Showing papers by "Marina Neophytou published in 2017"
TL;DR: In this paper, the authors investigated outdoor urban ventilation in a real complex urban area by introducing a new ventilation indicator, the "air delay", and performed computational fluid dynamics (CFD) simulations.
118 citations
TL;DR: In this paper, the authors investigate the representativeness of the pollutant exchange velocity as a quantitative metric for the actual pollutant removal capacity of a canyon under different pollution emission scenarios.
Abstract: In this work we investigate the representativeness of the pollutant exchange velocity as a quantitative metric for the actual pollutant removal capacity of a canyon under different pollution emission scenarios. We further explore its sensitivity to a change of the street canyon geometry aspect ratio as well as different exposure regions of interest within a 2-D canyon. We find that the effective pollutant removal capacity as quantified by the pollutant exchange velocity can vary substantially from its reference-nominal value as customarily derived for uniformly-distributed pollutant conditions in the canyon. We specifically find that for the case of the center and leeward wall locations of the source, the pollutant exchange velocity varied substantially exceeding a factor of 2 variations. Furthermore, we find that the highly nonhomogeneous pollutant distribution arising from the different source locations plays an important role in the pollutant removal rate accounting for both the turbulent and convective pollutant transport. As expected, the pollutant-exchange velocity was found to be dominated by the turbulent flux, reaching up to 2 to 3 times the convective pollutant flux at the rooftop level.
33 citations
TL;DR: In this article, the influence of real world conditions, including heterogeneity and natural variability of background wind, on the air flow and pollutant concentrations in a heterogeneous urban street canyon using both a series of field measurements and controlled laboratory experiments.
33 citations
TL;DR: In this paper, the rate of removal of pollutants within simplified urban street canyons is investigated using air flow fields obtained from Particle Image Velocimetry (PIV) experiments and Computational Fluid Dynamics (CFD) simulations of the resulting pollutant dispersion.
9 citations
TL;DR: In this article, the authors use the Westminster Borough of London City, as a case study to illustrate how a dynamic high-resolution dataset for the energy demands of the whole area can be analyzed using the Multi-Resolution Analysis (MRA) to provide insights into the urban and sub-urban (e.g. district) scale energy demand and therefore suggest how such an analysis can be exploited to guide smart urban energy-demand management.
3 citations
29 Sep 2017
TL;DR: In this article, high-resolution Computational Fluid Dynamics (CFD) simulations are performed based on the 3D unsteady Reynolds-Averaged Navier-Stokes equations to assess the air temperature and wind speed distributions.
Abstract: Considering the radical increase of urban population and the trend toward urbanization, the analysis of microclimatic conditions in the urban environment is getting more significant. In this perspective, this study analyzes microclimatic conditions in a real urban area. The real compact inhomogeneous urban area under study is located in Nicosia old town, in Cyprus. High-resolution Computational Fluid Dynamics (CFD) simulations are performed based on the 3D unsteady Reynolds-Averaged Navier-Stokes equations to assess the air temperature and wind speed distributions. The CFD results are compared with on-site measurements for the same area. The results show that CFD can predict air temperatures in compact real urban areas, with an average deviation of 6.8%. Based on the results, conclusions are going to be made regarding thermal comfort in the case study area.
1 citations