' technologies, that allows the minimization in the use of chemical and thermic treatments and products irradiation, diminishing the quantity of liquid wastes to be treated. In this first article phase equilibria thermodynamics and fluid mechanics of transport phenomena are reviewed [it
Appropriate fluid regimens to prevent bronchopulmonary dysplasia.
Tammela, O K
1995-01-01
Pulmonary oedema is an important problem in premature neonates with surfactant deficiency because of fluid accumulation in the lung interstitium and reduced urine output. Some retrospective reports suggest that excessive early hydration might increase the risk of bronchopulmonary dysplasia (BPD). Only three prospective studies evaluating low or conventional fluid administration regimens to very low birth weight infants have been published. According to their results no significant differences in the incidence of BPD have been shown. However, fluid restriction seems to improve the outcome of the infants because of decreased incidence of haemodynamically significant patent ductus arteriosus, necrotizing enterocolitis, pulmonary air leaks and decreased mortality. The appropriate amount of sodium in the intravenous fluids during the first days of life needs further evaluation. In tiny infants with birth weights from 500 to 800g intensive monitoring of fluid balance is essential to control the extremely high fluid losses due to evaporation. Undernutrition is a risk factor of BPD and therefore it is important to start parenteral nutrition early. The benefit of the use of colloids as volume expanders is controversial. According to some retrospective reports there might be an association with increased use of colloidal fluids during the first days of life and the development of BPD. Early excessive fluid administration might constitute a potential risk for low birth weight infants with hyaline membrane disease.(ABSTRACT TRUNCATED AT 250 WORDS)
Byzantine Parthenogenesis as Hierotopy of Fluid Brilliance
DEFF Research Database (Denmark)
Isar, Nicoletta
2014-01-01
Images Borne on Dewy Lightning Byzantine παρθένογένεσις as Hierotopy of Fluid Brilliance......Images Borne on Dewy Lightning Byzantine παρθένογένεσις as Hierotopy of Fluid Brilliance...
The Fluid Foil: The Seventh Simple Machine
Mitts, Charles R.
2012-01-01
A simple machine does one of two things: create a mechanical advantage (lever) or change the direction of an applied force (pulley). Fluid foils are unique among simple machines because they not only change the direction of an applied force (wheel and axle); they convert fluid energy into mechanical energy (wind and Kaplan turbines) or vice versa,…
Cryogenic fluid management program flight concept definition
Kroeger, Erich
1987-01-01
The Lewis Research Center's cryogenic fluid management program flight concept definition is presented in viewgraph form. Diagrams are given of the cryogenic fluid management subpallet and its configuration with the Delta launch vehicle. Information is given in outline form on feasibility studies, requirements definition, and flight experiments design.
Core-shell particles at fluid interfaces
Buchcic, C.
2016-01-01
There is a growing interest in the use of particles as stabilizers for foams and emulsions. Applying hard particles for stabilization of fluid interface is referred to as Pickering stabilization. By using hard particles instead of surfactants and polymers, fluid interfaces can be effectively
MRI of subdural fluid collections in infants
International Nuclear Information System (INIS)
Fukushima, Tsuneyuki; Takagi, Takuji; Nagai, Hajime; Banno, Tatsuo
1988-01-01
Twenty cases of subdural fluid collectioin in infants were examined by MRI (0.5 Tesla). The findings of MRI were classified into 3 groups as follows: Group I: Blood component is observed in the entire subdural fluid (4 cases, 20 %). Group II: Blood component is observed in a part of the subdural fluid (4 cases, 20 %). Group III: Subdural fluid consists of pure CSF (12 cases, 60 %). In general, operative treatment should be considered for cases which have blood components in the subdural space and/or symptoms and signs of increased ICP. In group I, operation was performed on 2 cases (50 %). In group II, subdural fluid collections were associated with dilated subarachnoid spaces and 2 cases were operated on in this group (50 %). In group III, only one case was operated on (8.3 %) and subdural fluid collections disappeared spontaneously in 4 cases of this group. The precise anatomical location of subdural fluid collections could not be decided in several cases even by MRI. The cases which had blood components, tended to demonstrate membranes frequently on MRI. However, the existence of blood components did not affect the DQ S significantly. The prognosis of subdural fluid collection is supposedly related to the degree of preexistent brain damage. (author)
Scale interactions in compressible rotating fluids
Czech Academy of Sciences Publication Activity Database
Feireisl, Eduard; Novotný, A.
2014-01-01
Roč. 193, č. 6 (2014), s. 1703-1725 ISSN 0373-3114 Keywords : compressible fluid * rotating fluid * singular limit Subject RIV: BA - General Mathematics Impact factor: 1.065, year: 2014 http://link.springer.com/article/10.1007%2Fs10231-013-0353-7
Steady laminar flow of fractal fluids
Energy Technology Data Exchange (ETDEWEB)
Balankin, Alexander S., E-mail: abalankin@ipn.mx [Grupo Mecánica Fractal, ESIME, Instituto Politécnico Nacional, México D.F., 07738 (Mexico); Mena, Baltasar [Laboratorio de Ingeniería y Procesos Costeros, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Sisal, Yucatán, 97355 (Mexico); Susarrey, Orlando; Samayoa, Didier [Grupo Mecánica Fractal, ESIME, Instituto Politécnico Nacional, México D.F., 07738 (Mexico)
2017-02-12
We study laminar flow of a fractal fluid in a cylindrical tube. A flow of the fractal fluid is mapped into a homogeneous flow in a fractional dimensional space with metric induced by the fractal topology. The equations of motion for an incompressible Stokes flow of the Newtonian fractal fluid are derived. It is found that the radial distribution for the velocity in a steady Poiseuille flow of a fractal fluid is governed by the fractal metric of the flow, whereas the pressure distribution along the flow direction depends on the fractal topology of flow, as well as on the fractal metric. The radial distribution of the fractal fluid velocity in a steady Couette flow between two concentric cylinders is also derived. - Highlights: • Equations of Stokes flow of Newtonian fractal fluid are derived. • Pressure distribution in the Newtonian fractal fluid is derived. • Velocity distribution in Poiseuille flow of fractal fluid is found. • Velocity distribution in a steady Couette flow is established.
Fast fluid registration of medical images
DEFF Research Database (Denmark)
Bro-Nielsen, Morten; Gramkow, Claus
1996-01-01
This paper offers a new fast algorithm for non-rigid viscous fluid registration of medical images that is at least an order of magnitude faster than the previous method by (Christensen et al., 1994). The core algorithm in the fluid registration method is based on a linear elastic deformation...
Capacitive system detects and locates fluid leaks
1966-01-01
Electronic monitoring system automatically detects and locates minute leaks in seams of large fluid storage tanks and pipelines covered with thermal insulation. The system uses a capacitive tape-sensing element that is adhesively bonded over seams where fluid leaks are likely to occur.
