arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2409.20541physics.flu-dynmath.DSnlin.PS
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快速旋转壁模对流

Rapidly Rotating Wall-Mode Convection

Geoffrey M. Vasil, Keaton J. Burns, Daniel Lecoanet, Jeffrey S. Oishi, Benjamin P. Brown, Keith Julien

AI总结:

本文推导了快速旋转极限下控制一般容器内部对流壁模不稳定性强非线性发展的简化方程组,揭示其多尺度特性,推导Ekman通量修正公式并通过模拟展示非线性动力学,为相关研究提供新途径。

摘要:

在快速旋转极限下,我们推导了一组平衡的简化方程,用于控制一般容器内部对流壁模不稳定性的强非线性发展。该模型表明,壁模对流是一种多尺度现象:主体内部的动力学诊断性地决定了侧壁Stewartson边界层内的小尺度动力学;侧壁边界层通过非线性横向热通量边界条件对内部反馈,形成封闭系统。在渐近薄边界层外,对流模连接到维持由域几何形状设定尺度的动态内部。在许多方面,最终的方程组类似于边界强迫的行星地转斜压动力学与正压准地转涡度的耦合。简化系统包含先前线性不稳定性理论的结果,但以基本方式捕捉,为研究强非线性区域的壁模对流提供了新途径。我们还推导了大泰勒数下对起始瑞利数的主导Ekman通量修正:无滑移边界时,$\textit{Ra} \approx 31.8 \textit{Ta}^{1/2} - 4.43 \textit{Ta}^{5/12} + \mathcal{O}(\textit{Ta}^{1/3})$。然而,我们发现有限圆柱中的线性起始与笛卡尔通道相比有显著差异。我们通过圆柱容器中的数值模拟展示了简化模型的一些非线性动力学。

英文摘要:

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.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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