Book Description

This thesis presents the results of an experimental and analytical study of single-port buoyant turbulent jets discharged into shallow water. The experimental results include the measured downstream dilution, centerline concentration and trajectory. Independent parameters considered were Froude number, submerged depth, discharge angle and velocity ratio. Results indicate that decreasing the discharge depth provides earlier occurrence of surface effect and greatly decreases dilution. Dilution increases with decreasing Froude number. Increasing the discharge angle from the horizontal into cross current increases the dilution ratio. The effect of ambient current on dilution depends on the angle of discharge. For cross-flow discharges, the dilution rate decreases with increasing ambient current, while for co-flow discharge the reverse trend was observed. As plumes reach the water surface, the dilution rate increases with increasing ambient velocity. The jets bend over rapidly for cross-flow discharges when large ambient currents are present. The analytical portion of this report presents an integral method proposed by Davis (1975) for merging multiple buoyant jets. This merging model was used to simulate the single-port buoyant jet in shallow water. This was done by using an image method where the submerged depth was simulated by the spacing between images. The entrainment function as presented by Kannberg and Davis (1978) was used except for a modification within the zone of merged plumes. Comparisons of the model prediction were made with experimental data. Results indicate that good predictions are obtained for buoyant jets discharging at 0 and 45 degrees into shallow water by using the image method as long as the Froude number is above 13.5. For lower Froude number and vertical discharges, model predictions are only fair.