Influence of Urban Infrastructure on Natural HVAC Dynamics

Tall buildings are key components of the urban canopy and can significantly alter airflow patterns over large areas. This study investigates the interaction between wind flow, high-rise structures, and the surrounding urban canopy within a realistic district in South London, complemented by tests on conceptual building layouts to further interpret the observed behaviour. Experiments were conducted in a boundary-layer wind tunnel using a 1:200 scale model featuring five tall buildings subjected to three prevailing wind directions. The findings reveal that an upstream high-rise has a pronounced impact on airflow at elevated levels, while wind behaviour near roof height is governed more by the immediate surrounding buildings than by distant tall structures. The experiments also show that the wake generated by a high-rise extends much farther downstream than typically assumed. To explore the environmental implications, dynamic outdoor thermal comfort analysis was performed, demonstrating that upstream tall buildings substantially modify airflow aloft and that increased building height is generally associated with reduced thermal comfort in downstream areas.