POD analysis for aerodynamic characteristics of tall linked buildings

This study investigates the aerodynamic characteristics of tall linked buildings (LBs). Wind pressure data on typical LBs with different gap distances between two buildings were measured in a series of wind tunnel tests, and proper orthogonal decomposition analysis was then applied to identify pressure patterns and their associated excitation mechanisms. For α = 0°, with a small gap distance, channeling is strong as indicated in the 1st mode, and the LB system behaves like a single bluff body, which is further suggested by the 2nd mode result. In contrast, with a large gap distance, the 1st mode is associated with weak channeling. Each building has its own isolated vortex shedding in the 2nd mode. Channeling in the 1st mode and vortex shedding in the 2nd mode are correlated with different aerodynamic characteristics. For α = 90°, the 2nd mode is correlated with the case where a small gap distance exists between the two buildings, and the downstream building is submerged in the shear layers of the upstream building. However, with a large gap distance, the pressure on the windward surface of the downstream building is positive because separated flows from the upstream building are reattached on the downstream building, showing that the gap distance is important for aerodynamic characteristics.