On the fluid mechanics of bilabial plosives
Pelorson, X.; Hofmans, G.C.J.; Ranucci, M.; Bosch, R.C.M.
1997-01-01
In this paper we present a review of some fluid mechanical phenomena involved in bilabial plosive sound production. As a basis for further discussion, firstly an in vivo experimental set-up is described. The order of magnitude of some important geometrical and fluid dynamical quantities is
Technical fluid dynamics. 7. rev. ed.
International Nuclear Information System (INIS)
Becker, E.; Piltz, E.
1993-01-01
An introductory textbook for students of engineering containing the following subjects: Definition and properties of fluids, hydrostatics, Bernoulli's equation, theorem of momentum for steadystate flows, wing lattice and single wing, plane parallel flow of a viscous fluid, pipe flow, boundary layers, gas flows. (orig.) [de
The Imperfect Fluid behind Kinetic Gravity Braiding
Pujolas, Oriol; Vikman, Alexander
2011-01-01
We present a standard hydrodynamical description for non-canonical scalar field theories with kinetic gravity braiding. In particular, this picture applies to the simplest galileons and k-essence. The fluid variables not only have a clear physical meaning but also drastically simplify the analysis of the system. The fluid carries charges corresponding to shifts in field space. This shift-charge current contains a spatial part responsible for diffusion of the charges. Moreover, in the incompressible limit, the equation of motion becomes the standard diffusion equation. The fluid is indeed imperfect because the energy flows neither along the field gradient nor along the shift current. The fluid has zero vorticity and is not dissipative: there is no entropy production, the energy-momentum is exactly conserved, the temperature vanishes and there is no shear viscosity. Still, in an expansion around a perfect fluid one can identify terms which correct the pressure in the manner of bulk viscosity. We close by formul...
Tribodynamic Modeling of Digital Fluid Power Motors
DEFF Research Database (Denmark)
Johansen, Per
. In fluid power motoring and pumping units, a significant problem is that loss mechanisms do not scale down with diminishing power throughput. Although machines can reach peak efficiencies above 95%, the actual efficiency during operation, which includes part-load situations, is much lower. The invention...... of digital fluid power displacement units has been able to address this problem. The main idea of the digital fluid power displacement technology is to disable individual chambers, by use of electrical actuated valves. A displacement chamber is disabled by keeping the valve, between the chamber and the low...... design methods and tools are important to the development of digital fluid power machines. The work presented in this dissertation is part of a research program focusing on the development of digital fluid power MW-motors for use in hydraulic drive train in wind turbines. As part of this development...
Fluid-bed process for SYNROC production
International Nuclear Information System (INIS)
Ackerman, F.J.; Grens, J.Z.; Ryerson, F.J.; Hoenig, C.L.; Bazan, F.; Peters, P.E.; Smith, R.; Campbell, J.H.
1983-01-01
SYNROC is a titanate-based ceramic waste developed for the immobilization of high-level nuclear reactor waste. Lawrence Livermore National Laboratory (LLNL) has investigated a fluid-bed technique for the large-scale production of SYNROC precursor powders. Making SYNROC in a fluid bed permits slurry drying, calcination and reduction-oxidation reactions to be carried out in a single unit. We present the results of SYNROC fluid-bed studies from two fluid-bed units 10 cm in diameter: an internally heated fluid-bed unit developed by Exxon Idaho and an externally heated unit constructed at LLNL. Bed operation over a range of temperatures, feed rates, fluidizing rates, and redox conditions indicate that SYNROC powders of a high density and a uniform particle size can be produced. These powders facilitate the densification step and yield dense ceramics (greater than 95% theoretical density) with well-developed phases and low leaching rates
Phase space density representations in fluid dynamics
International Nuclear Information System (INIS)
Ramshaw, J.D.
1989-01-01
Phase space density representations of inviscid fluid dynamics were recently discussed by Abarbanel and Rouhi. Here it is shown that such representations may be simply derived and interpreted by means of the Liouville equation corresponding to the dynamical system of ordinary differential equations that describes fluid particle trajectories. The Hamiltonian and Poisson bracket for the phase space density then emerge as immediate consequences of the corresponding structure of the dynamics. For barotropic fluids, this approach leads by direct construction to the formulation presented by Abarbanel and Rouhi. Extensions of this formulation to inhomogeneous incompressible fluids and to fluids in which the state equation involves an additional transported scalar variable are constructed by augmenting the single-particle dynamics and phase space to include the relevant additional variable
Fluid mechanics in the perivascular space.
Wang, Peng; Olbricht, William L
2011-04-07
Perivascular space (PVS) within the brain is an important pathway for interstitial fluid (ISF) and solute transport. Fluid flowing in the PVS can affect these transport processes and has significant impacts on physiology. In this paper, we carry out a theoretical analysis to investigate the fluid mechanics in the PVS. With certain assumptions and approximations, we are able to find an analytical solution to the problem. We discuss the physical meanings of the solution and particularly examine the consequences of the induced fluid flow in the context of convection-enhanced delivery (CED). We conclude that peristaltic motions of the blood vessel walls can facilitate fluid and solute transport in the PVS. Copyright © 2011 Elsevier Ltd. All rights reserved.
Endoscopic management of peripancreatic fluid collections.
Goyal, Jatinder; Ramesh, Jayapal
2015-07-01
Peripancreatic fluid collections are a well-known complication of pancreatitis and can vary from fluid-filled collections to entirely necrotic collections. Although most of the fluid-filled pseudocysts tend to resolve spontaneously with conservative management, intervention is necessary in symptomatic patients. Open surgery has been the traditional treatment modality of choice though endoscopic, laparoscopic and transcutaneous techniques offer alternative drainage approaches. During the last decade, improvement in endoscopic ultrasound technology has enabled real-time access and drainage of fluid collections that were previously not amenable to blind transmural drainage. This has initiated a trend towards use of this modality for treatment of pseudocysts. In this review, we have summarised the existing evidence for endoscopic drainage of peripancreatic fluid collections from published studies.
Single-particle Schroedinger fluid. I. Formulation
International Nuclear Information System (INIS)
Kan, K.K.; Griffin, J.J.
