The effect of moderate rotation on stratified turbulence: A case for Bolgiano-Obukhov scaling

AMS Citation:
Rosenberg, D. L., A. Pouquet, R. Marino, and P. D. Mininni, 2015: The effect of moderate rotation on stratified turbulence: A case for Bolgiano-Obukhov scaling. AGU Fall Meeting 2015, American Geophysical Union, San Francisco, CA, US.
Date:2015-12-14
Resource Type:conference material
Title:The effect of moderate rotation on stratified turbulence: A case for Bolgiano-Obukhov scaling
Abstract: We report on decaying rotating stratified turbulence with large scale isotropic initial conditions using direct numerical simulation (DNS) on grids of up to N3p = 40963 points. The Reynolds and Froude numbers are Re = 5.4x104 and F r = 0.024. The ratio of the Brunt-Vaisala to the inertial wave frequency, N/f, is taken to be equal to 4.95, a choice appropriate to model the dynamics of the southern abyssal ocean at mid latitudes. This gives a global buoyancy Reynolds number RB = ReF r2 = 32, a value sufficient for some isotropy to be recovered in the small scales beyond the Ozmidov scale, but still moderate enough that the intermediate scales where waves are prevalent are well resolved. Concentrating on the large-scale dynamics, we find a spectrum compatible with the Bolgiano-Obukhov scaling, and not inconsistent with self-simiilarity as developed in [1]. At least two characteristic scales emerge, and are identified by sharp variation in the spectral distribution of total energy and helicity (latter not shown). Large slanted layers are ubiquitous in the flow in the velocity and temperature fields, with local overturning events indicated by small Richardson numbers, and a small large-scale enhancement of energy directly attributable to the effect of rotation is also observed.
Peer Review:Non-refereed
Copyright Information:Copyright Author(s). This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
OpenSky citable URL: ark:/85065/d70003sp
Author(s):
  • Duane Rosenberg - NCAR/UCAR
  • Annick Pouquet - NCAR/UCAR
  • R Marino - NCAR/UCAR
  • Pablo Mininni
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