界面不稳定性引起混合过程的二维数值计算
Two-dimensional simulation of the mixing induced by interface instabilities
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摘要: 在可压缩多介质流体动力学高精度欧拉计算方法多介质流体分段抛物方法(multi-fluid piecewise parabolic method, MFPPM)基础上，运用算子分裂技术，增加二阶空间中心差方法和两步Rung-Kutta时间推进方法计算动力学黏性以及热流部分对流场的影响，发展适用于NS(Navier-Stokes)方程的可压缩多介质黏性流体计算方法多介质黏性流体分段抛物方法(multi-viscousity-fluid piecewise parabolic method, MVPPM). 文中采用MVPPM对英国AWE(atomic weapons establishment)激波管实验进行二维计算，给出了与实验图像基本一致的计算结果；应用MFPPM和MVPPM分别对二维柱对称内爆动力学界面不稳定性及其后期混合过程进行数值模拟，给出内外界面演化、速度历史以及后期中心气穴不同半径内因RT(Rayleigh-Taylor)界面不稳定性引起的混合量分布情况，从计算结果比较可见黏性对物质界面处混合量的分布影响明显.
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关键词:
- 界面不稳定性 /
- 混合 /
- 多介质粘性流体 /
- 高精度计算格式 /
- Navier-Stokes方程
Abstract: The compressible multi-viscousity-fluid piecewiseparabolic method (MVPPM) is developed for Navier-Stokes equations based onthe Eulerian multi-fluid piecewise parabolic method (MFPPM), the secondorder space central difference method and two-stage Rung-Kutta time marchingmethod. Simultaneously, a common mathematical approach, operator splittingtechnique was applied to obtain the molecule dynamics viscosity and heatflux effects on flow field. With the application of MVPPM, a numerical caseof a two-dimensional shock wave tube experiment from Atomic WeaponsEstablishment (AWE) is investigated to show a good agreement with theexperimental results. Moreover, the interface instability and subsequentmixing model of implosion dynamics are simulated with MFPPM and MVPPM in thetwo-dimensional cylindrical symmetry case. The evolvement of the inner andouter interfaces, velocity history and the distribution of subsequent mixingin the central cavitations induced by Rayleigh-Taylor (RT) interfaceinstability are obtained. The effect of dynamics viscosity on the mixingdistribution in the interface was clearly observed in the numerical results. -
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