A comparison of abnormal wave generation techniques for experimental modelling of abnormal wave-vessel interactions

• Main Authors: Bennett, S.S (Author), Hudson, D.A (Author), Temarel, P. (Author)
• Format: Article
• Language: English
• Published: 2012-09.
• Subjects: Article
• Online Access: Get fulltext

 The ability to model abnormal waves in an accurate and repeatable manner is important in order to achieve the objective of assessing vessel response in such conditions. Although techniques for the practical generation of abnormal waves are readily available in literature, no comparison of their suitability to modelling abnormal waves experimentally is available. The purpose of this paper is to provide such a comparison. Identified techniques are the NewWave, constrained NewWave and optimised sea, all based on sea spectra. A particular focus is the usefulness of each technique for modelling a travelling vessel encountering an abnormal wave. Experimental results are presented for each model compared to linear and second order wave theories, and the quality of results is assessed using an uncertainty analysis. Results demonstrate the constrained NewWave is highly repeatable, but suffers from discrepancies in the time domain when compared to predicted profiles. In order to generate a known wave profile, the NewWave or optimisation techniques appear the most suitable. Of these, NewWave should be used if only the local (abnormal) wave profile is required. To model a realistic scenario including the response history of a vessel, the optimised sea should be applied.