Numerical simulation of the coupled flutter instability for closed-box bridge decks

In this work a numerical investigation of aeroelastic phenomena for long-span bridge decks is proposed: a simulation model is presented by which the aerodynamic fields and the motion of the structure are simulated simultaneously and in a coupled manner. The structure is represented as a bidimensional elastically suspended rigid body with two degrees of freedom, and the aerodynamic fields are simulated by numerically integrating the ALE formulated 2D URANS equations with a finite volume scheme on moving grids which adapt to the structural motion. The numerical model is validated by the comparison between numerical and experimental results, and is utilised to study the aeroelastic stability of the Forth Road Bridge deck. A deep insight into the onset and the amplification mechanisms of coupled flutter for long span bridge decks is proposed. The numerical model is also used to test the effectiveness of a small aerodynamic modification on the aeroelastic stability of the deck. © 2017, North Atlantic University Union. All rights reserved.