5. Concluding remarks

The unsteady aerodynamic forces acting on the long-span curved roof have been investigated based on a numerical simulation (LES). A forced vibration test was carried out. First, the influence of a roof's vibration on the wind pressure was investigated. It is found that the wind pressure on a vibrating roof is strongly influenced by the roof's vibration. Furthermore, the flow field around a vibrating roof was also investigated. It is found that the vibration of the roof may restrain the separation of a vortex near the trailing edge of the roof. Finally, the characteristics of unsteady aerodynamic force acting on a long-span vaulted roof were evaluated. Both the wind tunnel experiment and CFD simulation show similar results for the variation of aerodynamic stiffness and damping coefficients aK and aC with reduced frequency of vibration fm \* , which implies that the LES is effective to investigate the characteristics of unsteady aerodynamic forces. The aerodynamic stiffness coefficient is generally positive, which decreases the total stiffness of the system, resulting in aeroelastic instability of long-span vaulted roofs with lower stiffness. On the other hand, the aerodynamic damping coefficient is negative, which results in an increase in the total damping of the system, resulting in a decrease in the response of the roof.

Therefore, it is necessary to consider the effects of unsteady aerodynamic forces in the windresistant design of long-span curved roof with lightweight and low stiffness for evaluating the response of the roof more reasonably.
