Flow, Turbulence and Combustion

, Volume 63, Issue 1–4, pp 343–360 | Cite as

A Direct Numerical Study of Transport and Anisotropy in a Stably Stratified Turbulent Flow with Uniform Horizontal Shear

  • Frank Jacobitz
  • Sutanu Sarkar
Article

Abstract

Direct numerical simulations of homogeneous turbulence in stably stratified shear flow have been performed to aid the understanding of turbulence and turbulent mixing in geophysical flow. Two cases are compared. In the first case, which has been studied in the past, the mean velocity has vertical shear and the mean density is vertically stably stratified. In the second case, which has not been studied systematically before, the mean velocity has horizontal shear and the mean density is again vertically stably stratified. The critical value of the gradient Richardson number, for which a constant turbulence level is obtained, is found to be an order of magnitude larger in the horizontal shear case. The turbulent transport coefficients of momentum and vertical mass transfer are also an order of magnitude larger in the horizontal shear case. The anisotropy of the turbulence intensities are found to be in the range expected of flows with mean shear with no major qualitative change in the range of Richardson numbers studied here. However, the anisotropy of the turbulent dissipation rate is strongly affected by stratification with the vertical component dominating the others.

stratified turbulence environmental mixing geophysical flows 

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Copyright information

© Kluwer Academic Publishers 2000

Authors and Affiliations

  • Frank Jacobitz
    • 1
  • Sutanu Sarkar
    • 2
  1. 1.College of EngineeringUniversity of California at RiversideRiversideU.S.A.
  2. 2.Mechanical and Aerospace EngineeringUniversity of California at San DiegoLa JollaU.S.A.

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