Large-scale anisotropy in stably stratified rotating flows

AMS Citation:
Marino, R., P. D. Mininni, D. L. Rosenberg, and A. Pouquet, 2014: Large-scale anisotropy in stably stratified rotating flows. Physical Review E, 90, 023018, doi:10.1103/PhysRevE.90.023018.
Date:2014-08-28
Resource Type:article
Title:Large-scale anisotropy in stably stratified rotating flows
Abstract: We present results from direct numerical simulations of the Boussinesq equations in the presence of rotation and/or stratification, both in the vertical direction. The runs are forced isotropically and randomly at small scales and have spatial resolutions of up to 10243 grid points and Reynolds numbers of ≈1000. We first show that solutions with negative energy flux and inverse cascades develop in rotating turbulence, whether or not stratification is present. However, the purely stratified case is characterized instead by an early-time, highly anisotropic transfer to large scales with almost zero net isotropic energy flux. This is consistent with previous studies that observed the development of vertically sheared horizontal winds, although only at substantially later times. However, and unlike previous works, when sufficient scale separation is allowed between the forcing scale and the domain size, the kinetic energy displays a perpendicular (horizontal) spectrum with power-law behavior compatible with ∼k−5/3⊥, including in the absence of rotation. In this latter purely stratified case, such a spectrum is the result of a direct cascade of the energy contained in the large-scale horizontal wind, as is evidenced by a strong positive flux of energy in the parallel direction at all scales including the largest resolved scales.
Peer Review:Refereed
Copyright Information:Copyright 2014 American Physical Society.
OpenSky citable URL: ark:/85065/d7bc40h8
Publisher's Version: 10.1103/PhysRevE.90.023018
Author(s):
  • Raffaele Marino - NCAR/UCAR
  • Pablo Mininni
  • D. Rosenberg
  • Annick Pouquet - NCAR/UCAR
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