Wind speed measurements and predictions over Belmont Hill, Wellington, New Zealand

The aim of the research described in this paper is to reduce the vulnerability of New Zealand's built infrastructure to wind damage through provision of improved wind speed prediction procedures for wind flow over complex terrain that could ultimately be incorporated into the AS/NZS 1170.2 loading standard. This paper presents results from a specific experiment which compares measured wind speedups (neutral atmosphere) over the rugged Belmont Hill region with wind speedups estimated from AS/NZS 1170.2 by two organisations, and from six other international wind-loading standards, through Computational Fluid Dynamics (Gerris and WAsP) modelling, and through wind-tunnel modelling. It was found that computer modelling with the large-eddy simulation CFD code Gerris and wind-tunnel measurements, agree remarkably well with the observations and differentiate considerably better between areas exposed or sheltered by the local terrain features compared to applying the CFD code WAsP (4.1), or applying the AS/NZS 1170.2 wind-loading standard. Furthermore, it was found that the AS/NZS1170.2 predictions differed significantly when carried out by different organisations. The wind speedup prediction methods from the six other international standards all use similar approaches and thus the predictions from all of them were quite similar, and did not agree particularly well with the field measurements. •Multiple method speedup comparison: Full-scale, Wind Tunnel, CFD LES and CFD WAsP.•Full-scale wind speedup measurements over complex terrain.•Large Collaboration: University of Auckland, NIWA, GNS Science, WPS-Opus.•Detailed analysis of wind speedup results and comparison with many wind standards.•Useful data for developing improved wind speedup algorithms for wind standards.