عنوان مقاله [English]
Estimation of discharge coefficient for lopac gates plays an important role in determining the discharge of such structure, as a flow control and regulation structure. The present research provides semi-analytical equations to estimate the discharge coefficient for submerged lopac gates for different conditions. The results indicate that the discharge coefficient depends on gate opening and submergence ratios. Theoretical equations for estimating the discharge coefficient were calibrated with experimental information for the conditions of without transition and with gradual and sudden transitions. The results show that the discharge coefficient of lopac gates with transition is less than that of without transition. The proposed equations for the discharge coefficient have maximum of 10% error. Comparing the results of theoretical equations with previous investigation also demonstrates the efficiency of present equations for estimating the discharge coefficient of submerged lopac gates.