Two numerical models for unsteady cavitating flows in turbomachinery are developed at The Turbomachinery and Cavitation team of LEGI (Grenoble). The first one was entirely developed in the laboratory for 2D unsteady flows, with the support of the French Space Agency CNES. It applies a pressure-correction method derived from the SIMPLE algorithm and a finite volume discretization on structured meshes. The second model for 3D flows has been developed in the FINE/TURBO TM CFD code in collaboration with the Numeca International society. The solver is based on an artificial compressibility method (preconditioning technique) with dual time stepping, adapted to the very large variation of the Mach number. The models are based on a single fluid approach to describe the liquid-vapour mixture. Applications are mainly performed using a barotropic state law to manage the relation between the local static pressure and the mixture density. The alternative consisting in solving a supplementary equation for the void ratio including empirical terms for vaporization and condensation has been tested in the 2D model and some comparative results between both physical approaches are presented. The lecture presents also a comparison between results obtained by the two numerical models on 2D unsteady cavitating flows, making use of the barotropic approach. A discussion about the influence of the numerical and physical parameters is proposed. Finally, examples of applications to 3D cavitating flows in centrifugal pump and turbopump inducer geometry are presented
