A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Advances in urban ventilation assessments using large-eddy simulation
Today, the majority of the world's population lives in city areas. This renders the urban climate to be the most impacting local climate to the global society. To understand and improve the urban climate, local governments demand urban ventilation assessments (UVAs). Such UVAs often simplify the highly complex urban climate in order to make an assessment possible. In order to simplify the assessed case, the general behaviour of the urban ventilation must be understood so that important impacts are not neglected. However, many interactions inside the urban atmospheric boundary layer are still unknown. In this thesis, two aspects of these unknown interactions of urban climate are studied in detail: (a) the ventilation of courtyards, particularly, the influence of lateral openings on courtyard ventilation; and (b) the interaction between neighbourhood ventilation and mean building parameters like mean building height and building density under different atmospheric stratification. These two aspects are investigated by means of large-eddy simulations. To confirm the liability of the utilized simulation model PALM, an evaluation study was conducted prior to the investigation of the two above-mentioned aspects. The comparison of simulation results against wind-tunnel data revealed differences in mean wind speed and wind direction of 5% and 4°, respectively, on average. The maximum differences occurred within the first grid points adjacent to obstacles and rapidly decreased with distance. Turbulence parameters like turbulence intensity and the spectral energy-density distribution agreed to a similar degree. Differences were found to be well within the acceptable margins. Hence, it was concluded that the model is able to correctly simulate the urban boundary layer. In the following part, the ventilation of courtyards through lateral openings was investigated. Various courtyard configurations were analysed in an idealized building setup. Lateral openings were found to have nearly no effect on the ventilation of wide ...
Advances in urban ventilation assessments using large-eddy simulation
Today, the majority of the world's population lives in city areas. This renders the urban climate to be the most impacting local climate to the global society. To understand and improve the urban climate, local governments demand urban ventilation assessments (UVAs). Such UVAs often simplify the highly complex urban climate in order to make an assessment possible. In order to simplify the assessed case, the general behaviour of the urban ventilation must be understood so that important impacts are not neglected. However, many interactions inside the urban atmospheric boundary layer are still unknown. In this thesis, two aspects of these unknown interactions of urban climate are studied in detail: (a) the ventilation of courtyards, particularly, the influence of lateral openings on courtyard ventilation; and (b) the interaction between neighbourhood ventilation and mean building parameters like mean building height and building density under different atmospheric stratification. These two aspects are investigated by means of large-eddy simulations. To confirm the liability of the utilized simulation model PALM, an evaluation study was conducted prior to the investigation of the two above-mentioned aspects. The comparison of simulation results against wind-tunnel data revealed differences in mean wind speed and wind direction of 5% and 4°, respectively, on average. The maximum differences occurred within the first grid points adjacent to obstacles and rapidly decreased with distance. Turbulence parameters like turbulence intensity and the spectral energy-density distribution agreed to a similar degree. Differences were found to be well within the acceptable margins. Hence, it was concluded that the model is able to correctly simulate the urban boundary layer. In the following part, the ventilation of courtyards through lateral openings was investigated. Various courtyard configurations were analysed in an idealized building setup. Lateral openings were found to have nearly no effect on the ventilation of wide ...
Advances in urban ventilation assessments using large-eddy simulation
Gronemeier, Tobias (author)
2021-01-01
Theses
Electronic Resource
English
Advances in urban ventilation assessments using large-eddy simulation
| UB Braunschweig | 2021
Ventilation and air quality in city blocks using large-eddy simulation-urban planning perspective
| TIBKAT | 2018
Measurement and large-eddy simulation of single-sided natural ventilation in urban building groups
| SAGE Publications | 2024