Instability of compound vortex layers and wakes
Instability of compound vortex layers and wakes
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复合涡层和尾流的不稳定性
DOI：
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发表时间：
1987
期刊：
影响因子：
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通讯作者：
J. Higdon
中科院分区：
文献类型：
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作者：
C. Pozrikidis;J. Higdon
本文分析了两个相邻涡层的稳定性，其中两个涡层的涡量为常数且符号相反。线性稳定性分析表明，两个家庭的不稳定性可能存在，这取决于涡层的相对强度。第一种类型的中长波产生同时增长的两个层上的扰动，而第二个短波主要与较弱的层。数值计算表明，各种类型的不稳定性的非线性增长导致不同性质的渐近状态。对于涡量分布相等但方向相反的尾流，增长最快的本征模导致形成纵横比为0.345的经典涡街。较长的波导致该层分裂成许多小涡区，产生无组织的运动和尾涡的一般扩散。对于强度不等的复合剪切层，增长最快的模式显示出从尾流行为到…
The stability of two adjoining vortex layers with constant vorticity of opposite sign is analyzed. Linear stability analysis shows that two families of instability may exist, depending on the relative strength of the vortex layers. The first type for moderate and long waves produces simultaneous growth of disturbances on both layers, while the second for short waves is associated primarily with the weaker layer. Numerical calculations show that the nonlinear growth of the various types of instability leads to asymptotic states of different character. For wake‐like flows with equal but opposite vorticity distributions, the fastest growing eigenmodes lead to the formation of a classic vortex street with an aspect ratio of 0.345. Longer waves lead to the break up of the layer into a number of small vortex regions producing disorganized motion and a general dispersal of the wake vorticity. For compound shear layers with unequal strength, the fastest growing modes show a progression from wake‐like behavior to ...