弯道水流二维浅水模型的修正研究

Investigation on the modification of 2D depth-averaged model for bend-flow simulation

借鉴有关弯道水流流速分布的研究成果,计入深度平均流速与真实流流速分布差值引起的扩散效应,在正交曲线坐标系下建立了平面二维浅水模型。采用以标准k-ε模型为基础的曲率效应修正紊流模型模拟紊动应力项,在一定程度上考虑了流线弯曲水流紊动应力的各向异性。应用控制体积法和交错网格法离散方程,并用SIMPLEC算法求解离散方程;同时采用修正后的模型对90o弯道水流进行了数值模拟,并与原模型的计算结果及实测资料进行了比较,结果表明该模型能够有效地模拟流线弯曲水流的水力特性。

The purpose of this paper is to present a 2D depth-averaged model for simulating and examining flow patterns in channel bends.In particular,this paper proposes a 2D depth-averaged model that takes into account the influence of the secondary flow phenomenon through the calculation of the dispersion stresses arisen from the integration of the products of the discrepancy between the mean and the true velocity distributions.The proposed model uses an orthogonal curvilinear coordinate system to efficiently and accurately simulate the flow field with irregular boundaries.The curvature correction turbulence model with effects of streamline curvature based on the standard k-ε turbulence model is used to compute turbulence stresses.The finite Volume method with the staggered grid and the SIMPLEC solution method are used to numerically solve the flow governing equations.By using the modified shallow water mathematical model,the behaviors of the flows through a bend are computed,and the computational results coincide well with the measured data.