Simulation of a gas bubble compression in water near a wall using the SPH-ALE method

Abstract

Abstract This paper is motivated by the cavitation phenomenon, which occurs when bubbles collapse near a hydraulic machine surface. The bubble compression close to the wall has been addressed as the fundamental mechanism producing cavitation damage, whose general behavior is characterized by the emission of pressure waves and the formation of a micro jet. In order to simulate the collapse of a gas bubble in water, it is proposed a multiphase and compressible model developed in SPH-ALE. This model does not diffuse the interface and guarantees the continuity of normal velocity and pressure at the interface between both fluids, allowing it to deal with interfaces of simple contact. The model solves the mass, momentum and energy conservation equations of Euler system using an equation of state for each phase without phase change. The compressible model was validated through monodimensional configurations, such as shock tube test cases for monophase and multiphase flows. Bubble collapse simulations in 2D are presented highlighting the principle features, i.e. pressure waves and micro jets. Also, it is analyzed the effect of the initial distance between the bubble and the wall ( H 0 ). Limitations and perspectives of SPH-ALE method on this particular subject are also discussed.