MPS (Moving particle semi-implicit) method is one of the popular particle methods. It is well known that calculation instability occurs especially for a slow fluid flow analysis, and the instability appears as unnatural pressure and velocity oscillation. This is because the MPS method adopts predictor-corrector method, and tentative position of particles are not corrected enough at the corrector phase. Therefore an improved multiple relaxation method is proposed in this study to improve the calculation stability. Pressure and velocity correction is conducted multiply in the correction phase, and also adjusting coefficient is adopted in the source term in the Poisson equation for the pressure. As a result, the proposed method improved the pressure and velocity distribution instability. The method was applied to complex shaped casting with a shoulder. The conventional method showed unnatural high pressure and the fluid hopped, whereas smooth and natural pressure field could be obtained using the proposed method.

This Paper was Originally Published in Japanese in J. JFS. 87 (2015) 702–708.