  We argue that turbulence in superfluids is governed by two dimensionless
parameters. One of them is the intrinsic parameter q which characterizes the
friction forces acting on a vortex moving with respect to the heat bath, with
1/q playing the same role as the Reynolds number Re=UR/\nu in classical
hydrodynamics. It marks the transition between the "laminar" and turbulent
regimes of vortex dynamics. The developed turbulence described by Kolmogorov
cascade occurs when Re >> 1 in classical hydrodynamics, and q << 1 in the
superfluid hydrodynamics. Another parameter of the superfluid turbulence is the
superfluid Reynolds number Re_s=UR/\kappa, which contains the circulation
quantum \kappa characterizing quantized vorticity in superfluids. This
parameter may regulate the crossover or transition between two classes of
superfluid turbulence: (i) the classical regime of Kolmogorov cascade where
vortices are locally polarized and the quantization of vorticity is not
important; and (ii) the quantum Vinen turbulence whose properties are
determined by the quantization of vorticity. The phase diagram of the dynamical
vortex states is suggested.
