title: Coefficient of restitution of colliding viscoelastic spheres.
abstract: We perform a dimension analysis for colliding viscoelastic spheres to show that the coefficient of normal restitution epsilon depends on the impact velocity g as epsilon=1-gamma(1)g(1/5)+gamma(2)g(2/5)-/+..., in accordance with recent findings. We develop a simple theory to find explicit expressions for coefficients gamma(1) and gamma(2). Using these and few next expansion coefficients for epsilon(g) we construct a Padé approximation for this function which may be used for a wide range of impact velocities where the concept of the viscoelastic collision is valid. The obtained expression reproduces quite accurately the existing experimental dependence epsilon(g) for ice particles.
authors.affiliation: Departamento de Fisica, FCFM, Universidad de Chile, Casilla 487-3, Santiago, Chile.
authors.forename: R
authors.initials: R
authors.lastname: Ramírez
authors.forename: T
authors.initials: T
authors.lastname: Pöschel
authors.forename: N V
authors.initials: NV
authors.lastname: Brilliantov
authors.forename: T
authors.initials: T
authors.lastname: Schwager