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Měřicí prostor pro profily a tělesa, studie proveditelnosti výzkumného projektu
Popelka, Lukáš
Article describes new 865x485x900mm3 test section of closed-circuit wind tunnel IT AS CR for airfoils and bodies, respectively. These setups are arranged primary for three-component aerodynamic balance and visualization techniques access. Prepared research programme aimed at reference measurements, outer stream turbulence, flow control and surface roughness influence on boundary layer transition and separation is presented.
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Symetrie turbulentních charakteristik uvnitř městské křižovatky
Kellnerová, Radka ; Jaňour, Zbyněk
The wind-tunnel modelling of dispersion is very sensitive to central symmetry. The asymmetry of concentration field inside the symmetrical model is often caused by two causes: inappropriate inlet conditions or non-symmetric set-up of model. The project has carried out the flow measurements by Laser Doppler Anemometer's probe merged into the tunnel. The aim was to investigate the flow processes inside the tunnel body-tube itself – i.e. without the model and inside the model of a symmetrical urban intersection. The influence of wind direction and model arrangement suppressing the lateral flow was tested. The largest deviations from symmetry were caused by the circumfluence of the measuring devices.
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Modelling of toxic gases substituents on the model of the Old Town Square in Prague
Bezpalcová, Klára
The model of the place and its vicinity was manufactured, an atmospheric boundary layer in the appropriate scale (i.e. in scale 1:270, in which the model was manufactured) was created in the wind tunnel, and the climatology of the location was study in order to select prevailing wind directions in the frame of the experiment preparation. Also a flow visualization using a smoke generator and laser sheet was conducted. The concentration of the toxic gas substituents (propan and pentyl acetate) were measured in the location of the Old Town Square in Pargue for 4 different source locations (corner of the Pařížské street, Hus monument, City Hall tower a passage by U Prince) and for 5 prevailing wind directions (NW, WNW, W, WSW, SW).
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Šíření znečišťujících látek v idealizované městské zástavbě
Šeděnková, Hana ; Jaňour, Zbyněk
The essence of the problem consists in the way of pollutant diffusion in the urban build-area. The measurement of the concentration field 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 the source against the 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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Study of velocity field in crossroads areas
Kellnerová, Radka ; Jaňour, Zbyněk
The aim of this project is to study the influence of boundary conditions on contaminant spreading in a urban area model. The urban area model was composed of simple elements shapes of crossroads: X-shaped, T-shaped and skew intersection. The project at the beginning - by now only results for T-shaped crossroads are available. The experiment took place in an environmental aerodynamics tunnel IT AS CR in Nový Knín. First results show accumulation of high values of Reynolds stress above the area of crossroads center, whereas the velocity field is weaker when compared with more remote area. In specific distance from the intersection the recirculating zone appears. With increasing distance from intersection the center of zone moves counter main flow and up.
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Proudění a rozptyl zněčištění v idealizované městské zástavbě
Šeděnková, Hana ; Jaňour, Zbyněk
The aim of the experiment was a measurement of the flow in the urban canopy layer - the portion of boundary layer of atmosphere between the roof tops and the ground. The work took place in the boundary layer wind tunnel. The Laser Doppler Anemometry was used as a flow measurement technique. The simplified model of the urban build-area (regularly placed cubes on the ground) was put into the tunnel. The big influence of the model on the flow was found.
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Modelování úniku a disperze nebezpečného plynu
Jaňour, Zbyněk ; Bezpalcová, Klára ; Erhart, Jakub ; Kellnerová, Radka ; Šeděnková, Hana
Liquefied industrial gases and liquefied energy gases are transported, stored and used in steadily increasing amounts.Since the vapours of many of these chemicals are either toxic or flammable or both, there is heightened concern amongst public and regulatory bodies on potential hazards in a case of accidental releases. The objective of this contribution is to present the concept and result of a wind tunnel study of the dispersion of pollution clouds in a atmospheric boundary layer. Scaling laws, which have to be fulfilled in order to ensure model/prototype similitary, have been developed. Examples of the method application have been demonstrated.
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Měření proudění v městském baldachýnu
Šeděnková, Hana ; Jaňour, Zbyněk
The aim of the experiment was a measurement of the flow in the urban canopy layer - the portion of boundary layer of atmosphere between the roof tops and the ground.The work took place in thwe boundary layer wind tunnel. The Laser Doppler Anemometry was used as a flow measurement technique. The simplifed model of the urban build-up area (regularly placed cubes on the ground) was put into the tunnel. The big influence of the model on the flow was found.
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