1976-01-01
The problem of a single quantal particle moving in a time-dependent external potential well is formulated specifically to emphasize and develop the fluid dynamical aspects of the matter flow. This idealized problem, the single-particle Schroedinger fluid, is shown to exhibit already a remarkably rich variety of fluid dynamical features, including compressible flow and line vortices. It provides also a sufficient framework to encompass simultaneously various simplified fluidic models for nuclei which have earlier been postulated on an ad hoc basis, and to illuminate their underlying restrictions. Explicit solutions of the single-particle Schroedinger fluid problem are studied in the adiabatic limit for their mathematical and physical implications (especially regarding the collective kinetic energy). The basic generalizations for extension of the treatment to the many-body Schroedinger fluid are set forth
Fluid dynamics theory, computation, and numerical simulation
Pozrikidis, C
2001-01-01
Fluid Dynamics Theory, Computation, and Numerical Simulation is the only available book that extends the classical field of fluid dynamics into the realm of scientific computing in a way that is both comprehensive and accessible to the beginner The theory of fluid dynamics, and the implementation of solution procedures into numerical algorithms, are discussed hand-in-hand and with reference to computer programming This book is an accessible introduction to theoretical and computational fluid dynamics (CFD), written from a modern perspective that unifies theory and numerical practice There are several additions and subject expansions in the Second Edition of Fluid Dynamics, including new Matlab and FORTRAN codes Two distinguishing features of the discourse are solution procedures and algorithms are developed immediately after problem formulations are presented, and numerical methods are introduced on a need-to-know basis and in increasing order of difficulty Matlab codes are presented and discussed for a broad...
Fluid mechanics a geometrical point of view
Rajeev, S G
2018-01-01
Fluid Mechanics: A Geometrical Point of View emphasizes general principles of physics illustrated by simple examples in fluid mechanics. Advanced mathematics (e.g., Riemannian geometry and Lie groups) commonly used in other parts of theoretical physics (e.g. General Relativity or High Energy Physics) are explained and applied to fluid mechanics. This follows on from the author's book Advanced Mechanics (Oxford University Press, 2013). After introducing the fundamental equations (Euler and Navier-Stokes), the book provides particular cases: ideal and viscous flows, shocks, boundary layers, instabilities, and transients. A restrained look at integrable systems (KdV) leads into a formulation of an ideal fluid as a hamiltonian system. Arnold's deep idea, that the instability of a fluid can be understood using the curvature of the diffeomorphism group, will be explained. Leray's work on regularity of Navier-Stokes solutions, and the modern developments arising from it, will be explained in language for physicists...
Bubble dynamics equations in Newton fluid
International Nuclear Information System (INIS)
Xiao, J
2008-01-01
For the high-speed flow of Newton fluid, bubble is produced and expanded when it moves toward the surface of fluid. Bubble dynamics is a very important research field to understand the intrinsic feature of bubble production and motion. This research formulates the bubble expansion by expansion-local rotation transformation, which can be calculated by the measured velocity field. Then, the related dynamic equations are established to describe the interaction between the fluid and the bubble. The research shows that the bubble production condition can be expressed by critical vortex value and fluid pressure; and the bubble expansion rate can be obtained by solving the non-linear dynamic equation of bubble motion. The results may help the related research as it shows a special kind of fluid motion in theoretic sense. As an application example, the nanofiber radium-voltage relation and threshold voltage-surface tension relation in electrospinning process are discussed
Fluid structure interaction in tube bundles
International Nuclear Information System (INIS)
Brochard, D.; Jedrzejewski, F.; Gibert, R.J.
1995-01-01
A lot of industrial components contain tube bundles immersed in a fluid. The mechanical analysis of such systems requires the study of the fluid structure interaction in the tube bundle. Simplified methods, based on homogenization methods, have been developed to analyse such phenomenon and have been validated through experimental results. Generally, these methods consider only the fluid motion in a plan normal to the bundle axis. This paper will analyse, in a first part, the fluid structure interaction in a tube bundle through a 2D finite element model representing the bundle cross section. The influence of various parameters like the bundle size, and the bundle confinement will be studied. These results will be then compared with results from homogenization methods. Finally, the influence of the 3D fluid motion will be investigated, in using simplified methods. (authors). 11 refs., 12 figs., 2 tabs
Fluid Effects in Polymers and Polymeric Composites
Weitsman, Y Jack
2012-01-01
Fluid Effects in Polymers and Polymeric Composites, written by the late Dr. Y. Jack Weitsman, addresses the wide range of parameters that affect the interaction of fluids with polymers and polymeric composites. The book aims at broadening the scope of available data, mostly limited up to this time to weight-gain recordings of fluid ingress into polymers and composites, to the practical circumstances of fluctuating exposure. Various forms of experimental data are given, in conjunction with theoretical models derived from basic scientific principles, and correlated with severity of exposure conditions and interpreted by means of rationally based theoretical models. The practical implications of the effects of fluids are discussed. The issue of fluid effects on polymers and polymeric composites is of concern to engineers and scientists active in aerospace and naval structures, as an increasing portion of these structures are made of polymeric composites and employ polymeric adhesives as a joining device. While...
FORMATE-BASED FLUIDS: FORMULATION AND APPLICATION
Directory of Open Access Journals (Sweden)
Nediljka Gaurina-Međimurec
2008-12-01
Full Text Available Formate-based fluids has been successfully used in over hunders HPHT well operations since they introduced in field practice. They have many advantages when compared with conventional HPHT drilling and completion fluids such as: minimal formation damage, maintenance of additve properties at high temperatures, reduced hydraulic flow resistance, low potential for differential sticking, naturally lubricating, very low corrosion rates, biodegradable and pose little risk to the environment etc. Formate-based fluids can be applied during deep slim hole drilling, shale drilling, reservoir drilling, salt and gas hydrate formations drilling. The laboratory research was carried out to evaluate the rheological behavior of formate-based fluids as a function of temperature. Formate-based fluids were formulated using potassium formate brine, xanthan polymer, PAC, starch and calcium carbonate. Experimental results show that potassium formate improves the thermal stability of polymers.
Bifurcated SEN with Fluid Flow Conditioners
Directory of Open Access Journals (Sweden)
F. Rivera-Perez
2014-01-01
Full Text Available This work evaluates the performance of a novel design for a bifurcated submerged entry nozzle (SEN used for the continuous casting of steel slabs. The proposed design incorporates fluid flow conditioners attached on SEN external wall. The fluid flow conditioners impose a pseudosymmetric pattern in the upper zone of the mold by inhibiting the fluid exchange between the zones created by conditioners. The performance of the SEN with fluid flow conditioners is analyzed through numerical simulations using the CFD technique. Numerical results were validated by means of physical simulations conducted on a scaled cold water model. Numerical and physical simulations confirmed that the performance of the proposed SEN is superior to a traditional one. Fluid flow conditioners reduce the liquid free surface fluctuations and minimize the occurrence of vortexes at the free surface.
Annual review of fluid mechanics. Volume 23
International Nuclear Information System (INIS)
Lumley, J.L.; Van Dyke, M.; Reed, H.L.
