The impact of the wind attack angle on a typical bridge deck's flutter behavior by the distributed aerodynamic characteristics method

To investigate the influence of the wind attack on a bridge deck's flutter performance, the concept of "pressure flutter derivatives" was introduced as a part of the "distributed aerodynamic characteristics" method, which can be used to visualize the dominant fluctuations of the pressure field. The distributions of the aerodynamic damping and stiffness under different wind attack angles were visualized, instead of using an overall force perspective. The analysis was carried out through two-dimensional computational fluid dynamics simulations based on a typical box deck section. Necessary data were obtained through the forced vibrations of the deck. The dominant pressure fluctuations were demonstrated, around which the wind attack angles' impact on the Scanlan flutter derivatives was discussed. For the deck section used in this study, the wind attack angle was found to most affect the windward parts of the deck. When wind attack angle ranged from -1.5 degrees to 3 degrees, two regions contributed the most: one located behind the windward faring vertex and the other located behind the first vertex of the upper slab. When the wind attack angle decreased to -3 degrees, a new dominant region appeared behind the first vertex of the lower slab, which caused a sudden reduction of the flutter critical speed.