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 language | English |
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Title of host publication | Proceedings of the ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering |
Number of pages | 12 |
Volume | Volume 7B: Ocean Engineering |
Publisher | The American Society of Mechanical Engineers (ASME) |
Publication date | 2019 |
Article number | OMAE2019-95299 |
ISBN (Print) | 978-0-7918-5885-1 |
DOIs | |
Publication status | Published - 2019 |
Event | ASME 38th International Conference on Ocean, Offshore and Arctic Engineering - Glasgow, United Kingdom Duration: 9 Jun 2019 → 14 Jun 2019 Conference number: 38 https://event.asme.org/OMAE2019 |
Conference
Conference | ASME 38th International Conference on Ocean, Offshore and Arctic Engineering |
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Number | 38 |
Country/Territory | United Kingdom |
City | Glasgow |
Period | 09/06/2019 → 14/06/2019 |
Internet address |
Keywords
- Nonlinear wave mechanics
- Directional energy transfers, wing waves
- OCEANWAVE3D