1991-01-01
Recent advances in theoretical, experimental, and computational fluid mechanics are discussed in a collection of annual review essays. Topics addressed include Lagrangian ocean studies, drag reduction in nature, the hydraulics of rotating strait and sill flow, analytical methods for the development of Reynolds-stress closures in turbulence, and exact solutions of the Navier-Stokes equations. Consideration is given to the theory of hurricanes, flow phenomena in CVD of thin films, particle-imaging techniques for experimental fluid mechanics, symmetry and symmetry-breaking bifurcations in fluid dynamics, turbulent mixing in stratified fluids, numerical simulation of transition in wall-bounded shear flows, fractals and multifractals in fluid turbulence, and coherent motions in the turbulent boundary layer
Fluid Dynamics Theory, Computation, and Numerical Simulation
Pozrikidis, Constantine
2009-01-01
Fluid Dynamics: Theory, Computation, and Numerical Simulation is the only available book that extends the classical field of fluid dynamics into the realm of scientific computing in a way that is both comprehensive and accessible to the beginner. The theory of fluid dynamics, and the implementation of solution procedures into numerical algorithms, are discussed hand-in-hand and with reference to computer programming. This book is an accessible introduction to theoretical and computational fluid dynamics (CFD), written from a modern perspective that unifies theory and numerical practice. There are several additions and subject expansions in the Second Edition of Fluid Dynamics, including new Matlab and FORTRAN codes. Two distinguishing features of the discourse are: solution procedures and algorithms are developed immediately after problem formulations are presented, and numerical methods are introduced on a need-to-know basis and in increasing order of difficulty. Matlab codes are presented and discussed for ...
Fluid Structure Interaction for Hydraulic Problems
International Nuclear Information System (INIS)
Souli, Mhamed; Aquelet, Nicolas
2011-01-01
Fluid Structure interaction plays an important role in engineering applications. Physical phenomena such as flow induced vibration in nuclear industry, fuel sloshing tank in automotive industry or rotor stator interaction in turbo machinery, can lead to structure deformation and sometimes to failure. In order to solve fluid structure interaction problems, the majority of numerical tests consists in using two different codes to separately solve pressure of the fluid and structural displacements. In this paper, a unique code with an ALE formulation approach is used to implicitly calculate the pressure of an incompressible fluid applied to the structure. The development of the ALE method as well as the coupling in a computational structural dynamic code, allows to solve more large industrial problems related to fluid structure coupling. (authors)
Minimizing the Fluid Used to Induce Fracturing
Boyle, E. J.
2015-12-01
The less fluid injected to induce fracturing means less fluid needing to be produced before gas is produced. One method is to inject as fast as possible until the desired fracture length is obtained. Presented is an alternative injection strategy derived by applying optimal system control theory to the macroscopic mass balance. The picture is that the fracture is constant in aperture, fluid is injected at a controlled rate at the near end, and the fracture unzips at the far end until the desired length is obtained. The velocity of the fluid is governed by Darcy's law with larger permeability for flow along the fracture length. Fracture growth is monitored through micro-seismicity. Since the fluid is assumed to be incompressible, the rate at which fluid is injected is balanced by rate of fracture growth and rate of loss to bounding rock. Minimizing injected fluid loss to the bounding rock is the same as minimizing total injected fluid How to change the injection rate so as to minimize the total injected fluid is a problem in optimal control. For a given total length, the variation of the injected rate is determined by variations in overall time needed to obtain the desired fracture length, the length at any time, and the rate at which the fracture is growing at that time. Optimal control theory leads to a boundary condition and an ordinary differential equation in time whose solution is an injection protocol that minimizes the fluid used under the stated assumptions. That method is to monitor the rate at which the square of the fracture length is growing and adjust the injection rate proportionately.
Aviator's Fluid Balance During Military Flight.
Levkovsky, Anna; Abot-Barkan, Sivan; Chapnik, Leah; Doron, Omer; Levy, Yuval; Heled, Yuval; Gordon, Barak
2018-02-01
A loss of 1% or more of bodyweight due to dehydration has a negative effect on cognitive performance, which could critically affect flight safety. There is no mention in the literature concerning the amounts of military pilots' fluid loss during flight. The aim of this study was to quantify fluid loss of pilots during military flight. There were 48 aviators (mean age 23.9) from the Israeli Air Force who participated in the study, which included 104 training flights in various flight platforms. Bodyweight, urine specific gravity, and environmental heat strain were measured before and after each flight. Fluid loss was calculated as the weight differences before and after the flight. We used a univariate and one-way ANOVA to analyze the effect of different variables on the fluid loss. The mean fluid loss rate was 462 ml · h-1. The results varied among different aircraft platforms and depended on flight duration. Blackhawk pilots lost the highest amount of fluids per flight, albeit had longer flights (mean 108 min compared to 35.5 in fighter jets). Jet fighter pilots had the highest rate of fluid loss per hour of flight (up to 692 ml, extrapolated). Overall, at 11 flights (11%) aircrew completed their flight with a meaningful fluid loss. We conclude that military flights may be associated with significant amount of fluid loss among aircrew.Levkovsky A, Abot-Barkan S, Chapnik L, Doron O, Levy Y, Heled Y, Gordon B. Aviator's fluid balance during military flight. Aerosp Med Hum Perform. 2018; 89(2):9498.
Viscoelastic gravel-pack carrier fluid
International Nuclear Information System (INIS)
Nehmer, W.L.
1988-01-01
The ability of a fluid to flow adequately into the formation during gravel-pack treatments is critical to achieving a good pack. Recent studies have indicated ''fish-eyes'' and/or ''microgels'' present in many polymer gelled carrier fluids will plug pore throats, leading to impaired leakoff and causing formation damage. Intensive manipulation of the polymer gelled fluid using shear and filter devices will help remove the particles, but it adds to the cost of the treatment in terms of equipment and manpower. Excessive shear will degrade the polymer leading to poor gravel suspension, while too little shear will cause filtration problems. A gelled carried fluid using a viscoelastic surfactant system has been found to leak off very efficiently to the formation, and cause no formation damage, without the use of shear/filter devices. Viscoelastic surfactant-base gelled fluids develop viscosity because of the association of surfactant moloecules into large rod-shaped aggregates. There is no hydration of polymer involved, so fish-eyes and microgels will not be formed in the viscoelastic fluid. A surfactant-base system having a yield point allows the gravel carrying properties to be much better than fluids gelled with conventional polymer systems (hydroxyethylcellulose [HEC]). For example, a gravel carried fluid gelled with 80 lb HEC/1,000 gal has a viscosity of about 400 cp at 170 sec/sup -1/; a viscoelastic surfactant-base system having only one-half the viscosity still flows into cores about four times more efficiently than the HEC-base fluid. The rheology, leakoff, formation damage and mixing properties of a viscoelastic, surfactant-base, gravel-pack carrier fluid are discussed
Rigid Body Sampling and Individual Time Stepping for Rigid-Fluid Coupling of Fluid Simulation
Directory of Open Access Journals (Sweden)
Xiaokun Wang
2017-01-01
Full Text Available In this paper, we propose an efficient and simple rigid-fluid coupling scheme with scientific programming algorithms for particle-based fluid simulation and three-dimensional visualization. Our approach samples the surface of rigid bodies with boundary particles that interact with fluids. It contains two procedures, that is, surface sampling and sampling relaxation, which insures uniform distribution of particles with less iterations. Furthermore, we present a rigid-fluid coupling scheme integrating individual time stepping to rigid-fluid coupling, which gains an obvious speedup compared to previous method. The experimental results demonstrate the effectiveness of our approach.
