Submerged flow regimes of rectangular sharp-crested weirs

This technical note presents the results of an experimental study on submerged flow over full-width sharp-crested rectangular weirs. Submerged flow was divided into impinging jet and surface flow regimes. A diagram has been developed to predict the occurrence of these regimes. The boundaries of these regimes depend upon the direction of change of the tailwater. A more definitive relation has been developed for the flow-reduction factor for the prediction of discharge for submerged flow.