等宽明渠交汇水流数值计算

Depth-averaged turbulence models for flow simulation at equal-width open-channel junction

针对明渠交汇口缓流流动特性,分别应用水深平均H-L模型及k-ε模型建立了二维数值模型.水深方向采用静压假定,可模拟自由面和河床地形变化;应用交错网格上的有限体积法对方程组进行离散并采用水深速度校正算法求解;每个代数方程求解采用TDMA逐行扫描法;针对交汇口几何特征,分区进行网格划分.应用实测资料对两种模型进行了验证比较,结果表明两种模型均可模拟明渠交汇口基本流动特性,但H-L模型所得的分离区计算结果比k-ε模型更为准确.

The depth-averaged numerical models using standard k-ε and H-L turbulence models respectively for simulation of flow at the junction of equal-width open-channel were developed. The hydrostatic pressure assumption was made in vertical direction for simulation of variations of water surface and riverbed topography. The finite volume method on staggered grids was used to discretize the equations. The depth-velocity correction procedure and the SOR solver coupling with TDMA, which could accelerate the convergence of solutions were employed to solve the algebraic equations. Furthermore, the junction area was divided into blocks for grid arrangement to deal with the complex geometric characteristics of the junction. The comparison of the numerical results with measured data indicates that both of the two models are effective for simulation of flow characteristics at the junction. However, the H-L model is much better in simulating the separation zone.