Flutter Control of Active Aerodynamic Flaps Mounted on Streamlined Bridge Deck Fairing Edges: An Experimental Study

Traditional aerodynamic measures with fixed geometric shapes make it difficult to relieve the wind-induced vibration issues under the continuous expansion of bridge spans. Active aerodynamic control measures would be an alternative way to improve the wind vibration performance of long-span bridges. In this study, a bridge flutter control method based on active flaps was proposed, and the main girder-active flap-suspended aeroelastic model was designed to study the control effect. A pair of active flaps was installed on both sides of the box girder near the lateral fairings, and the movement signal of the main girder was detected using internal sensors. The two flaps move relative to the deck according to the preset equations of motion. This improved the flutter stability of the system with high effectiveness compared to traditional passive aerodynamic measures. By adjusting the gain coefficient in the motion function of the flaps and the phase difference between the flaps and the deck, the changing characteristics of the critical flutter wind speed were revealed with a deeper understanding of the relationship between the phase differences and gain coefficient of the active flaps and main girder. Studies have shown that the flutter performance of the deck-flap system is significantly affected by the phase difference and gain coefficient on both sides of the aerodynamic flap. The control law of the windward flap is relatively stable, but the control effect of the leeward flap is greatly affected by the movement of the windward flap.