The Hydrodynamics of Grit Particles Moving round a Bend Using CFD Modelling

Abstract

CFD modelling has been used to investigate the secondary flow phenomenon and its effect on grit particles carried in curved open channel flow. A CFD model was calibrated against a case study and then validated against data from a physical model with a 30°bend. The flow was calculated by solving the full Reynolds-averaged Navier-Stokes equations and Reynolds Stress turbulence models with a finite-volume method; the air-water interaction at the free surface was simulated using a Volume of Fluid multi-phase model. The hydrodynamics of grit particles (63 to 2000 µm) moving round a bend was then modelled using Discrete Phase Modelling which was further calibrated using experimental data on grit movement from the physical model. Further parametric investigations were carried out using the numerical model on curved open channels for various angles of bend, flow rates, channel widths and radii of curvature to assess their effect on secondary flows.