LIQUID FILMS FLOWING CONCURRENTLY WITH AIR IN HORIZONTAL DUCT (5TH REPORT, INTERFACIAL SHEAR STRESS).

Abstract

Interfacial shear stress was measured for a thin liquid film flowing concurrently with air flow under wide ranges of gas and liquid flow rates in which various kinds of wave structures or flow patterns are realized. The results are summarized as follows: (1) Interfacial shear stress depends on flow pattern besides the condition of air flow. (2) The waves on the liquid film are not equivalent to the roughness on a solid wall especially for a higher air flow even when the crests of waves on the film do not jut above the viscous sublayer. (3) A correlation for friction factor which is equivalent to shear stress was proposed for the cases of turbulent air flow.