Comment on "On the relations between large-scale models of superfluid helium-4" [Phys. Fluids 33, 127124 (2021]"

Abstract

We comment on the paper by M. S\'ykora, M. Pavelka, M. La Mantia, D. Jou, and M. Grmela "On the relations between large-scale models of superfluid helium-4," Physics of Fluids, 33(12):127124(2021), where the authors have developed a formalism for describing a coarse-grained flow of superfluid helium. This formalism is greatly based on the Hall-Vinen-Bekarevich-Khalatnikov (HVBK) model. We strongly disagree with the use of the HVBK equation approach for the case of the three-dimensional quantum turbulence and expose our objections in this comment. We discuss the HVBK method and also criticize the so-called vortex bundles model, which serves as a basis for using the HVBK method in a three-dimensional quantum turbulence.