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Hybrid LES-RANS study on square cylinder unsteady heat transfer

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journal contribution
posted on 14.12.2016, 11:40 authored by Xiao-Sheng (Shaun) Chen, Hao XiaHao Xia
Flow passing a heated square cylinder is investigated using a hybrid LES-RANS approach on unstructured grids at a moderate Reynolds number of 22, 050. The implicit SGS is applied for LES and two turbulence models are tested for near-wall RANS: the Spalart-Allmaras model and the SST k-! model. Both models combined with the LES present good predictions of the time- and phase-averaged velocity profiles on a 4-million-cell grid. Results of the LES-SST approach agree better with the experimental data especially at locations close to the cylinder surface and this leads to improved surface convective heat transfer compared to LES-SA. Grid convergence study shows that grid resolution in the near-wall region and on the cylinder surfaces is important in resolving the unsteady convective heat transfer. Results of velocity field and surface heat transfer from the fine grid with 8 million cells compare favourably with the experimental data and show significant improvement over that of the medium and coarse grids. Analysis of turbulent statistics is performed by means of energy spectra and anisotropy invariants of the Reynolds stress tensor. Proper orthogonal decomposition (POD) is used to identify the vortex shedding phases. It is shown that the POD based phase-averaging produces more accurate velocity profiles than the conventional pressure-signal based method.

History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Aeronautical and Automotive Engineering

Published in

International Journal of Heat and Mass Transfer

Volume

108

Issue

Part A

Pages

1237-1254

Citation

CHEN, X. and XIA, H., 2017. Hybrid LES-RANS study on square cylinder unsteady heat transfer. International Journal of Heat and Mass Transfer, 108 pt A, pp.1237-1254.

Publisher

© Elsevier

Version

AM (Accepted Manuscript)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Acceptance date

24/10/2016

Publication date

2016-12-16

Copyright date

2017

Notes

This paper was accepted for publication in the journal International Journal of Heat and Mass Transfer and the definitive published version is available at http://dx.doi.org/10.1016/j.ijheatmasstransfer.2016.10.081

ISSN

0017-9310

Language

en