Author(s): Anastasia Zubova; Gosse Oldenziel; Tom O’Mahoney

Linked Author(s):

Keywords: CFD; PIV; Turbulence; Hydraulic flow; Verification

Abstract: The current state-of-the-art for the verification of flows near the hydraulic structures, for instance, the stability of the bed protection, is a physical scale model. Nonetheless, a reliable Computational Fluid Dynamics (CFD) tool for conducting virtual testing should be able to provide necessary insights into the hydraulic flows. Thus, the present work has been focused on an idealized turbulent weir flow represented by a gate underflow and investigating whether a CFD model could form the basis of a new reliable flow verification approach. In the majority of available theoretical studies, flow generated by an opening near the river/basin bottom is related to a plane wall jet and focuses on predicting the streamwise maximum velocity profiles in its potential core. In practice, a turbulent jet downstream of a weir is affecting the surrounding flow field by generating velocity perturbations and flow mixing further downstream of the jet potential core. Since the hydrodynamic loads on the bed protection are related to the instantaneous local flow velocities, adequately representing the turbulent nature of the flow in space and time is important. To evaluate the predictive capability of the numerical model, a set of experimental tests were performed by Deltares. Particle image velocimetry (PIV) has been applied to characterize flow fields, where flow velocity and turbulence near the bed downstream of a gate could be assessed. Numerical modeling of similar flow conditions was performed within the commercial CFD software package STAR-CCM+ v14.04.Results of modeled and time-averaged flow fields were compared with the results of experimentally measured. Flow velocity components, turbulent kintetic energy levels, and Reynolds stresses, when reasonable, were used in the performed analysis.

DOI: https://doi.org/10.3850/IAHR-39WC252171192022408

Year: 2022