Accession Number:

ADP013706

Title:

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

Descriptive Note:

Conference paper

Corporate Author:

PENNSYLVANIA STATE UNIV UNIVERSITY PARK APPLIED RESEARCH LAB

Report Date:

2001-08-01

Pagination or Media Count:

6.0

Abstract:

Turbulent channel flow is used to study energy-containing-range modeling using a hybrid RANSLES 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 Karmans 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.

Subject Categories:

  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE