Numerical and wind-tunnel investigation of wind flow over urban areas

Abstract

The study investigates one of the major causes of damage in severe wind events in urban areas: windborne debris, using a case study of a location in the Auckland city centre, New Zealand. The probability and risk of paving stone ballast becoming windborne from the podium of a tall building was evaluated through wind-tunnel experiments and numerical simulations. These results were used to determine: the local wind speeds at the location of the stones; overall wind behaviour in the urban area; the threshold wind speed at which the stones start rolling or becoming windborne debris. These results were combined with long-term Auckland Meteorological data to predict the expected probability of the "rolling" and "take-off" wind speeds being exceeded in the vicinity of the case study building. It was found that there was a very low risk of stone ballast being blown off the podium.