Research Seminar in Mathematics - Simulations of a porous particle settling in density stratified ambient

Speaker

Mac Panahbehagh, Örebro Universitet.

Abstract

We study numerically the settling of a porous sphere in a density-stratified ambient fluid. Simulations are validated against prior laboratory experiments and compared to two mathematical models. Two main effects cause the particle to slow down as it enters a density gradient: lighter fluid within the particle and entrainment of the density-stratified ambient fluid. The numerical simulations accurately capture the particle retention time. We quantify the delay in settling due to ambient fluid entrainment and lighter internal fluid becoming denser through diffusion as a function of different parameters. A simple fitting formula is presented to describe the settling time delay as a function of each of those non-dimensional parameters.