Curvilinear flow over round-crested weirs

Curvilinear flow over round-crested weirs is a problem of both theoretical and practical significance because of its presence in overflow structures used in dam engineering, and its connection to the critical flow principle of hydraulics. The Jaeger theory is generalized, assuming a linear law for the radius of curvature of the streamlines along a normal. A potential flow equation is developed and compared with experimental data concerning spillways operating at high heads. In addition, a new parameter governing the flow features is presented. A reasonable agreement is found between the computed and measured discharge coefficients, the critical flow depth, the bottom pressure over the spillway profiles and the velocity and pressure distributions. The proposed curved streamline flow model reproduces reasonably well the flow features of spillway flow up to an operating head twice the design head.