The interplay between helicity and rotation in turbulence: Implications for scaling laws and small-scale dynamics

AMS Citation:
Pouquet, A., and P. D. Mininni, 2010: The interplay between helicity and rotation in turbulence: Implications for scaling laws and small-scale dynamics. Philosophical Transactions of the Royal Society. Series A, Mathematical, Physical & Engineering Sciences, 368, 1635-1662, doi:10.1098/rsta.2009.0284.
Date:2010-04-13
Resource Type:article
Title:The interplay between helicity and rotation in turbulence: Implications for scaling laws and small-scale dynamics
Abstract: Invariance properties of physical systems govern their behaviour: energy conservation in turbulence drives a wide distribution of energy among modes, as observed in geophysical or astrophysical flows. In ideal hydrodynamics, the role of the invariance of helicity (correlation between velocity and its curl, measuring departures from mirror symmetry) remains unclear since it does not alter the energy spectrum. However, in the presence of rotation, significant differences emerge between helical and non-helical turbulent flows. We first briefly outline some of the issues such as the partition of energy and helicity among modes. Using massive numerical simulations, we then show that small-scale structures and their intermittency properties differ according to whether helicity is present or not, in particular with respect to the emergence of Beltrami core vortices that are laminar helical vertical updraft vortices. These results point to the discovery of a small parameter besides the Rossby number, a fact that would relate the problem of rotating helical turbulence to that of critical phenomena, through the renormalization group and weak-turbulence theory. This parameter can be associated with the adimensionalized ratio of the energy to helicity flux to small scales, the three-dimensional energy cascade being weak and self-similar.
Subject(s):Turbulence, Helicity, Scaling laws, Universality, Structures, Intermittency
Peer Review:Refereed
Copyright Information:Copyright 2010 Author(s). Published under license by The Royal Society.
OpenSky citable URL: ark:/85065/d7n29xc7
Publisher's Version: 10.1098/rsta.2009.0284
Author(s):
  • Annick Pouquet - NCAR/UCAR
  • Pablo Mininni - NCAR/UCAR
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