Numerical simulation and experimental study of water entry of a wedge in free fall motion

The hydrodynamic problem of a two-dimensional wedge entering water through free fall motion is analysed based on the velocity potential theory. The gravity effect on the flow is ignored as our interest is over a short period of time. When the tip of the wedge touches water the flow is assumed to be similar. The problem of this similarity flow is solved by a boundary element method together with an analytical solution for the jet based on the shallow water approximation. This is then used as the initial condition for the subsequent solution which is obtained by the same boundary element method in a stretched coordinate system together with the time marching technique to follow the body motion and the free surface deformation. An auxiliary function is introduced to decouple the mutual dependence of the hydrodynamic force and the body acceleration. Experimental study is also undertaken. The numerical predication is found to be in good agreement with the measured data for wedges with different weight, dead-rise angle and entry speed. (C) 2004 Elsevier Ltd. All rights reserved.