Prevalence, extension and characteristics of fluid-fluid levels in bone and soft tissue tumors
Energy Technology Data Exchange (ETDEWEB)
Dyck, P. van; Venstermans, C.; Gielen, J.; Parizel, P.M. [University Hospital Antwerp, Department of Radiology, Edegem (Belgium); Vanhoenacker, F.M. [University Hospital Antwerp, Department of Radiology, Edegem (Belgium); AZ St-Maarten, Department of Radiology, Duffel/Mechelen (Belgium); Vogel, J. [Leiden University Medical Centre, Department of Orthopedics, Leiden (Netherlands); Kroon, H.M.; Bloem, J.L. [Leiden University Medical Centre, Department of Radiology, Leiden (Netherlands); Schepper, A.M.A. de [University Hospital Antwerp, Department of Radiology, Edegem (Belgium); Leiden University Medical Centre, Department of Radiology, Leiden (Netherlands)
2006-12-15
The purpose of this study was to determine the prevalence, extension and signal characteristics of fluid-fluid levels in a large series of 700 bone and 700 soft tissue tumors. Out of a multi-institutional database, MRI of 700 consecutive patients with a bone tumor and MRI of 700 consecutive patients with a soft tissue neoplasm were retrospectively reviewed for the presence of fluid-fluid levels. Extension (single, multiple and proportion of the lesion occupied by fluid-fluid levels) and signal characteristics on magnetic resonance imaging of fluid-fluid levels were determined. In all patients, pathologic correlation was available. Of 700 patients with a bone tumor, 19 (10 male and 9 female; mean age, 29 years) presented with a fluid-fluid level (prevalence 2.7%). Multiple fluid-fluid levels occupying at least one half of the total volume of the lesion were found in the majority of patients. Diagnoses included aneurysmal bone cyst (ten cases), fibrous dysplasia (two cases), osteoblastoma (one case), simple bone cyst (one case), telangiectatic osteosarcoma (one case), ''brown tumor'' (one case), chondroblastoma (one case) and giant cell tumor (two cases). Of 700 patients with a soft tissue tumor, 20 (9 males and 11 females; mean age, 34 years) presented with a fluid-fluid level (prevalence 2.9%). Multiple fluid-fluid levels occupying at least one half of the total volume of the lesion were found in the majority of patients. Diagnoses included cavernous hemangioma (12 cases), synovial sarcoma (3 cases), angiosarcoma (1 case), aneurysmal bone cyst of soft tissue (1 case), myxofibrosarcoma (1 case) and high-grade sarcoma ''not otherwise specified'' (2 cases). In our series, the largest reported in the literature to the best of our knowledge, the presence of fluid-fluid levels is a rare finding with a prevalence of 2.7 and 2.9% in bone and soft tissue tumors, respectively. Fluid-fluid levels remain a non-specific finding and can
Joseph, Daniel D
1976-01-01
The study of stability aims at understanding the abrupt changes which are observed in fluid motions as the external parameters are varied. It is a demanding study, far from full grown"whose most interesting conclusions are recent. I have written a detailed account of those parts of the recent theory which I regard as established. Acknowledgements I started writing this book in 1967 at the invitation of Clifford Truesdell. It was to be a short work on the energy theory of stability and if I had stuck to that I would have finished the writing many years ago. The theory of stability has developed so rapidly since 1967 that the book I might then have written would now have a much too limited scope. I am grateful to Truesdell, not so much for the invitation to spend endless hours of writing and erasing, but for the generous way he has supported my efforts and encouraged me to higher standards of good work. I have tried to follow Truesdell's advice to write this work in a clear and uncomplicated style. This is not ...
Mesoscale Models of Fluid Dynamics
Boghosian, Bruce M.; Hadjiconstantinou, Nicolas G.
During the last half century, enormous progress has been made in the field of computational materials modeling, to the extent that in many cases computational approaches are used in a predictive fashion. Despite this progress, modeling of general hydrodynamic behavior remains a challenging task. One of the main challenges stems from the fact that hydrodynamics manifests itself over a very wide range of length and time scales. On one end of the spectrum, one finds the fluid's "internal" scale characteristic of its molecular structure (in the absence of quantum effects, which we omit in this chapter). On the other end, the "outer" scale is set by the characteristic sizes of the problem's domain. The resulting scale separation or lack thereof as well as the existence of intermediate scales are key to determining the optimal approach. Successful treatments require a judicious choice of the level of description which is a delicate balancing act between the conflicting requirements of fidelity and manageable computational cost: a coarse description typically requires models for underlying processes occuring at smaller length and time scales; on the other hand, a fine-scale model will incur a significantly larger computational cost.
Principles of computational fluid dynamics
International Nuclear Information System (INIS)
Wesseling, P.
2001-01-01
The book is aimed at graduate students, researchers, engineers and physicists involved in flow computations. An up-to-date account is given of the present state- of-the-art of numerical methods employed in computational fluid dynamics. The underlying numerical principles are treated with a fair amount of detail, using elementary mathematical analysis. Attention is given to difficulties arising from geometric complexity of the flow domain and of nonuniform structured boundary-fitted grids. Uniform accuracy and efficiency for singular perturbation problems is studied, pointing the way to accurate computation of flows at high Reynolds number. Much attention is given to stability analysis, and useful stability conditions are provided, some of them new, for many numerical schemes used in practice. Unified methods for compressible and incompressible flows are discussed. Numerical analysis of the shallow-water equations is included. The theory of hyperbolic conservation laws is treated. Godunov's order barrier and how to overcome it by means of slope-limited schemes is discussed. An introduction is given to efficient iterative solution methods, using Krylov subspace and multigrid acceleration. Many pointers are given to recent literature, to help the reader to quickly reach the current research frontier. (orig.)
Cerebrospinal fluid circulation and hydrocephalus.
