Journal of Ocean Engineering and Science

Volume 4, Issue 2

(3)Generation of rogue waves at model scale

Bailey Groves, Nagi Abdussamie ^∗

National Centre for Maritime Engineering and Hydrodynamics, Australian Maritime College, University of Tasmania, Launceston, Tasmania, Australia

Received 7 September 2018; received in revised form 9 February 2019; accepted 9 February 2019

Available online 16 February 2019

Abstract

The study of rogue waves is becoming increasingly important, as the offshore oil and gas, as well as renewable energy industries, expand. The unpredictability of such disastrous waves poses a signiﬁcant risk to ﬂoating and ﬁxed structures, making it necessary to develop methods capable of recreating rogue waves for model testing purposes. In this paper, an investigation into the useability of the NewWave theory, a theoretical formula for producing focused waves, was conducted in model test facilities with a wavemaker. The numerical modelling of rogue waves was performed using MATLAB codes developed to create several types of wave packets. The success of the numerical generation of design rogue waves was dependent on the number of wave components used during construction such that a suitable rogue wave ( H max / Hs>2.0) could be created using 400 or more components. It was found that the NewWave technique could construct and physically generate design rogue waves within a close range of the predicted height provided the main wavemaker stroke was smooth enough (at around 0.8 s trough-crest for the tested model scale). The measured rogue waves were found to be complex; highly non-linear in amplitude with the behaviour of up to the 3rd order. Furthermore, it was observed that rogue waves, created based on a 100-year sea state, were very similar to the New Year Wave conﬁrming that such extreme waves, approximately 25–27 m high at full scale, can indeed occur in severe sea states. © 2019 Shanghai Jiaotong University. Published by Elsevier B.V.

This is an open access article under the CC BY-NC-ND license. (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Keywords: Rogue waves; Numerical modelling; Design rogue waves; Model testing; New Year Wave.