Дисертації з теми "Inhomogeneous flow"
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1
Batycky, Richard Panko. "Inhomogeneous Stokes flow through porous media." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/36640.
Повний текст джерела
2
Alves, Portela Felipe. "Turbulence cascade in an inhomogeneous turbulent flow." Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/63233.
Повний текст джерелаАнотація:
The inhomogeneous, anisotropic turbulence downstream of a square prism is investigated by means of direct numerical simulations (DNS) and two-point statistics. As noted by Moffatt (2002) “it now seems that the intense preoccupation [...] with the problem of homogeneous isotropic turbulence was perhaps misguided” acknowledging there is now a revived interest in studying inhomogeneous turbulence. The full description of the turbulence cascade requires a two-point analysis which re- volves around the recently derived Kármán-Howarth-Monin-Hill equation (KHMH). This equation is the inhomogeneous/anisotropic analogue to the so-called Kolmogorov equation (or Kármán-Howarth equation) used in Kolmogorov’s 1941 seminal papers (K41) which are the foundation to the most successful turbulence theory to date. Particular focus is placed on the near wake region where the turbulence is anticipated to be highly inhomogeneous and anisotropic. Because DNS gives direct access to all ve- locity components and their derivatives, all terms of the KHMH can be computed directly without resorting to any simplifications. Computation of the term associated with the non-linear inter-scale transfer of energy (Π) revealed that this rate is roughly constant over a range of scales which increases (within the bounds of our database) with distance to the wake generator, provided that the orientations of the pairs of points are averaged-out on the plane of the wake. This observation appears in tandem with a near −5/3 power law in the spectra of fluctuating velocities which deteriorates as the constancy of Π improves. The constant non-linear inter-scale transfer plays a major role in K41 and is required for deriving the 2/3-law (which is real space equivalent of the −5/3). We extend our analysis to a triple decomposition where the organised motion associ- ated with the vortex shedding is disentangled from the stochastic motions which do not display a distinct time signature. The imprint of the shedding-associated motion upon the stochastic component is observed to contribute to the small-scale anisotropy of the stochastic motion. Even though the dynamics of the shedding-associated motion differs drastically from that of the stochastic one, we find that both contributions are required in order to preserve the constant inter-scale transfer of energy. We further find that the inter- scale fluxes resulting from this decomposition display local (in scale-space) combinations of direct and inverse cascades. While the inter-scale fluxes associated with the coherent motion can be explained on the basis of simple geometrical arguments, the stochastic motion shows a persistent inverse cascade at orientations normal to the centreline despite its energy appearing to be roughly isotropically distributed.
3
DOLCE, MICHELE. "Linear stability analysis of stationary Euler flows for passive scalars and inhomogeneous fluids." Doctoral thesis, Gran Sasso Science Institute, 2020. http://hdl.handle.net/20.500.12571/15111.
Повний текст джерелаАнотація:
This thesis is concerned with the study of linear stability properties of some particular
fluid flows, within the framework of quantitative hydrodynamic stability. In the last decade, the problem has received a lot of attention thanks to the introduction
of new analytical techniques particularly useful to tackle classical problems that date back to the end of the nineteen century. The purpose of this thesis is threefold. We first investigate the asymptotic decay properties of a passive scalar driven by a vortex with a power-law velocity field in the
whole plane. In particular, we quantify the enhanced dissipation mechanism caused by fluid mixing, namely, the transfer of energy from large to small scales due to transport.
We provide sharp (up to a logarithmic correction) bounds on the dissipation time-scales, which are faster than the standard diffusive one.
The rest of the thesis is dedicated to the study of the stability of parallel flows in 2D inhomogeneous fluids. The second problem we deal with concerns a linear stability
analysis for the Couette flow with constant density in an isentropic compressible fluid. We consider both the inviscid and the viscous case. In the inviscid case, we
give the first rigorous mathematical justification to a Lyapunov instability mechanism previously addressed in the physics literature. More precisely, we show that the L^2
norms of the density and the irrotational component of the velocity field grow as t^(1/2) Instead, the solenoidal component of the velocity strongly converges to zero in L^2, a
mechanism known as inviscid damping. In the viscous case, we present the first enhanced dissipation result for an inhomogeneous fluid. The exponential decay become
effective on a time-scale O(
u^(-1/3)), with
u being proportional to the inverse of the Reynolds number, and there is a large transient growth of order O(
u^(-1/6)) caused by
the inviscid instability. The estimates are valid also in a large Mach number regime. We finally study the stability of a particular class of stratified shear flows. We consider
an inhomogeneous, inviscid and incompressible fluid under the action of gravity, near shear flows close to Couette with an exponentially stratified density profile. Under
the Miles-Howard criterion, we prove the inviscid damping for the velocity field and the (scaled) density. The decay rates are slower with respect to the classical homogeneous
case without gravity. This is due to a Lyapunov instability mechanism for the vorticity that we characterize in the Couette case.