Leinonen, Ville; Vanninen, Ritva; Rauramaa, Tuomas
2017-01-01
Hydrocephalus (HC) is classically defined as dynamic imbalance between the production and absorption of cerebrospinal fluid (CSF) leading to enlarged ventricles. Potential causative factors include various brain disorders like tumors causing obstruction of CSF flow within the ventricular system or the subarachnoid space. Classification of HC is based on the site of CSF flow obstruction guiding optimal treatment, with endoscopic third ventriculostomy in intraventricular obstruction and CSF shunt in communicating HC. Another clinically relevant classification is acute and chronic; the most frequent chronic form is idiopathic normal-pressure hydrocephalus (iNPH). The reported incidence of HC varies according to the study population and classification used. The incidence of congenital HC is approximately 0.4-0.6/1,000 newborns and the annual incidence of iNPH varies from 0.5/100,000 to 5.5/100,000. Radiologically, ventricular dilatation may be nonspecific, and differentiation of iNPH from other neurodegenerative diseases may be ambiguous. There are no known specific microscopic findings of HC but a systematic neuropathologic examination is needed to detect comorbid diseases and possible etiologic factors of HC. Depending on the etiology of HC, there are several nonspecific signs potentially to be seen. Copyright © 2017 Elsevier B.V. All rights reserved.
Bulk viscosity of molecular fluids
Jaeger, Frederike; Matar, Omar K.; Müller, Erich A.
2018-05-01
The bulk viscosity of molecular models of gases and liquids is determined by molecular simulations as a combination of a dilute gas contribution, arising due to the relaxation of internal degrees of freedom, and a configurational contribution, due to the presence of intermolecular interactions. The dilute gas contribution is evaluated using experimental data for the relaxation times of vibrational and rotational degrees of freedom. The configurational part is calculated using Green-Kubo relations for the fluctuations of the pressure tensor obtained from equilibrium microcanonical molecular dynamics simulations. As a benchmark, the Lennard-Jones fluid is studied. Both atomistic and coarse-grained force fields for water, CO2, and n-decane are considered and tested for their accuracy, and where possible, compared to experimental data. The dilute gas contribution to the bulk viscosity is seen to be significant only in the cases when intramolecular relaxation times are in the μs range, and for low vibrational wave numbers (<1000 cm-1); This explains the abnormally high values of bulk viscosity reported for CO2. In all other cases studied, the dilute gas contribution is negligible and the configurational contribution dominates the overall behavior. In particular, the configurational term is responsible for the enhancement of the bulk viscosity near the critical point.
Fluid dynamics of Ribbed Annuli
International Nuclear Information System (INIS)
McCreery, G. E.; Pink, R. J.; Condie, K. G.; McEligot, D. M.
2003-01-01
Typical advanced gas-cooled reactor designs use periodic spacer ribs to center rods in circular cooling channels, e.g., as for control rods (General Atomics and others) and fuel rods (HTTR). In contrast to classical studies of axisymmetric annuli, the flow becomes three-dimensional but is typically periodic in the circumferential direction and - in some cases - in the streamwise direction. Fundamental measurements have been obtained for two idealizations of these complex geometries: an annulus with three ribs circumferentially and one with four. Laser Doppler Velocimetry (LDV) was employed with INEEL's unique Matched-Index-of-Refraction (MIR) flow facility to determine the velocity and turbulence fields. The initial experiment was aimed at obtaining benchmark data to test the capabilities of CFD (Computational Fluid Dynamics) codes to handle ribbed annular geometries without the complications of turbulent transport. The Reynolds number was about 1120. These conditions correspond to some stages during a pressurized cooldown (LOFA) event. Power spectral densities were obtained to determine the eddy shedding frequency downstream of the ribs. For the second experiment LDV measurements were obtained in another ribbed-annular model at a higher flow rate. For this nominally turbulent flow, evidence of laminarization appears in the flow converging to pass between ribs. The measurements indicated flow details which could be useful for assessment of CFD codes
Fluid mechanics of environmental interfaces
Gualtieri, Carlo
2012-01-01
Preface Preface of the first editionBiographies of the authors Part one - Preliminaries1. Environmental fluid mechanics: Current issues and future outlook B. Cushman-Roisin, C. Gualtieri & D.T. MihailovicPart two - Processes at atmospheric interfaces2. Point source atmospheric diffusionB. Rajkovic, I. Arsenic & Z. Grsic3. Air-sea interaction V. Djurdjevic & B. Rajkovic4. Modelling of flux exchanges between heterogeneous surfaces and atmosphere D.T. Mihailovic & D. Kapor5. Desert dust uptake-transport and deposition mechanisms - impacts of dust on radiation, clouds and precipitation G. Kallos, P. Katsafados & C. SpyrouPart three - Processes at water interfaces6. Gas-transfer at unsheared free-surfaces C. Gualtieri & G. Pulci Doria7. Advective diffusion of air bubbles in turbulent water flows H. Chanson8. Exchanges at the bed sediments-water column interface F.A. Bombardelli & P.A. Moreno9. Surface water and streambed sediment interaction: The hyporheic exchange D. Tonina10. Environm...
Supercritical fluid extraction of hops
Directory of Open Access Journals (Sweden)
ZORAN ZEKOVIC
2007-01-01
Full Text Available Five cultivars of hop were extracted by the method of supercritical fluid extraction using carbon dioxide (SFE–CO2 as extractant. The extraction (50 g of hop sample using a CO2 flow rate of 97.725 L/h was done in the two steps: 1. extraction at 150 bar and 40°C for 2.5 h (sample of series A was obtained and, after that, the same sample of hop was extracted in the second step: 2. extraction at 300 bar and 40 °C for 2.5 h (sample of series B was obtained. The Magnum cultivar was chosen for the investigation of the extraction kinetics. For the qualitative and quantitative analysis of the obtained hop extracts, the GC-MS method was used. Two of four themost common compounds of hop aroma (a-humulene and b-caryophyllene were detected in samples of series A. In addition, isomerized a-acids and a high content of b-acids were detected. The a-acids content in the samples of series B was the highest in the extract of the Magnum cultivar (it is a bitter variety of hop. The low contents of a-acids in all the other hop samples resulted in extracts with low a-acids content, i.e., that contents were under the prescribed a-acids content.
Heat exchanger with intermediate evaporating and condensing fluid
International Nuclear Information System (INIS)
Fraas, A.P.
1978-01-01
A shell and tube-type heat exchanger, such as a liquid sodium-operated steam generator for use in nuclear reactors, comprises a shell containing a primary fluid tube bundle, a secondary fluid tube bundle at higher elevation, and an intermediate fluid vaporizing at the surface of the primary fluid tubes and condensing at the surface of the secondary fluid tubes
Design guide for calculating fluid damping for circular cylindrical structures
International Nuclear Information System (INIS)
Chen, S.S.
