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Průchod posivního polutentu idealizovanou městskou zástavbou
Bezpalcová, Klára ; Jaňour, Zbyněk ; Leitl, B. ; Schatzmann, M.
The regular obstacle array of the Mock Urban Setting Test (MUST) field site in the Utah West Desert has been replicated in the large boundary layer wind tunnel at Hamburg University. Dispersion from a point source within an idealised urban canopy for an oblique wind direction was a main focus of the wind tunel measurements. Two different methods were used to estimate the travelling time of a passive tracer through the array. The first evident method was based on a measured instantaneous behaviour of the plume while switching on and off thepassive pullant source; the second one used the spatial concentration correlation coefficients obtained from the simultaneous measurement at two positions. Different travelling time behaviour for the points situated along and perpendicular to the street canyons has been detected.
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Pollutant diffusion in the idealized build-up area
Šeděnková, Hana ; Jaňour, Zbyněk ; Leitl, B.
The essence of the problem consist in the way of pollutant diffusion in the urban build-up area. The measurement of the concentration field of the emission from the point (chimney) and line (street) source in the model of the idealized urban build-up area was done in the boundary layer wind tunnel. Dependence on the location of this source against model and also dependence on the geometric setting of the model (both density of buildings and location of street canyons) was found.
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Proudění uvnitř idealizované městské zástavbě
Bezpalcová, Klára ; Harms, F. ; Leitl, B. ; Jaňour, Zbyněk
The regular obstacle array of the Mock Urban Setting Test (MUST) fiedl site in the Utah West Desert (USA) has been replicated in the large boundary layer wind tunnel at University of Hamburg. The trials run during the field campaign were repeated in the wind tunnel as well as additional measurements of flow.The strong flow inhomogeneities were observed on the vertical profiles of shear stress as well as on the horizontal mean flow for different array orientation.
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Wind tunnel modelling of flow and dispersion in the street canyon
Bezpalcová, Klára ; Leitl, B. ; Jaňour, Zbyněk
There used method of physical moddeling,which is successful in solution of the atmospheric boundary layer problems.The first step was to estabilish charakteristics of the boundary layer in thewind tunnel.The measurement was done on a very simple model of a steet canyon. Atfirst there was measured a flow field and its charakteristics as the mean velocity,the intensity of turbulence and the shear stress by the method of the Laser DopplerAnemometry. Flame Ionization Detector was used for measurements of the concentration of apassive contamination from a line source. There was estimated the critical Building Reynolds Numberfor this setup on the basis of the measurement of concentration. Finally themeasured dimensionless concentration was used to estimete a concentration ofthe air pollution in a real street in a urban area and this estimate was compared with the pollutant limits.
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