Lift-drag characteristics and unsteady cavitating flow of bionic hydrofoil

Abstract

The hydrofoil, a basic blade cross-section shape, is widely used in various hydraulic machinery. We establish two bionic hydrofoil models (Sside and Stop) through 3D reverse engineering and numerically simulate these models with large eddy simulation to reveal the transient evolution mechanism of the cavitating flow of a bionic hydrofoil. The simulation results of the classic Clark-Y hydrofoil are highly consistent with the experimental results. In a single cycle, the lift–drag coefficient is related to the leading edge amount and cavity range. The cavitation number affects the lift–drag coefficient and cavity length L, and large cavitation numbers are associated with small values of lift–drag coefficient and cavity length. In contrast to the Sside scheme, the Stop scheme forms a relatively stable attachment vortex near the leading edge, the influence range of the vortex stretching is weak, and the baroclinic torque term that determines the cavity vortex is enhanced. The pressure fluctuation shown by the trailing edge of the bionic hydrofoil is significantly greater than that shown by the leading edge, and the main frequency of pressure fluctuation is proportional to the cavitation number.