二维可压缩流体Kelvin-Helmholtz不稳定性

Kelvin-Helmholtz instability in compressible fluids

利用高精度数值格式,研究了二维可压缩流体中的Kelvin-Helmholtz不稳定性,主要研究了可压缩性对Kelvin-Helmholtz稳定性增长率的影响.模拟定量的给出低Mach和高Mach数两种情况下,初始静压和对流Mach数以及Kelvin-Helmholtz不稳定性线性增长率的关系.模拟结果和自由剪切层以及混合层的实验结果以及理论分析一致.模拟表明,对流Mach数是描述流体可压缩性的合适参数,对流Mach数越小流体越不可压,Kelvin-Helmholtz不稳定性的线性增长率随对流Mach数的增加而减小.

Kelvin-Helmholtz instability in two-dimensional compressible fluid is analyzed by the high precision numerical scheme. The linear growth rate of the Kelvin-Helmhohz instability is especially explored. The relations among the initial static pressure, conductive Mach number and linear growth rate of the Kelvin-Helmholtz instability are quantitatively achieved at the case of the low and high Mach numbers. The simulation results agree with the experiment results in free shear layers and mixing layers. Simulation results show that the conductive Mach number is the proper parameter in definition the compression effect. The smaller the conductive Mach number is, the less compressible the fluid is. The linear growth rate of the Kelvin-Helmholtz instability decreases with the increasing conductive Mach number.