title: Active viscoelastic matter: from bacterial drag reduction to turbulent solids.
abstract: A paradigm for internally driven matter is the active nematic liquid crystal, whereby the equations of a conventional nematic are supplemented by a minimal active stress that violates time-reversal symmetry. In practice, active fluids may have not only liquid-crystalline but also viscoelastic polymer degrees of freedom. Here we explore the resulting interplay by coupling an active nematic to a minimal model of polymer rheology. We find that adding a polymer can greatly increase the complexity of spontaneous flow, but can also have calming effects, thereby increasing the net throughput of spontaneous flow along a pipe (a "drag-reduction" effect). Remarkably, active turbulence can also arise after switching on activity in a sufficiently soft elastomeric solid.
authors: Department of Physics, Durham University, Science Laboratories, South Road, Durham DH1 3LE, United Kingdom.
authors: E J
authors: EJ
authors: Hemingway
authors: CCMT, Department of Physics, Indian Institute of Science, Bangalore 560 012, India.
authors: A
authors: A
authors: Maitra
authors: Physics Department and Syracuse Biomaterials Institute, Syracuse University, Syracuse, New York 13244, USA.|James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA.
authors: S
authors: S
authors: Banerjee
authors: Physics Department and Syracuse Biomaterials Institute, Syracuse University, Syracuse, New York 13244, USA.
authors: M C
authors: MC
authors: Marchetti
authors: CCMT, Department of Physics, Indian Institute of Science, Bangalore 560 012, India.|TIFR Centre for Interdisciplinary Sciences, 21 Brundavan Colony, Osman Sagar Road, Narsingi, Hyderabad 500 075, India.
authors: S
authors: S
authors: Ramaswamy
authors: Department of Physics, Durham University, Science Laboratories, South Road, Durham DH1 3LE, United Kingdom.
authors: S M
authors: SM
authors: Fielding
authors: SUPA, School of Physics and Astronomy, University of Edinburgh, James Clerk Maxwell Building, Peter Guthrie Tait Road, Edinburgh EH9 3FD, United Kingdom.
authors: M E
authors: ME
authors: Cates
mesh_terms: D001419:Bacteria / Q000737:chemistry; D018407:Bacterial Physiological Phenomena; D050866:Liquid Crystals / Q000737:chemistry; D008954:Models, Biological; D008956:Models, Chemical; D012212:Rheology / Q000379:methods; D013550:Swimming; D055682:Viscoelastic Substances / Q000737:chemistry*
chemical_list: D055682:Viscoelastic Substances