Imperial College London
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Dr. Oliver Buxton

Faculty of Engineering, Department of Aeronautics

Reader in Experimental Fluid Mechanics
 
 
 
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Contact

 

+44 (0)20 7594 5118o.buxton Website CV

 
 
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Location

 

213City and Guilds BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Baj:2019:10.1017/jfm.2019.11,
author = {Baj, P and Buxton, ORH},
doi = {10.1017/jfm.2019.11},
journal = {Journal of Fluid Mechanics},
pages = {181--220},
title = {Passive scalar dispersion in the near wake of a multi-scale array of rectangular cylinders},
url = {http://dx.doi.org/10.1017/jfm.2019.11},
volume = {864},
year = {2019}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - The near wakes of flows past single- and multi-scale arrays of bars are studied by means of planar laser induced fluorescence (PLIF) and particle image velocimetry (PIV). The aim of this research is to better understand dispersion of passive scalar downstream of the multi-scale turbulence generator. In particular, the focus is on plausible manifestations of the space-scale unfolding (SSU) mechanism, which is often considered in the literature as the reason for the enhancement of the turbulent scalar flux in flows past fractal grids (i.e. specific multi-scale turbulence generators). The analysis of qualitative and quantitative PLIF results, as well as the simultaneously acquired PIV results, confirms the appearance of a physical scenario resembling the SSU mechanism. Unlike the anticipation of the literature, however, this scenario applies to some extent also to the flow past the single-scale obstacle. Application of a triple decomposition technique (which splits the acquired fields into their means, a number of coherent fluctuations and their stochastic parts) and a conditional-averaging technique reveals that the SSU mechanism is active in the vicinity of an intersection point between two adjacent wakes and is driven almost exclusively by coherent fluctuations associated with the larger of the intersecting wakes. This suggests that the SSU mechanism is related to the coherent fluctuations embedded in the flow rather than to the fine-scale turbulence and its underlying integral length scale, as proposed in previous works.
AU  - Baj,P
AU  - Buxton,ORH
DO  - 10.1017/jfm.2019.11
EP  - 220
PY  - 2019///
SN  - 0022-1120
SP  - 181
TI  - Passive scalar dispersion in the near wake of a multi-scale array of rectangular cylinders
T2  - Journal of Fluid Mechanics
UR  - http://dx.doi.org/10.1017/jfm.2019.11
UR  - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000458517800001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
UR  - https://www.cambridge.org/core/journals/journal-of-fluid-mechanics/article/passive-scalar-dispersion-in-the-near-wake-of-a-multiscale-array-of-rectangular-cylinders/4B349031D14F0A5280D81C634BF8BF3B
UR  - http://hdl.handle.net/10044/1/67422
VL  - 864
ER  -
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