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NJIT Applied Mathematics Colloquium

Friday, September 17th 2010, 11:30am
Cullimore Lecture Hall II
New Jersey Institute of Technology

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Inertia in suspension dynamics

Jeff Morris

City College of New York

The large majority of suspension dynamics research has been devoted to consideration of Stokes-flow conditions. Neglect of inertia is valid for many cases of interest, and the field has progressed because the linearity of the hydrodynamic equations in the Stokes-flow limit has allowed for accurate simulation tools, which combine with experiments to allow theory to progress. In the past few years, the lattice-Boltzmann (LB) simulation method for suspension flow has been developed to allow many-body simulations with finite inertia, comparable to simulations for Stokes flow. This talk will first discuss LB simulation results for finite-Reynolds-number shear flow, considering one and two particles to give an idea of the fluid motion and particle trajectory dependence on Reynolds number, and then consider the properties of a many-body sheared suspension. To probe the interaction of a suspension flow with a bluff body, experiments have been performed in a microfluidic device. These experiments have bulk Reynolds numbers of O(100) and particle Reynolds numbers of O(1). The particles are found to be depleted in the steady closed-streamline wake of the bluff bodyÑin some cases there are no particles at all in this wake. Fluid flow simulation and experimental trajectory analysis are applied in an effort to develop mechanistic understanding of the particle-depleted wake.