Investigation of the 2D Aerodynamic Admittances of a Closed-Box Girder in Sinusoidal Flow Field

Abstract

This study investigates the aerodynamic admittances of a closed-box girder in both streamwise (u-) and vertical (w-) sinusoidal flow fields. A series of sinusoidal flows with discrete oscillation frequencies (fu = 00.2–1.2 Hz) and different oscillation amplitudes (Δu = 0.5 – 2.0 m/s) are experimentally generated, which are fully coherent in the span-wise direction. Meanwhile, the Computational Fluid Dynamics (CFD) method is utilized to simulate streamwise sinusoidal flows with higher frequencies (fu = 0.2–14 Hz). The u-turbulence-related two-dimensional aerodynamic admittance functions (2D AAFs) of the closed-box girder are identified frequency by frequency. On the other hand, the vertical sinusoidal flows are numerically simulated (fw = 0.2–14 Hz, Δw = 1.2 m/s), and the w-turbulence-related 2D AAFs are identified. Finally, the differences between u-, w- admittances and the equivalent ones are compared. The results indicate that u- and w-turbulence-related AAFs have different trends with the reduced frequency, and thus it is inaccurate to treat the contributions of u- and w-turbulence to admittances as equivalent in previous studies.