도로협곡내 보행공간에서 식생에 의한 교통 대기오염 저감효과에 대한 CFD 시뮬레이션 연구

Abstract

The changes of traffic-induced sidewalk air pollution are investigated after trees are planted in a street canyon, using FDS(Fire Dynamics Simulator), an open source CFD(Computational Fluid Dynamics) code. The roles of tree permeability, its planting location, and its shapes are examined. Extensive amount of simulations are carried out to produce 399 sets of valid data out of 400 scenario cases, which include 1) the shrub layer only cases, 2) the small-tree layer over shrub layer cases, and 3) the tall-tree layer over shrub layer cases. The steady state pollution concentrations averaged over the sidewalk planes are reduced more than 10% after the trees are planted, regardless of its planting type. The largest reduction of about 45% is achieved for a shrub layer only case. The vortical flows which transport the pollution materials directly from vehicle lanes to the sidewalk are distorted favorably by the shrub layer, which provide the underlying physical explanations for these reductions.