Application canopy model to actual urban area and LES analysis on fluctuating dispersion

Abstract

Even inside urban areas, there is a possibility that the accidental spilage of hazardous materials for the transportation and storage and intensional release by chemical and biological terrorism occur. Therefore, the characteristics of concentration fluctuation around regularly arrayed cubes (in-line and staggered) have been studied by wind tunnel and field experiments. However, taking into consideration aspects of actual urban canopy, the height and width of buildings, their arrangement, the spacings between them and the width of the streets change variously. Therefore, aspects of actual urban roughness are so complicated that characteristics of plume dispersion in surface layer are very different from those of plume dispersion in typical urban model arrayed regularly. Therefore, we use LES(large-eddy simulation) to investigatethe the chracteristics of flow and plume dispersion in actual urban area and estimate peak concentrations based on various kinds of surface roughness.