Exploratory RANS simulations of partial cavitation and its dynamics

Partial cavitation on a 2D foil at given incidence goes through various stages when the cavitation number is lowered. This paper explores by numerical simulation the transition from more or less steady to dynamic behaviour, eventually leading to periodic shedding of vapour clouds. Cavitation modeling is in this paper based upon the single, variable-density fluid approach, solving the RANS equations with the k-ω SST turbulence model and the Sauer/Schnerr mass transfer model. Results are presented for the NACA0015 foil at six degrees incidence. Effects of spatial and temporal resolution are included in the investigation. When shedding of vapour clouds occurs, the results clearly show that it is accompanied with dynamic stall behaviour, i.e. the flow on the suction side of the foil is intermittently separated and attached