A. M. Salehizadeh, A. Shafiei,
Volume 38, Issue 2 (2-2020)
Abstract
This paper presents a numerical analysis of granular column collapse phenomenon using a two-dimensional smoothed particle hydrodynamics model and a local constitutive law proposed by Jop et al. This constitutive law, which is based on the viscoplastic behaviour of dense granular material flows, is characterized by an apparent viscosity depending both on the local strain rate and the local pressure. The rheological parameters are directly derived from the experiments. A simple proposed regularization method used in the viscosity relation to reproduce the stopping condition and the free surface of a granular flow where the pressure is disappeared. Pressure oscillation, as the main disadvantage of the weakly compressible SPH method, leads to an inaccurate pressure distribution. In this research, a new algorithm is proposed to remove the nonphysical oscillations by relating the divergence of velocity to the Laplacian of pressure. The simulations based on the proposed SPH algorithm satisfactorily capture the dynamics of gravity-driven granular flows observed in the experiments. The maximum thickness of a granular flowing on a rough inclined plane is obtained based on the local rheology model and compared with the experimental results. The run-out distances and the slopes of the deposits in the simulations showed a good agreement with the values found in the experiments. The results of the simulation proved that the initial column ratio played an important role in spreading the granular mass
