Session: 12-01-01 Blue Economy I

Submission Number: 156523

Short-Term Distribution and Variability of Fish Cage Responses Under Irregular Waves 

This paper will investigate the short-term variability of fish cage response in irregular waves. The finite element method-based software package AquaSim is used to simulate the hydroelastic response of the fish cage, where the floating collar is modelled as beam elements, the mooring line is modelled as truss elements, and the fish net is modelled as membrane elements. A set of irregular wave series is generated by the JONSWAP wave spectrum, and the response samples are extracted using the zero up-crossing technique. Statistical tests indicate that the responses of mooring load and collar stress can be better described by the 3-parameter Weibull distribution. However, since the floating collar oscillates associated with the waves, the motion of the collar can be still described by the Rayleigh distribution. Two methods are proposed to determine the short-term variability of cage response. The first method directly determines the maximum response distribution by the response distribution. The second method generates the maximum response samples through Monte Carlo simulation and fits the data distribution using the generalized extreme value distribution. The study found that the Monte Carlo method has better fitting performance, but is heavily dependent on the data performance of the generated samples. This study provides a valuable reference for engineers when performing hydro-structure calculations of fish cages.

Presenting Author: Mingyuan Ma Griffith University

Presenting Author Biography: Dr. Mingyuan Ma is a Research Fellow at the Cities Research Institute at Griffith University with a background in civil and ocean engineering. His research interests focus on wave hydrodynamics, computational fluid dynamics, offshore floating structures, marine aquaculture and metocean data modelling.