Imperial College London
Professor John Christos Vassilicos

ProfessorJohn ChristosVassilicos

Faculty of Engineering, Department of Aeronautics

Visiting Professor
 
 
 
//

Contact

 

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

 
 
//

Assistant

 

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

 
//

Location

 

CAGB 314City and Guilds BuildingSouth Kensington Campus

//

Summary

 

Publications

Citation

BibTex format

@article{Paul:2018,
author = {Paul, I and Papadakis, G and Vassilicos, C},
journal = {Journal of Fluid Mechanics},
title = {DNS of heat transfer from a cylinder immersed in the production and decayregions of grid-element turbulence},
url = {http://hdl.handle.net/10044/1/58986},
year = {2018}
}
Download

RIS format (EndNote, RefMan)

TY  - JOUR
AB  - The present DNS study, the rst of its kind, explores the eect 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 ne-scale resolution requirements, the simulations are carried out for a low Reynolds number. Three locations downstream of the gridelement, inside the production, peak and decay regions, respectively are considered. The turbulent ow 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 11%, while the peak location has the highest turbulent intensity of 15%. 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 63%, while in the decay region it is enhanced by only 28%. This dierence cannot be explained only by the increased approaching velocity in the production region. The existing correlations for the stagnation point heat transfer coecient are found invalid for the production and peak locations, while they are satised in the decay region. It is established that the ow 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 cylinder, and therefore the latter is very responsive to the impinging d
AU  - Paul,I
AU  - Papadakis,G
AU  - Vassilicos,C
PY  - 2018///
SN  - 0022-1120
TI  - DNS of heat transfer from a cylinder immersed in the production and decayregions of grid-element turbulence
T2  - Journal of Fluid Mechanics
UR  - http://hdl.handle.net/10044/1/58986
ER  -
Download