Hydrodynamic behaviour of floating polygonal ring structures under wave action. (1st April 2022)

• Record Type: Journal Article
• Authors: Park, Jeong Cheol; Wang, C.M.
• Is Part Of: Ocean engineering. Volume 249(2022)
• Publication Date: 2022-04-01
• Subjects: 3D hydrodynamic analysis -- Resonance -- Floating polygonal ring structure -- Fourier expansion -- Cosine-type radial perturbation -- Eigenfunction expansion method; Ocean engineering -- Periodicals; Ocean engineering; Periodicals; 620.4162
• DOI: 10.1016/j.oceaneng.2021.110195
• Languages: English
• ISSNs: 0029-8018

Abstract

Abstract: In this paper, a semi-analytical method has been developed for the hydrodynamic analyses for floating polygonal ring structures under wave action. The considered polygonal shapes include equilateral triangle, square, pentagon, hexagon and circle where their geometries are created from a parametric equation involving cosine-type radial perturbation. For the similar wetted volumes of considered polygonal ring structures, the added mass, radiation damping and RAOs (Response Amplitude Operators) are similar but the wave exciting forces and wave fields inside the ring structures are somewhat different depending on their shapes, dimensions and orientations. Resonances occur at various frequencies associated with large wave amplitudes due to wave trapping inside the ring structures. By changing the dimensions of the ring structures such as the draft and the horizontal ring width, resonance frequencies may be shifted or reduced. Also, the orientation of polygonal ring structures has a significant influence on wave forces and wave amplitudes inside the ring structures; particularly for triangular and square ring structures. The semi-analytical solutions presented herein can be used as benchmark solutions for verifying numerical formulations and computer codes in determining hydrodynamic behaviours of floating polygonal ring structures. Highlights: Formulation for 3D hydrodynamic analysis of floating enclosed polygonal ring structures. Observation of resonance occurrence inside the polygonal ring structures. Investigation of the factors to cause resonances and study of motion response effects. Rapid computation and easy generation of equilateral polygonal ring shapes such as triangular, square, pentagonal and hexagonal ring structures including a circular ring structure by using a single equation.