National Repository of Grey Literature 14 records found  1 - 10next  jump to record: Search took 0.00 seconds. 
TACR TJ04000365: Project EDIMO
Chaloupecká, Hana ; Jakubcová, Michala ; Fiala, R. ; Kozohorský, Jan
The report describes the work procedure on the project TACR TJ000365 for the entire duration of its solving. The work procedure, which is already described in the previous reports, is summarized in brief. In contrast, the report is engaged in the validation of the model in deep. The data acquired by the wind-tunnel modelling were utilized for the validation.
Aspects of Dosage from Short and Long Duration Emissions
Robins, A. ; Hayden, P. ; Gallacher, D. ; Pace, S. ; Chaloupecká, Hana
The objectives of this work were to use wind tunnel concentration measurements to describe the structure of dispersing clouds from an elevated source in a deep turbulent boundary layer and to develop scaling rules that reduce the results to a universal form. The experiments were carried out in the EnFlo meteorological wind tunnel at the University of Surrey. Ensembles of between 100 and 200\nrepeat emissions were used, emission durations between 0.067 and 1.02s and a reference flow speed of 2ms-1. The fetch studied extended to about six source heights downwind (about two boundary layer depths). The structure of the evolving clouds was analysed to determine time of flight, along-wind spread and dosage and to compare the dosage behaviour with the concentration field in a plume from the same source. This illustrated how the two were related and how cloud dosage statistics (mean and\nstandard deviation) could be derived from plume data. It also demonstrated that much larger ensembles were required to reduce the statistical uncertainty in the mean cloud properties. The next steps involve testing these conclusions in a wider range of flow and dispersion conditions, in the presence of obstacles or complex urban areas.
TACR TJ04000365: Project EDIMO in the year 2021
Chaloupecká, Hana ; Fiala, Roman ; Jakubcová, Michala ; Kozohorský, Jan
The paper describes methods of work on the project TACR TJ04000365 in the year 2021. The paper focuses on the description of the models SWIFT and SPRAY. Furthermore, the creation of a middle-model, which was necessary to develop as one step from many others to be able to merge both models, is described. Finally, the paper is engaged in the trial-run of the merged models. The paper introduces the input parameters and the outputs in the form of concentration maps. The appendix contains sensitivity study of the model SWIFT in respect to the main inputs.
Flow and diffusion characteristics inside the urban area
Chaloupecká, Hana ; Jaňour, Zbyněk (advisor) ; Brechler, Josef (referee)
Title: Flow and diffusion characteristics inside the urban area Author: Hana Chaloupecká Department: Department of meteorology and enviroment protection Supervisor: prof. RNDr. Zbyněk Jaňour, DrSc., IT AS CR, v. v. i. Supervisor's e - mail: janour@it.cas.cz Abstract: Uniqueness of different towns, consists of various shapes of buildings. The main topic of this work is to compare concentration diffusion within groups of buildings of various types. We pursued houses made of single blocks of two different lengths - they were placed parallel or in courtyards. For research of pollution diffusion within the housing estates a method of physical modelling has been used. For this purpose we summarized a theory of atmospheric boundary layer and physical modelling at first. Then we pursued experiments. Measuring took place in a model in scale 1 : 300 inside an aerodynamic wind tunnel of the Institute of Thermomechanics AS in Nový Knín. We checked out the requirements placed on similarity of the real boundary layer and boundary layer modelled in the tunnel. By the measuring of concentration in urban areas we weren't watching a plume from the pollution source but we were studying an inversion task. We measured concentrations in two fixed points from different point sources inside the defined areas. A sensitivity of...
