Imperial College London

ProfessorChristosMarkides

Faculty of EngineeringDepartment of Chemical Engineering

Professor of Clean Energy Technologies
 
 
 
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Contact

 

+44 (0)20 7594 1601c.markides Website

 
 
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Location

 

404ACE ExtensionSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Neophytou:2014:10.1063/1.4892979,
author = {Neophytou, MK-A and Markides, CN and Fokaides, PA},
doi = {10.1063/1.4892979},
journal = {Physics of Fluids},
pages = {086603--1--086603--21},
title = {An experimental study of the flow through and over two dimensional rectangular roughness elements: Deductions for urban boundary layer parameterizations and exchange processes},
url = {http://dx.doi.org/10.1063/1.4892979},
volume = {26},
year = {2014}
}

RIS format (EndNote, RefMan)

TY  - JOUR
AB - This paper investigates the flow through and over two-dimensional rectangular roughnesselements, arranged in a building-street canyon geometry through a series ofexperiments. Geometries of different packing densities of the roughness elements(λp) were examined and the packing density values ranged from λp = 0.30 to 0.67.The purpose of the work is: (i) to investigate the flow physics observed both at theboundary layer scale as well as at the scale within the roughness elements for a rangeof packing densities, (ii) to deduce parameterizations of the adjusted rough boundarylayer and their variation with a change in the packing density, and (iii) givena particular interest in and application to the urban atmosphere, a final aim at theroughness-element scale is to deduce the variation of the breathability with the packingdensity variation. Particle image velocimetery measurements of the velocity flowfield as well as the turbulent kinetic energy and the Reynolds Stress (within and upto well-above the street canyons) were conducted. The results reveal qualitative flowfeatures as well as features of the adjusted boundary layer structure—in particular theroughness and inertial sublayers, which can be associated with the surface roughnesslength, zero-plane displacement thickness, and the friction velocity. The lowest frictionvelocities are exhibited in the geometries with the highest- and lowest packingdensities while the maximum friction velocities are observed in the medium-packedgeometries. The exchange processes and breathability at the level of the roughnesselements top were characterized and quantified by a mean exchange velocity. Theresults show that unlike friction velocity, the normalized exchange velocity (overthe mean bulk velocity) for the most dense and sparse geometries differ by morethan 80%, with the denser-packed geometries exhibiting lower exchange velocities;this is shown to be related with the thickness of the developed roughness sublay
AU - Neophytou,MK-A
AU - Markides,CN
AU - Fokaides,PA
DO - 10.1063/1.4892979
EP - 1
PY - 2014///
SN - 1089-7666
SP - 086603
TI - An experimental study of the flow through and over two dimensional rectangular roughness elements: Deductions for urban boundary layer parameterizations and exchange processes
T2 - Physics of Fluids
UR - http://dx.doi.org/10.1063/1.4892979
UR - http://hdl.handle.net/10044/1/27194
VL - 26
ER -