Variational multiscale framework for cavitating flows

A numerical formulation for the modeling of turbulent cavitating flows is presented. The flow field is governed by the 3D, time-dependent Navier-Stokes equations for a compressible isothermal mixture. The Arbitrary Lagrangian-Eulerian Variational Multiscale (ALE-VMS) formulation is adopted to model the turbulent flow on moving domains with no-slip boundary conditions imposed weakly. The formulation is first tested on the cavitating flow over a 2D NACA0012 airfoil and compared to published numerical results. Next, the framework is applied to the benchmark problem for the flow over a hemispherical fore-body. The numerical results are compared to the reported experimental data, showing a good agreement over the range of cavitation numbers. Finally, the simulation of a hydrokinetic turbine in cavitating flow at a low cavitation number is presented in order to test the stability of the formulation and the capability to handle real engineering problems involving turbulent cavitating flows on moving domains.