USE OF THE MOMENTUM INTERPOLATION METHOD FOR FLOWS WITH A LARGE BODY FORCE

Abstract

A numerical study of the use of the momentum interpolation method for flows with a large body force is presented. The inherent problems of the momentum interpolation method are discussed first. The origins of problems of the momentum interpolation method are the validity of linear assumptions employed for the evaluation of the cell-face velocities, the enforcement of mass conservation for the cell-centered velocities, and the specification of pressure and pressure correction at the boundary. Numerical experiments are performed for a typical flow involving a large body force. The numerical results are compared with those by the staggered grid method. The fact that the momentum interpolation method may result in physically unrealistic solutions is demonstrated. Numerical experiments changing the numerical grid have shown that a simple way of removing the physically unrealistic solution is a proper grid refinement where there is a large pressure gradient. An effective way of specifying the pressure and pressure correction at the boundary by a local mass conservation near the boundary is proposed, and it is shown that this method can effectively remove the inherent problem of the specification of pressure and pressure correction at the boundary when one uses the momentum interpolation method.