4
Panin, Gennadij N., Gerd Tetzlaff, Armin Raabe, Hans-Jürgen Schönfeldt, and A. E. Nasonov. "Inhomogeneity of the land surface and the parameterization of surface fluxes." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-213104.
Повний текст джерелаАнотація:
Modem measurement methods ofthe surface turbulent fluxes (STF) of heat, moisture and momentum in the near surface atmospheric layer by the eddy correlation method and their calculation, relay on the validity of the similarity theory of Monin-Obukhov, which requests stationarity and horizontal homogeneity. Experimental data taken at specially selected sites allowed to develop this concept. Recently performed experiments, purposely conducted in non-ideal conditions showed an underestimation ofthe STF values. To systematise this effect it is suggested to parameterize such underestimation as the influence of inhomogeneity and nonstationarity of the landscape and the atmosphere around the point of observation. This scheme might prove to be useful for the design of new validation experiments in non-ideal terrainModeme Meßmethoden zur Erfassung der turbulenten Oberflächenflüsse für fühlbare und latente Wärme sowie Impuls mit Hilfe der Eddy-Korrelations-Methode basieren für die bodennahe Grenzschicht auf der Monin-Obukhov-Turbulenztheorie, die stationäre und horizontal homogene Verhältnisse voraussetzt. Über speziell ausgewählten Oberflächen wurde dieses Konzept häufig mit Erfolg überprüft. Experimente jedoch, die gezielt unter inhomogenen Verhältnissen durchgeführt werden, zeigen oft eine Unterschätzung der turbulenten Oberflächenflüsse. Es wird vorgeschlagen, diese Unterschätzungen als einen Einfluß inhomogener Umbegungsbedingungen und instationärer atmosphärischer Prozesse zu interpretieren und zu systematisieren. Dieses Schema kann dazu beitragen, eine neue Art von Validierungsexperimenten unter natürlichen Verhältnissen einer inhomogenen Umgebung zu entwerfen
5
Zhao, Sicheng. "Interactive dynamics of fluid flow and metallic alloys solidification." Thesis, Aix-Marseille 3, 2011. http://www.theses.fr/2011AIX30010.
Повний текст джерелаАнотація:
Nous avons étudié les phénomènes convectifs et leur interaction dynamique avec la formation des microstructures pendant la solidification dirigée d’alliages étalliquesbinaires.La méthode post-mortem a été utilisée d’abord pour étudier la Transition olonnaire-Equiaxe pendant la solidification dirigée d’échantillons cylindriques d’Al-3,5wt%Ni non affiné sous la Technique de Rotation Accélérée de Creuset. La simulation numérique a été éffectuée et acquérie les résultats en concordance avec les manipulations.La technique in-situ a été appliquée pour comprendre l’évolution en fonction de temps des grains pendant solidification d’Al-4wt%Cu. La caractéstiques tatistiques des grains ont été discutées.La convection d’instabilité déclenchée par la poussée ou la tension superfaciale sous les gradients thermiques verticale et horizontale dans un système de double couches liquide-zone poreuse ont réspectivement étudié par analysis d’instabilité linéaire.L’inhomogénéité de la perméabilité de zone pateuse dendritique a été tenue en compte afin de comprendre son influence sur le début de convection pendant la solidification dirigée d’Al-3,5wt%LiWe studied the convective phenomena and their dynamical interaction with the formation of the microstructurs during directional solidification of binary metallic alloys.The post-mortem method was used first to study the Columnar-Equiaxed-Transition during the directional solidification of unrefined Al-3.5wt%Ni in cylindric samples under the Accelerated Crucible Rotation Technique. The numerical imulation was carried out and achieved the results in agreement with experiments.The in-situ technique was applied to understand the evolution of equiaxed grains during solidification of Al-4wt%Cu in function of time. The statistical characteristics of equiaxed grains were discussed.The buoyancy-driven and surface-tension-driven instability convection under vertical and horizontal thermal gradients in a liquid-porous double-layered system were respectively investigated through linear instability analysis.The inhomogeneity of the dendritic mush permeability was taken into account in order to understand its influence on the triggering of convection during the directional solidification of Al-3.5wt%Li
6
Panin, Gennadij N., Gerd Tetzlaff, Armin Raabe, Hans-Jürgen Schönfeldt, and A. E. Nasonov. "Inhomogeneity of the land surface and the parameterization of surface fluxes." Wissenschaftliche Mitteilungen des Leipziger Instituts für Meteorologie ; 4 = Meteorologische Arbeiten aus Leipzig ; 2 (1996), S. 204-215, 1996. https://ul.qucosa.de/id/qucosa%3A15066.
