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Large-Eddy Simulation of Homogeneous Turbulence and Diffusion in Stably Stratified Shear Flow

Kaltenbach, H.-J. and Gerz, T. and Schumann, U. (1994) Large-Eddy Simulation of Homogeneous Turbulence and Diffusion in Stably Stratified Shear Flow. Journal of Fluid Mechanics, 280, pp. 1-40. doi: 10.1017/S0022112094002831.

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Official URL: http://journals.cambridge.org/action/displayAbstract?aid=353534

Abstract

By means of large-eddy simulation, homogeneous turbulence is simulated for neutrally and stably stratified shear flow at gradient-Richardson numbers between zero and one. We investigate the turbulent transport of three passive species which have uniform gradients in either the vertical, downstream or cross-stream direction. The results are compared with previous measurements in the laboratory and in the stable atmospheric boundary layer, as well as with results from direct numerical simulations. The computed and measured flow properties agree with each other generally within the scatter of the measurements. At strong stratification, the Froude number becomes the relevant flow-controlling parameter. Stable stratification suppresses vertical overturning and mixing when the inverse Froude number based on a turn-over timescale exceeds a critical value of about 3. The turbulent diffusivity tensor is strongly anisotropic and asymmetric. However, only the vertical and the cross-stream diagonal components are of practical importance in shear flows. The vertical diffusion coefficient is much smaller than the cross-stream one at strong stratification. This anisotropy is stronger than predicted by second-order closure models. Turbulence fluxes in downstream and cross-stream directions follow classical mixing-length models.

Item URL in elib:https://elib.dlr.de/31863/
Document Type:Article
Title:Large-Eddy Simulation of Homogeneous Turbulence and Diffusion in Stably Stratified Shear Flow
Authors:
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Kaltenbach, H.-J.UNSPECIFIEDUNSPECIFIED
Gerz, T.UNSPECIFIEDUNSPECIFIED
Schumann, U.UNSPECIFIEDUNSPECIFIED
Date:1994
Journal or Publication Title:Journal of Fluid Mechanics
Open Access:Yes
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Volume:280
DOI :10.1017/S0022112094002831
Page Range:pp. 1-40
Status:Published
Keywords:stratification, shear, turbulence
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:L VU - Air Traffic and Environment (old)
DLR - Research area:Aeronautics
DLR - Program:L VU - Air Traffic and Environment
DLR - Research theme (Project):L - Low-Emission Air Traffic (old)
Location: Oberpfaffenhofen
Institutes and Institutions:Institute of Atmospheric Physics
Deposited By: DLR-Beauftragter, elib
Deposited On:02 Apr 2006
Last Modified:31 Jul 2019 19:17

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