Shilpa Khatri : Settling of a Porous Sphere in Stratified Stokes Flow (Mar 26, 2012 4:25 PM)

Marine snow, composed of organic and inorganic aggregates, plays a major role in marine carbon cycling. Most of these macroscopic particles are extremely porous, allowing diffusion of salt from the ambient fluid to affect the density and therefore the settling of these particles. In a first approximation, these particles can be modeled as spheres. This talk will present a study of the effect of porosity and salt diffusion in the dynamics of a sphere settling under gravity in a salt-stratfied fluid analytically and semi-analytically (depending on the ambient density gradient) in viscosity dominated regimes. For linear stratification, an explicit solution for the sphere's position in time is derived. For more general ambient fluid stratification, the sphere's position can be solved for numerically, under the asymptotic assumptions about the typical time scales of diffusion and settling. A parametric study of the settling behaviors and preliminary comparisons with experiments will be presented.

• Category: Applied Math and Analysis
• Duration: 01:34:36
• Date:  March 26, 2012 at 4:25 PM
• Views: 108
• Tags:   seminar, Applied Math And Analysis Seminar