Повний текст джерелаАнотація:
Modem measurement methods ofthe surface turbulent fluxes (STF) of heat, moisture and momentum in the near surface atmospheric layer by the eddy correlation method and their calculation, relay on the validity of the similarity theory of Monin-Obukhov, which requests stationarity and horizontal homogeneity. Experimental data taken at specially
selected sites allowed to develop this concept. Recently performed experiments, purposely conducted in non-ideal conditions showed an underestimation ofthe STF values. To systematise this effect it is suggested to parameterize such underestimation as the influence of inhomogeneity and nonstationarity of the landscape and the atmosphere around the point of observation. This scheme might prove to be useful for the design of new validation experiments in non-ideal terrain.Modeme Meßmethoden zur Erfassung der turbulenten Oberflächenflüsse für fühlbare und latente Wärme sowie Impuls mit Hilfe der Eddy-Korrelations-Methode basieren für die bodennahe Grenzschicht auf der Monin-Obukhov-Turbulenztheorie, die stationäre und horizontal homogene Verhältnisse voraussetzt. Über speziell ausgewählten Oberflächen wurde dieses Konzept häufig mit Erfolg überprüft. Experimente jedoch, die gezielt unter inhomogenen Verhältnissen durchgeführt werden, zeigen oft eine Unterschätzung der turbulenten Oberflächenflüsse. Es wird vorgeschlagen, diese Unterschätzungen als einen Einfluß inhomogener Umbegungsbedingungen und instationärer atmosphärischer Prozesse zu interpretieren und zu systematisieren. Dieses Schema kann dazu beitragen, eine neue Art von Validierungsexperimenten unter natürlichen Verhältnissen einer inhomogenen Umgebung zu entwerfen.
7
Do, Khac Minh. "Use of orthogonal wavelets in the analysis of two and three-dimensional inhomogeneous turbulent flows /." Châtillon : ONERA, 1998. http://catalogue.bnf.fr/ark:/12148/cb369938476.
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8
Storozhenko, V. A., A. V. Myagkiy, and R. P. Orel. "Filtering of interference of inhomogeneous regular structure in thermal non-destructive control of cellular structures." Thesis, Eskisehir technical university, 2021. https://openarchive.nure.ua/handle/document/18954.
Повний текст джерелаАнотація:
Honeycomb constructions are the most widely used materials in contemporary aviation and space technology. They are the basis for the housings of practically all products of this sector, where reliability of all parts should meet the in-creased requirements. Special attention is paid to the quality of composite materials and to the absence of defects such as the places of adhesion failure (exfoliation) between the skin and the honeycomb filler. Therefore, increase in the efficiency and reliability of thermal flaw detection, based on in-depth analysis of the processes of detecting defects and development of the principles of optimization of both the procedure of control and subsequent processing of the obtained information, is an important and relevant task.
9
Zhang, Xin. "Étude qualitative des solutions du système de Navier-Stokes incompressible à densité variable." Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC1215/document.
