Numerical Simulation of Wind Characteristics at Bridge Sites in Complex Mountainous Terrains

In order to investigate the variation of spatial characteristics of the wind field at bridge sites in complex terrains, a mountainous terrain was built in FLUENT to simulate wind field characteristics. The Lvzhi River Bridge located at a gorge area in the southwest of China was chosen as the engineering background, in which 36 cases with different wind directions were analyzed. Under the influence of the complex terrain, the profiles of average transverse wind velocities along the height direction and bridge axes are quite different. The complex terrain still has an impact on the wind field at 400 m above the peak of the terrain near the bridge site. Affected by large angle bending of the river, the bridge site area forms a terrain similar to the " one-way open slot”. The incoming wind along the river downstream direction is blocked by the mountain, so the wind speed at each bridge is lower than that in the river upstream direction. The average of the velocity differences between these two directions reaches 13.6 m/s. The wind attack angles of all bridges are mainly negative. The suddenly widened gorge results in a part of limited distributary of the wind field and the wind speeds decrease slightly in the widening area. After crossing the widened section, the gorge narrows and the wind speeds remain large.