Numerical investigation of the coupled flutter onset mechanism for streamlined bridge deck cross-sections

In this work the aeroelastic stability of long-span bridge decks is numerically investigated. A simulation model is presented by which the aerodynamic fields and the structural motion are simultaneously and jointly simulated. The bridge deck is schematised as a bidimensional rigid body subject to elastic restraints corresponding to the torsional and the vertical degree of freedom, and the ALE formulated 2D URANS equations are numerically integrated by a finite volume technique on meshes which deform according to the motion of the structure. The validation of the numerical model is performed by comparing the numerical results with those of an experimental campaign, and is used to investigate the aeroelastic stability of the Forth Road Bridge deck. A profound insight into the onset and the amplification mechanisms of coupled flutter for longspan bridge decks is proposed. Key-Words: Bridge aeroelasticity; finite volume; moving grids, turbulence modelling.