[Science] Transition from turbulent to coherent flows in confined three-dimensional active fluids
Transport of fluid through a pipe is essential for the operation of macroscale machines and microfluidic devices. Conventional fluids only flow in response to external pressure. We demonstrate that an active isotropic fluid, composed of microtubules and molecular motors, autonomously flows through meter-long three-dimensional channels. We establish control over the magnitude, velocity profile, and direction of the self-organized flows and correlate these to the structure of the extensile microtubule bundles. The inherently three-dimensional transition from bulk-turbulent to confined-coherent flows occurs concomitantly with a transition in the bundle orientational order near the surface and is controlled by a scale-invariant criterion related to the channel profile. The nonequilibrium transition of confined isotropic active fluids can be used to engineer self-organized soft machines.
Kun-Ta Wu1, Jean Bernard Hishamunda1, Daniel T. N. Chen1, Stephen J. DeCamp1, Ya-Wen Chang2, Alberto Fernández-Nieves2, Seth Fraden1,*, Zvonimir Dogic1,* 1Department of Physics, Brandeis University, 415 South Street, Waltham, MA 02453, USA. 2School of Physics, Georgia Institute of Technology, 837 State Street, Atlanta, GA 30339, USA. ↵*Corresponding author. Email: email@example.com (S.F.); firstname.lastname@example.org (Z.D.)
Science 24 Mar 2017: Vol. 355, Issue 6331, eaal1979 DOI: 10.1126/science.aal1979