Computational Fluid Dynamics Simulation of Pollutant Dispersion Around a High-Rise Building Considering Effect of Plume Buoyancy

Abstract:

In this paper， large-eddy simulations （LES） were conducted to investigate the pollutant dispersion around a high-rise building， with different plume buoyancies produced by the density difference between ambient air and polluted gas being considered. The accuracy of the numerical method used in this paper was validated by comparing the simulated results with the wind tunnel experiment data. The effects of different plume buoyancies on the time-averaged concentration， concentration transportation， and concentration fluctuation were discussed. The positive buoyancy of the light gas significantly increases the vertical convection and turbulent flux in the wake region behind the building， enhancing the dilution of pollutant. In contrast， heavy gas has an opposite effect under the influence of negative buoyancy. In addition， the upward plume buoyancy further enhances the concentration fluctuation， while the downward plume buoyancy suppresses it to some degree.

Key words:pollutant dispersion;plume buoyancy;high-rise building;large-eddy simulation;concentration fluctuation