Free Cooling of a Granular Gas in Microgravity

POSTER

Abstract

Granular gases as dilute ensembles of particles in random motion are not only at the basis of elementary structure-forming processes in the universe and involved in many industrial and natural phenomena, but also excellent models to study fundamental statistical dynamics. A vast number of theoretical and numerical investigations have dealt with this seemingly simple non-equilibrium system. The essential difference to molecular gases is the energy dissipation in particle collisions, a subtle distinction with immense impact on their global dynamics. Its most striking manifestation is the so-called granular cooling, the gradual loss of mechanical energy in absence of external excitation. We report the first experimental study of homogeneous cooling of three-dimensional (3D) granular gases in microgravity. The asymptotic scaling E(t)∼ t-2 obtained by Haff's minimal model [J. Fluid Mech. 134 401 (1983)] proves to be robust, despite the violation of several of its central assumptions.

Presenters

  • Kirsten Harth

    University of Twente, Physics of Fluids and Max Planck Center of Complex Fluid Dynamics, University of Twente, Institute of Exp. Physics, Otto von Guericke University, Institute for Experimental Physics, Otto von Guericke University

Authors

  • Kirsten Harth

    University of Twente, Physics of Fluids and Max Planck Center of Complex Fluid Dynamics, University of Twente, Institute of Exp. Physics, Otto von Guericke University, Institute for Experimental Physics, Otto von Guericke University

  • Torsten Trittel

    Institute for Experimental Physics, Otto von Guericke University, Institute of Exp. Physics, Otto von Guericke University, Institute of Experimental Physics, Otto von Guericke University

  • Sandra Wegner

    Institute for Experimental Physics, Otto von Guericke University

  • Ralf Stannarius

    Institute for Experimental Physics, Otto von Guericke University, Institute of Exp. Physics, Otto von Guericke University, Institute of Experimental Physics, Otto von Guericke University