Imperial College London
Portrait Picture

DrPaulBruce

Faculty of Engineering, Department of Aeronautics

Reader in High-Speed Aerodynamics
 
 
 
//

Contact

 

+44 (0)20 7594 5048p.bruce

 
 
//

Location

 

333City and Guilds BuildingSouth Kensington Campus

//

Summary

 

Publications

Citation

BibTex format

@article{Melina:2017:10.1016/j.ijheatmasstransfer.2017.02.024,
author = {Melina, G and Bruce, P and Hewitt, G and Vassilicos, JC},
doi = {10.1016/j.ijheatmasstransfer.2017.02.024},
journal = {International Journal of Heat and Mass Transfer},
pages = {537--554},
title = {Heat transfer in production and decay regions of grid-generated turbulence},
url = {http://dx.doi.org/10.1016/j.ijheatmasstransfer.2017.02.024},
volume = {109},
year = {2017}
}
Download

RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Heat transfer measurements around the centreline circumference of a cylinder in crossflow areperformed in a wind tunnel. The cylinder is placed at several stations downstream of threeturbulence-generating grids with different geometries and different blockage ratiosσg: a reg-ular grid (RG60) withσg= 32%, a fractal-square grid (FSG17) withσg= 25%and a single-square grid (SSG) withσg= 20%. Measurements are performed at 20 stations for 3 nominalReynolds numbers (based on the diameterDof the cylinder)Re∞= 11 100,24 500,37 900.Hot-wire measurements are performed along the centreline, without the cylinder in place,to characterise the flow downstream of the grids. The extent of the turbulence productionregion, where the turbulence intensityTuincreases with the streamwise distancexfrom thegrid, is higher for SSG and more so for FSG17 than for RG60. The angular profiles of theNusselt numberNuare measured in the production regions of these two grids and are com-pared to those obtained in the decay regions, whereTudecreases withx. This comparison ismade at locations with approximately sameTu. It is found that, for SSG,Nu/Re0.5on thefront of the cylinder (boundary layer region) is lower in the production region than in thedecay region. This is explained by the presence of clear and intense vortex shedding in theproduction region of SSG which reduces the turbulent fluctuations which are “effective” inenhancing the heat transfer across a laminar boundary layer. For higherRe∞, the values ofNu/Re0.5on the front of the cylinder are higher in the production region of FSG17 than inthat of SSG, despiteTubeing higher for SSG. This is consistent with a lower intermittencyof the flow for FSG17 caused by the presence of the fractal geometrical iterations. The recov-ery ofNuon the back of the cylinder (wake region) is appreciably higher in the productionregion than in the decay region for both FSG17 and for SSG. This can be due to the lowerint
AU  - Melina,G
AU  - Bruce,P
AU  - Hewitt,G
AU  - Vassilicos,JC
DO  - 10.1016/j.ijheatmasstransfer.2017.02.024
EP  - 554
PY  - 2017///
SN  - 0017-9310
SP  - 537
TI  - Heat transfer in production and decay regions of grid-generated turbulence
T2  - International Journal of Heat and Mass Transfer
UR  - http://dx.doi.org/10.1016/j.ijheatmasstransfer.2017.02.024
UR  - http://hdl.handle.net/10044/1/44424
VL  - 109
ER  -
Download