Imperial College London
Professor John Christos Vassilicos

ProfessorJohn ChristosVassilicos

Faculty of Engineering, Department of Aeronautics

Visiting Professor
 
 
 
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Contact

 

+44 (0)20 7594 5137j.c.vassilicos

 
 
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Assistant

 

Miss Jackie O'Neill +44 (0)20 7594 5079

 
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Location

 

CAGB 314City and Guilds BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Paul:2018:10.1017/jfm.2018.331,
author = {Paul, I and Papadakis, G and Vassilicos, JC},
doi = {10.1017/jfm.2018.331},
journal = {Journal of Fluid Mechanics},
pages = {452--488},
title = {Direct numerical simulation of heat transfer from a cylinder immersed in the production and decay regions of grid-element turbulence},
url = {http://dx.doi.org/10.1017/jfm.2018.331},
volume = {847},
year = {2018}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - The present direct numerical simulation (DNS) study, the first of its kind, explores the effect that the location of a cylinder, immersed in the turbulent wake of a grid-element, has on heat transfer. An insulated single square grid-element is used to generate the turbulent wake upstream of the heated circular cylinder. Due to fine-scale resolution requirements, the simulations are carried out for a low Reynolds number. Three locations downstream of the grid-element, inside the production, peak and decay regions, respectively, are considered. The turbulent flow in the production and peak regions is highly intermittent, non-Gaussian and inhomogeneous, while it is Gaussian, homogeneous and fully turbulent in the decay region. The turbulence intensities at the location of the cylinder in the production and decay regions are almost equal at 11Â %, while the peak location has the highest turbulence intensity of 15Â %. A baseline simulation of heat transfer from the cylinder without oncoming turbulence was also performed. Although the oncoming turbulent intensities are similar, the production region increases the stagnation point heat transfer by 63Â %, while in the decay region it is enhanced by only 28Â %. This difference cannot be explained only by the increased approaching velocity in the production region. The existing correlations for the stagnation point heat transfer coefficient are found invalid for the production and peak locations, while they are satisfied in the decay region. It is established that the flow in the production and peak regions is dominated by shedding events, in which the predominant vorticity component is in the azimuthal direction. This leads to increased heat transfer from the cylinder, even before vorticity is stretched by the accelerating boundary layer. The frequency of oncoming turbulence in production and peak cases also lies close to the range of frequencies that can penetrate the boundary layer developing on the
AU  - Paul,I
AU  - Papadakis,G
AU  - Vassilicos,JC
DO  - 10.1017/jfm.2018.331
EP  - 488
PY  - 2018///
SN  - 0022-1120
SP  - 452
TI  - Direct numerical simulation of heat transfer from a cylinder immersed in the production and decay regions of grid-element turbulence
T2  - Journal of Fluid Mechanics
UR  - http://dx.doi.org/10.1017/jfm.2018.331
UR  - http://hdl.handle.net/10044/1/66642
VL  - 847
ER  -
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