A numerical investigation of non-uniform film flow

Abstract

The problem of non-uniform film flow is considered and numerical solution of an approximated equation of motion and the mechanical energy equation are compared. The study is restricted to “convergent” films. Solution of the equation of motion indicates that away from an “entrance” region in which the velocity profile undergoes major rearrangement the profile is given by: ▪ This is termed “similarity” and occurs at positions away from the equilibrium film thickness. The position of a specified approach to “similarity” and the film thickness at that point are shown to be unique functions of the initial film thickness and correlations are presented. The usual assumptions in the derivation of the mechanical energy equation are discussed in detail. It is demonstrated that the basic assumption is that of profile “similarity”.