Symmetry breaking of rotating convection due to Non-Oberbeck-Boussinesq effects

Fuente: arXiv
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Main Authors: Wang, Shuang, Kang, Wanying
Format: Preprint
Published: 2024
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author Wang, Shuang
Kang, Wanying
author_facet Wang, Shuang
Kang, Wanying
contents The non-Oberbeck--Boussinesq (NOB) effects arising from variations in thermal expansivity are theoretically and numerically studied in the context of rotating Rayleigh--Bénard convection in forms of two-dimensional (2D) rolls. The thermal expansivity increases with pressure (depth), and its variation is measured by a dimensionless factor $ε$. Utilizing an asymptotic expansion with weak nonlinearity, we derive an amplitude equation, revealing that NOB effects amplify the magnitude of convection. An $ε^2$-order NOB correction leads to a symmetry breaking about the horizontal mid-plane, manifested in the strengthening of convection near the bottom and its weakening near the top, forming bottom-heavy profiles. At $ε^3$-order, the conjunction of NOB effects and nonlinear advection leads to a horizontal symmetry breaking. The values of Taylor number and Prandlt number determine whether upward or downward plumes are stronger. Numerical calculations validate the theoretical analyses in weakly nonlinear regime. This work advances our understanding of hydrothermal plumes in some winter lakes on Earth, and in the subglacial oceans on icy moons as well as tracer transport from the seafloor to the ice shell.
format Preprint
id arxiv_https___arxiv_org_abs_2405_01721
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Symmetry breaking of rotating convection due to Non-Oberbeck-Boussinesq effects
Wang, Shuang
Kang, Wanying
Fluid Dynamics
Atmospheric and Oceanic Physics
The non-Oberbeck--Boussinesq (NOB) effects arising from variations in thermal expansivity are theoretically and numerically studied in the context of rotating Rayleigh--Bénard convection in forms of two-dimensional (2D) rolls. The thermal expansivity increases with pressure (depth), and its variation is measured by a dimensionless factor $ε$. Utilizing an asymptotic expansion with weak nonlinearity, we derive an amplitude equation, revealing that NOB effects amplify the magnitude of convection. An $ε^2$-order NOB correction leads to a symmetry breaking about the horizontal mid-plane, manifested in the strengthening of convection near the bottom and its weakening near the top, forming bottom-heavy profiles. At $ε^3$-order, the conjunction of NOB effects and nonlinear advection leads to a horizontal symmetry breaking. The values of Taylor number and Prandlt number determine whether upward or downward plumes are stronger. Numerical calculations validate the theoretical analyses in weakly nonlinear regime. This work advances our understanding of hydrothermal plumes in some winter lakes on Earth, and in the subglacial oceans on icy moons as well as tracer transport from the seafloor to the ice shell.
title Symmetry breaking of rotating convection due to Non-Oberbeck-Boussinesq effects
topic Fluid Dynamics
Atmospheric and Oceanic Physics
url https://arxiv.org/abs/2405.01721