https://doi.org/10.1051/epjconf/20134501053
Quadrant analysis of turbulent pollution flux above the modelled street intersection
1 Charles University in Prague, Faculty of Mathematics and Physics, The Department of Meteorology and Environment Protection, Czech Republic
2 Institute of Thermomechanics Academy of Sciences of the Czech Republic, v.v.i., Dolejškova 1402/5, 182 00 Prague, Czech Republic
a e-mail: kukacka@it.cas.cz
The objective of this experimental study is to determine processes of a vertical turbulent pollution transport above the X-shaped street intersection in an idealised symmetric urban area for several approach flow directions. An experimental set-up for simultaneous measurement of the flow velocity and the tracer gas concentration in a high temporal resolution is assembled. Vertical turbulent scalar fluxes are computed from the measured data in a horizontal plane above the street intersection. The quadrant analysis was applied to the vertical turbulent pollution fluxes data. Events with dominant contribution to vertical turbulent pollution flux were detected. The mean duration, repetition frequency and the duration percentage were computed for these events. A strong influence of the approach flow direction on the the type of dominant events and their characteristics was resolved.
© Owned by the authors, published by EDP Sciences, 2013
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