一种改进的多介质ALE动量重映算法

传统多介质任意拉格朗日欧拉(arbitrary Lagrange-Euler,ALE)方法在解决强间断、大变形等问题时,采用现有的重分重映算法进行计算会出现耗散现象.在计算过程中,为保证计算结果的可靠性并提高算法的鲁棒性,往往需要多次的重分重映计算,导致耗散现象更加严重,甚至出现非物理的计算结果.通过对传统重映算法进行测试和分析研究,发现了重映过程中数值耗散的产生机理,并对传统重映算法进行了改进,使得其在满足质量守恒、动量守恒和能量守恒的基础上,更好地还原重分重映前的物理场空间分布,从而提高了重映算法的计算精度和计算结果的可靠性,有效解决流体力学中强间断、高密度比、高压力比和强冲击等问题.

A New Remapping Method to Suppress Velocity Nonphysical Propagation

The severe numerical dissipative phenomenon exists in the multi-material arbitrary Lagrange-Euler (ALE) method with original remapping algorithm when strong discontinuities and large deformations are simulated. In order to improve reliability of calculation results and robustness of the algorithms, it is necessary to use repeated re-mapping technique. Through some numerical tests and analysis with the traditional remapping technique, it was found that the numerical dissipation meets with nonphysical velocity. Then, an improved remapping method was presented, which not only restores the spatial distribution of the physical field but satisfies mass conservation, momentum conservation and energy conservation. Thus the new method shows more accuracy and reliability for the numerical simulation of hydrodynamic problems such as strong discontinuities, high density-ratio, high pressure-ratio, and strong shocks.