Abstract

For a stratified turbulent Couette flow, the eigenmodes and optimal disturbances of corresponding simplified equations linearized around a steady state are considered. It is shown that the spectrum of these equations is symmetric with respect to the real axis and lies strictly in the left half-plane, i.e., all eigenmodes are stable, and the main part of an optimal disturbance is a linear combination of a large number of modes corresponding to eigenvalues with largest real parts. The number of the most significant modes in this linear combination grows with increasing Reynolds number.

中文翻译：

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分层湍流库埃特流最优扰动的频谱分析

摘要

对于分层湍流库埃特流，考虑了在稳态附近线性化的相应简化方程的本征模和最佳扰动。结果表明，这些方程的谱线相对于实轴对称，并且严格位于左半平面，即所有本征模态都是稳定的，最优扰动的主要部分是大量的线性组合。对应于具有最大实部的特征值的模式。该线性组合中最有效模式的数量随雷诺数的增加而增加。