Diffusion characteristics of a plane jet discharged in a wavy crossflowing stream

An experimental investigation has been undertaken to study the effect of a wavy crossflow on a plane jet discharged vertically downwards 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. For each experiment, measurements using a laser Doppler anemometry system were made at six stations downstream of the exit of the jet nozzle. During the course of the experiments, the channel flow velocity was maintained fairly constant, 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 the 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.