Numerical Simulation of Hydrofoil Cavitation in Pitching Motion

Abstract

Based on CFD, the NACA4412 pitching motion hydrofoil is compared and analyzed for the lift/drag coefficient, the pressure and the gas volume fraction at different attack angles. The result is that the lift/drag coefficient curve of the dynamic hydrofoil is a closed curve. When the hydrofoil is pitching up, the lift/drag coefficient will be generally greater than that in the static state, which first increases and then decreases as attack angles increases. When the hydrofoil is down, the lift/drag coefficient will be generally smaller than that in the static state, which first decreases and then increases as attack angles decreases. Moreover, when the hydrofoil is pitching upwards, there will be a sudden change in pressure on the subsurface, resulting in an extreme value. In addition, there is more comprehensive cavitation on the upper surface of the dynamic hydrofoil, and local cavitation on the subsurface.