Author(s): E. F. R. Bollaert; M. Grünzner

Linked Author(s): Erik Bollaert

Keywords: fluid-solid coupling; novel software; plunge pool; rock scour

Abstract: This paper presents a novel approach for detailed 2D numerical assessment of rock scour in plunge pools or unlined channels downstream of hydraulic structures. The approach is based on an automated coupling between the 3D hydraulics and the turbulence of an impacting jet (or any other turbulent flow environment) and the detailed bathymetric evolution with time of the rocky bottom that is being scoured, for a given flood event. Detailed flow hydraulics are thereby computed by the FLOW-3D® CFD software, allowing sound implementation of air entrainment and defining the main flow parameters at the water-rock interface. Bathymetric evolution with time of the eroding rock mass downstream of the hydraulic structure is computed by the rocsc@r® software, a cloud-based digital tool implementing the latest and most widely used computational methods for scour prediction. This novel fluid-solid interactive approach has been tested and applied to large-scale laboratory experiments of scour hole formation in broken-up rock, generated by rectangular-shaped oblique jets impinging in a plunge pool made of cobblestones, performed at the laboratory of the Civil Engineering Department at Stellenbosch University, South Africa (Bosman and Basson (2020), Bosman (2021)). The scour formation observed during the experiments has been reproduced by the FLOW-3D® - rocsc@r® numerical coupling. Benefitting from a dedicated, user customizable and fully automated interface between both software programs, this coupling requests only very short computational times and constitutes a cutting-edge tool available to engineers for real-life applications and projects. The results obtained for different computational methods of scour formation and a set of CFD modelling parameters are pointed out.

DOI: https://doi.org/10.26077/1180-7bd6

Year: 2022