  The paradigmatic model of the directed percolation process is studied near
its second order phase transition between an absorbing and an active state. The
model is first expressed in a form of Langevin equation and later rewritten
into a field-theoretic formulation. The ensuing response functional is then
analyzed employing Feynman diagrammatic technique and perturbative
renormalization group method. Percolation process is assumed to occur in
external velocity field, which has an additional effect on spreading
properties. Kraichnan rapid change ensemble is used for generation of velocity
fluctuations. The structure of the fixed points structure is obtained within
the two-loop approximation.
