A mesh-free numerical method for direct simulation of gas-liquid phase interface

A numerical method is presented for mesh-free calculation of moving interfa ce problems in two-phase flow In this method, the moving particle semi-impl icit (MPS) method is combined with the meshless advection using flow-direct ional local-grid (MAFL) method, for an arbitrary Lagrangian-Eulerian calcul ation. Moving interfaces ar-e directly traced in Lagrangian coordinates, wh ile fixed boundaries such as inlet and outlet flows are calculated in Euler ian coordinates. The phase interface in two-phase flow is clearly calculate d by tracing the computing points on the bubble surface. A calculation mode l for surface tension force is presented using the curvature of radius. The volume decrease in a gas bubble due to surface tension force is successful ly computed. A kernel function with a variable kernel size is introduced to allow local concentration of computing points. A two-dimensional hear diff usion problem is solved using the variable kernel size model, and the resul t agrees with the exact solution. The void generation process in superheate d liquid is simulated using the present method The calculated bubble growth rate exactly coincides with the analytical solution. Rising bubble shapes in viscous liquid are also simulated in two dimensions, and the estimated s hapes show good agreement with those of experiments.