Hydraulic Jump Properties Over a Rough Bed

Abstract

Hydraulic jump characteristics were measured over several artificially roughened test beds in a horizontal rectangular flume with smooth side walls. A smooth test bed, two strip roughness test beds and three densely packed gravel test beds provided a relative roughness range from 0.0–0.9. The testing program involved some 200 hydraulic jump observations which included flow rate, upstream depth, tailwater depth and jump length. Observations showed that boundary roughness reduces both the sequent depth and the length of a hydraulic jump, and that the observed reductions were related to both Froude number and the degree of roughness. The observed hydraulic jump characteristics were consistent with theory, and a proposed approximation for a theoretical hydraulic jump equation was found to compare favorably with the observed characteristics.