  We consider the compressible Kraichnan model of turbulent advection with
small molecular diffusivity and velocity field regularized at short scales to
mimic the effects of viscosity. As noted in ref.[5], removing those two
regularizations in two opposite orders for intermediate values of
compressibility gives Lagrangian flows with quite different properties.
Removing the viscous regularization before diffusivity leads to the explosive
separation of trajectories of fluid particles whereas turning the
regularizations off in the opposite order results in coalescence of Lagrangian
trajectories. In the present paper we re-examine the situation first addressed
in ref.[6] in which the Prandtl number is varied when the regularizations are
removed. We show that an appropriate fine-tuning leads to a sticky behavior of
trajectories which hit each other on and off spending a positive amount of time
together. We examine the effect of such a trajectory behavior on the passive
transport showing that it induces anomalous scaling of the stationary 2-point
structure function of an advected tracer and influences the rate of
condensation of tracer energy in the zero wavenumber mode.