1983-06-01
Fluid damping plays an important role for structures submerged in fluid, subjected to flow, or conveying fluid. This design guide presents a summary of calculational procedures and design data for fluid damping for circular cylinders vibrating in quiescent fluid, crossflow, and parallel flow
Working fluid selection for organic Rankine cycles - Impact of uncertainty of fluid properties
DEFF Research Database (Denmark)
Frutiger, Jerome; Andreasen, Jesper Graa; Liu, Wei
2016-01-01
of processmodels and constraints 2) selection of property models, i.e. Penge Robinson equation of state 3)screening of 1965 possible working fluid candidates including identification of optimal process parametersbased on Monte Carlo sampling 4) propagating uncertainty of fluid parameters to the ORC netpower output......This study presents a generic methodology to select working fluids for ORC (Organic Rankine Cycles)taking into account property uncertainties of the working fluids. A Monte Carlo procedure is described as a tool to propagate the influence of the input uncertainty of the fluid parameters on the ORC....... The net power outputs of all the feasible working fluids were ranked including their uncertainties. The method could propagate and quantify the input property uncertainty of the fluidproperty parameters to the ORC model, giving an additional dimension to the fluid selection process. In the given analysis...
XXII Fluid Mechanics Conference (KKMP2016)
International Nuclear Information System (INIS)
2016-01-01
This Journal of Physics: Conference Series contains papers that have been presented at XXII Fluid Mechanics Conference (XXII FMC) held in Słok near Bełchatów in Poland during llth-14th September of 2016. The Conference is organized by Wrocław University of Science and Technology, Polish Academy of Sciences - Committee of Mechanics and Foun-dation for Development of Wroclaw University of Science and Technology. Let us recall some historical facts: Fluid Mechanics Conferences have been taking place every two years since 1974, which makes a total of forty-two years. The goal of this conference is to provide a forum for exposure and exchange of ideas, methods and results in fluid mechanics. We have already met in Bełchatów 10 years ago (XVII KKMP). It was a successful meeting. Since then the National Conference on Fluid Mechanics has changed title and has started to be named Fluid Mechanics Conference in the hopes that it will attract more participants from other countries. English became the Conference's first language and we started to invite world leading scientists - working in the field of fluid mechanics. At the 2006 conference we hosted for the first time prof. Keith Moffatt from the Cambridge University. In this year prof. Moffatt once again promised us to arrive to Bełchatów. The whole fluid mechanics community celebrates 9 2 anniversary of his birthday. So let us also wish happy anniversary to prof. Moffatt. In the mean time we had to pay last respects to our collages. Prof. Prosnak who is regarded as a founder of the Notational Conference on Fluid Mechanics and is well known through his books. Prof. Puzyrewski who was present at all conferences so far. He was providing via his discussions a special value to these conferences, and our colleague prof. Konrad Bajer who was intended to be the organizer and host of the present conference. Short memories to them will be given during the opening ceremony. Conference topics include, but are not limited
Experimental investigation of non-Newtonian droplet collisions : the role of extensional viscosity
Finotello, Giulia; De, Shauvik; Vrouwenvelder, Jeroen C.R.; Padding, J.T.; Buist, Kay A.; Jongsma, Alfred; Innings, Fredrik; Kuipers, J.
2018-01-01
We investigate the collision behaviour of a shear thinning non-Newtonian fluid xanthan, by binary droplet collision experiments. Droplet collisions of non-Newtonian fluids are more complex than their Newtonian counterpart as the viscosity no longer remains constant during the collision process.
Magnelok technology: a complement to magnetorheological fluids
Carlson, J. David
2004-07-01
Magnetorheological or MR fluids have been successfully used to enable highly effective semi-active control systems in automobile primary suspensions to control unwanted motions in civil engineering structures and to provide force-feedback in steer-by-wire systems. A key to the successful use of MR fluids is an appreciation and understanding of the balance and trade-off between the magnetically controlled on-state force and the ever-present off-state viscous force. In all MR fluid applications, one must deal with the fact that MR fluids never fully decouple or go to zero force in their off-state. Magnelok devices are a magnetically controlled compliment to traditional MR fluid devices that have been developed to enable a true force decoupling in the off-state. Magnelok devices may be embodied as linear or rotary dampers, brakes, lockable struts or position holding devices. They are particularly suitable for lock/un-lock applications. Unlike MR fluid devices they contain no fluid yet they do provide a variable level of friction damping that is controlled by the magnitude of the applied magnetic field. Magnelok devices are low cost as they easily accommodate relatively loose mechanical tolerances and require no seals or accumulator. A variety of controllable Magnelok devices and applications are described.
Drilling Fluids Using Multiwall Carbon Nanotube (MWCNT
Directory of Open Access Journals (Sweden)
Mostafa Sedaghatzadeh
2012-11-01
Full Text Available Designing drilling fluids for drilling in deep gas reservoirs and geothermal wells is a major challenge. Cooling drilling fluids and preparing stable mud with high thermal conductivity are of great concern. Drilling nanofluids, i.e. a low fraction of carbon nanotube (CNT well dispersed in mud, may enhance the mixture thermal conductivity compared to the base fluids. Thus, they are potentially useful for advanced designing high temperature and high pressure (HTHP drilling fluids. In the present study, the impacts of CNT volume fraction, ball milling time, functionalization, temperature, and dispersion quality (by means of scanning electron microscopy, SEM on the thermal and rheological properties of water-based mud are experimentally investigated. The thermal conductivities of the nano-based drilling fluid are measured with a transient hot wire method. The experimental results show that the thermal conductivity of the water-based drilling fluid is enhanced by 23.2% in the presence of 1 vol% functionalized CNT at room temperature; it increases by 31.8% by raising the mud temperature to 50 °C. Furthermore, significant improvements are seen in the rheological properties—such as yield point, filtration properties, and annular viscosity—of the CNTmodified drilling fluid compared to the base mud, which pushes forward their future development.
Directed Fluid Transport with Biomimetic ``Silia'' Arrays
Shields, A. R.; Evans, B. A.; Carstens, B. L.; Falvo, M. R.; Washburn, S.; Superfine, R.
2008-10-01
We present results on the long-range, directed fluid transport produced by the collective beating of arrays of biomimetic ``silia.'' Silia are arrays of free-standing nanorods roughly the size of biological cilia, which we fabricate from a polymer-magnetic nanoparticle composite material. With external permanent magnets we actuate our silia such that their motion mimics the beating of biological cilia. Biological cilia have evolved to produce microscale fluid transport and are increasingly being recognized as critical components in a wide range of biological systems. However, despite much effort cilia generated fluid flows remain an area of active study. In the last decade, cilia-driven fluid flow in the embryonic node of vertebrates has been implicated as the initial left-right symmetry breaking event in these embryos. With silia we generate directional fluid transport by mimicking the tilted conical beating of these nodal cilia and seek to answer open questions about the nature of particle advection in such a system. By seeding fluorescent microparticles into the fluid we have noted the existence of two distinct flow regimes. The fluid flow is directional and coherent above the tips of the silia, while between the silia tips and floor particle motion is complicated and suggestive of chaotic advection.
Packing frustration in dense confined fluids.
