Numerical investigations of the Kelvin-Helmholtz instability based on a multi-resolution Moving particle Semi-implicit method

The Multiphase Moving Particle Semi-implicit (MMPS) method is adopted to simulate the Kelvin-Helmholtz instability (KHI) process in an incompressible viscous two-phase immiscible fluid. To capture the interface more accurately, a multi-resolution technique is developed, which mainly involves the novel number density calculation and a modified discretization. Single-mode disturbance KHI cases were studied and quantitatively compared with analytical solutions, showing good agreement with theoretical predictions. The effect of density ratios, Reynolds numbers, and Richardson numbers controlled separately by gravitation and surface tension on the interface disturbance behavior, velocity fields, vorticity distribution, and the rolled-up height are investigated. Multi-mode KHI is simulated, and absorption of small wavelength disturbances by the larger ones is observed. Cases with realistic physical properties are carried out at the end of this study to show the potential of the current method in simulating the realistic scenario in nuclear reactor.The study could offer potential contributions to the safety analysis of nuclear reactors.