Investigation of erosion capability of density current on sloping mobile bed with Lagrangian approach

Density currents are of considerable practical importance in different industrial and natural phenomena. These currents are driven by density difference. A density difference can exist between two fluids because of a difference in temperature, salinity, or concentration of suspended sediment. In this research, a three-dimensional density current is modelled in a channel with a mobile bed on a slope based on the large eddy simulation (LES) method with the aim of OpenFOAM software. Eulerian-Lagrangian approach is used to simulate the flow and the particles on mobile bed. Effect of inlet concentration, inlet velocity, and particle density on particle resuspension was investigated. It was concluded that by increase of inlet concentration and inlet velocity and also decrease of particle density, number of resuspended particles was increased. However, effect of particle density is far more significant than concentration and velocity. The results indicated that the most of sedimentation occurs at the end part of the mobile bed while the most resuspension of particles occur at the beginning of it. In no slope part of the channel the deposition profile throughout the bed was shown; deposition is strongly affected by particle’s density. Also, number of deposited particles decays almost exponentially.

Keywords:

Density current , Large eddy simulation , Particle , Eulerian-Lagrangian , OpenFOAM