The effect of multi-scale roughness on the structure of atmospheric turbulence

It is estimated that cities, in the future, will host an increasing percentage of the world’s population thanks to the proliferation of tall buildings. These, shape the atmospheric turbulence influencing both the pedestrian comfort and the air quality at street level. In this project, you will perform a series of wind tunnel experiments to explore the effect of different geometric features of these tall buildings on the structure of the atmospheric turbulence to inform urban air quality.

Start date

1 October 2021


36 months plus 6 month extension (must be approved by funder)

Application deadline

Funding source


Funding information

  • Standard research council annual rate (tax free), + home fees covered
  • EPSRC project FUTURE is connected to aspects of this scholarship.


It is estimated that by 2050 our cities will host 68 per cent of the world’s population. This increase in urban population density is accomplished by the proliferation of tall buildings that maximise the provision of housing/office per footprint area. These tall structures are often characterised by complex geometry and unusually shaped components/terraces/balconies.

To complicate the problem, these buildings are subjected to an incoming Atmospheric Boundary Layer. An assessment of the effects of these buildings on the wind and temperature fields within cities, which affect both pedestrian comfort and air quality at street level is, therefore, needed to provide reference data to assist and influence policymakers and regulators.


The project is divided into two phases:

Phase one

A series of wind tunnel experiments will be designed and carried out to assess the turbulence structure over urban morphologies, characterised by tall buildings of uniform height and a packing density that is typical of megacity environments. The level of details characterising the model of the buildings will be progressively increased, to produce a multi-scale roughness.

The turbulence structure developed over single- and multi-scale roughness will be compared to assess similarities/differences. Scaling laws based on the characteristic length scales of the morphologies will be explored. For all cases, the drag generated by the morphologies will be measured by instrumenting a building with static pressure ports on all faces. Velocity profiles will be collected with Laser Doppler Anemometry.

Phase two

The effect of thermal stratification will be examined in the unique ‘EnFlo’ wind tunnel (NERC National facility). Similar single- and multi-scale urban roughness will be investigated. Concentration measurements via fast-response flame ionisation detector are also planned to complement the velocity profiles, and inform the urban dispersion phenomenon as a function of both the atmospheric stability and buildings length scales.

Related links

FUTURE project Centre for Aerodynamics and Environmental flow

Eligibility criteria

We are seeking candidates with a first-class degree or a good 2:1 in a relevant engineering field (aeronautics, environmental, civil, mechanical) or physical/environmental science (physics, meteorology), with excellent communications skills.

Previous experience with experimental work and computer programming would be beneficial.

How to apply

Applications should be submitted via the Aerodynamic and Environmental Flow PhD programme page on the "Apply" tab. Please clearly state the studentship title and supervisor on your application.

Application deadline

Contact details

Marco Placidi (he/him)
01 AB 02
Telephone: +44 (0)1483 684632

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