Wake-induced vibrations of tandem flexible cable models in a wind tunnel

摘要

A pair of flexible cable models were fabricated to simulate the wake induced vibration (WIV) of two tandem stay cables. The center-to-center separation of the two cable models was fixed to be 4D. The in-plane and out-of-plane accelerations of both upstream and downwind models were measured as the incoming wind speed increased from 3 m/s to 40 m/s (R-e = 0.96 x 10(4)-1.28 x 10(5)). The response characteristics of WIVs, including the vibration amplitude, power spectral density, and non-dimensional trajectory, were investigated in detail. The results show that the downstream model begin to strongly vibrate when the wind speed is above a critical value, and the WIV is dominated by the in-plane oscillation, which is consistent with those observed from an elastic model test in previous reports. However, different from the previous experimental results, three critical reduced speeds were observed, and four reduced speed ranges were proposed according to the response characteristics of WIV. The reasons for the response characteristics of WIV are qualitatively analyzed. The wake stiffness and the drag force effect are the main reasons that the dominating frequency of WIV is always higher than the fundamental frequency and increases with the wind speed.