Surface wave scattering by multiple flexible fishing cage system

Abstract

A study of the wave dynamics around a multiple cylindrical fishing cage system is carried out under the assumption of linear water wave theory and small-amplitude wave response. The Fourier-Bessel series expansion of the velocity potential is derived for the regions enclosed under the open-water and cage systems and the immediate vicinity. The scattering between the cages is accounted for by employing Graf's addition theorem. The porous flexible cage system is modeled using Darcy's law and the three-dimensional membrane equation. The edges of the cages are moored along their circumferences to balance its position. The unknown coefficients in the potentials are obtained by employing the matched eigenfunction method. In addition, the far-field scattering coefficients for the entire system are obtained by expanding the Bessel and Hankel functions in the plane wave representation form. Numerical results for the hydrodynamic forces, scattering coefficients, and power dissipation are investigated for various cage and wave parameters. The time simulation for the wave scattering from the cage system is investigated. The study reveals that wave loading on the cage system can be significantly reduced by the appropriate spatial arrangement, membrane tension, and porous-effect parameter. Moreover, the far-field results suggest that the cage system can also be used as a breakwater.

Water wave scattering by impermeable and perforated plates

“…In marine engineering, thin plates are attached to Spar platforms to provide extra added mass and damping so that violent wave-frequency heave resonance is avoided (Molin, 2011). Fixed and floating breakwaters are usually equipped with perforated plates to attenuate waves in coastal engineering (Huang, Li, and Liu, 2011;Behera and Sahoo, 2015;Selvan et al, 2021). In offshore renewable energy, piezoelectric and perforated disks (Renzi, 2016;Meylan, Bennetts, and Peter, 2017;Zheng et al, 2020b,a) as well as flap-type wave energy converters (WECs) (Renzi and Dias, 2012;Sarkar, Renzi, and Dias, 2014) have huge potential for wave-power extraction.…”

Wave power extraction from a floating elastic disk-shaped wave energy converter

“…Additionally, the wave scattering of porous elastic plates was studied, but not extensively, e.g. see Behera & Sahoo (2015), Koley, Mondal & Sahoo (2018) and Selvan et al (2021).…”

“…Later, Williams & Meylan (2012) extensively, e.g. see Behera & Sahoo (2015), Koley, Mondal & Sahoo (2018) and Selvan et al (2021).…”

A Semi-Analytical Model for Studying Hydroelastic Behaviour of a Cylindrical Net Cage under Wave Action

“…The transverse displacement of the circular cage is assumed to be governed by the vibration equation of the elastic beam in [19,20], and the deflection of the horizontal net plate can be described by the twodimensional membrane vibration equation, which was introduced by [21]. Selvan et al [22] extend the theory of [21] to the interference effect of multiple cages. Furthermore, Guo et al [23] present a detailed review about the mathematical modelling of wave interaction with flexible net-type structures.…”

“…Secondly, fish net cages may be designed with submerged capabilities to avoid strong surface waves. However, the above analytical models from [20][21][22] do not consider this scenario. Thirdly, for the net cage exposed to a wave field, knowledge about its hydroelastic behaviours is scarce.…”