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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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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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A deliberation about a misuse of "home-made" prepared sarine gas
Klouda, K. ; Dudáček, A. ; Bezpalcová, Klára
Contribution presents information about a method of sarine gas preparation commonly approachable substances, analysis of determination of the location, where the sarin gas could be misused. The calculation of dependency of evaporation and dispersion of sarin gas on atmospheric conditions was carried out. The preparation of the wind-tunnel modeling in the case of Old Town Square in Prague in cooperation with Institute of Thermomechanics was described.
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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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Wind tunnel concentration field study in a urban area
Jaňour, Zbyněk ; Kellnerová, Radka ; Bezpalcová, Klára
The aim of the project was to study the influence of boundary conditions on contaminant spreading in a urban area model. The experiment was conducted a low-speed open-circuit tunnel. The urban area model was scaled down to 1:200. The model aimed to simulate a typical street with intense traffic, in our case specifically the Podbielski Strasse in Hannover (Germany). The downstreet flow was at an aproximate angle of 45 degrees to the street axis. Traffic was simulated by a double-line source. In the course of the experiment we have replaced a convoluted model of a park in the upstream area with simpler elements of varying size and density. We then compared the concentration field of the new arrangement with the original concentration field. All configurations led to a decrease of concentration . In ares where the original concentration had reached the highest values, the most significant decrease was obtained.
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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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