Dresden 2020 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 67: Active Matter V (joint session DY/BP/CPP)
DY 67.4: Talk
Friday, March 20, 2020, 10:45–11:00, ZEU 160
The role of advection in the diffusioosmosis of an active micropump — •Gonçalo Antunes1,2, Paolo Malgaretti1,2, Jens Harting3,4, and Siegfried Dietrich1,2 — 1MPI-IS, Stuttgart, Germany — 2U. Stuttgart, Stuttgart, Germany — 3HI-ERN, Forschungszentrum Jülich, Nürnberg, Germany — 4TU/e, Eindhoven, The Netherlands
Diffusioosmosis can be exploited to fabricate active colloids that swim in a fluid/solute mixture through a self-generated inhomogeneous concentration of solute [1]. Using the same mechanism, an active channel can be fabricated such as to pump fluid in a way that is tunable via the geometry and chemistry of the channel.
In this talk, we study the flow inside an active hourglass-shaped channel. Our Lattice Boltzmann simulations are combined with a finite-difference solver for the advection-diffusion equation that determines the solute dynamics [2]. We find that even when the channel is fore-aft symmetric, advection can lead to the pumping of fluid, in analogy to the steady motion of isotropic colloids [3,4]. Furthermore, sustained oscillations are found where the magnitude of the flow oscillates with a tunable frequency. Our findings are thus relevant for those who wish to exploit surface-driven flows at small scales.
[1] J. L. Anderson, Ann. Rev. Fluid Mech. 21 61-99 (1989) [2] T. Peter, P. Malgaretti, N. Rivas, A. Scagliarini, J. Harting, S. Dietrich, arXiv:1911.06324 (2019) [3] S. Michelin, E. Lauga, and D. Bartolo, Phys. Fluids 25 061701 (2013) [4] P. de Buyl, A. S. Mikhailov, and R. Kapral, EPL 103 60009 (2013)