As an important part of road transportation, bridge engineering plays a pivotal role in infrastructure construction. The wind field characteristics of the bridge site area have an essential influence on both the construction and operation period of the bridge, especially in mountainous canyon terrain. In this paper, a numerical simulation using computational fluid dynamics software was conducted to examine the intricate wind field characteristics in mountainous regions. The study focused on ideal V-shaped and U-shaped canyons, aiming to investigate the influence of various parameters. These parameters included three distinct heights, seven angles, and seven widths of the canyon. The findings indicate that in both ideal V-shaped and U-shaped canyons, the canyon acceleration effect weakens as the angles or widths of the canyon increase. The wind speed amplification effect gradually disappears when the V-shaped canyon angle exceeds 160° or when the U-shaped canyon has a width-to-height ratio of approximately 5:1. The wind speed amplification effect strengthens as the canyon height increases. The wind speed acceleration effect exhibits a linear relationship with the angle of the V-shaped canyon, while it demonstrates a logarithmic relationship with the width of the U-shaped canyon. Additionally, the wind speed amplification factor follows a logarithmic distribution along the canyon height. The wind field characteristics observed in this study offer valuable insights for future bridge designs in mountainous regions featuring V-shaped and U-shaped canyons.

Bridges in mountainous areas are indispensable nodes in transportation networks, and wind resistance capabilities have become a controlling factor of long-span bridges built in mountain areas. Therefore, it is necessary to study the characteristics of wind fields under complex terrain. An improved inlet boundary by fitting the boundary curve was proposed in this study. The inlet fluctuating wind field was generated by the Correlation Improved Random Flow Generation method (CIRFG). The results of the numerical simulations show that the fluctuating wind input generated by CIRFG tallies with the target wind field, which proves the reliability of the proposed method. The method of fitting boundary curves to give inlet wind speed profiles can achieve non-uniform wind profile inputs. The results show the wind direction of the gorge varies significantly by height. The wind speed at the summit will accelerate affected by the terrain. Also influenced by the terrain, the turbulence intensity profiles in the simulated area show an S-shape. The transverse wind and angle of attack are uneven along the main girder, especially near slopes. The conclusions obtained in the study can provide references for the wind resistance of bridges built in mountainous areas.