Nonlinear Evolution of a Steep, Focusing Wave Group in Deep Water Simulated with OceanWave3D

Dylan Barratt*, Harry B. Bingham, Thomas A. A. Adcock

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review

Abstract

Steep, focusing waves can experience fast and local nonlinear evolution of the spectrum due to wave-wave interactions resulting in energy transfer to both higher and lower wavenumber components. The shape and kinematics of a steep wave may, thus, differ substantially from the predictions of linear theory. We have investigated the role of nonlinear interactions on group-shape for a steep, narrow-banded, directionally-spread wave group focusing in deep water using the fully-nonlinear potential flow solver, OceanWave3D. Exact second-order correction of the initial conditions has been implemented together with a novel third-order approximate correction based on a Stokes-type formulation for surface elevation combined with a scaling-argument for the third-order velocity potential. Four-phase separation reveals that the third-order scheme provides a good estimate for the third-order superharmonics. A quantitative assessment of numerical error has also been performed for the spatial and temporal discretization, including energy conservation, a reversibility check and validation against previous simulations performed with a higher-order spectral (HOS) code. The initially narrow-banded amplitude spectrum exhibits the formation of sidelobes at angles of approximately ±35° to the spectral peak during the simulated extreme wave event, occurring in approximately 10 wave periods, with a preferential energy transfer to high-wavenumber components. The directional energy transfer is attributed to resonant third-order interactions with a discussion of the engineering implications.
Original languageEnglish
Title of host publicationProceedings of the ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering
Number of pages12
Volume Volume 7B: Ocean Engineering
PublisherAmerican Society of Mechanical Engineers
Publication date2019
Article numberOMAE2019-95299
ISBN (Print)978-0-7918-5885-1
DOIs
Publication statusPublished - 2019
EventASME 38th International Conference on Ocean, Offshore and Arctic Engineering - Glasgow, United Kingdom
Duration: 9 Jun 201914 Jun 2019
https://event.asme.org/OMAE2019

Conference

ConferenceASME 38th International Conference on Ocean, Offshore and Arctic Engineering
CountryUnited Kingdom
CityGlasgow
Period09/06/201914/06/2019
Internet address

Keywords

  • Nonlinear wave mechanics
  • Directional energy transfers, wing waves
  • OCEANWAVE3D

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