Author(s): P. Langohr; B. M. Crookston; D. B. Bung

Linked Author(s): Brian Crookston

Keywords: CFD; energy dissipation; labyrinth weirs

Abstract: The replacement of existing classical weirs with labyrinth weirs is a proven techno-economical solution and a means to increase the discharge capacity when rehabilitating existing structures. However, flows exiting a labyrinth weir are complex, three-dimensional, and aerated; additional information is needed regarding energy dissipated by such weirs. In this study, three labyrinth weirs with different crest lengths were simulated with FLOW-3D HYDRO. Reynolds-averaged Navier-Stokes (RANS) modeling with the use of finite-volume method and Re-Normalisation Group (RNG) k-ε turbulence closure were employed. An attempt was made to more precisely account for the flow field in the downstream region. Consequently, the velocity head was determined with both depth-averaged and section-averaged velocities. Additionally, the kinetic energy correction coefficient was considered. A comparison of the computational fluid dynamics (CFD) results with prior experimental data showed that the residual energy was influenced by factors such as probe position and geometric parameters. A minor influence was observed for the kinetic energy correction coefficient. Overall, the high amount of energy dissipation was underlined and an acceptable agreement between simulated and literature data was documented.

DOI: https://doi.org/10.26077/fdab-c7cd

Year: 2022