Oscillatory instability of buoyancy convection in a laterally heated cube with perfectly thermally conducting horizontal boundaries is studied. The effect of the spanwise boundaries on the oscillatory instability onset is studied. The problem is treated by Krylov-subspace-iteration based Newton and Arnoldi methods. The Krylov basis vectors are calculated by a novel approach, based on the SIMPLE iteration and projection onto a space of functions satisfying all linearized and homogeneous boundary conditions. The finite volume grid is gradually refined from 1003 to 2563 finite volumes. A self-sustaining oscillatory process responsible for the instability onset is revealed, visualized and discussed.

中文翻译：

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具有完美传导水平边界的横向加热立方体中自然对流的不稳定性

研究了具有完美导热水平边界的横向加热立方体中浮力对流的振荡不稳定性。研究了展向边界对振荡不稳定开始的影响。该问题由基于 Krylov 子空间迭代的 Newton 和 Arnoldi 方法处理。Krylov 基向量是通过一种新颖的方法计算的，基于 SIMPLE 迭代和投影到满足所有线性化和齐次边界条件的函数空间上。有限体积网格从1003个有限体积逐渐细化到2563个有限体积。揭示、可视化和讨论了导致不稳定开始的自我维持振荡过程。