CFD-DEM · NUMERICAL SIMULATION OF SEDIMENT ENTRAINMENT

Sediment transport is important for predicting the impact of human intervention on river and coastal systems. The numerical modelling of individual particles on the bed of a turbulent open channel is particularly difficult because it not only involves the correct modelling of the turbulence but also the movement of the particles themselves. This project is aimed at investigating the influence of turbulence on the entrainment and movement of coarse particles on the bed of an open channel. In order to do this it will be necessary to couple existing in-house discrete element and computational fluid dynamics codes. The final code will be able to correctly model the turbulence in the channel and around the particles. From a geomorphological point of view, the research will be a major contribution to the understanding of sediment dynamics by focusing on the movement of individual particles, turbulence around these discrete particles and the role of turbulent eddies in particle entrainment. It will lead to improved understanding of bed mobility in rivers with non-cohesive sediment. Simulations will be carried out to investigate the influence of turbulence on the entrainment of the particles. We shall look at factors that influence the stability of the particles, such as: drag and lift forces, degree of protrusion, blocking by particles upstream, effect of particles downstream on the points of rotation of a moving particle.""