Theoretical and Computational Fluid Dynamics

, Volume 2, Issue 5, pp 279–290

Subgrid length-scales for large-eddy simulation of stratified turbulence

  • Ulrich Schumann
Article

DOI: 10.1007/BF00271468

Cite this article as:
Schumann, U. Theoret. Comput. Fluid Dynamics (1991) 2: 279. doi:10.1007/BF00271468

Abstract

The influence of buoyancy on the length-scales for the dissipation rate of kinetic energy, and for momentum, heat, and other scalar transport has to be known for subgrid-scale (SGS) models in a large-eddy simulation (LES). For the inertial subrange, Lilly (1967) has shown that grid spacing is the relevant length-scale for SGS effects. Deardorff (1980) proposed to reduce all the length-scales for stable stratification. Numerical and experimental data show, however, that the dissipation length-scale may strongly increase in stable layers with little shear. Lumley's (1964) theory for the energy spectrum in a stratified fluid also suggests such an increase. In this paper we apply the analysis of previous algebraic second-order closure SGS models, parameter studies with different length-scale models in LES, and the analysis of direct simulations of sheared and unsheared stably stratified homogeneous turbulence. These analyses show advantages of first-order closures for LES and suggest that the limiting effect of stratification should only be applied to the length-scales of vertical eddy-diffusivities of heat and scalars but not to those of momentum and dissipation.

Copyright information

© Springer-Verlag 1991

Authors and Affiliations

  • Ulrich Schumann
    • 1
  1. 1.DLR, Institute of Atmospheric PhysicsOberpfaffenhofenFederal Republic of Germany