Status: this preprint was under review for the journal NPG. A final paper is not foreseen.
Cascade processes in rapidly rotating turbulence
Maxim Reshetnyakand Oleg Pokhotelov
Maxim Reshetnyak
Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences, B.Gruzinskaya, 10-1, Moscow, 123242, Russia
Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation RAS, Kalujskoe Hwy 4, Moscow, Troitsk, 108840, Russia
Oleg Pokhotelov
Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences, B.Gruzinskaya, 10-1, Moscow, 123242, Russia
Abstract. The process of the kinetic energy and kinetic helicity transfer over the spectrum in an incompressible, rapidly rotating turbulent flow is considered. An analogue of the Fjortoft theorem for 3D rapidly rotating turbulence is proposed. It is shown that, similar to 2D turbulence, there are two cascades simultaneously: the inverse cascade of the kinetic energy and the direct cascade of the kinetic helicity, which in the case of 2D turbulence corresponds to the cascade of enstrophy. The proposed scenario is in agreement with our earlier calculations, some recent numerical simulations, and physical experiment on rotating turbulence.
The interaction of waves can lead to inverse cascades, when energy is transferred from small scales to large ones. In dynamo theory, this corresponds to the alpha-effect, where turbulence generates large-scale magnetic field, in two-dimensional hydrodynamic turbulence transfer of kinetic energy from small scales to large ones is observed. We suggest simple analytical model that explains existence of inverse cascades of kinetic energy in rapidly rotating turbulence.
The interaction of waves can lead to inverse cascades, when energy is transferred from small...