An Experimental Investigation of a Plane Jet in a Wavy Crossflow

Abstract

An experimental investigation has been undertaken to study the effect of a wavy crossflow on a plane jet discharged vertically downward in a water channel. Two groups of experiments were performed; one group for a jet discharged into a uniform crossflow, the second group for a jet discharged into a wavy crossflow. Experiments were conducted for four jet-to-crossflow velocity ratios (R = 1, 3, 5, and 7). For each experiment, measurements using LDA system were made at six stations downstream of the exit of the jet nozzle (x = 0.0, 6, 12, 18, 27, and 36 mm). During the course of the experiments, the channel flow velocity was maintained fairly constant at 15 cm/s, and the wave generated in the channel was not very steep. The results revealed that the oscillatory motion associated with the waves has a significant effect on both the mean and turbulent velocity fields. The mean velocity profiles were found to have no maximum values, compared with those of a uniform crossflow. The effect was most pronounced in the zone of flow establishment, where a region of intense fluid mixing arises, resulting in a significant shortening of the zone and a rapid development of the jet flow.