University of Illinois Urbana-Champaign

Optimal large-eddy simulation formulations for isotropic turbulence

Langford, Jacob A.; Moser, Robert D.

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https://hdl.handle.net/2142/112590

Description

Title
Optimal large-eddy simulation formulations for isotropic turbulence
Author(s)
  • Langford, Jacob A.
  • Moser, Robert D.
Issue Date
1998-07
Keyword(s)
  • Isotropic Turbulence
  • Large Eddy Simulation Formulations
Abstract
A new concept of optimal LES formulations is presented, in which the subgrid is considered to be stochastic and the problem of subgrid modeling is treated as an error-minimization problem. It is argued that a subgrid model should be chosen to minimize the RMS error of the instantaneous time-derivative of filtered velocity, and that for a particular flow and a given filter there is a conditional average that minimizes such error while accurately reproducing all large-scale spatial statistics. It is shown that a relatively simple, but general class of one-point estimates can be computed from two-point correlation data, and that these estimates can accurately reproduce the dissipation of the real system. These estimates are computed in the case of isotropic turbulence, and it is found that except for dissipation, the effect of the subgrid scales on the large-scale dynamics is virtually unpredictable using one-point estimation. This suggests that for isotropic turbulence the best subgrid model may be able to do little more than predict the average dissipation of the system.
Publisher
Department of Theoretical and Applied Mechanics. College of Engineering. University of Illinois at Urbana-Champaign
Series/Report Name or Number
  • TAM R 884
  • 1998-6010
ISSN
0073-5264
Type of Resource
text
Language
eng
Permalink
http://hdl.handle.net/2142/112590
Sponsor(s)/Grant Number(s)
Air Force Office of Scientific Research CTS-9616219; National Science Foundation; NASA NGT 2-52229
Copyright and License Information
Copyright 1998 Board of Trustees of the University of Illinois

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Technical Reports - Theoretical and Applied Mechanics (TAM) PRIMARY
TAM technical reports include manuscripts intended for publication, theses judged to have general interest, notes prepared for short courses, symposia compiled from outstanding undergraduate projects, and reports prepared for research-sponsoring agencies.