Dam-break of mixtures consisting of non-Newtonian liquids and granular particles

Abstract

This paper revisits the classical dam break problem based on coupled Computational Fluid Dynamics and Discrete Element Method (CFD-DEM) modeling and analysis. We consider the collapse of mixtures comprised of non-Newtonian liquids and particles, and compare them with cases of a particle-water mixture, a dry particle column and three pure liquids. In all cases, the fluid is simulated by the CFD, while the granular particles are modeled by the DEM. Interactions between the fluid and the particles are considered by exchanging interaction forces between the CFD and DEM computations. Both the macroscopic and microscopic characteristics of the particle system, the liquid and the mixture during the dam break are examined, with particular attention placed on the effect of solid-liquid interaction and the distinct flow behaviors considering non-Newtonian liquid in a mixture in comparison with water. The non-Newtonian liquids are found to conform with the particles well during the collapse process, in contrast to the separated profiles of water and particles. In comparison with pure liquid cases and dry particle case, the solid-liquid interactions are found to play a crucial role in affecting all aspects of the flow behavior of a mixture during its collapse, including the initiation of the collapse, the conformity of flow profile, the evolution of flow front and the energy change. The underpinning physical mechanisms are analyzed and correlated to the macro observations.