Sudden release of toxic gas in built-up environment
Chaloupecká, Hana ; Jaňour, Zbyněk (advisor) ; Zelinger, Zdeněk (referee) ; Efthimiou, George (referee)
The dissertation thesis deals with short-term gas releases (puffs) in an urban canopy studied utilizing wind-tunnel modelling. The urban canopy was composed of buildings with pitched roofs organised into closed courtyards. Into it, a ground-level point gas source was placed. The first part of the thesis is focused on specific definitions of puff characteristics. New definitions of puff arrival and departure times are presented. Various definitions of puff arrival time were applied on the same datasets and the results were compared. Moreover, it was studied how slight changes in determination of puff departure time can affect its values and other derived puff characteristics. The second part of the thesis is focused on modelling of probability density functions of puff characteristics with knowledge of sampling positions towards the gas source and mean values of concentrations valid for long-term gas sources. The found equations will be utilized in an operational model. The outputs in the form of the probability density functions of puff characteristics distinguish my model from the usually utilized operational models, in which only the ensemble-averaged puff outline and concentration field can be predicted.
Sudden release of toxic gas in built-up environment
Chaloupecká, Hana ; Jaňour, Zbyněk (advisor) ; Zelinger, Zdeněk (referee) ; Efthimiou, George (referee)
The dissertation thesis deals with short-term gas releases (puffs) in an urban canopy studied utilizing wind-tunnel modelling. The urban canopy was composed of buildings with pitched roofs organised into closed courtyards. Into it, a ground-level point gas source was placed. The first part of the thesis is focused on specific definitions of puff characteristics. New definitions of puff arrival and departure times are presented. Various definitions of puff arrival time were applied on the same datasets and the results were compared. Moreover, it was studied how slight changes in determination of puff departure time can affect its values and other derived puff characteristics. The second part of the thesis is focused on modelling of probability density functions of puff characteristics with knowledge of sampling positions towards the gas source and mean values of concentrations valid for long-term gas sources. The found equations will be utilized in an operational model. The outputs in the form of the probability density functions of puff characteristics distinguish my model from the usually utilized operational models, in which only the ensemble-averaged puff outline and concentration field can be predicted.
Experiments of gas leakages of various durations utilizing wind-tunnel modelling
Chaloupecká, Hana ; Kluková, Zuzana ; Kozohorský, Jan ; Radnic, Tomáš ; Jakubcová, Michala
The report describes the process of dealing with the experimental part of the project TACR TJ04000365 between August and December 2020. At first, the choice of the model is discussed. Then, the report describes the fulfillment of the similarity of the model and the reality. Finally, the experiments, data analysis and the experiments results are introduced.
Wind-tunnel modelling & development of emergency software
Chaloupecká, Hana ; Kluková, Zuzana ; Jakubcová, Michala ; Kellnerová, Radka ; Jurčáková, Klára
The report describes the procedure of work on the two-year project TACR TJ01000383.\nIn the year 2018, relations between characteristics of short-term and long-term gas leakages for an urban area were searched utilizing the database COST ES1006. Then, releases of short-term and long-term gases for a rural area were studied. A dimensionless database I. was created from the data.\nIn the year 2019, the dispersion of short-term and long-term gas releases in an industrial area was studied. The measured data were analysed and the dimensionless database II. was created. The databases I. and II. were utilized for the validation of the model. We developed software as the main goal of the project.
Core of emergency model for urban canopy & Experiments of gas leakages for rural area
Chaloupecká, Hana ; Jakubcová, Michala ; Kellnerová, Radka ; Jurčáková, Klára
The report consists of two parts.\nThe first part copes with the development of an emergency model core for short-term gas leakages for urban canopy. It is explained a procedure in the development of the model, in which after recording input data describing a gas leakage as an output probability density functions for individual puff characteristics and exposed places are obtained. From the output, one can see for example the most probable puff characteristics, which can occur during an accident as well as extreme cases. This is the biggest difference in comparison with the usually used emergency models, in which only mean puff contours and concentration fields are the output. \nIn the second part, experiments of gas leakages for rural area are described. Fulfilment of similarity criterions in wind-tunnel modelling as well as the experiments themselves and the database development is showed.\n

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