Повний текст джерелаАнотація:
Dans cette thèse, on s'intéresse à deux problèmes provenant de l'étude mathématique des fluides incompressibles visqueux : la propagation de la régularité tangentielle et le mouvement d'une surface libre.La première question concerne plus particulièrement l'étude qualitative de l'évolution de quantités thermodynamiques telles que la température dans l'équation de Boussinesq sans diffusion et la densité dans le système de Navier-Stokes non homogène. Typiquement, on suppose que ces deux quantités sont, à l'instant initial, discontinues le long d'une interface à régularité h"oldérienne. Comme conséquence de résultats de propagation de régularité tangentielle pour le champ de vitesses, on établit que la régularité des interfaces persiste pour tout temps aussi bien en dimension deux d'espace, qu'en dimension supérieure (avec condition de petitesse). Notre approche suit celle du travail de J.-Y. Chemin dans les années 90 pour le problème des poches de tourbillon dans les fluides incompressiblesparfaits.Dans le cas présent, outre cette hypothèse de régularité tangentielle, nous n'avons besoin que d'une régularité critique sur le champ de vitesses.La démonstration repose sur le calcul para-différentiel et les espaces de multiplicateurs.Dans la dernière partie de la thèse, on considère le problème à frontière libre pour le système de Navier-Stokes incompressible à deux phases. Ce système permet de décrire l'évolution d'un mélange de deux fluides non miscibles tels que l'huile et l'eau par exemple. Différents cas de figure sont étudiés : le cas d'un réservoir borné, d'une goutte ou d'une rivière à profondeur finie.On établit l'existence et l'unicité à temps petit pour ce problème. Notre démonstration repose fortement sur des propriétés de régularité maximale parabolique de type $L_p$-$L_qThis thesis is dedicated to two different problems in the mathematical study of the viscous incompressible fluids: the persistence of tangential regularity and the motion of a free surface.The first problem concerns the study of the qualitative properties of some thermodynamical quantities in incompressible fluid models, such as the temperature for Boussinesq system with no diffusion and the density for the non-homogeneous Navier-Stokes system. Typically, we assume those two quantities to be initially piecewise constant along an interface with H"older regularity.As a consequence of stability of certain directional smoothness of the velocity field, we establish that the regularity of the interfaces persist globally with respect to time both in the two dimensional and higher dimensional cases (under some smallness condition). Our strategy is borrowed from the pioneering works by J.-Y.Chemin in 1990s on the vortex patch problem for ideal fluids.Let us emphasize that, apart from the directional regularity, we only impose rough (critical) regularity on the velocity field. The proof requires tools from para-differential calculus and multiplier space theory.In the last part of this thesis, we are concerned with the free boundary value problem for two-phase density-dependent Navier-Stokes system.This model is used to describe the motion of two immiscible liquids, like the oil and the water. Such mixture may occur in different situations, such as in a fixed bounded container, in a moving bounded droplet or in a river with finite depth. We establish the short time well-posedness for this problem. Our result strongly relies on the $L_p$-$L_q$ maximal regularity theoryfor parabolic equations
10
Leroy, Christophe. "Etude experimentale de la dispersion d'un traceur dans des milieux stratifies ou fortement inhomogenes." Paris 6, 1987. http://www.theses.fr/1987PA066491.
Повний текст джерелаАнотація:
Etude experimentale et numerique de la dispersion de taylor dans un tube capillaire. Mise en oeuvre d'une methode d'etude d'un milieu poreux (dit d'injection et retour) dans un systeme de tubes capillaires. Les milieux stratifies constituent un cas modele de milieu heterogene. On etudie la dispersion en fonction du debit, de la distance parcourue et de l'epaisseur des couches
11
Pulugundla, Gautam [Verfasser], Christian [Akademischer Betreuer] Karcher, Jörg [Gutachter] Schumacher, and Oleg [Gutachter] Zikanov. "Numerical Modelling of Liquid Metal Flows Interacting with Strongly Inhomogeneous Magnetic Fields / Gautam Pulugundla ; Gutachter: Jörg Schumacher, Oleg Zikanov ; Betreuer: Christian Karcher." Ilmenau : TU Ilmenau, 2013. http://d-nb.info/117818451X/34.
Повний текст джерела
12
Croizet, Didier. "Etude experimentale et numérique du comportement à haute température d'un nitrure de silicium." Paris, ENMP, 1992. http://www.theses.fr/1992ENMP0516.
