Bridge Flutter Characteristics Under a Non-uniform Attack Angle Wind Field

The non-uniform inflow of wind with a large attack angle in mountainous areas poses a considerable challenge to the wind resistance design of long-span bridges. With the increase in the number of bridges in mountainous areas, the aerodynamic characteristics of bridges in a non-uniform wind field, especially the flutter stability, merit consideration. Through comparative analysis, this study examines the influence of amplitude and other parameters on the computational fluid dynamics (CFD) identification accuracy of flutter derivatives. Moreover, it provides the recommended values of each parameter. The flutter response of bridges in three typical non-uniform attack angle wind fields (linear, cubic parabolic, and quadratic parabola distribution) is analyzed, and the influence of the characteristic parameters on the critical flutter wind speed is determined. The results show that the mid-span is the attack-angle-sensitive area. Taking the maximum attack angle as a reference is too conservative, while it is sometimes dangerous to use the mean attack angle. Based on the principle of response equivalence, the three kinds of non-uniform wind fields can be simplified by appropriate attack angle reference value, which can provide reference for the wind resistance design of bridges in mountainous areas.