Numerical simulation of underwater explosion bubble with a refined interface treatment

With the intermediate flow states predicted by local two phase Riemann problem, the modified ghost fluid method (MGFM) and its variant (rGFM) have been widely employed to resolve the interface condition in the simulation of compressible multi-medium flows. In this work, the drawback of the construction procedure of local two phase Riemann problem in rGFM was investigated in detail, and a refined version of the construction procedure was specially developed to make the simulation of underwater explosion bubbles more accurate and robust. Beside the refined rGFM, the fast and accurate particle level set method was also adopted to achieve a more effective and computationally efficient capture of the evolving multi-medium interfaces during the simulation. To demonstrate the improvement brought by current refinement, several typical numerical examples of underwater explosion bubbles were performed with original rGFM and refined rGFM, respectively. The results indicate that, when compared with original rGFM, numerical oscillations were effectively removed with the proposed refinement. Accordingly, with present refined treatment of interface condition, a more accurate and robust simulation of underwater explosion bubbles was accomplished in this work.