Повний текст джерелаАнотація:
Le matériau céramique que nous avons étudié est un nitrure de silicium obtenu par frittage naturel. Ce matériau biphase est constitué d'une phase principale correspondant à une solution solide de type Sialon et d'une phase secondaire cristallisée en grenat d'yttrium et d'aluminium après traitement thermique post-frittage. Le premier point de cette étude concerne la caractérisation mécanique du matériau à haute température avec une attention toute particulière à 1250 C. A cet effet, des essais de flexion 4 points, de traction et de compression ont été réalisés en utilisant la technique du dip-test. Ceux-ci ont mis en évidence un comportement viscoplastique, asymétrique en traction-compression avec apparition d'une contrainte interne lors du processus de déformation. Sur cette base expérimentale, une loi de comportement tridimentionnelle, viscoplastique, non associée, caractérisée par un critère d'écoulement de Drucker-Prager et une règle d'écrouissage cinématique, a été proposée. Le deuxième point concerne l'implantation de lois de comportement viscoplastique dans le code d'éléments finis Zébulon. Une formulation générale de ces lois a été définie dans le cadre de la thermodynamique des processus irréversibles. La plasticité y est traitée comme un cas particulier de la viscoplasticité. Cette formulation permet d'écrire un programme standard prenant en compte le comportement non linéaire d'une grande variété de matériaux tels que les métaux, les alliages, les roches, les sols ou les céramiques. L'utilisation d'une méthode d'intégration implicite, appelée thêta-Newton, permet l'évaluation d'une matrice tangente viscoplastique
13
Morris, Jeffrey Franklin. "Suspensions: microstructure, diffusion, and inhomogeneous flow." Thesis, 1996. https://thesis.library.caltech.edu/109/1/Morris_jf_1996.pdf.
Повний текст джерелаАнотація:
NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document.
A theory of self-diffusivity in sheared suspensions valid for any particle volume fraction [phi], Peclet number Pe, and lengthscale of disturbance in [phi] is developed. The theory is applied to the determination of the full tensor self-diffusivity in a weakly- sheared (Pe << 1) suspension of hydrodynamically-interacting hard spheres and a strongly-sheared (Pe >> 1) suspension of hard spheres without hydrodynamic interactions, both at [phi] << 1.
The influence of weak Brownian motion alone and in conjunction with a repulsive interparticle force of hard-sphere type upon the pair-distribution function, g(r) where r is the separation vector of a pair of particles, is analyzed for a suspension of spheres at Pe >> 1 and [phi] << 1. At large Pe, the radial fluxes of pair probability due to advection and Brownian diffusion balance in a thin [...] boundary layer at contact, with a the sphere radius. The boundary-layer analyses demonstrate that Brownian diffusion renders g finite at contact in the absence of interparticle forces, and that within the boundary layer there is generally a large excess of pair probability along the compressional axes. By calculation of the bulk normal stress differences in the case with repulsive forces, it is shown how this asymmetry of the microstructure yields non-Newtonian constitutive behavior in the limit Pe[superscript -1] = 0.
Hydrodynamic resistance functions relating the particle and bulk motions to the bulk isotropic stress are developed. Application of these functions is demonstrated by calculations of the shear-induced correction to the osmotic pressure and the particle contribution to the pressure in a sheared lattice.
Pressure-driven flow in a channel at vanishing Reynolds number of a suspension of particles denser than the suspending fluid has been dynamically simulated by Stokesian Dynamics over ranges of the particle fraction, channel width, and a buoyancy parameter characterizing the relative strength of the buoyancy to shearing forces. The predictions of the flow by the suspension-balance model are in good agreement with simulation results.
14
Ursescu, Ana. "Channel flow of electrorheological fluids under an inhomogeneous electric field." Phd thesis, 2005. https://tuprints.ulb.tu-darmstadt.de/556/1/Dissertation_Ana_Ursescu.pdf.
Повний текст джерелаАнотація:
This thesis is a theoretical study of the steady pressure driven channel flow of electrorheological fluids (ERF) under a space dependent electric field generated by finite electrodes. Chapter 1 consists in a general description of ERF and their engineering applications and presents also the motivation, the goal and the borders of this work. Chapter 2 summarizes the governing equations of electrorheology with the corresponding jump conditions. It is assumed that the flow does not affect the electric field and consequently, the electrical problem is decoupled from the mechanical one. Both electrical and mechanical boundary value problems are formulated for various configurations of finite electrodes with different potentials placed along the channel walls. The simple case of two infinite electrodes which generate a homogeneous electric field is solved analytically. In Chapter 3 analytical solutions for different mixed boundary value problems arising from the electrical problem formulated in Chapter 2 are found by use of the Wiener-Hopf method. The solutions are given in terms of infinite series involving Gamma functions. The results can be used to describe the electric field generated between two infinite grounded electrodes by either one long electrode or two long electrodes charged in an anti-symmetric or a non-symmetric way. The electric field in the vicinity of the electrode edges is asymptotically evaluated. Some parametric studies are made with respect to the ratio between the permittivity of the electrorheological fluid and the permittivity of the isolating material outside the channel. We compare the analytical with numerical solutions and find good agreement which is considered as a validation of the numerical method. Chapter 4 treats the mechanical problem in more detail. First a review of the constitutive models used to describe the ER-fluids in the literature is given. Then two-dimensional alternative constitutive laws appropriate for numerical simulations originating from the Casson-like and power law models are introduced using a parameter. In the end we non-dimensionalize the problem in both cases. In the last Chapter, we simulate numerically the flow of the Rheobay TP AI 3565 ER-fluid using the alternative Casson-like model and the EPS 3301 ER-fluid using the alternative power-law model by applying a finite element program. The behaviour of different fields such as velocity, pressure, generalized viscosity and the second invariant of the strain rate tensor near the electrode edges is studied for both fluids. A comparison with the experimental data is performed, validating the simulations. In order to investigate how the numerical solution depends on the constitutive model we perform a parallel analysis of the two rheological models by applying them to the same material (Rheobay). Then we optimize the configuration of the electrodes by using the inhomogeneities caused by the end effects of the electrodes in order to obtain an enhancement of the ER-effect.
