  Accretion disks in binary systems can experience hydrodynamic impact at inner
as well as outer edges. The first case is typical for protoplanetary disks
around young T Tau stars. The second one is typical for circumstellar disks in
close binaries. As a result of such an impact, perturbations with different
scales and amplitudes are excited in the disk. We investigated the nonlinear
evolution of perturbations of a finite, but small amplitude, at the background
of sub-Keplerian flow. Nonlinear effects at the front of perturbations lead to
the formation of a shock wave, namely the discontinuity of the density and
radial velocity. At this, the tangential flow in the neighborhood of the shock
becomes equivalent to the flow in in the boundary layer. Instability of the
tangential flow further leads to turbulization of the disk. Characteristics of
the turbulence depend on perturbation parameters, but alpha-parameter of
Shakura-Sunyaev does not exceed ~0.1.
