3-D Aerodynamic Analysis of Long-Span Bridge Deck Sections Using DES and Block-Iterative Coupling

The design of long-span bridges often depends on wind tunnel testing of sectional or full aeroelastic models. Recently, some progresses have been made to find a computational alternative to replace these physic tests. A novel computational fluid dynamic (CFD) method is presented in this paper, where the fluid-structure interaction is conducted through a self-developed code combined with ANSYS-CFX solver. A new mesh control method based on block-iterative coupling is used for two dimensional (2-D) and three dimensional (3-D) bridge deck modeling. Detached eddy simulation (DES) for 3-D viscous turbulent incompressible flow was applied to the analysis of bridge deck sections. Firstly, numerical simulations of a U-shape cross section based on 2-D and 3-D models are practiced. The comparisons of aerodynamic coefficients thus obtained show that the 3-D CFD simulation is more accurate than the 2-D one. secondly, the 2-D and 3-D CFD simulations were performed for two generic deck sections to produce their aerodynamic coefficients and flutter derivatives. The computational results agree well with the available computational and wind tunnel results that shows the proposed 3-D CFD simulations are quite effective. Finally, the 3-D based flow field is obtained, which is also an advantage of the proposed 3-D CFD simulation.