Abstract: The influence of stable stratification with different Richardson numbers (Ri_b) on the flow structure and pollutant dispersion around a 1∶1∶2 (length∶width∶height) high-rise building using the k-epsilon high Reynolds number turbulence model was simulated. The results show that the temperature stratification significantly affects the flow structure around the building. As Ri_b increases, the leeward stagnation point gradually moves towards the top of the building, the recirculation region on the top of the building shifts backward, and the length of the recirculation region on the windward side of the building first increases and then decreases. The vortex position gradually moves above the building. The high TKE/u_H² region around the building is mainly distributed on the top of the building and in the downwind recirculation region. As Ri_b increases, the TKE/u_H² decreases in the top and wake regions of the building. With increasing Ri_b, the ground-level pollutant concentration first increases and then decreases, the height of the downwind plume gradually decreases, and the maximum concentration in the plume rises.

Key words: numerical simulation, stable stratification, high-rise building, dispersion