Authors: Issam AL-KHATIB
Abstract: A series of laboratory experiments were carried out in a flow measurement flume of rectangular compound cross section to investigate the effect of downstream expansion on the values of discharge coefficient, Cd, and approach velocity coefficient, Cv. For this reason, nine different models made of Plexiglas were tested in a horizontal laboratory flume for large range of discharges. In each test, the head, h1, over the crest elevation of depth measurement section was measured. The calculated discharge and approach velocity coefficients were related to relevant parameters, and general equations to be used in the head discharge equation were found. By using the general equations of Cd and Cv with the related parameters, one can estimate the flow discharge of a flume, when h1 value is given with an absolute error of 4%. Head-Discharge equations for symmetrical flow measurement flumes of compound cross sections were derived and the final results only are presented.
Keywords: Open channel, Downstream expansion, Compound cross section, Discharge coefficient, Flow measurement