Numerical Simulation on the Flow Characteristics of a Three-Dimensional L-Bend Pipe Based on Hybrid RANS/LES Methods
L-bend pipe is a typical shipboard component,which can realize the functions of fluid mass transport and heat exchange.Due to the influence of geometric curvature,the flow in the L-bend pipe is extremely complicated.The traditional reynolds averaged method(RANS)is unable to simulate the complex three-dimensional flow in the pipe while the large eddy simulation method(LES)bears large computational cost.Therefore,the hybrid RANS/LES method is adopted to conduct a numerical research on the flow characteristics in the classic L-bend pipe.this method adopts RANS method in the near-wall region and LES method in the turbulent core region,which can not only maintain the simulation accuracy but also be suitable for engineering applications with low grid demand.Two types of RANS/LES methods in commercial software,i.e.improved delayed detached-eddy simulation method(1DDES)and stress blended eddy simulation method(SBES),are compared and analyzed for the simulation of the flow characteristics.Moreover,the influence of the curvature correction model is also considered.The results show that the SBES method possesses a better ability of simulation on the secondary flow(Dean Vortex)in the bend pipe compared with the IDDES method.Besides,the curvature correction model could further improve the ability of SBES.
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