High resolution DNS of shear-convective turbulence and its implications to second-order parameterizations

K. L. Tse, Alex Mahalov, B. Nicolaenko, B. Joseph

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

Shear-convective turbulence is studied using a high resolution 3D direct numerical simulation (DNS). Flow configuration consisting of a modeled jet capping a thermally unstable layer is simulated and the results are compared with the reference situation where only the convective layer is present. Quasi-equilibrium turbulent datasets, in which the turbulent energy budgets are nearly balanced, are obtained. A 'mechanical' barrier is identified near the jet centerline in the shear-convective case. Intense and elongated vorticity regions are created in a narrow layer above the barrier in a way similar to the shear-sheltering effect. Vertical profiles of turbulence statistics and budgets are presented. We have unambiguously identified layers of counter-gradient momentum and heat fluxes which occur near regions of penetrative convection. Using quasi-equilibrium DNS datasets, we evaluate the performance of some popular second-order closure models of turbulence. The models satisfactorily predict the triple moments and dissipation, except in the counter-gradient region. The models, however, fail to predict the pressure correlation terms.

Original languageEnglish (US)
Pages (from-to)445-462
Number of pages18
JournalTheoretical and Computational Fluid Dynamics
Volume17
Issue number5-6
DOIs
StatePublished - Sep 1 2004

Keywords

  • Inhomogeneous shear-convective turbulence
  • Tropopause dynamics

ASJC Scopus subject areas

  • Computational Mechanics
  • Condensed Matter Physics
  • Engineering(all)
  • Fluid Flow and Transfer Processes

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