An OpenFOAM solver for computing suspended particles in water currents

Abstract

A new OpenFOAM solver has been developed for computing the spatial variation of particle concentrations in flowing water. The new solver was programmed in C ++ using OpenFOAM libraries, and the source code has been made openly available. The current article describes the coding of how the water flow and particle movements are computed. The solver is based on a Eulearian approach, where the particles are computed as concentrations in cells of a grid that resolves the computational domain. The Reynolds-averaged Navier–Stokes equations are solved by simpleFoam, using the k-ε turbulence model. The new solver uses a drift-flux approach to take the fall or rise velocity of the particles into account in a convection-diffusion equation. The model is therefore called sediDriftFoam. The results from the solver were tested on two cases with different types of particles. The first case was a sand trap with sand particles. The geometry was three-dimensional with a recirculation zone. The computed sediment concentrations in three vertical profiles compared well with earlier numerical studies and laboratory measurements. The second case was a straight channel flume with plastic particles that had a positive rise velocity. In this case, the results also compared well with the laboratory measurements.