Study the Effect of Upstream and Downstream Slope of Crump Weir on Coefficient of Discharge

Abstract

This article aimed to study the effect of the slope of upstream and downstream of crump weirs on flow coefficient adjusted into three categories: (1) upstream slope 1:2 and downstream slope 1:5, (2) upstream slope 1:2 and downstream slope 1:2, and (3) upstream slope 90o and downstream slope 1:5. The flow coefficient and flow pattern from upstream to downstream were investigated in this experiment. The result showed the highest average flow coefficient at 0.83 in category (2), and 0.76 in category (1) respectively. In the aspect of flow pattern, category (1) contains stable curvature of water surface with gradual curve parallel to the weir. On the contrary, category (2) exhibits rapid curve of the curvature of water surface. Furthermore, the high slope of downstream results in high flow rate and slight water transition at the toe of a weir. Lastly, category (3) illustrates undular wave at upstream face and curve of the curvature of water surface at downstream face.