Nygård, Kim; Sarman, Sten; Kjellander, Roland
2014-09-07
Packing frustration for confined fluids, i.e., the incompatibility between the preferred packing of the fluid particles and the packing constraints imposed by the confining surfaces, is studied for a dense hard-sphere fluid confined between planar hard surfaces at short separations. The detailed mechanism for the frustration is investigated via an analysis of the anisotropic pair distributions of the confined fluid, as obtained from integral equation theory for inhomogeneous fluids at pair correlation level within the anisotropic Percus-Yevick approximation. By examining the mean forces that arise from interparticle collisions around the periphery of each particle in the slit, we calculate the principal components of the mean force for the density profile--each component being the sum of collisional forces on a particle's hemisphere facing either surface. The variations of these components with the slit width give rise to rather intricate changes in the layer structure between the surfaces, but, as shown in this paper, the basis of these variations can be easily understood qualitatively and often also semi-quantitatively. It is found that the ordering of the fluid is in essence governed locally by the packing constraints at each single solid-fluid interface. A simple superposition of forces due to the presence of each surface gives surprisingly good estimates of the density profiles, but there remain nontrivial confinement effects that cannot be explained by superposition, most notably the magnitude of the excess adsorption of particles in the slit relative to bulk.
Big bang nucleosynthesis with a stiff fluid
International Nuclear Information System (INIS)
Dutta, Sourish; Scherrer, Robert J.
2010-01-01
Models that lead to a cosmological stiff fluid component, with a density ρ S that scales as a -6 , where a is the scale factor, have been proposed recently in a variety of contexts. We calculate numerically the effect of such a stiff fluid on the primordial element abundances. Because the stiff fluid energy density decreases with the scale factor more rapidly than radiation, it produces a relatively larger change in the primordial helium-4 abundance than in the other element abundances, relative to the changes produced by an additional radiation component. We show that the helium-4 abundance varies linearly with the density of the stiff fluid at a fixed fiducial temperature. Taking ρ S10 and ρ R10 to be the stiff fluid energy density and the standard density in relativistic particles, respectively, at T=10 MeV, we find that the change in the primordial helium abundance is well-fit by ΔY p =0.00024(ρ S10 /ρ R10 ). The changes in the helium-4 abundance produced by additional radiation or by a stiff fluid are identical when these two components have equal density at a 'pivot temperature', T * , where we find T * =0.55 MeV. Current estimates of the primordial 4 He abundance give the constraint on a stiff fluid energy density of ρ S10 /ρ R10 <30.
Empirical Modelling of Nonmonotonous Behaviour of Shear Viscosity
Czech Academy of Sciences Publication Activity Database
David, Jiří; Filip, Petr; Kharlamov, Alexander
2013-01-01
Roč. 2013, August (2013) ISSN 1687-6822 R&D Projects: GA ČR GA103/09/2066 Institutional support: RVO:67985874 Keywords : shear viscosity * Galindo-rosales * Carreau-yasuda Subject RIV: BK - Fluid Dynamics Impact factor: 0.500, year: 2012 http://www.hindawi.com/journals/amse/2013/658187/
International Nuclear Information System (INIS)
Durandet, E.; Gibert, R.J.; Gantenbein, F.
1988-01-01
The internal structures of a pool-type breeder reactor are mainly axisymmetric shells separated by fluid volumes which are connected one to another by small communications. Unfortunately, the communications destroy the axisymmetry of the problem and a correct modelisation by finite element method generally need a lot of small elements compared to the size of the standard mesh of the fluid volumes. To overcome these difficulties, an equivalent axisymmetric element based on a local tridimensional solution in the vicinity of the fluid communication is defined and will be described in the paper. This special fluid element is characterized by an equivalent length and annular cross-section. The second part of the paper is devoted to the application to an horizontal seismic calculation of breeder reactor
Geothermal energy production with supercritical fluids
Brown, Donald W.
2003-12-30
There has been invented a method for producing geothermal energy using supercritical fluids for creation of the underground reservoir, production of the geothermal energy, and for heat transport. Underground reservoirs are created by pumping a supercritical fluid such as carbon dioxide into a formation to fracture the rock. Once the reservoir is formed, the same supercritical fluid is allowed to heat up and expand, then is pumped out of the reservoir to transfer the heat to a surface power generating plant or other application.
Technical Competencies Applied in Experimental Fluid Dynamics
Tagg, Randall
2017-11-01
The practical design, construction, and operation of fluid dynamics experiments require a broad range of competencies. Three types are instrumental, procedural, and design. Respective examples would be operation of a spectrum analyzer, soft-soldering or brazing flow plumbing, and design of a small wind tunnel. Some competencies, such as the selection and installation of pumping systems, are unique to fluid dynamics and fluids engineering. Others, such as the design and construction of electronic amplifiers or optical imaging systems, overlap with other fields. Thus the identification and development of learning materials and methods for instruction are part of a larger effort to identify competencies needed in active research and technical innovation.
A microsphere suspension model of metamaterial fluids
Directory of Open Access Journals (Sweden)
Qian Duan
2017-05-01
Full Text Available Drawing an analogy to the liquid phase of natural materials, we theoretically propose a microsphere suspension model to realize a metamaterial fluid with artificial electromagnetic indexes. By immersing high-ε, micrometer-sized dielectric spheres in a low-ε insulating oil, the structured fluid exhibits liquid-like properties from dispersing phase as well as the isotropic negative electromagnetic parameters caused by Mie resonances from dispersed microspheres. The work presented here will benefit the development of structured fluids toward metamaterials.
Conformal symmetry inheritance in null fluid spacetimes
International Nuclear Information System (INIS)
Tupper, B O J; Keane, A J; Hall, G S; Coley, A A; Carot, J
2003-01-01
We define inheriting conformal Killing vectors for null fluid spacetimes and find the maximum dimension of the associated inheriting Lie algebra. We show that for non-conformally flat null fluid spacetimes, the maximum dimension of the inheriting algebra is seven and for conformally flat null fluid spacetimes the maximum dimension is eight. In addition, it is shown that there are two distinct classes of non-conformally flat generalized plane wave spacetimes which possess the maximum dimension, and one class in the conformally flat case
Method and apparatus for injecting fluid
Energy Technology Data Exchange (ETDEWEB)
Hyde, W E
1966-07-05
A method and apparatus are described for injecting grouting material into porous, fractured, unconsolidated, or other formations, whose cohesion is to be increased and/or whose permeability is to be decreased. A tool for injecting the fluid consists of a packer and valves through which the pressurized fluid may pass from the interior of the tool to the packer to expand it. Another valve allows pressure fluid to be vented so as to allow contraction of the packer. A third valve allows a flow of pressurized flow out of the tool and into the material when a predetermined pressure within the tool has been attained. (9 claims)