Experimental Study on Vortex-Induced Motions of Floating Circular Single Cylinders with Low Aspect Ratio and Different Heave Plate Geometries

Abstract

Experiments regarding vortex-induced motions (VIM) of floating circular cylinders with low aspect ratio, 𝐿/𝐷 = 2.0, and different heave plate configurations were carried out in a recirculation water channel; where 𝐷 is the diameter and 𝐿 is the submerged length of the cylinder. The floating circular cylinders were elastically supported by a set of linear springs to provide low structural damping on the system. Twelve different heave plate conditions were tested combining three heave plate diameters, 𝐷(, and four heave plate heights, 𝐻(. The geometry conditions were 𝐷(/𝐷 = 1.2, 1.6 and 2.0, and 𝐻(/𝐷=0.0, 0.2, 0.4, and 0.6. Additionally, a single-cylinder case without a heave plate was experimented, i.e., 𝐷(/𝐷 = 1.0. These different heave plate conditions were selected to promote changes in the structures shedding around the free end of the cylinder. The aim was to understand the heave plate effects on the VIM amplitudes. The range of Reynolds number covered 3,000 < 𝑅𝑒 < 24,000, and the reduced velocity ranged 2 < 𝑉1 < 15. The increase in the heave plate dimensions decreased the VIM amplitudes. The increase in the heave plate height decreased the drag force. The heave plate may be a reasonable solution to mitigate the VIM of offshore single column systems and perhaps of multi-column floaters.

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2020 – Goncalves et al – Experimental Study on Vortex-Induced Motions of Floating Circular Single Cylinders with Low Aspect Ratio and Different Heave Plate Geometries

Keywords

vortex-induced motions, floating model, circular cylinder, heave plate, model tests

Authors

Rodolfo Trentin Gonçalves1

Raíza Oliveira Pereira da Silva2

Matheus Antonio Marques3

Shinichiro Hirabayashi4

Gustavo Roque da Silva Assi2

Alexandre Nicolaos Simos2

Hideyuki Suzuki1