Comment on “Turbulent compressible fluid: Renormalization group analysis, scaling regimes, and anomalous scaling of advected scalar fields”

Recently, asymptotic scaling behavior of the compressible randomly forced Navier-Stokes equation has been analyzed with the use of field-theoretic renormalization group near four dimensions [Phys. Rev. E 95, 033120 (2017)]. Two infrared stable nontrivial asymptotic scaling patterns have been found and their parameters determined in the one-loop approximation. Here, it is pointed out that the asymptotic scaling behavior predicted in this way may not be realized in physical fluid systems. This is a consequence of restrictions on viscosities imposed by the energy balance equation which the one-loop fixed-point value of the relative viscosity fails to meet.