Level set method for numerical simulation of a cavitation bubble, its growth, collapse and rebound near a rigid wall

摘要

A level set method of non-uniform grids is used to simulate the whole evolution of a cavitation bubble, inclu-ding its growth, collapse and rebound near a rigid wall. Single-phase Navier-Stokes equation in the liquid region is solved by MAC projection algorithm combined with second-order ENO scheme for the advection terms. The moving inter-face is captured by the level set function, and the interface velocity is resolved by "one-side" velocity extension from the liquid region to the bubble region, complementing the second-order weighted least squares method across the inter-face and projection inside bubble. The use of non-uniform grid overcomes the difficulty caused by the large computatio-nal domain and very small bubble size. The computation is very stable without suffering from large flow-field gradients, and the results are in good agreements with other studies. The bubble interface kinematics, dynamics and its effect on the wall are highlighted, which shows that the code can effecti-vely capture the "shock wave"-like pressure and velocity at jet impact, toroidal bubble, and complicated pressure struc-ture with peak, plateau and valley in the later stage of bubble oscillating.