Studies on submerged jets

Abstract

This thesis deals with the studies on submerged jets. In the first part of the thesis, a critical survey of the existing literature has been made with a bibliographical chart on the subject up to date. The second part deals with the investigations conducted to study (i) the effect of submergence and velocity on jet expansion and on the velocity profiles of the jet and the surrounding mass of water (ii) the rate of energy dissipation of the jet in a stationary mass of water, (iii) the deceleration of velocity along the axis of the jet and (iv) the criteria for design of stilling basins for submerged jet. It has been found that the jet expands linearly with a certain angle of divergence up to a certain distance and after that also it expands linearly with a greater angle of divergence indicating two different zones as got by House and others. In all the studies made it was noted that more than 80% energy of the jet is dissipated within 48 times the diameter of the jet. This result will be very useful for the design of stilling basin. It has been found that the deceleration of central velocity follows different law in different region of its penetration in the stilling basin. Finally a chart giving the relationship between the relative length of the stilling basin required and the relative depth of the stilling basin with the relative position of the jet as the third parameter has been proposed. This chart will be very useful in fixing up the stilling basin dimensions from model studies.