Note on the use of momentum interpolation method for unsteady flows

Further modification of the Rhie-Chow scheme based on the momentum interpolation method is necessary for the simulation of unsteady flows to obtain a convergent solution that is independent of the size of the time step and relaxation factors. The problems associated with the use of the Rhie-Chow scheme can be removed by strictly writing down the discretized momentum equations for the cell face and cell-centered velocity components, with all the important terms expressed explicitly. The equations for the cell face velocity components are derived by employing suitable assumptions. The accuracy of the method is dependent on the validity of the assumptions used.