Fluid Mechanics Research Group, Department of Civil Engineering, University of Surrey (U.Surrey), United Kingdom
Main topics:
- A wind tunnel investigation of the flow within simulated urban street canyons influenced by large turbulent structures in the approaching wind and solar heating of the canyon ground and walls
The research will involve detailed examination of the wind tunnel flows over and within simulated rectangular cavities, representing urban street canyons. The influence of canyon geometry, in terms of the canyon width(W)/canyon height(H) ratio, for a single street with normal wind direction and well-defined boundary conditions will be studied in the range 0.3<W/H<10. This will permit precise definition of the different types of street canyon flow regimes. In addition, the effects of large-scale turbulent structures in the wind flow which then impinge upon the separating cavity shear layer will be examined, using a combination of conventional thermal anemometry techniques, for velocity and turbulence data, smoke flow visualisation using computer-based video imaging techniques, and thermochromic liquid crystal coatings for assessing building wall and ground temperature distributions. Part of the initial research programme will be to extend the existing capabilities of the liquid crystal technique to permit application to these cavity flows. The experiments will encompass the effects of wall/ground heating, due to the influence of solar radiation, covering Froude numbers in the range 0.1 to 10 being examined.
The flow field data obtained from these experiments will be utilised in the validation of the numerical prediction codes at the other participating institutions, notably ECN, TNO, NERI and ETHZ. Indeed, the Group at Surrey collaborates closely with the Group led by Dr P Mestayer at ECN and the research has been focused upon assessment of the effects of large-scale, periodic turbulent structures which interact with a separated backward-facing step flow, representing a simplified street canyon geometry. A wind tunnel investigation has indicated the extent of the effects of the perturbation upon parameters such as the mean recirculation length and the turbulent length scales in the recirculation region. The aim of studying such perturbed flows is to test the effectiveness of the turbulence models and investigate methods by which canyon-scale turbulence models and city-wide mesoscale LES models might be coupled.
Positions Offered.
