0
Research Papers: Fundamental Issues and Canonical Flows

Wall-Modeled Large-Eddy Simulations of Flows With Curvature and Mild Separation

[+] Author and Article Information
Senthilkumaran Radhakrishnan

 University of Maryland, College Park, MD 20742

Ugo Piomelli1

 University of Maryland, College Park, MD 20742

Anthony Keating2

 University of Maryland, College Park, MD 20742

1

Present address: Department of Mechanical and Materials Engineering, Queen's University, Kingston, ON K7L 3N6.

2

Present address: Exa Corporation, Burlington, MA.

J. Fluids Eng 130(10), 101203 (Sep 02, 2008) (9 pages) doi:10.1115/1.2969458 History: Received January 17, 2008; Revised June 14, 2008; Published September 02, 2008

The performance of wall-modeled large-eddy simulation (WMLES) based on hybrid models, in which the inner region is modeled by Reynolds-averaged Navier–Stokes (RANS) equation and the outer region is resolved by large-eddy simulation (LES), can make the application of LES attainable at high Reynolds numbers. In previous work by various authors, it was found that in most cases a buffer region exists between the RANS and LES zones, in which the velocity gradient is too high; this leads to an inaccurate prediction of the skin-friction coefficient. Artificially perturbing the RANS∕LES interface has been demonstrated to be effective in removing the buffer region. In this work, WMLES has been performed with stochastic forcing at the interface, following the previous work by our group on two nonequilibrium complex flows. From the two flows studied, we conclude that the application of stochastic forcing results in improvements in the prediction of the skin-friction coefficient in the equilibrium regions of these flows, a better agreement with the experiments of the Reynolds stresses in the adverse pressure gradient and the recovery region, and a good agreement of the mean velocity field with experiments in the separation region. Some limitations of this method, especially in terms of CPU requirements, will be discussed.

FIGURES IN THIS ARTICLE
<>
Copyright © 2008 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 6

Mean velocity profile in wall coordinates. —, WMLES with stochastic forcing, coarse mesh; ------, WMLES with stochastic forcing, fine mesh; –△–, WMLES without stochastic forcing, coarse mesh; ---△---, WMLES without stochastic forcing, fine mesh; ●, experiments.

Grahic Jump Location
Figure 7

Profiles of the (a) mean horizontal velocity, (b) total (resolved + modeled) Reynolds shear stress, and (c) rms of horizontal velocity fluctuations. —, WMLES with stochastic forcing, coarse mesh; ------, WMLES with stochastic forcing, fine mesh; –△–, WMLES without stochastic forcing, coarse mesh; ---△---, WMLES without stochastic forcing, fine mesh; ●, experiments.

Grahic Jump Location
Figure 8

Profiles of the (a) streamwise two-point correlation of u′ fluctuations and (b) streamwise two-point correlation of v′ fluctuations. —, WMLES with stochastic forcing, coarse mesh; ------, WMLES with stochastic forcing, fine mesh; –△–, WMLES without stochastic forcing, coarse mesh; ---△--- WMLES without stochastic forcing, fine mesh; ●, experiments.

Grahic Jump Location
Figure 9

Flow configuration for the two-dimensional bump calculation

Grahic Jump Location
Figure 10

rms of the stochastic forcing

Grahic Jump Location
Figure 11

Profiles of the (a) pressure coefficient and (b) skin-friction coefficient. —, WMLES with stochastic forcing; ---, WMLES without stochastic forcing; ●, experiments.

Grahic Jump Location
Figure 12

Mean horizontal velocity profile. —, WMLES with stochastic forcing; ---, WMLES without stochastic forcing; ●, experiments.

Grahic Jump Location
Figure 13

Streamwise velocity rms fluctuations. —, WMLES with stochastic forcing; ---, WMLES without stochastic forcing; ●, experiments.

Grahic Jump Location
Figure 5

Profiles of the (a) skin-friction coefficient and (b) pressure coefficient —. WMLES with stochastic forcing, coarse mesh; ------, WMLES with stochastic forcing, fine mesh; –△–, WMLES without stochastic forcing, coarse mesh; ---△---, WMLES without stochastic forcing, fine mesh; ●, experiments.

Grahic Jump Location
Figure 4

rms of the stochastic forcing: —, coarse mesh; ------, fine mesh

Grahic Jump Location
Figure 3

Mean streamlines and contours of the total Reynolds shear stress (⟨u′v′⟩)

Grahic Jump Location
Figure 2

Flow configuration for the contoured ramp calculation

Grahic Jump Location
Figure 1

Resolved (—) and modeled (---) stresses in calculations that use a DES based wall model

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In