Numerical study of hydraulic characteristics around the vertical and diagonal sharp crested weirs using Flow3D simulation.

Abstract

WWeirs are important structures in the river and are the most common means of flow measurement in open chan-nels. One type of these structures are sharp crested weirs which are categorized based on the shape of crest to tri-angular, rectangular, circular, trapezoidal and parabolic. In this study, numerical simulation is used to predict over-flow around sharp crested weir and attributes like height, Froude number and Reynolds number in the overflow with three different slope angles of 50, 70 and 90 degrees from horizontal and discharge coefficient of rectangular over-flow has been investigated. An equation between discharge and inflow coefficient k-ε is proposed, and the best turbu-lence model due to better simulation is adopted among three turbulence models with correlation coefficient of 0.96. The results indicated that when Froude number is less than 1 and Reynolds number is more than 2000 and weirs have a 50-degree slope, inflow will have its maxi-mum volume with inflow coefficient of 0.747. Also, effect of slope on scouring around the weirs with respect to the pressure and velocity of inflow is studied.

Keywords

• sharp crested weirs
• hydraulic characteristics
• numerical simulation
• k-ε turbulence model
• flow-3d modeling