a1 National Center for Atmospheric Research, PO Box 3000, Boulder, CO 80307, USA
We present numerical evidence of how three-dimensionalization occurs at small scale in rotating turbulence with Beltrami () forcing, creating helical flow. The Zeman scale at which the inertial and eddy turn-over times are equal is more than one order of magnitude larger than the dissipation scale, with the relevant domains (large-scale inverse cascade of energy, dual regime in the direct cascade of energy and helicity , and dissipation) each moderately resolved. These results stem from the analysis of a large direct numerical simulation on a grid of points, with Rossby and Reynolds numbers, respectively, equal to and . At scales smaller than the forcing, a helical wave-modulated inertial law for the energy and helicity spectra is followed beyond by Kolmogorov spectra for and . Looking at the two-dimensional slow manifold, we also show that the helicity spectrum breaks down at , a clear sign of recovery of three-dimensionality in the small scales.
(Received September 20 2011)
(Reviewed January 26 2012)
(Accepted February 10 2012)
(Online publication April 13 2012)
‡ Also at Departamento de Fí sica, Facultad de Ciencias Exactas y Naturales and IFIBA, CONICET, Ciudad Universitaria, 1428 Buenos Aires, Argentina.