Influence of Upstream Wind Shear and Turbulence on the Wind Pattern and PollutantConcentrations within Street Canyons: A Numerical Simulation Study

摘要

The study shows that the canyon geometry and the upstream boundary conditionshave significant influences on the flow and concentration fields in the vicinity of urban street canyons. Pollutants emitted within a canyon will generally not be transported to the front of the upstream buildings. When there is more than one canyon in the downwind direction, the upstam flow conditions can be very critical to the flow and dispersion fields inside the first canyon, but they are not as important to the concentration fields inside the consecutive canyons. The dispersion fields in the vicinity of the first canyon are very similar to the corresponding cases, involving only one canyon and the same upstream boundary conditions. The fields in the vicinity of the following canyons are comparable to cases that have the same relative geometric configuration on two sides of the canyon but with the atmospheric shear and turbulence in the upstream flow.