Wave boundary effects on the aerodynamic force coefficients of a box girder in the wind-wave coupled field

This study experimentally investigates the influence of wave boundary effects on the aerodynamic force coefficients of a box girder in the wind-wave coupled field. The aerodynamic shape of the box girder was selected from the design used in the Norwegian E39 project. A set of aerodynamic tests was performed to explore the effects on coefficients under different clearance (c), wave height (H), wave period (T), and relative wind velocity (U/C) conditions. The wind angle of attack range was selected from −12° to 12°. Experimental results showed that the aerodynamic coefficients exhibited periodic fluctuations consistent with the wave frequency. The surface pressure distribution and Proper Orthogonal Decomposition (POD) modes results were used to understand the mechanism of wave boundary effects. Due to the bluff body characteristics of the girder, the wave boundary effects were more complex compared to the thin plate. Furthermore, an empirical formula for the aerodynamic coefficients considering wave boundary effects was proposed. This study aimed to contribute to the design and development of large-scale floating bridge structures.