ON THE MODEL-EQUATIONS OF GIBILARO AND FOSCOLO WITH CORRECTED BUOYANCY FORCE

This note is intended to provide modifications to several conclusive model equations presented by Gibilaro and Foscolo. These equations appeared in their work concerning drag force, dynamic wave velocity and stability criterion. The modifications are made by considering the correct buoyancy force expression which is based on the density of fluid alone. The presentation is preceded by brief reviews and comments on pertinent literature which lead to the assertion that the expression of the buoyancy force should be based on the density of the fluid rather than that of fluid-particle suspension as claimed by Gibilaro and Foscolo.