Dresden 2014 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 41: Poster - Pattern/ Nonlinear Dyn./ Fluids/ Granular/ Critical Phen.
DY 41.28: Poster
Thursday, April 3, 2014, 17:00–19:00, P3
Scaling of Wet Particle Collisions — •Thomas Müller, Ingo Rehberg, and Kai Huang — Experimentalphysik V, Universität Bayreuth, 95440 Bayreuth, Germany
For the description of natural phenomena like debris flow or the formation of planetary rings as well as for the development of industrial applications, a thorough knowledge about the dynamics of granular matter is crucial. In many of these systems, the surfaces of the interacting particles are covered with a thin liquid film. Consequently, compared to the description of dry systems, additional energy losses due to the wetting liquid have to be taken into account.
We investigate macroscopic spheres bouncing on a flat surface that is covered with a liquid film. The coefficient of normal restitution en, defined as the ratio between the relative rebound and impact velocity of a binary impact is used to characterize the amount of energy dissipation during the collision. Our primary goal is to understand how various parameters, such as impact velocity, particle and liquid properties, influence en. Experiments with glass spheres have already shown, that en can be rescaled with the Stokes number which depends on the ratio between inertia forces and viscous forces, as long as the ratio between sphere size and liquid film thickness is kept constant. Here, we present further experimental results with spherical particles of different materials, in order to test the universality of such a scaling behavior and to understand the associated energy dissipation mechanisms.