Effect of aspect ratio on the aerodynamic performance and correlation of square section building exposed to twisted wind profile

This study investigates the aerodynamic performance of three square-section buildings with different aspect ratio (AR = 1:1, 1:4, and 1:6) exposed to twisted wind profile (TWP) by pressure measurement test. The effect of AR on the correlation of wind loads specifically for TWP is systematically revealed from both time–frequency domain and local–global perspective. Results show that compared with its counterparts in conventional wind profile (CWP), the effect of AR on aerodynamic load under TWP becomes significantly different and more prominent, which can be categorized into two types of patterns. For pattern low-rise building, TWP is more resembling the condition of CWP with certain attack angle. For pattern high-rise building, TWP results in stronger momentum exchange along building height but suppresses fluctuating feature associated with Karman vortex. As a result, under TWP, mean base moments of all buildings are enhanced except for longitudinal component of case AR = 1:4 and 1:6; while the fluctuating base moment for three AR cases is all reduced, which indicates that dynamic pattern of wake flow is suppressed. Moreover, the discrepancy of local wind load between case CWP and TWP concentrates on the lower-middle location for high-rise building but distributed evenly along all low-rise building height. Additionally, it is found that the effect of AR on aerodynamic correlation exhibits different mechanisms and patterns when building is under the impact of CWP or TWP.