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The methodology of the evaluation of the dissemination of dust in the complicated terrain after the dust-proof walls
Nosek, Štěpán ; Jaňour, Zbyněk
The report describes the methodology for the assessment of the spread of coal dust from surface mine in the complicated terrain after the dust-proof walls. First, the methodology is described that uses physical modeling, specifically the so-called Townsend´s method of independence on Reynolds ' number is applied. The methodology is applied to the case of the spread of dust from the surface of the coal mine Libouš in the case where a substantial source of pollution in the vicinity is located the dust-proof wall and the diffusion of dust particles is studied in the immediate vicinity of the source. After the configuration of set up of the wind tunnel that simulates flow in MVA in the scale, was made the measurement of turbulent characteristics of flow and diffusion, and was designed by its optimal configuration. The results were compared with the results of the SW.
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The methodology of the evaluation of the dissemination of dust in the complicated terrain after the implementation of the major topographical changes
Nosek, Štěpán ; Jaňour, Zbyněk
The report describes the methodology for the assessment of the spread of coal dust from surface mine in the complicated terrain. First, the methodology is described that uses physical modeling, specifically the Townsend´s method is applied the so-called independence on Reynolds ' number. The methodology is applied to the case of the dissemination of coal dust from surface mine in the configuration Libouš, which occurs after the planned extraction in the year 2024. For this the planned configuration is designed and manufactured plastic model. After the configuration settings of the wind tunnel that simulates flow measurement was carried out in the MVA of turbulent characteristics of flow and diffusion. With the help of these results is a validated mathematical model.
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The methodology of the evaluation of the dissemination of dust in the complicated terrain with area source
Nosek, Štěpán ; Jaňour, Zbyněk
The report describes the methodology for the assessment of the spread of coal dust from surface mine in the complicated terrain, first described the methodology, which uses the method of physical modelling. For an estimate of the area of the most important processes is used, the method of similarity between laminar and turbulent flow. In this area, the Townsendova method is applied the so-called independence on Reynolds ' number. The methodology is applied to the case of the dissemination of coal dust from surface mine and Libouš selected results of flow and diffusion. Are discussed the shortcomings of the methodology of SYMOS, which is used for these cases and the rationale for the proposed methodology. With the help of these results is a validated mathematical model
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Neutrally stratified flow modelling over complex terrain at meso-scale: open-cut coal mine study
Nosek, Štěpán ; Jaňour, Zbyněk ; Jurčáková, Klára ; Kellnerová, Radka ; Kukačka, Libor
The objective of this case study was to determine the influence of the coal mine cavity and its vicinity on the main flow field with respect to prevailing wind direction. In order to model the neutrally stratified flow over extremely huge open-cut coal mine Libouš situated at north-west of Czech Republic the laminar flow analogy was applied. The model was scaled down to 1:9000 according to dimensions of wind-tunnel and selected coal mine surroundings. The measurements of longitudinal and lateral velocity components in selected vertical, resp. horizontal planes were performed by LDA. The measured data will be used for validation of CFD simulation and for selections of area of interest at bigger scales where turbulent flow modelling will be performed. The results revealed that not only of cavity shape and deepness but also the surroundings orography has influence on flow pattern, hence on ventilation, within the area of interest.
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Quadrant analysis of turbulent pollution flux above the modelled street intersection
Kukačka, Libor ; Nosek, Štěpán ; Kellnerová, Radka ; Jurčáková, Klára ; Jaňour, Zbyněk
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 con-centration 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 type of dominant events and their characteristics was resolved.
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