Three-dimensional transverse instabilities in detached boundary layers
Three-dimensional transverse instabilities in detached boundary layers
复制标题
分离边界层中的三维横向不稳定性
DOI：
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发表时间：
2007
影响因子：
3.7
通讯作者：
U. Ehrenstein
中科院分区：
文献类型：
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作者：
F. Gallaire;M. Marquillie;U. Ehrenstein
对绕流的不可压缩N-S方程的直接数值模拟表明，当雷诺数Re=400时，定常纵向不稳定。用三维整体模线性分析解释了这些结果，结果表明，最不稳定的本征模在回流泡中是稳定的和局域的，跨向波长约为10个凸起高度。然后提出并修正了闭合流线上的无粘几何光学分析，以考虑粘性效应。这引发了关于观测到的不稳定性的物理起源的最后讨论。
A direct numerical simulation of the incompressible Navier–Stokes equations of the flow over a bump shows a stationary longitudinal instability at a Reynolds number of Re = 400. A three-dimensional global mode linear analysis is used to interpret these results and shows that the most unstable eigenmode is steady and localized in the recirculation bubble, with spanwise wavelength of approximately ten bump heights. An inviscid geometrical optics analysis along closed streamlines is then proposed and modified to account for viscous effects. This motivates a final discussion regarding the physical origin of the observed instability.