An experimental study of dilution and mixing with turbulent jets in crossflows

This thesis is written in the paper format and includes three contributions. The first contribution presents the results of an experimental study on the dilution of circular non-buoyant turbulent surface jets of diameter d, discharged perpendicularly into relatively deep crossflows with depth D in the mixing region. The jet velocity was varied from 2.1 to 12.3 times the velocity of the crossflow. Concentration measurements were carried out as far as x/d = 630, where x is the distance downstream from the nozzle along the crossflow. Minimum dilutions of about 100 were attained in this mixing region. A general correlation has been developed to predict the minimum dilution in terms of the transformed distance {dollar}rmalpha x/d{dollar} where {dollar}alpha{dollar} is the ratio of the jet to crossflow velocity. The concentration profiles in the vertical and the transverse directions were found to be similar. Expressions were developed to describe the growth of the width and thickness of the deflected jets. The effect of some submergence of the jet nozzle on the minimum dilution was also investigated.; The second contribution presents the results of a laboratory study on the mixing characteristics of circular non-buoyant multiple jets discharged into relatively deep river-like crossflows. Experiments were performed for the velocity ratio {dollar}alpha{dollar} varying from 3.5 to 10 where {dollar}alpha{dollar} is the ratio of the jet to that of the crossflow. The concentration profiles in the vertical as well as the lateral directions in the planes of maximum concentration were found to be similar. A minimum dilution up to 80 reached the mixing region. It was found that the minimum dilution decreased with the increase of the velocity ratio {dollar}alpha{dollar} and the increase of the number of ports. Increase of the spacing between ports resulted in a considerable enhancement of the dilution. The trajectory of the multiple jets was identified based on the location of the maximum concentration.; The results of an experimental study on rapid mixing and dilution with multiple turbulent jets is presented in the third contribution. (Abstract shortened by UMI.)...