Rapidly Rotating Wall-Mode Convection

Fuente: arXiv
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Autores principales: Vasil, Geoffrey M., Burns, Keaton J., Lecoanet, Daniel, Oishi, Jeffrey S., Brown, Benjamin P., Julien, Keith
Formato: Preprint
Publicado: 2024
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author Vasil, Geoffrey M.
Burns, Keaton J.
Lecoanet, Daniel
Oishi, Jeffrey S.
Brown, Benjamin P.
Julien, Keith
author_facet Vasil, Geoffrey M.
Burns, Keaton J.
Lecoanet, Daniel
Oishi, Jeffrey S.
Brown, Benjamin P.
Julien, Keith
contents In the rapidly rotating limit, we derive a balanced set of reduced equations governing the strongly nonlinear development of the convective wall-mode instability in the interior of a general container. The model illustrates that wall-mode convection is a multiscale phenomenon where the dynamics of the bulk interior diagnostically determine the small-scale dynamics within Stewartson boundary layers at the sidewalls. The sidewall boundary layers feedback on the interior via a nonlinear lateral heat-flux boundary condition, providing a closed system. Outside the asymptotically thin boundary layer, the convective modes connect to a dynamical interior that maintains scales set by the domain geometry. In many ways, the final system of equations resembles boundary-forced planetary geostrophic baroclinic dynamics coupled with barotropic quasi-geostrophic vorticity. The reduced system contains the results from previous linear instability theory but captured in an elementary fashion, providing a new avenue for investigating wall-mode convection in the strongly nonlinear regime. We also derive the dominant Ekman-flux correction to the onset Rayleigh number for large Taylor number, $\textit{Ra} \approx 31.8 \,\textit{Ta}^{1/2} - 4.43 \,\textit{Ta}^{5/12} + \mathcal{O}(\textit{Ta}^{1/3})$ for no-slip boundaries. However, we find that the linear onset in a finite cylinder differs noticeably compared to a Cartesian channel. We demonstrate some of the reduced model's nonlinear dynamics with numerical simulations in a cylindrical container.
format Preprint
id arxiv_https___arxiv_org_abs_2409_20541
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Rapidly Rotating Wall-Mode Convection
Vasil, Geoffrey M.
Burns, Keaton J.
Lecoanet, Daniel
Oishi, Jeffrey S.
Brown, Benjamin P.
Julien, Keith
Fluid Dynamics
Dynamical Systems
Pattern Formation and Solitons
In the rapidly rotating limit, we derive a balanced set of reduced equations governing the strongly nonlinear development of the convective wall-mode instability in the interior of a general container. The model illustrates that wall-mode convection is a multiscale phenomenon where the dynamics of the bulk interior diagnostically determine the small-scale dynamics within Stewartson boundary layers at the sidewalls. The sidewall boundary layers feedback on the interior via a nonlinear lateral heat-flux boundary condition, providing a closed system. Outside the asymptotically thin boundary layer, the convective modes connect to a dynamical interior that maintains scales set by the domain geometry. In many ways, the final system of equations resembles boundary-forced planetary geostrophic baroclinic dynamics coupled with barotropic quasi-geostrophic vorticity. The reduced system contains the results from previous linear instability theory but captured in an elementary fashion, providing a new avenue for investigating wall-mode convection in the strongly nonlinear regime. We also derive the dominant Ekman-flux correction to the onset Rayleigh number for large Taylor number, $\textit{Ra} \approx 31.8 \,\textit{Ta}^{1/2} - 4.43 \,\textit{Ta}^{5/12} + \mathcal{O}(\textit{Ta}^{1/3})$ for no-slip boundaries. However, we find that the linear onset in a finite cylinder differs noticeably compared to a Cartesian channel. We demonstrate some of the reduced model's nonlinear dynamics with numerical simulations in a cylindrical container.
title Rapidly Rotating Wall-Mode Convection
topic Fluid Dynamics
Dynamical Systems
Pattern Formation and Solitons
url https://arxiv.org/abs/2409.20541