Dissipation-range geometry and scalar specta in sheared stratified turbulence Public Deposited

http://ir.library.oregonstate.edu/concern/defaults/bn9998265

Descriptions

Attribute NameValues
Creator
Abstract or Summary
  • Direct numerical simulations of turbulence resulting from Kelvin{Helmholtz instability in stratified shear flow are used to examine the geometry of the dissipation range in a variety of flow regimes. As the buoyancy and shear Reynolds numbers that quantify the degree of isotropy in the dissipation range increase, alignment statistics evolve from those characteristic of parallel shear flow to those found previously in studies of stationary, isotropic, homogeneous turbulence (e.g. Ashurst et al. 1987; She et al. 1991; Tsinober et al. 1992). The analysis yields a limiting value for the mean compression rate of scalar gradients that is expected to be characteristic of all turbulent flows at sufficiently high Reynolds number. My main focus is the value of the constant q that appears in both the Batchelor (1959) and Kraichnan (1968) theoretical forms for the passive scalar spectrum. Taking account of the effects of time-dependent strain, I propose a revised estimate of q, denoted qe, which appears to agree with spectral shapes derived from simulations and observations better than do previous theoretical estimates. The revised estimate is qe = 7.3±0.4, and is expected to be valid whenever the buoyancy Reynolds number exceeds O(10²). The Kraichnan (1968) spectral form, in which effects of intermittency are accounted for, provides a better fit to the DNS results than does the Batchelor (1959) form.
Resource Type
Date Available
Date Issued
Citation
  • Smyth, W. D. (1999). Dissipation-range geometry and scalar specta in sheared stratified turbulence. Journal of Fluid Mechanics, 401, 209-242.
Series
Rights Statement
Funding Statement (additional comments about funding)
Publisher
Language
Replaces
Additional Information
  • description.provenance : Submitted by Eric Vanderwall (ewscanner@gmail.com) on 2010-09-17T20:29:37Z No. of bitstreams: 1 Smyth_J_Fluid_Mech_1999.pdf: 785758 bytes, checksum: adc0be1dae9f1c85b6b4dcbee435ac77 (MD5)
  • description.provenance : Approved for entry into archive by Digital Production(digitalproduc@gmail.com) on 2010-09-30T19:03:57Z (GMT) No. of bitstreams: 1 Smyth_J_Fluid_Mech_1999.pdf: 785758 bytes, checksum: adc0be1dae9f1c85b6b4dcbee435ac77 (MD5)
  • description.provenance : Made available in DSpace on 2010-09-30T19:03:57Z (GMT). No. of bitstreams: 1 Smyth_J_Fluid_Mech_1999.pdf: 785758 bytes, checksum: adc0be1dae9f1c85b6b4dcbee435ac77 (MD5) Previous issue date: 1999

Relationships

Parents:

This work has no parents.

Last modified

Downloadable Content

Download PDF

Items