Numerical Simulation Study On Improving Measures For Supercritical Flow Bend

In natural rivers the rushing current bend channel is very common, and is a common natural phenomenon of water flow. The bend channel is needed in actual water projects. After the straight water current getting into the bend channel, the surface morphology which was smooth become disordered, and diamond-shaped shock-wave appears. The structure of water flow was changed, the water surface of concave bank is higher and the water surface of convex bank is lower. The transverse gradient of the water surface in the bend channel was produced. The combined effect of centrifugal force and gravity caused the formation of the transverse circulation. The readjustment of water structure caused the velocity re-distribution along the direction the width of rive, the depth of water and the vertical direction. The adjustment of the water flow in bend channels is based on the change of the water surface. The transverse circulation is the root cause which made convex bank eroded and the concave bank silted. The velocity re-distribution is the most important and significant characteristics of the bend flow. To improve the structure of the bend flow is the key factor to solve the problem of erosion and siltation.Domestic and foreign scholars had done a lot of useful attempts in the project measures to improve the flow curve. Someone took reasonable forms of the bend curve, someone took double curvature channel slab to prevent shock-wave, someone took the method of fan-shaped elevation. There are many support measures, such as guide wall, diversion pier. These measures had played a good role to reduce the transverse gradient of the water surface, improved the fluid state.In this paper, inverse extra-high on bended channel base had been taken in-depth study. Numerical simulation methods were used to establish the geometric models. Three different flow conditions of normal bended channel base had been respectively simulated. Compared with the experimental results, numerical simulation method had been proved effective.Numerical simulation of the water flow in bent channel has been simulated by using RNG k -εturbulent model. The equations were segregated by using the Finite Volume Method (FVM). It took VOF method to make tracks for free surface.According to the theory of volume balanced, the three designed sizes of the inverse extra-high on bended channel base had been respectively simulated. The most effective plan for improvement measures have been chose, it can provide reference for the actual project. The calculated results show that, inverse extra-high on bended channel base can make the fluid condition better. And it can reduce the transverse gradient of the water surface. The size of the third designed plan showed the best effects for the transition section of the entrance.This paper researched the special characteristics of fluid condition and the inverse extra-high on bended channel base. The measure is foundation of basic research and the significance of academic research.