Resolved Large Eddy Simulations of a Settling or Rising Spherical Microplastic Particle

The settling and rising of spherical microplastic particles with different Reynolds numbers, Re, were studied using a fully coupled large eddy simulation–discrete element method (LES-DEM) model, where the particles were treated using the immersed boundary method. Twelve different simulations were performed to find the drag coefficient CD, particle trajectories, and wake patterns of both settling and rising microplastic particles. Results were compared to experimental findings from the literature and the comparisons show that the present LES-DEM model produces accurate values for CD when Re≲310 and qualitatively captures both wake patterns and particle trajectories for 1≲Re≲5235.