B‐Jumps at Abrupt Channel Drops

Hydraulic jumps at abrupt bottom drops in rectangular, prismatic channels are either A-jumps (downstream controlled), B-jumps (upstream controlled), or undular jumps (transition between the two). B-jumps are investigated in detail by accounting for the effective pressure distribution at the vertical drop. Traditional description, which assumes strictly hydrostatic pressure distribution at the drop, is modified to yield smaller downstream flow depths for given inflow Froude number, drop height, and inflow depth, a trend suggested by comparing the present formulation with observations. All results are given in terms of design quantities, which enables simple estimation of the major flow characteristics.