Using Numerical Modeling to Correct Flow Rates for Submerged Montana Flumes

Abstract

AbstractA Parshall flume is a common device for measuring open-channel flows. Some Parshall flumes, however, have been modified or constructed without a downstream diverging section. A Parshall flume that does not have its divergent section is known as a Montana flume. Both physical modeling and computational fluid dynamics (CFD), or numerical modeling, have been utilized to assess the accuracy of and calibrate Montana flumes. Montana flumes under free-flow conditions operate similarly to Parshall flumes and, therefore, share the same rating curves. However, Montana flumes that operate under submerged conditions can deviate by as much as 15% from equations used to correct the submerged Parshall flume flow rate. The research summarized in this paper illustrates comparable results between numerical and physical modeling tests performed on a 6-in. (15.2-cm) submerged Montana flume. In addition, with the numerical model calibrated to the physical model, the same numerical procedure is used to expand testing t...