Simplified numerical method for flutter analysis of bridge based on steady-simplified wind field from unsteady flow

The efficient and quick evaluation for flutter stability of long-span bridges is studied via numerical method. Based on the Force Vibration Technique to identify flutter derivatives, the wind flow field around two dimensional bridge sections in wind tunnel experiment can be simulated by solving two dimensional viscous incompressible Navier-Stokes equations and RNG k-ε turbulent equations. The finite volume method is used for dispersing the equations. The aerodynamic forces of bridge sections at a few discrete time instant points of one periodic movement are calculated with the wind flow field and the flutter derivatives can be got with the Least-square method. The flutter stability is estimated by flutter critical wind speed worked out by the Scanlan method. The two flutter critical wind speed results of the Great Belt East Bridge in Denmark and the Humen bridge in China are computed with the present numerical method. The present numerical results are very close to the experimental ones so the present simplified numerical method is validated.