Air pollutants from traffic in highly dense urbanized cities such as Hong Kong have negative impacts on human health. To create a liveable environment and mitigate existing environmental problems, architects and town planners have been working together, attempting to discover optimum building layouts being consolidated by assessments practiced by environmental scientists via model simulations.

The research began by assessing commonly practiced environmental models including the ? − ? family eddy viscosity models and perturbation theory based models in prediction of wind profile deficits at near and far wakes of cuboids, aiming to achieve a better understanding on the flow mechanisms and behaviours. The study was then extended by comparing the simulation results from both the Re...[ Read more ]

Air pollutants from traffic in highly dense urbanized cities such as Hong Kong have negative impacts on human health. To create a liveable environment and mitigate existing environmental problems, architects and town planners have been working together, attempting to discover optimum building layouts being consolidated by assessments practiced by environmental scientists via model simulations.

The research began by assessing commonly practiced environmental models including the ? − ? family eddy viscosity models and perturbation theory based models in prediction of wind profile deficits at near and far wakes of cuboids, aiming to achieve a better understanding on the flow mechanisms and behaviours. The study was then extended by comparing the simulation results from both the Realizable ? − ? model and Menter’s SST ? − ? model, with the wind tunnel wind and pollutant concentration experimental data from the Tokyo Polytechnic University. It has been discovered that results from the two aforementioned models produce non-satisfactory correlation with the wind experiment data and are not the best choices of model in wind and pollutant dispersion simulations. An improved formulation of the SST ? − ? turbulence model which is capable to produce better correlation results with the wind tunnel experiment data has been proposed. Various sensitivity studies on the key parameters of the improved model were also carried out.

Targeting to come upon an optimal design strategy, the Improved SST ? − ? model was then applied on various idealized city morphologies with different building permeability and building height profiles. In order to further confirm the findings from the idealized cases, further simulations were performed on real conceptual cities. The findings of the study have demonstrated that maintaining at least 20% building permeability together with variations in building height profiles would facilitate pollutant dispersion within urbanized areas, in which the findings are also consistent with the building design requirements documented in the Sustainable Building Guidelines.