Micro scale characterization of fluid flow in a uniform particle pack using coupled discrete element lattice Boltzmann method
Particle scale investigation of geo mechanical phenomena using numerical simulations has increasingly attracted the attention of researchers stimulated by recent advances in computational capacities. In this paper, the pore scale characteristics of flow in a particulate soil pack is investigated. A randomly distributed pack of uniform particles is created using a discrete element simulation of 500 particles with 9mm diameter settling freely into a box. Then the lattice Boltzmann method is utilized to simulate a constant flow passing through the particle pack with a wide range of Reynolds numbers from 10 4 to 18. Subsequently, the pressure loss occurred in the flow when it passes through the particles is studied to characterize the transformation of flow conditions from laminar to turbulent mode. The pore scale characteristics of the flow, e.g. fow tortuosity, are then compared to those of pack scale, e.g. fluid pressure difference between base and top of the particle pack to acquire more understanding on transforming from laminar to turbulent flow in micro (pore scale) and macro (pack) levels. Furthermore, the effects of flow rates demonstrated by Reynolds numbers are examined on the drag forces applied on particles. Discussions on the micro scale behaviour of flow in porous media based on the results obtained from numerical simulations are provided.