Experimental investigation on the vortex-induced vibration of a rectangular 4:1 cylinder under skew winds

Abstract

The characteristics of vortex-induced vibration (VIV) of a rectangular 4:1 cylinder are comprehensively investigated under different wind yaw angles (β = 0°, 5°, 10°, 15°, 20°, 25°, and 30°) and wind angles of attack (αm = +5°, +3°, and 0°) using wind tunnel tests. For the VIVs of a rectangular 4:1 cylinder, the lock-in regions, amplitudes, frequencies, hysteresis effects, and the applicabilities of independence principle (IP) for various cases are analyzed. Experimental results suggest that the maximum VIV amplitude and the onset wind speed for VIV respectively decreases and increases with increasing β. Hence, it is reasonable to assume that the most unfavorable state of VIV occurs for β = 0° for the rectangular 4:1 cylinder. However, the IP theory is inapplicable for predicting its VIV responses under skew winds. The maximum amplitude increases with the increase of αm, while the lock-in region shrinks with αm. For the rectangular 4:1 cylinder under skew winds, the experimental VIV response may provide a benchmark for checking the prediction accuracies of mathematical models and computational fluid dynamic simulations.