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Large-eddy simulation of flow over a cylinder with Re_D from to 3.9 x 10^3 to 8.5 x 10^5: a skin-friction perspective

Cheng, W. and Pullin, D. I. and Samtaney, R. and Zhang, W. and Gao, W. (2017) Large-eddy simulation of flow over a cylinder with Re_D from to 3.9 x 10^3 to 8.5 x 10^5: a skin-friction perspective. Journal of Fluid Mechanics, 820 . pp. 121-158. ISSN 0022-1120. https://resolver.caltech.edu/CaltechAUTHORS:20170602-084638629

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Abstract

We present wall-resolved large-eddy simulations (LES) of flow over a smooth-wall circular cylinder up to Re_D = 8.5 × 10^5, where Re_D is Reynolds number based on the cylinder diameter D and the free-stream speed U_∞. The stretched-vortex subgrid-scale (SGS) model is used in the entire simulation domain. For the sub-critical regime, six cases are implemented with 3.9 × 10^3 ⩽ Re_D ⩽ 10^5. Results are compared with experimental data for both the wall-pressure-coefficient distribution on the cylinder surface, which dominates the drag coefficient, and the skin-friction coefficient, which clearly correlates with the separation behaviour. In the super-critical regime, LES for three values of Re_D are carried out at different resolutions. The drag-crisis phenomenon is well captured. For lower resolution, numerical discretization fluctuations are sufficient to stimulate transition, while for higher resolution, an applied boundary-layer perturbation is found to be necessary to stimulate transition. Large-eddy simulation results at Re_D = 8.5 × 10^5, with a mesh of 8192 × 1024 × 256, agree well with the classic experimental measurements of Achenbach (J. Fluid Mech., vol. 34, 1968, pp. 625–639) especially for the skin-friction coefficient, where a spike is produced by the laminar–turbulent transition on the top of a prior separation bubble. We document the properties of the attached-flow boundary layer on the cylinder surface as these vary with ReDReD . Within the separated portion of the flow, mean-flow separation–reattachment bubbles are observed at some values of Re_D, with separation characteristics that are consistent with experimental observations. Time sequences of instantaneous surface portraits of vector skin-friction trajectory fields indicate that the unsteady counterpart of a mean-flow separation–reattachment bubble corresponds to the formation of local flow-reattachment cells, visible as coherent bundles of diverging surface streamlines.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1017/jfm.2017.172DOIArticle
ORCID:
AuthorORCID
Cheng, W.0000-0003-3960-4162
Samtaney, R.0000-0002-4702-6473
Additional Information:© 2017 Cambridge University Press. Received 11 October 2016; revised 14 March 2017; accepted 14 March 2017; Published online: 05 May 2017. W.C. and R.S. were supported by the KAUST Office of Competitive Research Funds (OCRF) under award no. URF/1/1394-01. D.I.P. was partially supported under KAUST OCRF award no. URF/1/1394-01 and partially by NSF award CBET 1235605. The Cray XC40, Shaheen, at KAUST was utilized for all of the reported LES.
Funders:
Funding AgencyGrant Number
King Abdullah University of Science and Technology (KAUST)URF/1/1394-01
NSFCBET-1235605
Record Number:CaltechAUTHORS:20170602-084638629
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20170602-084638629
Official Citation:Cheng, W., Pullin, D., Samtaney, R., Zhang, W., & Gao, W. (2017). Large-eddy simulation of flow over a cylinder with Re_D from 3.9 x 10^3 to 8.5 x 10^5: A skin-friction perspective. Journal of Fluid Mechanics, 820, 121-158. doi:10.1017/jfm.2017.172
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:77907
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:02 Jun 2017 18:20
Last Modified:03 Oct 2019 18:03

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