二维气/液界面不稳定性数值模拟

摘要

以多介质的体积分数方法和三阶PPM(Piecewise Parabolic Method)方法为基础,给出了适用于多介质流体动力学数值模拟的计算方法和程序MFPPM.利用MFPPM程序对在高压气体冲击作用下的气体/液体交界面的Richtmyer-Meshkov (RM) 不稳定性及其引起的流体混合现象进行了数值模拟研究.主要研究在不同的初始扰动情况下流体混合区的发展,并细致研究了流体混合区的宽度、气泡和尖钉高度随时间的增长情况及不同初始扰动对它们的影响;同时还研究了网格尺度不同时混合区、气泡以及尖钉的构型和高度的增长情况.通过对计算结果的分析得出,流体混合区、气泡以及尖钉的发展与初始扰动有密切的关系,特别是在后期影响更为显著;混合区宽度的变化过程和尖钉相似,而气泡高度的变化基本上呈线性增长趋势,且受初始扰动的影响比较小,但是其构型却有明显差别;网格的影响也主要体现在对混合区、气泡和尖钉的构型上.%On the basis of multi-fluid volume fraction(VOF) and piecewise parabolic method(PPM),a multi-fluid hydrodynamic program MFPPM(Multi-Fluid Piecewise Parabolic Method) was developed and performed to study the Richtmyer-Meshkov instability of gas/liquid interface.The influences of initial perturbations and grids on the fluid mixing zone(FMZ) were mainly researched when it is accelerated by shock waves,and the FMZ width,bubble and spike height growing with time were presented simultaneously.By comparing the computational results,it shows that the initial perturbations affect the FMZ growth rate extremely,especially at late times.The evolution of spike is similar to the FMZ,the bubble height increases linearly with time basically,and influenced little by initial perturbations,but the configuration is quite different,and as the effect of grid size is.