Modeling the Flow Characteristics of Granular Materials under Low Gravity Environments Using Discrete Element Method

New understandings on the processing behavior of granular materials under low-gravitational environments are required in space engineering and planetary ground exploration activities. Micromechanical characteristics of granular materials are inherently complex and heterogeneous due to their discrete nature. Although significant progresses have been achieved in the past, especially on the storage, handling, and transportation properties of granular materials under earth gravity condition, micromechanical aspects of granular flow under low-gravitational environments is still poorly understood. In this study, three-dimensional discrete element modeling (DEM) has been used to evaluate the role of low-gravitational environments on the angle of repose (AOR) of granular pile and compared with existing experimental findings. Furthermore, the effects of key particle-scale properties on the flow characteristics of granular materials are investigated under simulated low gravity conditions. The AOR predicted by the current simulations agrees well with corresponding parabolic flight experimental results reported in the literature. Furthermore, the current results enlighten on the effects of particle-scale properties on the complex interactions between the grains and their subsequent effects on the flow characteristics especially under Earth, Mars, and lunar (EML) gravity environments. Overall, DEM could be applied well for understanding low-gravitational granular flows and to reduce relying on complex flow experiments, for example, using parabolic flight campaigns in which low gravitational environments are available only for a limited duration of time.