Article

 

Anistropy of turbulence in stably stratified mixing layers Public Deposited

Downloadable Content

Download PDF
https://ir.library.oregonstate.edu/concern/articles/3j333404c

Descriptions

Attribute NameValues
Creator
Abstract
  • Direct numerical simulations of turbulence resulting from Kelvin–Helmholtz instability in stably stratified shear flow are used to study sources of anisotropy in various spectral ranges. The set of simulations includes various values of the initial Richardson and Reynolds numbers, as well as Prandtl numbers ranging from 1 to 7. We demonstrate that small-scale anisotropy is determined almost entirely by the spectral separation between the small scales and the larger scales on which background shear and stratification act, as quantified by the buoyancy Reynolds number. Extrapolation of our results suggests that the dissipation range becomes isotropic at buoyancy Reynolds numbers of order 105, although we cannot rule out the possibility that small-scale anisotropy persists at arbitrarily high Reynolds numbers, as some investigators have suggested. Correlation-coefficient spectra reveal the existence of anisotropic flux reversals in the dissipation subrange whose magnitude decreases with increasing Reynolds number. The scalar concentration field tends to be more anisotropic than the velocity field. Estimates of the dissipation rates of kinetic energy and scalar variance based on the assumption of isotropy are shown to be accurate for buoyancy Reynolds numbers greater than O(10²). Such estimates are therefore reliable for use in the interpretation of most geophysical turbulence data, but may give misleading results when applied to smaller-scale flows.
Resource Type
DOI
Date Available
Date Issued
Citation
  • Smyth, W. D., & Moum, J. N. (2000). Anistropy of turbulence in stably stratified mixing layers. Physics of Fluids, 12(6), 1343-1362.
Journal Title
Journal Volume
  • 12
Rights Statement
Funding Statement (additional comments about funding)
  • National Science Foundation Grant No. OCE9521359.
Publisher
Language
Replaces

Relationships

Parents:

This work has no parents.

Items