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DY: Fachverband Dynamik und Statistische Physik

DY 13: Fluid Dynamics and Turbulence I

DY 13.6: Talk

Tuesday, March 15, 2011, 11:45–12:00, ZEU 118

Numerical study of inertial microfluidics using stochastic rotation dynamics — •Michael Gierlak and Holger Stark — Technische Universität Berlin

The method of stochastic rotation dynamics is an efficient solver for the Navier-Stokes equations which captures hydrodynamic interactions between objects suspended in a viscous fluid as well as thermal fluctuations. It is therefore particularly suited to study microfluidic systems. Recently, inertial microfluidics has been established where colloidal suspensions at non-zero Reynolds number are studied with applications for particle sorting and filtering [1].

We present numerical results for colloid flow through a cylindrical microchannel at moderate Reynolds numbers (1-90), where inertial effects become important. In this range, inertial focusing is observed, where a uniform colloid concentration turns into an annular concentration profile with a peak situated between the channel axis and wall[2].

We investigate the formation of these concentration profiles as a function of flow velocity and colloid size. Due to this inertial focusing, colloids migrate away from the channel axis. Using feedback control with external fields, we try to revert this effect and stabilize the colloids near the channel center.

[1] D. Di Carlo, J. F. Edd, K. J. Humphry, H. A. Stone, and M. Toner, Particle segregation and dynamics in confined flows, Phys. Rev. Lett. 102, 094503 (2009)

[2] Segre G, Silberberg A, Nature 189:209*210.(1962)