Hydrodynamic behaviour of a two-stage channel with horizontal and inclined floodplains: a numerical investigation

This paper presents the hydrodynamic behaviour of the two-stage River Blackwater model with horizontal and inclined floodplains using two-dimensional (2D) and threedimensional (3D) numerical models. The 2D model solves the shallow water depth-averaged continuity and Navier-Stokes equations with the depth-averaged form of the k −ε turbulence model for free surface flow. The 3D model solves the three-dimensional Reynoldsaveraged continuity and Navier-Stokes equations with the renormalization group (RNG) k −ε turbulence model for steady-state flow. The performance of the models is assessed by comparing predicted results with the experimental data obtained from a 1:5 scale physical model of the River Blackwater, located at the UK Flood Channel Facility. The predicted model results are used to investigate the flow processes along the channel in both the horizontal and inclined floodplain cases.