VELOCITY PROFILE IN "CALMING ZONE" OF FALLING LIQUID FILMS ON INCLINED PLATES

Abstract

Falling liquid films on inclined plates have been experimentally studied with special attention to the "calming zone", where the surface is mirror-like in the range of Re from 2500 to 6000.
Velocity profile by the hydrogen bubble method and film thickness by the pointer and gauge method were measured, and the film surface behavior was observed by laser beam reflection. Film flow in the calming zone is laminar with air drag at the air-liquid interface.