A numerical model for calculating velocity distribution in cross-section of an open channel

• Published in: Applied water science Vol. 14; no. 3; pp. 37 - 11
• Main Authors: Kakavandi, Hanieh, Heidari, Mohammad Mehdi, Ghobadian, Rasool
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.03.2024; Springer Nature B.V; SpringerOpen
• Subjects: Accuracy; Aquatic Pollution; Average flow; Boundary shear; Channel flow; Channels; Comparative Law; Distribution; Earth and Environmental Science; Earth Sciences; Eddy viscosity; Finite volume method; Flow velocity; Hydraulic structures; Hydraulics; Hydrogeology; Industrial and Production Engineering; International & Foreign Law; Mathematical models; Momentum; Momentum transfer; Nanotechnology; Navier-Stokes equations; Numerical models; Open channel flow; Open channels; Original Article; Private International Law; River engineering; Sediment transport; Shear stress; Stable channels; Trapezoidal channels; Two dimensional flow; Unstructured triangular mesh; Velocity; Velocity distribution; Viscosity; Vortices; Wall-function approach; Waste Water Technology; Water Industry/Water Technologies; Water Management; Water Pollution Control; Finite volume method; Unstructured triangular mesh; Eddy viscosity; Wall-function approach
• ISSN: 2190-5487; 2190-5495
• DOI: 10.1007/s13201-023-02090-2

Flow velocity in open channels is a fundamental hydraulic parameter with wide-ranging applications, including the development of rating curves and the study of sediment transport. While some river engineering projects may only require the calculation of average flow velocity, others, such as the design of hydraulic structures and stable channels, as well as the assessment of boundary shear stress, necessitate a more comprehensive understanding of flow dynamics, including the two-dimensional velocity distribution within open channels. To address this, various mathematical models have been proposed for estimating the two-dimensional distribution of flow velocity across transverse and depth directions. However, these models often come with complexities that hinder their practical application. In this research, we introduce a simplified numerical model that combines simplified Navier–Stokes equations with an eddy viscosity formula. This innovative approach aims to estimate velocity distribution in both rectangular and trapezoidal channels. The accuracy of our developed model hinges on the momentum transfer coefficient used in the eddy viscosity formula. Through the execution of the numerical model and the utilization of observational data, we determined the optimal value of the momentum transfer coefficient to be 0.241. To validate the effectiveness of our numerical model, we compared its predictions with laboratory data encompassing diverse hydraulic conditions. The results demonstrated a high level of accuracy, with the calculated velocity distribution and flow discharge differing by no more than 7.6% and 6.8%, respectively.