Numerical Simulation of 2-D Supercavitation and Partial Cavitation, Using Boundary Element Method

In this work, potential flow with supercavitation and partial cavitation has been studied, using boundary element method. For this purpose, vortex distribution is used in the boundary of the flow. The impermeable condition is used on the wetted surface of the hydrofoil-cavity (zero vertical velocity), while constant tangential velocity condition is used on the wetted surface of the cavity; the Kutta condition is also used at the trailing edge of the hydrofoil for partial cavitation and the continuity of tangential velocity condition is used for supercavitation. In this method, the length of the cavity is assumed to be known and an initial guess for the cavity shape is considered. The results of the numerical solution of partial cavitation flow around NACA0009 hydrofoil and supercavitation from over a flat surface and a wedge are compared with the experimental results. The results in partial cavitation show the accuracy of this numerical method for cavity length of less than 75% of the cord. Thus, for better accordance with the experimental results, a new method is used in which this method, the effect of a counter clockwise independent vortex, which is formed downstream of the flow in partial cavitation, has been studied. Furthermore, the effect of changing the cavity starting point has been studied, which shows that it does not have great influence on the ratio of thickness to length of the cavity.