a1 Department of Mechanical and Aerospace Engineering, University of California, Irvine, CA 92697-3975, USA
a2 Department of Aerospace Engineering and Mechanics, University of Minnesota, MN 55455, USA
In this study, we present experimental results on particle-wall collision in viscoelastic fluids. A sphere is released in a tank filled with poly(ethylene-oxide) (PEO) mixed with water with varying concentrations up to 1.5%. The effect of Stokes and Deborah numbers on the rebound velocity of a spherical particle colliding onto a wall is considered. It has been observed that the slope at which the coefficient of restitution increases with Stokes number is smaller for higher Deborah numbers. Higher rebound occurs for higher PEO concentration at the same stokes number. However, the results for the coefficient of restitution in polymeric liquids can be collapsed together with the Newtonian fluid behaviour if one defines the Stokes number based on the local strain rate.
(Received September 08 2008)
(Revised May 28 2009)