Characteristics of Flow over Weirs of Finite Crest Width

Abstract

The characteristics of flow over weirs of rectangular cross-section with finite crest width depend on h/P, h/B, a characteristic Reynolds number, K/h, and Weber number, wherein h, P, B, and K represent head over the weir, height of the weir, width of the weir in the direction of flow and roughness height for the weir surface, respectively. Parameters h/P and h/B are the most important and a unified understanding of the whole family of weirs can be obtained by considering the variation of these parameters. The variation of discharge coefficient and water-surface profiles with n/P and h/B for weirs with a sharp upstream corner have been determined from the experimental studies. For weirs with a streamlined upstream corner, for values of h/B in the range 0.05 to 0.25, the ratio of the brink depth to the critical depth has been found to be close to 0.715 and the values of the discharge coefficients have been found to be close to the values calculated by Ippen's method.