An improved mathematical model for the sedimentation of microplastic particles in a lid-driven cavity with obstacle

In this paper, we developed a mathematical model for the sedimentation process of small particles in a lid-driven cavity flow with an obstacle to model the transport of microplastic particles in rivers. A stationary incompressible Navier-Stokes simulation at moderate Reynolds-numbers provides the background flow field. Spherical particles are injected into this flow field and their equation of motion is solved to determine the number of particles that sediment on the surface of the obstacle. To capture the effect of typical biological organisms and biofilms on the bottom surface of river beds, the obstacle can exert an attraction force onto the particles. Various simulations and parameter studies are carried out to determine the influence of the obstacle geometry, particle densities, and the attraction force on the sedimentation process.