Research On Three-dimensisnal Numerical Simuhition Of Water Flow In Bend Diversion Headwork

The bend diversion headwork in which the bend flow characteristics are used is an effective engineering measure to solve the sediment problems. Bend flow in the bend diversion headwork is the direct driving force for sediment movement. Bend flow in the bend diversion headwork is mainly studied from theoretical analysis, experimental study and numerical simulation in this research. In this thesis, three-dimensional numerical simulation of bend flow in the bend diversion headwork is simulated with the method of different turbulence models provided by computational fluid dynamics software FLUENT introduced into VOF tracing free surface. The most suitable turbulence model is obtained comparing with the test results of test results. Then, three-dimensional numerical simulation is simulated with bend flow in different flows, horizontal bottom slopes and enter-regulation sections upstream. The main contents and conclusions are as follows:(1) The hydraulic characteristics of bend flow are obtained from the numerical simulation with three turbulence models of bend flow in bend diversion headwork. Re ynolds Stress model of the bend flow have the highest accuracy, and the simulated internal flow structure fit the actual situation the best. Followed by RNGK-ε model. The maximum deviation is K-ε model.(2) The conclusion that the max migration of the longitudinal current velocity is influenced by the sizes of the flow is obtained using the three-dimensional numerical simulation of bend flow under two typical flows with RNGK-ε model. The max longitudinal current velocity approach the centerline of the channel the most as the flow Q increasing, it means that it tends to the straight line. And migration extent gets bigger contrarily.(3) The three-dimensional numerical simulation is simulated in two different situations of with and without lateral gradient at channel bottom. The results shows that the hydraulic architecture with lateral gradient meet the demand of diversion sediment ejection.(4) The numerical simulation is taken with the bend flow in two different situations of straight and "S" types in enter control segment. The results shows that the shape change of the enter regulation section influence the flow structure in bend part. The numerical simulation results can provide reference for the design of the canal head in practical engineering.