Berlin 2018 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 70: Poster: Flows, Patterns, Delay, Reaction Diffusion
DY 70.9: Poster
Donnerstag, 15. März 2018, 15:30–18:00, Poster A
Using the Saffman effect to opitmally control colloidal trajectories in inertial microfluidics — •Felix Rühle1, Christian Schaaf1, Fredi Tröltzsch2, and Holger Stark1 — 1Institut für Theoretische Physik, TU Berlin, Hardenbergstr. 36, 10623 Berlin — 2Institut für Mathematik, TU Berlin, Straße des 17. Juni 136, 10623 Berlin
Inertial microfluidics is used for particle sorting and separation in biomedical applications [1]. Here, fluid inertia at intermediate Reynolds numbers drives cross-streamline migration of colloidal particles under Poiseuille flow and eventually lets them reach lateral steady state positions. These stable positions are determined by stable fixed points in the lateral lift-force profiles and can be controlled via the Saffman effect by applying axial forces [2-4].
We determine the lateral lift-force profiles for different external axial forces using lattice Boltzmann simulations [4]. We then interpret this axial force as a control term [4] and use optimal control theory to numerically determine optimal, time-dependent forces in order to steer particles with variable sizes to target positions in a microchannel. We provide the proof of principle that this is indeed possible.
[2] P.G. Saffman, J. Fluid Mech. 22, 385 (1965).
[3] W.Y. Kim and J.Y. Yoo, Lab Chip 9, 1043 (2009).
[4] C. Prohm and H. Stark, Lab Chip 14, 2115 (2014).