Enhancement of performance and stability of MPS mesh-free particle method for multiphase flows characterized by high density ratios

The paper presents an enhanced stabilized MPS (Moving Particle Semi-implicit) method for simulation of multiphase flows characterized by high density ratios. The developed method benefits from four previously developed schemes [1] as well as a novel one proposed for accurate, consistent modeling of density at the phase interface. The new scheme can be considered as an extended version of a commonly applied density smoothening scheme and is shown to keep the sharpness of spatial density variations while enhancing the stability and performance of simulations. Further, the paper highlights the importance of applying a Taylor series consistent scheme for calculation of pressure gradient in multiphase MPS-based simulations. By presenting a simple perturbation analysis, it is shown that some commonly applied MPS-based pressure gradient models are prone to increase the level of unphysical perturbations at the phase interface leading to numerical instabilities. The original MPS gradient model with a Gradient Correction [1] is shown to provide stable and accurate results even in case of violent multiphase flows characterized by high density ratios.