Numerical solving of incompressible Navier-Stokes equations using an original local multigrid refinement method

Numerical simulation of complex flows involving unsteady structures, bounda ry layers or free surfaces on a unique grid is very greedy in time and CPU because a great number of calculation point is needed to ensure a satisfact ory description of the different scales of the problem. An original local m ultigrid method, able to refine the grid at the cell scale, is proposed to solve the Navier-Stokes and energy equations. The results obtained for the natural convection in a square cavity are compared to the one of the litera ture for Rayleigh numbers in the range 10(5)-10(8). (C) 2000 Academie des s ciences/Editions scientifiques et medicales Elsevier SAS.