Surface-flow patterns in oscillating-triangular-jet nozzles

Abstract

A triangular-jet nozzle which usually produces an oscillating-jet flow can, for a narrow range of geometric parameters, produce a stationary deflected jet which reattaches to the internal surface of the nozzle. Surface-flow-visualisation images and surface-pressure maps from the stationary deflected jet contain a wealth of detail not available from similar experiments with the oscillating-jet flow. In the topological model constructed from this data, the most significant feature is a strong sink focus. The model suggests that most of the reverse flow through exit plane of the nozzle is attracted towards this sink focus before it is entrained by the jet flow and ejected from the nozzle.