Buoyancy-Driven Flows With Navier-Slip Boundary Conditions

Fuente: arXiv
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Main Author: Bleitner, Fabian
Format: Preprint
Published: 2024
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author Bleitner, Fabian
author_facet Bleitner, Fabian
contents In this dissertation two-dimensional buoyancy-driven flows are investigated. While usually the Navier-Stokes equations are equipped with no-slip boundary conditions here we focus on the Navier-slip conditions that, depending on the system at hand, better reflect the physical behavior. In particular, we study two systems, Rayleigh-Bénard convection and a closely related problem without thermal diffusion. In the former, bounds on the vertical heat transfer, given by the Nusselt number, with respect to the strength of the buoyancy force, characterized by the Rayleigh number, are derived. These bounds hold for a broad range of applications, allowing for non-flat boundaries, any sufficiently smooth positive slip coefficient, and are valid over all ranges of the Prandtl number, a system parameter determined by the fluid. For the thermally non-diffusive system, regularity estimates are proven. Up to a certain order, these bounds hold uniformly in time, which, combined with estimates for their growth, provide insight into the long-time behavior. In particular, solutions converge to the hydrostatic equilibrium, where the fluid's velocity vanishes and the buoyancy force is balanced by the pressure gradient.
format Preprint
id arxiv_https___arxiv_org_abs_2409_14230
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Buoyancy-Driven Flows With Navier-Slip Boundary Conditions
Bleitner, Fabian
Analysis of PDEs
Mathematical Physics
35B40, 35B65, 76D03, 76E20, 76F35, 76R10, 80A19
In this dissertation two-dimensional buoyancy-driven flows are investigated. While usually the Navier-Stokes equations are equipped with no-slip boundary conditions here we focus on the Navier-slip conditions that, depending on the system at hand, better reflect the physical behavior. In particular, we study two systems, Rayleigh-Bénard convection and a closely related problem without thermal diffusion. In the former, bounds on the vertical heat transfer, given by the Nusselt number, with respect to the strength of the buoyancy force, characterized by the Rayleigh number, are derived. These bounds hold for a broad range of applications, allowing for non-flat boundaries, any sufficiently smooth positive slip coefficient, and are valid over all ranges of the Prandtl number, a system parameter determined by the fluid. For the thermally non-diffusive system, regularity estimates are proven. Up to a certain order, these bounds hold uniformly in time, which, combined with estimates for their growth, provide insight into the long-time behavior. In particular, solutions converge to the hydrostatic equilibrium, where the fluid's velocity vanishes and the buoyancy force is balanced by the pressure gradient.
title Buoyancy-Driven Flows With Navier-Slip Boundary Conditions
topic Analysis of PDEs
Mathematical Physics
35B40, 35B65, 76D03, 76E20, 76F35, 76R10, 80A19
url https://arxiv.org/abs/2409.14230