Coupled CFD-DEM method for soils incorporating equation of state for liquid

The Tait equation of state for liquid is implemented into the N-S equations-based computational fluid dynamics (CFD). This method is then coupled with the distinct element method (DEM) so as to establish CFD-DEM codes to simulate the porous media with weakly compressive fluid. Firstly, the governing equations for the coupled CFD-DEM method are introduced, including equations for fluid-particle interaction forces, N-S equations, Tait equation of state for liquid and motion equations for particle system. Then, a coupled CFD-DEM scheme is implemented into the DEM commercial software PFC^2D. Finally, two benchmarking examples, namely, single particle free settling and one-dimensional consolidation, are used to validate the coupled CFD-DEM method. The results show that in the CFD-DEM simulations the free settling velocity of single particle meets the Stokes's solution, and the excess pore pressure and degree of consolidation at different values of T_v are close to those of the Terzaghi's consolidation theory.