A direct simulation method for particle-fluid systems

A coupled numerical method for the direct simulation of particle fluid systems is formulated and implemented. The Navier-Stokes equations governing fluid flow are solved using the lattice Boltzmann method, while the equations of motion governing particles are solved with the discrete element method. Particle fluid coupling is realized through an immersed moving boundary condition. Particle forcing mechanisms represented in the model to at least the first-order include static and dynamic fluid-induced forces, and intergranular forces including particle collisions, static contacts, and cementation. The coupling scheme is validated through a comparison of simulation results with the analytical solution of cylindrical Couette flow. Simulation results for the fluid-induced erosive failure of a cemented particulate constriction are presented to demonstrate the capability of the method.