Experimental investigation of turbulent flow and wind comfort characteristics of fractal wind fences

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Date

2017

Author

Çoşkun, Şemsi

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The characteristics of turbulent flow behind the fractal fences are rather new research area. Previous studies on fractal fences showed that there are clear differences in the flow characteristics as compared with the conventional fences. This study presents the results and comparisons of an experimental study that investigates the turbulent flow and wind comfort characteristics of fractal wind fences. Four different wind fences, three of which have fractal geometries, with the same height, width, and porosity ratio were tested. The experiments were conducted in a suction-type wind tunnel at the Center for Wind Energy, METU. Velocity field around the fences were measured with PIV technique and Reynolds number based on the fence height (Re) was calculated as 53794. It is observed that in the near wake region, mean flow field characteristics such as streamwise and vertical velocity, vorticity, and turbulent flow characteristics are directly affected by the jet flows passing through the openings and bar wakes of the fractal fences. Although jet flow passing through the gaps of the conventional fence are quite uniform and mix out quickly, there are non-uniform jets at fractal fences which affect far downstream distances. Moreover, in order to investigate the wind comfort characteristics of the fences, two different dimensionless parameters which are wind speed reduction coefficient and shelter parameter are calculated. The results show that high degree of wind velocity reduction and shelter efficiency can be achieved by different fractal types of fences. Furthermore, fractal fences may allow custom design of their fractal geometries according to the desired wind conditions in the downstream regions.

Subject Keywords

Winds., Turbulence., Wind-pressure., Winds

URI

http://etd.lib.metu.edu.tr/upload/12620677/index.pdf
https://hdl.handle.net/11511/26212

Collections

Graduate School of Natural and Applied Sciences, Thesis

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Citation Formats

Ş. Çoşkun, “Experimental investigation of turbulent flow and wind comfort characteristics of fractal wind fences,” M.S. - Master of Science, Middle East Technical University, 2017.