A Critical Assessment of the Smagorinsky Model and a New Approach to Large-Eddy Simulations

Abstract

The Smagorinsky model for the large-eddy simulation of turbulence is critically assessed from a basic theoretical standpoint. It is shown that this model does not respond properly to the coarsening of the mesh because of its incorrect dependence on the dimensional mesh size. Rather, it is the dimensionless ratio of the computational mesh size to the Kolmogorov length scale that determines how well resolved a computation is and should be used to parameterize subgrid scale models. Furthermore, the Smagorinsky model has no dependence on rotational strains and depends improperly on the irrotational strain rate invariants. These facts tend to explain why the Smagorinsky constant is not in reality a constant in applications. An entirely new methodology for large-eddy simulations that is suitable for complex geometries is proposed that eliminates these deficiencies. In this new approach to large-eddy simulations, subgrid scale models go continuously to Reynolds stress models in the coarse mesh/infinite Reynolds number limit.

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Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1997
Accession Number
ADA332772

Entities

People

  • Charles G. Speziale

Organizations

  • Boston University

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Abstracts
  • Computational Fluid Dynamics
  • Computational Science
  • Equations
  • Equations Of Motion
  • Flow
  • Fluid Dynamics
  • Fluid Flow
  • Geometry
  • Kinetic Energy
  • Large Eddy Simulation
  • Mechanics
  • Military Research
  • Reynolds Number
  • Simulations
  • Strain Rate
  • Turbulent Flow

Readers

  • Computational Fluid Dynamics (CFD)
  • Fluid Dynamics.