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Area Assessment of a Pedestrian Wind Environment Using Point Wind Speed Measurements

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posted on 2021-11-10, 10:35 authored by Kepka, Benjamin Jan

This research has successfully produced a means of creating a reliable area measurement of a pedestrian level wind environment from a reasonable number of point wind speed measurements. To complete this aim a contouring script was developed through MATLAB. The script has the ability to read in series of point wind speed measurements coupled with cartesian co-ordinates and generate a reliable contour diagram. The foundation for this research is a resource of over 150 wind tunnel tests conducted for code compliance in Wellington City. The District Plan in Wellington requires any building over 18.6m in height to have a wind tunnel analysis conducted to assess the changes in wind speed with respect to pedestrian safety. Wellington compliance criteria require two forms of measurement to be conducted. Point measurements are taken to quantify wind speeds accurately, but are unable to efficiently assess large areas. Area measurement techniques are used to assess the comparative windiness of zones around the development site. Through examination of 3000 measured data points it has been demonstrated that the correlation between these two measurement techniques is relatively low. Until now, neither test alone has been sufficient to accurately quantify the impact of a new development on the pedestrian level wind environment as a whole. Interpolation methods were used to generate pseudo measurements between points at which wind speeds were measured. A series of three building configurations were assessed using the MATLAB script to visualise the effect of increasing building height on pedestrian level winds. The building configurations assessed were: a uniformly distributed grid of 25 half cubes (60m x 60m x 30m), central full cube (60m x 60m x 60m), and, a central tall tower (60m x 60m x 240m). Each building configuration was simulated through the contouring script and the resultant contours were assessed to ensure a realistic depiction of easily predictable wind flow patterns such as downwash and the corner effect. The resolution of the output contours in any case is directly related to the number of point wind speed measurements used. It has been found that measurement points should be more densely located (15m in scale) around the site in question, and more sparsely located (30m in scale) around the outer regions of the desired testing area. This is the most efficient method of generating contours for use in commercial pedestrian level wind laboratories. Mathematically generated contours have the potential to provide a more reliable output than those produced through current methods of area testing.

History

Copyright Date

2010-01-01

Date of Award

2010-01-01

Publisher

Te Herenga Waka—Victoria University of Wellington

Rights License

Author Retains Copyright

Degree Discipline

Building Science

Degree Grantor

Te Herenga Waka—Victoria University of Wellington

Degree Level

Masters

Degree Name

Master of Building Science

Victoria University of Wellington Item Type

Awarded Research Masters Thesis

Language

en_NZ

Victoria University of Wellington School

School of Architecture

Advisors

Donn, Michael; Carpenter, Paul