The effect of angle of attack on flow-induced vibration of low-side-ratio rectangular cylinders

Tommaso Massai (1) , Jisheng Zhao (2) , David Lo Jacono (3) , Gianni Bartoli (1) , John Sheridan (2)

1 UniFI - Università degli Studi di Firenze = University of Florence = Université de Florence
2 Fluids Laboratory for Aeronautical and Industrial Research - FLAIR (Victoria, Australia)
3 IMFT - Institut de mécanique des fluides de Toulouse

This study investigates the effect of angle of attack on flow-induced vibrations (FIVs) of sharp-edged rectangular cylinders. In particular, the effect of the afterbody of a rectangular cross-section with low mass ratio and the side ratio ranging from 0.67 to 1.5 is analysed by changing the angle of attack with respect to the oncoming free-stream. As already shown for a different side ratio’s rectangle, namely a square section (see Nemes et al., 2012), the angle of attack variation can make the flow-induced amplitude response switch between vortex-induced vibration (VIV) and galloping. Some considerations with respect to the interaction between the two phenomena typical of FIV, VIV and galloping, are also given for the side ratios of 1.5 and 0.67. The amplitude and frequency responses are carefully analysed, comparing the results with those of a square section of comparable mass ratio. The results showed a marked effect of the after-body, even for slight increments of the angle of attack. This can result in different amplitude response curves, as classified by the features of the response. In addition, the influence of interacting higher harmonics components on the amplitude response is also shown and discussed.

Mots clés: FIV; VIV; Galloping; Sharp-edged rectangular bodies; VIV–galloping interference

Domaines: Vibrations [physics.class-ph]; Mécanique des fluides [physics.class-ph]

Tommaso Massai, Jisheng Zhao, David Lo Jacono, Gianni Bartoli, John Sheridan. The effect of angle of attack on flow-induced vibration of low-side-ratio rectangular cylinders. Journal of Fluids and Structures, 2018, 82, pp.375-393. ⟨10.1016/j.jfluidstructs.2018.07.011⟩. ⟨hal-02045174⟩