The stability criterion based on the spurious pressure oscillation analysis of MPS method

The Moving Particle Semi-implicit (MPS) method has been widely used in nuclear engineering due to its unique advantages in capturing moving interfaces. However, the unphysical numerical oscillation in MPS method is still a hotspot and difficulty in current study, and also a bottleneck hindering its high-accuracy numerical simulation of nuclear engineering. To obtain more accurate and stable numerical simulation, the spurious pressure oscil-lation behavior is studied theoretically and numerically. Through theoretical analysis, it is found that the incompressible compensation term is the main cause of spurious pressure oscillation. Besides, three mainstream forms of PPE are analyzed in detail. The simulations are carried out to study the effects of corrective matrix, time step, external force, numerical resolution and velocity on pressure oscillation. Finally, the stability criterion of spurious oscillation phenomenon is newly proposed to determine the time step, and reliable simulation results are obtained as well.