Critical Water Depth Features over Broad-Crested Weirs.(Dept.C)

Abstract

The characteristics of flow over suppressed broad-crested weirs have been extensively studied by old and recent investigations, while for contraeled ones, the studies are limited. In the present study, the charaeteristies of the critical water depth over the contracted weirs were investigated. The effects of the different weir geometrical ratios and different flow parameters on the critical water depth locations were discussed. Experiments were conducted on a laboratory flume and the measured data were analyzed. An empirical equation, in terms of the weir and the flow parameters was developed to predict the critical water depth over the broad-crested weirs. Another empirical equation was also developed 10 predict the location of the critical water depth over such weirs. A good agreement was found between the developed equations and the experimental observations of die present study and that of others. Hence, the passing flow discharge becomes easy to be determined using one of the developed empirical equations and applying the discharge equation in terms of the esitical water depth in a rectangular open channel.