Validation of rooftop wind measurements in the urban environment: Comparison between wind tunnel results and field data

Urban airflow characteristics from a full-scale field test were compared to those from a model-scale wind tunnel test to validate the use of model-scale data in the development of urban airflows guidance and recommendations. Rooftop-mounted anemometer measurements were acquired during a field study conducted in Montréal, Canada in 2023, and wind-tunnel data were acquired at the same relative rooftop-anemometer locations using a 1:300 scale model. The comparison between the field study and wind-tunnel test was enabled by identifying a compatible set of reference conditions. The airflow properties, including the mean wind speed, turbulence intensity, and flow angularity, had better agreement between field data and wind-tunnel data for the buildings that were in the core of the urban environment, where building wakes are the dominant flow feature. Flow speed and turbulence intensity were often higher in the field than in the wind tunnel, although the general trends in these parameters were predicted adequately overall. The use of airport-weather station data as the reference conditions in the field was shown to be a practical approach in the absence of a local reference in the city. A comparison of the velocity spectra between the field test and the wind-tunnel test showed good agreement over the range of full-scale frequencies that are related to typical building-widths and to the size of future urban air mobility vehicles. • Rooftop wind measurements were conducted in Montréal, Canada. • A 1:300 wind tunnel study evaluated urban airflow at the equivalent locations. • The field-test data were used to validate the wind-tunnel methodology. • The wind-tunnel results predicted the variation in pitch and yaw characteristics as a function of wind direction. • The wind-tunnel results predicted velocity spectra over characteristic lengths that are applicable to urban air mobility.