Behaviour of a dimensionless angular momentum flux for initial vortex of perturbations defined by Eqs. (65)–(67) shown for q = −10 and M = 1. Solid and dashed lines correspond to R_nl = 1400 and R_nl = 1200, respectively. It was checked that turbulence for R_nl = 1400 does not decay at least during the three thousands shear times |q|t. The horizontal dot-dashed line corresponds to the value of α_ν in this case.