  We demonstrate the results of the numerical modelling of a plane
two-dimensional viscous incompressible flow in a channel with a back-step. As a
mathematical model we take equations for a incompressible flow based on the
quasi-hydrodynamic (QHD) equations. We present a phenomenological derivation of
the QHD equations and show a relation of these equations to the Navier-Stokes
system. We test the proposed numerical algorithm by computing of certain
laminar flows