15
Ursescu, Ana [Verfasser]. "Channel flow of electrorheological fluids under an inhomogeneous electric field / vorgelegt von Ana Ursescu." 2005. http://d-nb.info/975134825/34.
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16
Parvar, Saeed. "LES model for inhomogeneous wall-free turbulent flows and flow characteristics in laminar wall-free and wall-dominated viscoelastic fluid flows." Doctoral thesis, 2021. https://hdl.handle.net/10216/133298.
Повний текст джерела
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Parvar, Saeed. "LES model for inhomogeneous wall-free turbulent flows and flow characteristics in laminar wall-free and wall-dominated viscoelastic fluid flows." Tese, 2021. https://hdl.handle.net/10216/133298.
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Chiu, Te Hsin, and 邱德欣. "Explicit Algebraic Stress Modelling of homogeneous flows and inhomogeneous flows." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/02996848248608534167.
Повний текст джерелаАнотація:
碩士國立清華大學
動力機械工程學系
89
In this study, the capabilities of the explicit algebraic stress models used to predict homogeneous and inhomogeneous shear flows are examined. The applications of the models are first focused on the homogeneous flow under shear (homogeneous shear flow) and purely irrotational strains flows (plane strain, axisymmetric contraction and axisymmetric expansion). The ratio of the production to dissipation rate in the explicit algebraic stress model is obtained explicitly. This is found to be important to predict correctly the anisotropy levels of the homogeneous strain flows under purely irrotational strains at elevated strain rates. The asymptotic analysis is also adopted to analyse the model behavior at the state where strain approaches infinity. Comparisons of the predicted results with DNS data and measurements indicate that the model predicts reasonable well the homogeneous shear and axisymmetric contraction cases. The predicted anisotropic level under axisymmetric expansion is too high, and in the plane strain case, the model produces higher level of anisotropy and a wrong sign of the stress anisotropy in the direction without strain. Finally, turbulent recirculating flows within sudden expanding pipes are further simulated with explicit algebraic stress model and anisotropic eddy viscosity model. Both models show a betteer stress-strain interaction, showing a reasonable shear layer development. The anisotropic stress fields are also accurately predicted by the models, though the anisotropic eddy viscosity model of Craft et al. returns marginally better results.
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Öncül, Ahmet Alper [Verfasser]. "Simulation of interacting populations in inhomogeneous flows using reduced models / von: Ahmet Alper Öncül." 2010. http://d-nb.info/1011576449/34.
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Nhan, Phan-Thien, and Xi-Jun Fan. "Viscoelastic Mobility Problem Using A Boundary Element Method." 2002. http://hdl.handle.net/1721.1/4021.
Повний текст джерелаАнотація:
In this paper, the complete double layer boundary integral equation formulation for Stokes flows is extended to viscoelastic fluids to solve the mobility problem for a system of particles, where the non-linearity is handled by particular solutions of the Stokes inhomogeneous equation. Some techniques of the meshless method are employed and a point-wise solver is used to solve the viscoelastic constitutive equation. Hence volume meshing is avoided. The method is tested against the numerical solution for a sphere settling in the Odroyd-B fluid and some results on a prolate motion in shear flow of the Oldroyd-B fluid are reported and compared with some theoretical and experimental results.Singapore-MIT Alliance (SMA)