An investigation of the pressure dip phenomenon within conical sandpiles using CFD-DEM

Abstract

Although the pressure dip in conical sandpiles has been studied for several decades, this counterintuitive phenomenon is still not fully understood due to the intrinsic complexity of granular materials. This paper reports a series of combined computational fluid dynamics and discrete element method (CFD-DEM) simulations of the formation process of conical sandpiles. Samples with spherical or realistically shaped particles were simulated, and both dry and submerged conditions were considered to elucidate the effects of particle shape and the presence of water on the formation and intensity of the pressure dip inside sandpiles. The repose angle, packing density, force chain network and bottom stress distribution were analyzed and compared for all simulated piles. The presence of a pressure dip in all simulations was confirmed. As expected, both in dry and submerged conditions, an irregular particle shape was confirmed to increase the repose angle and pressure dip but decrease the packing density. Furthermore, a more homogeneous internal fabric structure was obtained for submerged sandpiles, and the pressure dip was alleviated.