Large-Eddy Simulation of plume dispersion within various actual urban areas

摘要

Plume dispersion of hazardous materials within urban area resulting fromaccidental or intentional releases is of great concern to public health.Many researchers have developed local-scale atmospheric dispersion modelsusing building-resolving computational fluid dynamics. However, an importantissue is encountered when determining a reasonable domain size of thecomputational model in order to capture concentration distribution patternsinfluenced by urban surface geometries. In this study, we carried outLarge-Eddy Simulations (LES) of plume dispersion within various urban areaswith a wide range of obstacle density and building height variability. Thedifference of centerline mean and r.m.s. concentration distributions amongvarious complex urban surface geometries becomes small for downwinddistances from the point source greater than 1.0 km. From these results, itcan be concluded that a length of a computational model should be at least1.0 km from a point source.