Influence of thermal effects on street canyon circulations

A numerical study has been carried out to investigate the influence of large-scale thermal effects and strong local-scale temperature gradients near the ground on the circulation inside a street canyon. The results show that the dynamical forcing dominates the circulation inside a street canyon. But this forcing is influenced by the large-scale thermal stability. Thus, atmospheric stability indirectly controls the street canyon circulation. Small temperature gradients inside the street-canyon are neutralised by the external dynamical forcing. Strong temperature gradients inside the street-canyon show an impact on the street canyon circulation. While stable stratification reduces the circulation for the building configuration investigated, convective stratification seems to intensify it.