Calculation of tip vortex cavitation flows around three-dimensional hydrofoils and propellers using a nonlinear k-ɛ turbulence model

Simulations of tip vortex wetted flows and cavitating flows are carried out by using a RANS model. Two types of turbule- nce models, with and without the Boussinesq turbulent-viscosity hypothesis, are adopted in comparing with experimental results regarding the vorticity, the strain rate and the Reynolds shear stress distributions in the vortex region. The numerical results imply that the spatial phase shift between the mean strain rate and the Reynolds stresses can be accurately modeled by the nonlinear k-ɛ turbulence model, the tip vortex cavitation region can only be predicted using the nonlinear k-ɛ turbulence model. The mecha- nism of the over-dissipation due to the turbulence model is analyzed in terms of the turbulence production, which is one of the dominant source terms in the transport equations of energy.