An experimental investigation of oscillating flow in a tapered channel

Abstract

Oscillating flow in a tapered channel was studied experimentally by observing the deformation of a dye streak within a Plexiglas channel during piston induced, volume-cycled oscillations. The observed steady streaming was compared to theoretical calculations. Both the theoretical and experimental results show bi-directional drift for all frequencies, with characteristics dependent upon the value of the Womersley parameter, /, e.g. , e.g. α < 5, the fluid drifted towards the narrow end at the wall and the wide end of the channel along the centreline. Applications to mass transport in the lung are discussed.