Hits:

Indexed by:Journal Papers

Date of Publication:2015-06-01

Journal:CHINA OCEAN ENGINEERING

Included Journals:SCIE、EI、ISTIC、Scopus

Volume:29

Issue:3

Page Number:341-356

ISSN No.:0890-5487

Key Words:floating collars; random waves; hydrodynamic characteristics; in-plane and out-of-plane deformation; net effect

Abstract:As the main load-bearing component of fish cages, the floating collar supports the whole cage and undergoes large deformations. In this paper, a mathematical method is developed to study the motions and elastic deformations of elastic floating collars in random waves. The irregular wave is simulated by the random phase method and the statistical approach and Fourier transfer are applied to analyze the elastic response in both time and frequency domains. The governing equations of motions are established by Newton's second law, and the governing equations of deformations are obtained based on curved beam theory and modal superposition method. In order to validate the numerical model of the floating collar attacked by random waves, a series of physical model tests are conducted. Good relationship between numerical simulation and experimental observations is obtained. The numerical results indicate that the transfer function of out-of-plane and in-plane deformations increase with the increasing of wave frequency. In the frequency range between 0.6 Hz and 1.1 Hz, a linear relationship exists between the wave elevations and the deformations. The average phase difference between the wave elevation and out-of-plane deformation is 60A degrees with waves leading and the phase between the wave elevation and in-plane deformation is 10A degrees with waves lagging. In addition, the effect of fish net on the elastic response is analyzed. The results suggest that the deformation of the floating collar with fish net is a little larger than that without net.