Numerical Simulation of Free-Surface Flows around 3-D Submerged Hydrofoil by N-S Solver

The N-S solver is applied to investigate the flow characteristics of 3-D submerged foil with free-surface. Flows of five different cases are simulated and compared each other to discuss the free-surface effects on 3-D hydrofoils where the submergence depth and angle of attack are changed. The no-slip condition used for the viscous flow realizes the shock-free condition for pressure around the trailing edge, which proves to be an advantage of the present numerical simulation over the potential method where Kutta condition is imposed. Through the numerical computation, it is found that the lift and drag are seriously influencd by the free-surface waves which are affected greatly by the submergence depth and angle of attack. The large-amplitude waves, under the suspect of breaking, have much influence on the lift and drag forces because the pressure fields are seriously affected by the waves. The righting moment, which comes from the non-symmetrical lift distribution along the span, is also calculated for the heeled case.