3维Mortar谱元法模拟Kelvin-Helmhtz不稳定性混合层

采用Mortar谱元法和多处理器并行计算技术模拟了Kelvin-Helmhtz界面不稳定性湍流的混合发展过程，通过对混合层动量厚度、能谱和总动能的计算，评估了Kelvin-Helmhtz混合层的演化机理。计算结果表明:3维Mortar谱元法具有高计算精度和光滑区域的指数收敛特性，可以有效模拟混合层流动的湍流混合和演化，能够捕捉到涡的合并现象和大涡到小涡的级联过程；初期的混合层层流运动发展成具有连续谱结构的湍流运动过程，实现了Kelvin-Helmhtz界面不稳定性混合层流动从2维发展到3维的转捩特征，总湍流统计动能的变化反映了粘性耗散过程的作用。通过对Kelvin-Helmhtz 3维界面不稳定性混合层流动和3维层流向湍流转捩过程的数值模拟，程序的有效性得到了验算，表明谱元法应用于湍流混合模拟是可行的。

Simulation of Kelvin-Helmhtz instability with three-dimensional Mortar spectral element method

The Mortar spectral element method and message passing interface(MPI) parallel computation technique have been used in studying turbulent mixing of Kelvin-Helmhtz instabilities, and the evolution mechanism of Kelvin-Helmhtz instabilities has been estimated with the calculation of momentum thickness, energy spectrum and total kinetic energy. The results show that, the three-dimensional Mortar spectral element method can effectively capture the turbulent mixing of Kelvin-Helmhtz instability, with cascading and combination of turbulent eddies clearly shown. In addition, the initial laminar fluid flow of Kelvin-Helmhtz instability gradually developed into a turbulent flow with continuous spectrum structure in the simulation, thus two-dimensional to three-dimensional transition can be achieved. The statistical turbulent kinetic energy reflects the viscous dissipation of the turbulent mixing. The validity of the spectral element co