Local Head-Loss Coefficient at the Rectangular Transition from a Free-Surface Channel to a Conduit

Experimental tests have been performed to observe and determine, in stationary flow conditions, the local head loss at the transition from a free-surface channel to a conduit. These investigations considered a wide range of discharge and varied dimensions and positions of a rectangular cross-sectional conduit connected to the downstream extremity of a rectangular free-surface channel. From the head-loss evaluation results, simple analytical expressions to predict the local head-loss coefficient value at the rectangular transition from a channel to a conduit are proposed and validated. (C) 2013 American Society of Civil Engineers.