Author(s): Fikry Purwa Lugina; Tatsuhiko Uchida; Yoshihisa Kawahara

Linked Author(s): Fikry Purwa Lugina, Yoshihisa Kawahara

Keywords: Curved open channel; Depth-integrated model; Secondary flow; Flow structures; Momentum transfer

Abstract: This paper presented the advantages of advanced depth-integrated models to overcome the issues of long computation time of three-dimensional calculation (3DC) model and lack of computation detail of two-dimensional calculation (2DC) model. The method is the so-called bottom velocity computation (BVC) method which includes several models, such as simplified bottom velocity calculation (SBVC) with shallow water assumption and general bottom velocity calculation (GBVC) method without the assumptions. BVC method is an integrated multiscale simulation of flows and bed variations in rivers that can evaluate vertical distributions of velocities and bottom velocity distributions by introducing depth-averaged horizontal vorticity and horizontal momentum equations on a water surface. In this paper, the method was validated using experimental datasets of sharply and mildly curved channels and results of 3DC model. The mechanism of three-dimensional flows is discussed with several calculation models, including 2DC, 3DC, and the advanced-depth integrated models based on BVC: SBVC2, SBVC3, and GBVC3. The results show that the BVC method is able to reproduce the three-dimensional structures of the flow in sharply and mildly curved channels.

DOI: https://doi.org/10.3850/IAHR-39WC252171192022827

Year: 2022