Sudden blocking of a subcritical open–channel flow

This paper reports results of experiments in which a steady nonuniform flow in a rectangular channel with an even horizontal bottom was blocked by a rapidly falling shield. Data on the height of the splash–up of water on the shield and the shape, propagation speed, height, and internal structure of the upstream propagating wave of the bore type are obtained for various liquid flow rates at the channel entrance. It is established that the bore produces a strong stratification in the liquid particle velocity, and under particular conditions, the speed of propagation and height of the bore, and the height of the water splash–up on the wall are constant and are determined only by the critical depth for unperturbed flow, i.e., by the specified flow rate.