Direct solution for discharge in generalized trapezoidal free overfall

作者：Vatankhah Ali R^*

来源：Flow Measurement and Instrumentation, 2013, 29: 61-64.

DOI：10.1016/j.flowmeasinst.2012.09.006

• Free overfall
• Flow measurement
• Generalized trapezoidal section
• Sharp-crested weir
• Direct solution
• Experimental data

In open channels, free overfall can be used as a discharge measuring structure by a single measurement of depth at the end of the channel. If the slope of channel is negative, zero or mild, the flow at upstream of end section will be critical and end depth value depends only on the shape of the approach channel and its critical depth. This research presents a theoretical end depth-discharge (EDD) relationship for free overfall (end section) in a horizontal open channel with generalized trapezoidal section. The generalized trapezoidal shape reduces to the commonly used trapezoidal section as well as to the A-shaped section. Two direct discharge equations in terms of end depth for subcritical flows are proposed by simulating free overfall as a weir without crest. Experimental data are then used to verify the proposed EDD relationships. The calculated discharges, using the proposed EDD relationships, show excellent agreement with the experimental data.

• 出版日期2013-3