Pedestrian-level Wind Environment (Neighborhood Scale)

Fine-Scale Assessment of Pedestrian-level Wind in High-Density Cities

The aerodynamic properties of urban areas are a necessary component in the current urban planning and design.

This study develops an approach to model the pedestrian-level wind speed at a high spatial resolution within urban areas. This study describes the balance between the momentum transfer and drag force in both an averaged sense over an area and a moving air particle to extend conventional frontal area density (λf) to a point-specific index (λf_point). Through correlation with data from wind tunnel experiments, λf_point was determined to be a good index to assess the pedestrian-level wind speed at a test point with multiple input wind directions.

Using this approach, urban planners and architects can estimate the neighbourhood-scale pedestrian-level wind speed at 1 m × 1 m resolution, and optimise proposed planning and design at the onset of the procedure.

Outputs:

• A practical modelling-mapping way is created for the fine-scale wind assessment;
• Momentum transfer and balance in the urban canyon are discussed;
• Spatially averaged morphological index is extended to a point-specific index;
• Regression models are applied to correlate the morphological index with wind data;
• Case studies are provided for the implementation in urban planning and design.

Publication:

• Yuan C*, Norford LK, Britter R, Ng E, 2016, A Modelling-Mapping Approach for Fine-Scale Assessment of Pedestrian-level Wind in High-Density Cities, Building and Environment. 97, pp. 152-165.

Figure. Validation by comparing with wind tunnel results.