Flow measurement using free overfall in inverted semi-circular channel

Free overfall at the abrupt end of a channel offers a method for measurement of discharge. This paper presents a theoretical end-depth-discharge (EDD) relationship for free overfall in an inverted semi-circular channel. The theoretical procedure applied to compute the discharge over a weir is applied to the free overfall to get the EDD relationship. The pressure at the brink is assumed to be zero. The available experimental data are used to verify the proposed EDD relationship. The calculated discharges, using the proposed EDD relationship, show excellent agreement with the experimental values in subcritical flows; however, the agreement is not so good in supercritical flows.