ON THE NUMERICAL SOLUTION OF RECIRCULATING BUBBLES AT LARGE REYNOLDS NUMBER

The convergence of numerical solutions in recirculating flows at large Reynolds number has been studied by means of both theoretical and numerical analysis. In particular a flow with a large recirculating bubble has been computed at different Re by two numerical schemes over halving meshes. The study shows that to obtain a grid-independent Navier-Stokes solution, different grid-requirements depending on Re have to be satisfied in the bubble core and in the bubbleboundary. Concerning the numerical solutions of Euler equations it is shown that they are scheme dependent and do not represent the limit of Navier-Stokes solutions as Re tends to infinity.