Wind fields and turbulence statistics in an urban street canyon

• This is the first paper of a long-term measurement campaign to explore wind, temperature, radiation and energy fieldswithin an urban canyon. A canyon and a rooftop mast were installed in a canyon with an aspect ratio (Height/Width)of 2.1 in Goteborg, Sweden. A number of instruments including sonic anemometers, radiometers and thermocoupleswere mounted in vertical profiles and across the width of the canyon. The experimental set-up, the characteristics of thecanyon flow pattern and mean and turbulence statistics with respect to above canyon flow are examined using datacollected under clear-sky conditions in summer and autumn 2003. Results show that under cross-canyon (within 601 oforthogonal) flow, a single helical vortex exists. High temporal resolution analysis suggests that eddies frequentlypenetrate the shear stress layer at the canyon top disrupting established flow patterns. A combination of complexbuilding roof shapes and local topography may contribute to this effect by maintaining a high degree of turbulence. Theprofile of mean wind speed within the canyon and the relation with that above canyon depends on the ambient flowdirection in relation to the canyon long axis. Turbulence statistics show results similar to other field studies, withturbulence kinetic energy and vertical mixing greatest toward the windward wall.

Subject headings

NATURVETENSKAP  -- Geovetenskap och miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences (hsv//eng)

Keyword

Vortex

Urban canyon flow

Turbulence

Urban canyon flow; Turbulence; Vortex

Publication and Content Type

art (subject category)

ref (subject category)