Application of high order one dimensional equation in predicting open channel flow properties with lateral contraction

Canal structures with lateral contraction are commonly used to measure discharge in open channel. According to three dimensional flow, extracting rating curve for these structures is done by using a physical or three dimensional mathematical flow models. A considerable amount of time and money iare required when utilizing these models. Boussinesq equations, which is extracted by considering streamline curvature and slope, exhibit high accuracy in predicting hydraulic properties in structures with varying bed. In this paper, the equations are developed for contraction. The extracted equations are used for obtaining the rating curve of Parshall flume and predicting water surface profile of Khafagi flume and rating curve s of Parshall flume. Comparing experimental data with equations shows the high accuracy of Boussinesq equation to predicting water surface profile and the rating curve of structures with contraction and varying bed. The time for solving the one dimensional equations is much less than the three dimensional model FLOW3D.