2011 Volume 67 Issue 2 Pages I_335-I_344
We propose the Multi-Size-Mesh Hermite Scheme to perform the N-body simulations with short-range interactions and apply it to the sedimentary simulations of granular materials in fluid. The Multi-Size-Mesh Hermite Scheme is effective to the simulations with a wide range of scales both spatially and temporarily, because both the time steps and the mesh sizes of each particle are discretized as the power of 2. As for the sedimentary simulations of monodisperse spheres, we found that the porosity increases as the deposition intensity is enhanced. As for the sedimentary simulations of polydisperse spheres, on the other hand, the porosity depends not only on the intensity but also on the grain-size distributions. In fact, the porosity decreases as the fraction of smaller particles increases for the simulations with strong deposition intensity, while it becomes almost constant for those with weak deposition intensity. Especially, in the latter, segregation was found to occur in the deposit, i.e., the smaller particles sink from the top to the bottom in deposit, which suggests that the segregation plays a key role in determining the packing states in the sedimentary simulations of polydisperse spheres.
