Limiting operational conditions for a well boat

PhD-student: Yugao Shen

Supervisors: Professor Marilena Greco

Duration: 08 2013 – 11 2018


This study focuses on the operational limits of floating-collar  fish farms in waves and current, and examines also the influence of  the well boat when it operates at the fish farm.

Dynamic response of a floating circular collar-type  fish farm, without and with well-boat presence, in current, regular and irregular waves is analyzed.  A modern design well boat and a realistic fish farm (with single cage) are considered. The latter comprises a floating collar, an elastic sinker tube, a flexible-closed net cage and a complex mooring system. The main purpose is to determine the operational conditions for the isolated  fish farm and for the well boat-fish farm system.

A time-domain numerical solver for the fish farm, without and with well-boat presence,  is developed with the different components modeled with the state-of-the-art theoretical and numerical formulations.

The operational limits of the fish farm are determined through systematic simulations in regular waves and current, indicating that the net volume reduction is the main constraint preventing the studied  fish farm operating in more exposed regions.

Systematic simulations are also performed to determine the operational conditions of the coupled system, considering long-crested irregular waves and current.  Numerical results show that the maximum stress in the floating collar can be close to the yield stress when the system operates in moderate exposure sea states, thus it should be of major concern.

  • Shen, Y.-G., Greco, M. and Faltinsen, O. M. (2018a), Numerical study of a well boat operating at a  fish farm in current. J. Fluid. Struct, accepted
  • Shen, Y.-G., Greco, M. and Faltinsen, O. M. (2018b), Numerical study of a well boat operating at a  fish farm in long-crested irregular waves and current. J. Fluid. Struct, accepted.
  • Shen, Y.-G., Greco, M., Faltinsen, O. M., Nygaard, I., (2018c), Numerical and experimental investigations on mooring loads of a marine fish farm in waves and current. J. Fluid. Struct 79, 115-136.
  • Faltinsen, O. M., Shen, Y.-G., (2018d), Wave and current effects on floating fish farms.  J. Marine. Sci. Appl. (2018). https://doi.org/10.1007/s11804-018-0033-5.