Abstract
A standing wave with a peak line toward downstream appears on the surface of a liquid film flowing around a horizontal circular cylinder. The amplitude of the wave grows in the downward direction and finally a part of the wave separates from the film. A theoretical model was proposed to explain the physical mechanism of separation. The wave peak would separate when the resultant of the centrifugal force, gravitational force, surface tension and negative pressure acting on the wave root is not sufficient to supply the flow rate necessary to maintain the wave amplification. The points of separation on the cylinder were calculated theoretically for three kinds of test liquids, i.e., water, ethanol and glycerin solutions. The results agree with those from experiments for various flow rates of the film flow.
