混合层中四涡合并过程的数值研究

Numerical Research on the Merging of Four Vortices in a Mixing Layers

用拟谱方法对混合层四涡合并的规律进行了数值研究 .分析了基波和次谐波之间相位差对涡合并过程的影响 ,并引入旋转点和拉伸点的概念对这种影响进行了解释 .计算结果表明 :四涡的合并存在 6种形式 ,因此 ,可以通过施加多级次谐波并改变它们之间的相位差来主动控制拟序涡的发展和演变 .

The merging of four vortices in mixing layers are simulated numerically with the pseudo spectral method. The effect of phase differences among disturbance waves is examined. The results show that the processes of vortex merging are strongly influenced by changing phase differences. It is observed that there are six ways for amalgamation of four vortices. Therefore, the evolution of vortices can be controlled positively by superimposing multi harmonics and changing their phase differences.