自由剪切流大尺度结构的二次稳定性<sup>*</sup>

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自由剪切流大尺度结构的二次稳定性^*

基金项目: * 国家自燃科学基金

摘要: 本文用二次稳定性理论研究自由剪切湍流中周期性基本流空间增长扰动的稳定性。数值结果表明三维亚谐扰动对横向波数有很强的选择性,二维亚谐波的空间增长率最大。与之相反,基本模式的三维扰动在很大的波数范围内存在不稳定性,证明β=0时存在“转移”不稳定性;当KH波的幅值A≥0.06时出现分叉现象。
- 二次稳定性 /
- 大尺度结构 /
- 分叉
Abstract: The secondary instability theory is used to study the behavior of spatially growing disturbance in free turbulent shear layer.The numerical results indicate that secondary instability of subharmonic mode shows a strong choice of spanwise wavenumber andthe maximum growth two dimensional case.In contrast to that secondary instabilities of the fundamental mode occur in a wide scope of spanwise wavenumber.We have found so called translative at β=0 and bifurcation phenomenon for an amplitude of the KH wave larger than 0.06.
- secondary instabilities /
- large scale structure /
- bifurcation

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