COMPUTATION OF THE FREE SURFACE FLOW OF A THIN LIQUID FILM AT ZERO AND NORMAL GRAVITY

Abstract

The results of numerical computations are presented for the free surface flow of a thin liquid film in the presence or absence of a gravitational body force. Three different flow systems were studied: a falling film down a vertical wall, plane and radial film flows under zero gravity, and plane and radial film flows along a horizontal plate in the presence of gravity. Computations were performed using a boundary-fitted coordinate system where the irregular free surface conformed to one of the flow boundaries. The distributions of film height and friction coefficient were found to be strongly affected by the magnitude and orientation of the gravitational body force. Besides the Reynolds number, the Froude number of the film, which characterizes the flow regime (i.e., supercritical or subcritical), is found to be an important parameter for horizontal flow in the presence of gravity.