Numerical Modeling of Flow around Bridge Piers in Meandering Channel

The existence of bridge pier in streamflow causes a complex 3D flow formation، which also causes the scouring around bridge pier. Since rivers are usually curved، it is necessary to investigate the impact of change in flow patterns caused by passage of flow through the curve on the scouring around bridge pier. By developing Computational Fluid Dynamics (CFD)، there is a possibility to simulate the flow pattern around the bridge piers. Therefore، the purpose of this research is modeled a 3D flow stream near the bridge piers in a curved channel. For this purpose a fluent model software was employed، and solved by stream equations using finite volume method of centralism. For discretization of Navier Stocks equation، three turbulence models of K-ε، K-ω، and RSM were used. In order to consider free surface، Fluid Volume Method was applied. The numerical model was validated with measured experimental data around the bridge piers in the meandering flume with 5 sequential curve paths. The results showed that the RSM turbulence model performed well compared to the other two models. When comparing the flow of upstream to downstream of bridge piers it can be observed that the placement of bridge piers in the middle of curved shape channel may lead secondary flow towards the inner curve of a channel. Also، the resulted vortex continues with a 150 degree curve.