Simulations of soil flow properties using the discrete element method (DEM)

Abstract

Understanding soil flow properties is important for designing high-performance soil-engaging tools in agriculture. In this study, soil flow tests were conducted for a sandy loam soil using the lifting cylinder method to obtain the angle of repose (AOR) of the soil. The soil flow was simulated using a numerical model developed based on the discrete element method (DEM). The model was validated with the measured AOR. The validated model was then used to monitor dynamic properties of soil flow. Results of simulated kinetic energy showed that particles were most dynamic at the beginning of the flow process. The boundary work accumulated linearly over time, maximizing when all particles flowed out of the cylinder. The body and friction energies were also accumulating, but with varying accumulation rates over time. The simulated heap angle decreased exponentially over time during the flowing process, and the simulated AOR (29.0°) was obtained when the heap became stable. This simulated AOR matched the measured AOR with a relative error of 1.7%. Model particle diameter significantly affected the kinetic energy of particles but had little effect on the simulated AOR. The model developed in this study was capable of capturing dynamics of particle assembly and individual particles.