Melam - Methods for Large Amplitude Ship Motions in Waves

Large amplitude roll motions have been identified as a problem for modern container and RoRo ships. Large motions have been reported not only for head or following sea which may lead to parametric excited roll motion, but also for varying encounter angles in sea states that are not extreme. It is suggested that the wave amplitude variation in time is important for the occurrence of large amplitude motions. Two wave trains of the same sea state may lead to different motions. One wave train may lead to critical amplitude motions while other wave trains do not.

It is expected that nonlinear effects will become important for the large amplitude motions that may occur. An accurate representation of the hull and the free-surface is therefore of importance for the analysis. A time domain nonlinear 3-dimensional free-surface model will therefore be developed. The development will be based on a well validated existing nonlinear free-surface potential flow model for steady flow. The existing model will be extended to handle incoming and outgoing waves.

Project member outside Chalmers:

  • Giorgio Contento, University of Trieste
University of Trieste (Trieste, Italy)

Published: Wed 13 Apr 2016.