A Conservative and Entropy-Nondecreasing Subgrid Closure Model for Two Compressible Materials in a Grid Cell

摘要

A general and robust subgrid closure model for two materials in a cell is proposed. The conservative quantities of the entire cell are apportioned between two materials, and then pressure and velocity are fully or partially equilibrated by modeling subgrid wave interactions. A unconditionally stable and entropy-satisfying solution of the processes has been successfully found. The solution is valid for arbitrary level of relaxation. The model is numerically designed with care for any EOS, and is computational efficient without recourse to subgrid iterations or stepping. The generality, robustness and efficiency of the model make it useful in algorithms, such as arbitrary Lagrangian-Eulerian methods, VOF methods and even some mixture models, for compressible two-phase flow computations.