Cavitation aggressiveness on a hydrofoil

Abstract

To improve the analyses of the cavitation erosion phenomena, cavitating flows around an instrumented hydrofoil were studied experimentally and numerically. The experiments allowed the assessment of cavitation aggressiveness by measurements from PVDF pressure sensors. A matrix of 8 PVDF sensors was built, installed and tested for several hydrodynamic conditions corresponding to different flow velocities, angles of attack and cavitation numbers. The unsteady cavitating flows were simulated by applying the in-house 2D code, referred to as "IZ". Unsteady Reynolds Averaged Navier-Stokes equations were solved for a homogeneous fluid with variable density. To model the cavitation phenomenon and to close the governing equation system, a barotropic state law was used associated with a modified k-ϵ RNG turbulence model. In order to evaluate the cavitation aggressiveness, simulations were coupled with a cavitation erosion model based on the energy balance between the cavitating flow, the vapour bubble collapses, the emitted pressure waves, and the neighbouring solid walls. The paper presents the experimental and numerical tools, the post-processing methodologies and the obtained results. A method was proposed to assess locally the cavitation aggressiveness from both numerical and experimental results and the two approaches were compared.