SIMULATION ON THE INTERACTION BETWEEN RISING BUBBLES AND FREE SURFACE BY ISPH-FVM COUPLING METHOD

The interaction between the rising bubble and the free surface involves complex interface topological evolution, which has been one of the problems in the field of bubble flow. To investigate the dynamic behavior of the interaction between rising bubbles and free surface, an ISPH-FVM coupling method is proposed by combining incompressible smooth particle hydrodynamics (ISPH) and finite volume method (FVM). In the ISPH-FVM coupling method, the information exchange between particles and grids is realized by kernel approximation interpolation technique, and the continuous surface stress model (CSS) is introduced into the present coupling algorithm framework to evaluate the surface tension effect at the phase interface. In addition, the CSS model is discretized and calculated by the volume fraction defined on the FVM grid, and the volume fraction on the grid is obtained by kernel approximate interpolation of ISPH particles in the grid support domain. Subsequently, the ISPH-FVM coupling method is used to simulate the oscillation of circular bubble at the equilibrium state and the single bubble rising, the simulation results are compared with other numerical simulation results to verify the convergence of the surface tension model and the accuracy of the interface tracking in the present coupling method. To test the performance of ISPH-FVM coupling method in predicting bubble flow problems involving complex topological changes, the dynamic behavior of the interaction between rising bubbles and free surface is analyzed, and the effects of different weber number (We) and Reynolds number (Re) on the interaction between bubbles and free surface are also studied. The results show that with the increase of We number, the interface will be greatly deformed and distorted when rising bubbles interact with the free surface, and the number of entraining droplets will increase accordingly. However, the evolution of the interface during the collapse of the rising bubble is basically similar and there is no significant difference with the increase of Re number.