Numerical Investigation for Air Cavity Formation During the High Speed Water Entry of Wedges

In this paper, a nonlinear boundary element method is developed for investigating the air cavity formation during the high speed water entry of wedges. A novel technique is introduced to remove the saw-tooth instability of the free surface profile, which is often encountered in solving violent free surface flow problems by boundary element methods. This technique applies to both the equally spaced grids and the non-equally spaced grids, and is demonstrated to be quite efficient and practical by numerical simulations. When the flow reaches the knuckle of the wedge, separation will occur. The authors develop a purely numerical method to simulate the non-viscous flow separation. This nonlinear BEM has been verified by comparisons with similarity solutions. We also compare the numerical results with experimental results.