Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
Experimental Flow-Induced Motions of Array of Floating Cylinders with Circular, Square and Diamond Sections
Submission Author:
Rodolfo Gonçalves , SP , Japan
Co-Authors:
MARIA EDUARDA CHAME, Pedro Lopes, Nicole Hepp Hannes, Shinichiro Hirabayashi, Hideyuki Suzuki, Rodolfo Gonçalves
Presenter: Rodolfo Gonçalves
doi://10.26678/ABCM.COBEM2017.COB17-0441
Abstract
Experiments regarding the FIM - flow-induced motions on an array of three and four floating cylinders with low aspect ratio, H/L=1.5, with the distance between column centers, S/L=4, were carried out in a towing tank. The array of cylinders was elastic supported by a set of linear springs to provide low structural damping on the system. Three different section geometries were tested, namely circular, square and diamond. One current incident angle was tested, as 0 degrees. These configurations of arrays were selected to cover the range of the main offshore multi-column platforms, such as SS - semi-submersible, TLP – tension leg platform and FOWT – floating offshore wind turbine. The aims were understanding from fundamental tests the VIM – vortex-induced motions of the multi-column systems and compare the results of the single column. The range of Reynolds number covered 10,000 < Re < 150,000. For the single cylinders, the amplitude results showed a VIV – vortex-induced vibrations behavior for the single circular cylinder; for the single square cylinder, galloping behavior was observed for 0-degree incidence, and VIV one was observed for 45-degree incidence (diamond cylinder). For the array of four circular cylinders, the amplitude results in the transverse direction showed a VIV behavior for the circular cylinders and galloping was observed for four square cylinders. The amplitude results for the array of four cylinders were very similar to single cylinders for this distance between cylinders. These results are larger than VIM results obtained from a floating system with pontoons. For the array of three cylinders, the amplitude results showed to be larger than the array of four cylinders in high reduced velocities. Results of amplitudes and frequencies in the in-line and transverse directions corroborated for these statements.
Keywords
flow-induced motions, Vortex-Induced Vibration, vortex induced motions, galloping, array of cylinders, circular cylinder, square cylinder, model tests, towing tank
