CFD Simulation of Cloud and Tip Vortex Cavitation on Hydrofoils

The onset of cavitation around propellers, hydrofoils, ships, etc represents an important issue in terms of reduced performance, erosion and passenger/crew comfort due to cavitation induced vibrations and noise among other drawbacks. Consequently cavitation has been studied by many researchers, but up to now most of the investigations are still experiments. Since experimental investigations for marine applications are expensive, CFD simulations represent a powerful tool in order to investigate the phenomenon and consequently to improve the design of such components. A model to deal with cavitation and the pressure fluctuations introduced by it has been developed in ANSYS CFX, and a validation of it has been carried out. Two test cases have been chosen for this purpose. The first one is a 2D case containing a plano-convex profile, where cloud cavitation can be observed. The second one consists of a 3D case, where the fluid flows around a NACA 66 2-415 hydrofoil. A tip vortex is generated with high radial velocity gradients originating cavitation. In both cases the simulations have been carried out on refined grids and the numerical results have been compared to those in literature, showing good agreement with them in most of the cases.