Identifying higher-order interactions in wave time-series
Reliable design and reanalysis of coastal and offshore structures requires, amongst other things, characterisation of extreme crest elevation corresponding to long return periods, and of the evolution of a wave in space and time conditional on an extreme crest. Extreme crests typically correspond to...
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ftulancaster:oai:eprints.lancs.ac.uk:133156 2023-08-27T04:06:41+02:00 Identifying higher-order interactions in wave time-series Ewans, K. Christou, M. Ilic, Suzana Jonathan, Philip 2019-11-01 application/pdf https://eprints.lancs.ac.uk/id/eprint/133156/ https://eprints.lancs.ac.uk/id/eprint/133156/1/EnsEA19OMAE.pdf https://doi.org/10.1115/OMAE2019-95378 en eng ASME https://eprints.lancs.ac.uk/id/eprint/133156/1/EnsEA19OMAE.pdf Ewans, K. and Christou, M. and Ilic, Suzana and Jonathan, Philip (2019) Identifying higher-order interactions in wave time-series. In: Proceedings of the ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering OMAE2019 June 9-14, 2019, Glasgow, Scotland. ASME, GBR. ISBN 9780791858783 Contribution in Book/Report/Proceedings PeerReviewed 2019 ftulancaster https://doi.org/10.1115/OMAE2019-95378 2023-08-03T22:35:29Z Reliable design and reanalysis of coastal and offshore structures requires, amongst other things, characterisation of extreme crest elevation corresponding to long return periods, and of the evolution of a wave in space and time conditional on an extreme crest. Extreme crests typically correspond to focussed wave events enhanced by wave-wave interactions of different orders. Higher-order spectral analysis can be used to identify wave-wave interactions in time-series of water surface elevation. The bispectrum and its normalised form (the bicoherence) have been reported by numerous authors as a means to characterise three-wave interactions in laboratory, field and simulation experiments. The bispectrum corresponds to a frequency-domain representation of the third order cumulant of the time-series, and can be thought of as an extension of the power spectrum (itself the frequency-domain representation of the second order cumulant). The power spectrum and bispectrum can both be expressed in terms of the Fourier transforms of the original time-series. The Fast Fourier transform (FFT) therefore provides an efficient means of estimation. However, there are a number of important practical considerations to ensuring reasonable estimation. To detect four-wave interactions, we need to consider the trispectrum and its normalised form (the tricoherence). The trispectrum corresponds to a frequency-domain (Fourier) representation of the fourth-order cumulant of the time-series. Four-wave interactions between Fourier components can involve interactions of the type where f1 + f2 + f3 = f4 and where f1 + f2 = f3 + f4, resulting in two definitions of the trispectrum, depending on which of the two interactions is of interest. We consider both definitions in this paper. Both definitions can be estimated using the FFT, but it’s estimation is considerably more challenging than estimation of the bispectrum. Again, there are important practicalities to bear in mind. In this work, we consider the key practical steps required to correctly ... Text Arctic Lancaster University: Lancaster Eprints Volume 3: Structures, Safety, and Reliability |
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Reliable design and reanalysis of coastal and offshore structures requires, amongst other things, characterisation of extreme crest elevation corresponding to long return periods, and of the evolution of a wave in space and time conditional on an extreme crest. Extreme crests typically correspond to focussed wave events enhanced by wave-wave interactions of different orders. Higher-order spectral analysis can be used to identify wave-wave interactions in time-series of water surface elevation. The bispectrum and its normalised form (the bicoherence) have been reported by numerous authors as a means to characterise three-wave interactions in laboratory, field and simulation experiments. The bispectrum corresponds to a frequency-domain representation of the third order cumulant of the time-series, and can be thought of as an extension of the power spectrum (itself the frequency-domain representation of the second order cumulant). The power spectrum and bispectrum can both be expressed in terms of the Fourier transforms of the original time-series. The Fast Fourier transform (FFT) therefore provides an efficient means of estimation. However, there are a number of important practical considerations to ensuring reasonable estimation. To detect four-wave interactions, we need to consider the trispectrum and its normalised form (the tricoherence). The trispectrum corresponds to a frequency-domain (Fourier) representation of the fourth-order cumulant of the time-series. Four-wave interactions between Fourier components can involve interactions of the type where f1 + f2 + f3 = f4 and where f1 + f2 = f3 + f4, resulting in two definitions of the trispectrum, depending on which of the two interactions is of interest. We consider both definitions in this paper. Both definitions can be estimated using the FFT, but it’s estimation is considerably more challenging than estimation of the bispectrum. Again, there are important practicalities to bear in mind. In this work, we consider the key practical steps required to correctly ... |
format |
Text |
author |
Ewans, K. Christou, M. Ilic, Suzana Jonathan, Philip |
spellingShingle |
Ewans, K. Christou, M. Ilic, Suzana Jonathan, Philip Identifying higher-order interactions in wave time-series |
author_facet |
Ewans, K. Christou, M. Ilic, Suzana Jonathan, Philip |
author_sort |
Ewans, K. |
title |
Identifying higher-order interactions in wave time-series |
title_short |
Identifying higher-order interactions in wave time-series |
title_full |
Identifying higher-order interactions in wave time-series |
title_fullStr |
Identifying higher-order interactions in wave time-series |
title_full_unstemmed |
Identifying higher-order interactions in wave time-series |
title_sort |
identifying higher-order interactions in wave time-series |
publisher |
ASME |
publishDate |
2019 |
url |
https://eprints.lancs.ac.uk/id/eprint/133156/ https://eprints.lancs.ac.uk/id/eprint/133156/1/EnsEA19OMAE.pdf https://doi.org/10.1115/OMAE2019-95378 |
genre |
Arctic |
genre_facet |
Arctic |
op_relation |
https://eprints.lancs.ac.uk/id/eprint/133156/1/EnsEA19OMAE.pdf Ewans, K. and Christou, M. and Ilic, Suzana and Jonathan, Philip (2019) Identifying higher-order interactions in wave time-series. In: Proceedings of the ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering OMAE2019 June 9-14, 2019, Glasgow, Scotland. ASME, GBR. ISBN 9780791858783 |
op_doi |
https://doi.org/10.1115/OMAE2019-95378 |
container_title |
Volume 3: Structures, Safety, and Reliability |
_version_ |
1775347513106104320 |