Force on Slab beneath Hydraulic Jump

Abstract

Experiments have been carried out to measure the mean and fluctuating forces exerted on the slab beneath the free hydraulic jump. Slabs of various lengths and widths have been used at Froude numbers of the upstream flow varying from 4.0 to 10.0. The intensity of force fluctuations on an area of slab beneath a hydraulic jump depends on its length and width, and on its position from the toe of the jump. Experimental results show that the transverse scale of pressure producing patterns of the turbulent hydraulic jump is longer than the streamwise scale. The scales of these patterns vary with the Froude number of the flow and the position within the jump. The probability of the force fluctuations has been measured. The results with respect to large slabs are presented in a form that would help in estimating the intensity of force fluctuations. It is hoped that the results are useful to the designers of the stilling basin.