It is shown that the use of a high power α of the Laplacian in the dissipative term of hydrodynamical equations leads asymptotically to truncated inviscid conservative dynamics with a finite range of spatial Fourier modes. Those at large wave numbers thermalize, whereas modes at small wave numbers obey ordinary viscous dynamics [C. Cichowlas et al., Phys. Rev. Lett. 95, 264502 (2005)]. The energy bottleneck observed for finite α may be interpreted as incomplete thermalization. Artifacts arising from models with α>1 are discussed.
Frisch, U., Kurien, S., Pandit, R., Pauls, W., Ray, S.S., Wirth, A. and Zhu, J.Z., "Hyperviscosity, Galerkin Truncation, and Bottlenecks in Turbulence", Physical Review Letters, 101, p. 144501 (2008) (doi:10.1103/PhysRevLett.101.144501)