Imperial College London
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Professor Maarten van Reeuwijk

Faculty of Engineering, Department of Civil and Environmental Engineering

Professor of Urban Fluid Mechanics
 
 
 
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Contact

 

+44 (0)20 7594 6059m.vanreeuwijk Website CV

 
 
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Assistant

 

Miss Rebecca Naessens +44 (0)20 7594 5990

 
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Location

 

331Skempton BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Holzner:2017:10.1080/14685248.2016.1275655,
author = {Holzner, M and van, Reeuwijk M},
doi = {10.1080/14685248.2016.1275655},
journal = {Journal of Turbulence},
pages = {260--270},
title = {The turbulent/nonturbulent interface in penetrative convection},
url = {http://dx.doi.org/10.1080/14685248.2016.1275655},
volume = {18},
year = {2017}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - The effect of buoyancy on the turbulent/nonturbulent interface (TNTI) and viscous superlayer are studied by performing direct numerical simulation of penetrative convection. In this flow, rising turbulent thermals alternate with unmixed fluid entrained from above, forming a TNTI between the turbulent and irrotational flow regions. We detect the TNTI using a broad range of enstrophy iso-levels, from the very low levels of the outer fringes of the turbulent flow region to high levels located in the turbulent flow region. We study the local entrainment velocity vn by which the TNTI propagates outwards relative to the fluid flow while entraining unmixed fluid into the turbulent region. The relative entrainment velocity is decomposed into a viscous, an inertial and a baroclinic torque term, respectively. For low enstrophy levels we find a viscous superlayer (VSL) where viscous diffusion dominates, while inertial and baroclinic torque terms are small. It is only for higher iso-levels in the buffer region of the TNTI, which extends from the edge of the VSL to the threshold for which vn = 0, that the inertial enstrophy production term plays a significant role. Penetrative convection does not feature a turbulent core where vn > 0 (i.e. inward moving enstrophy isosurfaces) that has been previously identified in other entraining flows such as jets or gravity currents. Surprisingly, the baroclinic torque remains inactive throughout the whole range of enstrophy iso-levels. The smallness of the baroclinic torque against viscous effects in the TNTI is supported by a dimensional argument which predicts that at high Reynolds number the baroclinic torque term will be negligible.
AU  - Holzner,M
AU  - van,Reeuwijk M
DO  - 10.1080/14685248.2016.1275655
EP  - 270
PY  - 2017///
SN  - 1468-5248
SP  - 260
TI  - The turbulent/nonturbulent interface in penetrative convection
T2  - Journal of Turbulence
UR  - http://dx.doi.org/10.1080/14685248.2016.1275655
UR  - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000395074700004&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
UR  - http://hdl.handle.net/10044/1/82945
VL  - 18
ER  -
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