Acrosswind aerodynamic damping of rectangular tall buildings

The acrosswind behavior and aerodynamic damping of rectangular shaped tall buildings with various side ratio and mass-damping coefficient were studied through wind tunnel aeroelastic model tests. Experimental results show that, the long rectangular building shape, B/D=2.0, is an aerodynamic stable building cross section regardless of the flow conditions. For short rectangular building shape, B/D=0.4, 0.6, 1.0, negative acrosswind aerodynamic damping might occur as functions of side ratio and flow condition. For these potentially aerodynamic unstable shapes, the negative aerodynamic damping occurs when acrosswind motion exceeds certain thresholds. Data also suggests that a model's negative aerodynamic damping is related to the side face reattachment of the free shear layer.