Prospects for the Suppression of Aeroedynamic Vibrations of a Long-Span Bridge Using Boundary- Layer Control

Aerodynamic vibrations inherently occur on a long-span-length bridge. The vibrations are roughly classified into vortex-excited vibration and self-excited vibration both are induced by separation flow from the leading edge of the structure. As aerodynamic vibrations frequently cause fatal damage to the structure, the suppression method of vibration has been studied for a long time. Two methods have been proposed for suppression of the vibrations: a structural method and an aerodynamic method. The former is a tuned mass damper or a tuned liquid damper, and the latter is a separation flow control using a certain device of flap or faring. As the aerodynamic method is one of the solutions to eliminate the cause of aeroelastic vibration, the aerodynamic method is more useful than the structural method from the point of view of the suppression of vibrations. Sometimes, however, it may be more costly. This paper deals with the prospects for active control of separation flow to suppress vibrations for the girders and towers of a long-span-length bridge.