Abstract:
The study investigates effects of urban areas and structures on pedestrian level wind (PLW) speeds, which is one of the major causes of damage and discomfort in severe wind events in urban areas. The study uses a case study of a location in the Wellington city centre, Te Aro, New Zealand. The flow behaviour, mean and gust wind speedups, and the probability of exceedance of high wind speeds at locations around the target building were evaluated through wind-tunnel experiments, numerical simulations and analysis of long-term Wellington Meteorological wind records. For the wind-tunnel experiments, the erosion technique and Irwin probes were employed to visualise and measure the flow pattern and wind speed, respectively. The numerical simulation was conducted using the steady Reynolds-Averaged Navier–Stokes (RANS) method and the Shear Stress Transport (SST) turbulence model. The study also investigates the feasibility of the use of a relatively low-cost numerical approach to study wind flow in urban areas,
particularly for the purpose of commercial projects. The advantages and disadvantages of the employed methods are discussed in detail. It is demonstrated that numerical simulations provide more detailed information about the wind flow in the whole computational domain compared with wind-tunnel measurements, which can only be conducted at limited points. The analysis of wind speedup ratios and meteorological data shows that there are some locations within the investigated area where the annual gust wind speed and probability of exceedance of moderate and strong winds exceed the safety and comfort criteria for Wellington.