Energy-Containing-Range Modeling of Fully-Developed Channel Flow Using a Hybrid RANS/LES Technique

Abstract

Turbulent channel flow is used to study energy-containing-range modeling using a hybrid RANS/LES approach. The hybrid model relates the mean component of an LES-type subgrid diffusivity to the turbulence diffusivity from RANS via a transfer function. Details of this transfer function in the energy-containing-range of the turbulence are shown to be very important when modeling coarsely resolved flows. Three transfer function models are compared. One interpolates the turbulence diffusivity between the LES and RANS limits using an algebraic blending. The second uses von Karman's empirical fit to the turbulent kinetic energy spectrum to diagnose energy-containing-range structure. The third uses a modified Smagorinsky subgrid model corrected to have the proper mean time scale as diagnosed from RANS. Our Reynolds number is 640, based on the channel half height and on the friction velocity. Comparison of mean-field and root-mean-square statistics to other studies clearly identify the mean time-scale model as the best performer.

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Document Details

Document Type
Technical Report
Publication Date
Aug 01, 2001
Accession Number
ADP013706

Entities

People

  • Frank J. Zahackowski
  • Leonard J. Peltier

Organizations

  • Pennsylvania State University

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Channel Flow
  • Diffusion
  • Diffusivity
  • Energy
  • Equations
  • Flow
  • Flow Fields
  • Grids
  • Kinetic Energy
  • Models
  • Navier Stokes Equations
  • Numbers
  • Pressure Gradients
  • Reynolds Number
  • Scale Models
  • Strain Rate
  • Transfer Functions

Fields of Study

  • Physics

Readers

  • Computational Fluid Dynamics (CFD)
  • Fluid Mechanics and Fluid Dynamics.