Comment on "A self-adjusting flow dependent formulation for the classical Smagorinsky model coefficient" [Phys. Fluids 25, 055102 (2013)]

In this comment, we show that the novel formulation of the Smagorinsky model coefficient, proposed by Ghorbaniasl et al. [Phys. Fluids25, 055102 (2013)], satisfies neither the Galilean invariance nor the coordinate invariance, thus does not have physical significance. We conclude that their model is just to provide a coordinate-system-dependent dissipation term.