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Scale-adaptive simulation of unsteady cavitation around a Naca66 hydrofoil

Abstract:

The present paper focuses on the numerical simulation of unsteady cavitation around a NACA66 hydrofoil to improve the understanding of the cavitation effects on hydraulic machinery. For this aim, the Zwart-Gerber-Belamri cavitation model was updated and uploaded as a library file for OpenFOAM's solvers using C++ language. Furthermore, the hybrid Reynold average Navier-Stokes (RANS)-large eddy simulation (LES) model k ω w SST scale adaptive simulation (SAS) was implemented as a turbulence model for the present study of scale adaptive simulation. For validation, numerical results were compared with experimental results obtained by Leroux at the Naval Academy Research Institute in France. In order to highlight the benefits in terms of computational consumption and reproduction of the phenomenon the k ω w SST SAS model was compared against implicit large eddy simulation (ILES). Results show that the cavitation evolution including the maximum vapor length, the detachment and the oscillation frequency were reproduced satisfactorily using k ω w SST SAS. Moreover, k ω w SST SAS results pbkp_redicted a lower total vapor volume on time than ILES, which is related to observed pulses of pressure coefficient, Cp, and those match fairly well with the experimental results. To summarize, the k ω w SST SAS model pbkp_redicts with good accuracy unsteady cavitation behavior around hydrofoils and shows improved versatility over the ILES approach.