Fluid deformation in random steady three-dimensional flow
| Autor: | Daniel R. Lester, Felipe P. J. de Barros, Tanguy Le Borgne, Marco Dentz |
|---|---|
| Přispěvatelé: | European Research Council, Royal Melbourne Institute of Technology University (RMIT University), Institute of Environmental Assessment and Water Research (IDAEA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Géosciences Rennes (GR), Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), University of Southern California (USC), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS) |
| Rok vydání: | 2018 |
| Předmět: |
Chaotic advection
Stochastic modelling Porous media Lyapunov exponent 01 natural sciences Article 010305 fluids & plasmas law.invention Physics::Fluid Dynamics symbols.namesake law Intermittency 0103 physical sciences [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph] 010306 general physics Mixing and dispersion Physics Velocity gradient Turbulence Mechanical Engineering Fluid deformation Solute transport Mechanics Condensed Matter Physics Flow velocity Mechanics of Materials symbols steady flow stochastic modelling Continuous-time random walk Porous medium |
| Zdroj: | Journal of Fluid Mechanics Journal of Fluid Mechanics, Cambridge University Press (CUP), 2018, 855, pp.770-803. ⟨10.1017/jfm.2018.654⟩ Journal of Fluid Mechanics, 2018, 855, pp.770-803. ⟨10.1017/jfm.2018.654⟩ Digital.CSIC. Repositorio Institucional del CSIC instname |
| ISSN: | 0022-1120 1469-7645 |
| DOI: | 10.1017/jfm.2018.654 |
| Popis: | The deformation of elementary fluid volumes by velocity gradients is a key process for scalar mixing, chemical reactions and biological processes in flows. Whilst fluid deformation in unsteady, turbulent flow has gained much attention over the past half-century, deformation in steady random flows with complex structure - such as flow through heterogeneous porous media - has received significantly less attention. In contrast to turbulent flow, the steady nature of these flows constrains fluid deformation to be anisotropic with respect to the fluid velocity, with significant implications for e.g. longitudinal and transverse mixing and dispersion. In this study we derive an ab initio coupled continuous-time random walk (CTRW) model of fluid deformation in random steady three-dimensional flow that is based upon a streamline coordinate transform which renders the velocity gradient and fluid deformation tensors upper triangular. We apply this coupled CTRW model to several model flows and find that these exhibit a remarkably simple deformation structure in the streamline coordinate frame, facilitating solution of the stochastic deformation tensor components. These results show that the evolution of longitudinal and transverse fluid deformation for chaotic flows is governed by both the Lyapunov exponent and power-law exponent of the velocity probability distribution function at small velocities, whereas algebraic deformation in non-chaotic flows arises from the intermittency of shear events following similar dynamics as that for steady two-dimensional flow. © 2018 Cambridge University Press. European Research Council (ERC) through the project MHetScale (617511). |
| Databáze: | OpenAIRE |
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