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

This paper will investigate the short-term distribution and variability of fish cage responses under irregular waves. The finite element method-based software package AquaSim is used to simulate the hydroelastic response of a gravity-type fish cage. A set of irregular wave series is generated by the P-M wave spectrum, and the response cycle samples are extracted using the zero up-crossing technique. Four candidate probabilistic distribution models were examined for their goodness-of-fit to the response samples, and the variability of the maximum response under given sea conditions was quantitatively analyzed. The results indicate that the GEV distribution is suitable for fitting most mooring force response samples, while the Weibull distribution is better to describe the stress response and vertical displacement response of the floating collar in most cases. Compared to the design method based on regular waves, the maximum response of fish cages under irregular waves exhibits significant uncertainty, highlighting the need to consider short-term variability. These findings contribute to the safe design of fish cages.