Estimation of streamwise depth-averaged velocity and boundary shear stress are important requisites for modelling of river flows associated with flood events. Recently, many methods have emerged to predict these flow variables with great accuracy, but they provide unsatisfactory results in shear layer regions. This paper presents an improved methodology to predict depth-averaged velocity and bed shear stress for a straight compound channel flow. An analytical solution to the depth-integrated turbulent form of the Navier–Stokes equation is obtained. The transverse shear stress in the mixing region is modelled using an effective eddy viscosity concept that contains horizontal coherent structures and three-dimensional bottom turbulence. The secondary flow term is modelled by considering the log-law profile for streamwise velocity and half cosine curve for the transverse velocity component. The analytical solution is successfully applied to a wide range of experimental compound channels and field cases. The efficacy of the present solution has been successfully tested by comparing with observed values.

中文翻译：

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复合通道中深度平均速度和边界剪切的解析解

估计河流平均深度速度和边界剪应力是模拟与洪水事件相关的河流流量的重要必要条件。最近，出现了许多方法来非常准确地预测这些流动变量，但它们在剪切层区域提供的结果并不令人满意。本文提出了一种改进的方法来预测直线复合通道流的深度平均速度和床层剪切应力。获得了 Navier-Stokes 方程的深度积分湍流形式的解析解。混合区域中的横向剪切应力使用有效涡粘性概念建模，该概念包含水平相干结构和三维底部湍流。二次流动项通过考虑流向速度的对数定律曲线和横向速度分量的半余弦曲线来建模。该解析解已成功应用于各种实验复合通道和现场案例。通过与观测值的比较，成功地测试了本溶液的功效。