Non-uniform wind characteristics in mountainous areas and effects on flutter performance of a long-span suspension bridge

In mountainous areas, the approaching flow to a bridge shows the non-uniform characteristics that the wind parameters change along the span direction, causing potential effects on the flutter performance. This paper takes a long-span suspension bridge located in such areas as an example. Wind characteristics around the bridge are computed by computational fluid dynamics (CFD) simulations, and the distributions of wind velocities and angles of attack are obtained. After discussing the effects of non-uniform wind characteristics on the flutter performance, the flutter derivatives of an ideal plate at different wind speeds and angles of attack are extracted. Considering different distributions of wind velocities and angles of attack, the flutter performance of the bridge is computed based on full-order flutter analyses, and the change in critical flutter state is further discussed. The results show that the approaching flow to the bridge presents obvious non-uniform characteristics accompanied by large angles of attack. Compared with uniform incoming flow, however, non-uniform distributions of wind speeds and angles of attack significantly affect the critical flutter state of the bridge. As the bridge is more susceptible to stronger winds and larger angles of attack, the flutter stability is easy to worsen under such non-uniform wind characteristics.