A novel CFD-DEM coupling method with moving boundary for simulating one-dimensional consolidation test

The conventional CFD-DEM coupling method fails to dynamically modify the position of the drainage boundary during the simulation of one-dimensional consolidation tests (1d CT), resulting in inaccuracies in the numerical results. In this study, a novel CFD-DEM coupling method with moving boundaries is proposed to simulate 1d CT where the fluid boundary adaption and internal mesh reconstruction are implemented with reference to the real-time morphology of the consolidation specimen. Additionally, the convective terms in Navier-Stokes equations are modified to account for the moving drainage boundary and the equation of state (EOS) is introduced to consider fluid compressibility. A series of 1d CTs based on the traditional fixed boundary and the moving boundary are subsequently conducted for comparison. Moreover, the influence of fluid compressibility and mesh coarseness on the consolidation characteristics is briefly discussed. The proposed method is verified to serve well in revealing the underlying microscopic mechanism of the Mandel-Cryer effect and complementing the traditional consolidation theories.