Author(s): Fikry Purwa Lugina; Tatsuhiko Uchida; Yoshihisa Kawahara
Linked Author(s): Tatsuhiko Uchida, Yoshihisa Kawahara
Keywords: Open channel; Depth-integrated model; Curved channel
Abstract: Understanding flow characteristics in an open channel is crucial to assess velocity distribution and sediment transport patterns for bank protection. Numerical models are widely used to clarify the complex phenomena of flow structures and sediment transport in rivers after validation with reliable experimental datasets. However, the applications of a detailed three-dimensional (3D) model are still limited to small-scale phenomena, such as local scouring in an experimental channel because of long computational time, large memory requirements, and numerous computational tasks. Numerous depth-integrated models have been proposed to solve these problems. Numerical calculation validation was performed in this study by comparing a set of numerical models with a laboratory experiment conducted by De Vriend (1979). Numerical calculation method applied in this research is the bottom velocity computation (BVC) method, which evaluates bottom velocity distributions without computing the vertical distribution of velocity and pressure intensity, based on a depth-integrated method with horizontal vorticity equations. This paper presents the applicable ranges of a two-dimensional (2D) model and a quasi 3D model of a simplified bottom velocity computation (SBVC) model with shallow water assumption. A modified discretization for the dispersion term using the upwind scheme approach is introduced, and its merits over the previous scheme. The advantages of employing the SBVC method are demonstrated through a comparison with the 2D model. Measurement results indicate that the SBVC method can reproduce flow structures in a curved open channel.
Year: 2020