Numerical Simulation of Wind Characteristics over Bridge Site Near Y-shaped River Junction in Mountainous Area

To study the wind field characteristics in bridge site under the influence of Y-shaped river junction in mountainous areas, a long-span suspension bridge built over a deep-cutting gorge near a Y-shaped river junction is regarded as a typical example and a numerical model for the wind field distribution of the bridge site with complex terrain is established by computation fluid dynamics (CFD) method. According to comparative analysis of 36 cases in different groups, the influence laws of Y-shaped river junction on the average wind velocity, wind attack angle, wind profile, and wind velocity amplification factor along the bridge deck in different flow directions are discussed, and the effect of river diversion and flow around mountains at the junction are analyzed. The results show that unlike the wind characteristics in ordinary deep gorges, influenced by Y-shaped river junction, the maximum increase in the average wind velocities is up to 24m/s, the wind attack angles are mainly negative, and a large velocity amplification factor up to 1.13 occurs. The effect of river diversion and flow around mountains at the junction can lead to a large wind velocity difference on beam.