  The effects of purely elastic collisions on the dynamics of heavy inertial
particles is investigated in a three-dimensional random incompressible flow. It
is shown that the statistical properties of inter-particle separations and
relative velocities are strongly influenced by the occurrence of sticky elastic
collisions - particle pairs undergo a large number of collisions against each
other during a small time interval over which, hence, they remain close to each
other. A theoretical framework is provided for describing and quantifying this
phenomenon and it is substantiated by numerical simulations. Furthermore, the
impact of hydrodynamic interactions is discussed for such a system of colliding
particles.
