Quantitative prediction of the freak wave occurrence probability in co-propagating mixed waves

Wang, Lei; Ding, Kanglixi; Zhou, Binzhen; Li, Jinxuan; Liu, Shuxue; Tang, Tianning

doi:10.1016/j.oceaneng.2023.113810

Cited by 10 publications

(3 citation statements)

References 22 publications

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“…4 in Ref. [41]), and at least 5000 waves are ensured to be effectively collected by all gauges in each wave configuration.…”

Section: Please Cite This Article Asmentioning

confidence: 99%

Nonlinear statistical characteristics of the multi-directional waves with equivalent energy

Wang,

Ding,

Zhou

et al. 2023

Physics of Fluids

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Directional distribution is believed to have a significant impact on the statistical characteristics in multi-directional sea states. In real sea states, short-crested waves are discrete not only in frequency but also in direction. For the former one, they are well explained in unidirectional mode, but for the latter one, they are not. In this paper, the kurtosis of short-crested waves with equivalent energy is first discussed. Unimodal-spectrum-multi-direction sea states and bimodal-spectrum-multi-direction sea states are simulated for a long time in a numerical wave basin based on the high-order spectral method. In the equivalent sea-swell sea state, the spatial evolution of kurtosis becomes more inhomogeneous, along with the maximum value of kurtosis being larger and the area where the maximum value occurs wider in the configuration with a crossing angle β = 40° than that with β = 0°, while little variations in swell-dominated and wind-sea-dominated states. A positive linear correlation between wavelet group steepness and kurtosis is obtained in a unimodal sea state, but not applied to a crossing sea state characterized by a bimodal spectrum. The exceedance probability of wave height and wave crest distribution at maximum kurtosis is also given. These findings can help predict the probability of extreme waves occurring, guiding the selection of ocean engineering sites to avoid extreme configurations.

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“…4 in Ref. [41]), and at least 5000 waves are ensured to be effectively collected by all gauges in each wave configuration.…”

Section: Please Cite This Article Asmentioning

confidence: 99%

Nonlinear statistical characteristics of the multi-directional waves with equivalent energy

Wang,

Ding,

Zhou

et al. 2023

Physics of Fluids

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“…The aforementioned studies were mainly focused on unimodal waves (i.e., a sea state with only one peak in the frequency spectrum, corresponding to the behavior of a single-wave-group). However, in a real sea state, wave usually exhibits bimodal behaviors (i.e., a sea state with two peaks in the frequency spectrum, corresponding to the behavior of a double-wave-group), composed of wind-sea (with higher peak frequency) and swell (with lower peak frequency) [21] [22], which was also pointed out to be likely to generate extreme waves [23]. Although the physical mechanism of double-wave-group focusing, containing interactions within single-wave-group and those between wave groups, was investigated in our previous work (see Appendix D with the square and circular valves in Fig.…”

Section: Introductionmentioning

confidence: 99%

Influence of uniform currents on nonlinear characteristics of double-wave-group focusing

Zhou,

Ding,

Huang

et al. 2024

Physics of Fluids

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Current is considered to be a crucial environmental factor in producing extreme waves. The study of nonlinear characteristics in wave–current interactions has been explored, but the role of currents in the more complex interaction processes of double-wave-group focusing is not yet known. Based on our previous research about the nonlinear interactions between wave groups, the impact of uniform current on nonlinear characteristics of double-wave-group focusing is to be investigated in this paper. A fully nonlinear numerical model using the high-order spectral method is developed to simulate various currents interacting with focused bimodal waves. Three ranges of variation exist: strongly opposing current, weakly opposing current, and following current. Unlike the conclusion in the unimodal waves, the asymmetries of the wave crest and that of the wave envelope influenced by currents are not synchronous, which is explained by the changes in the asymmetry of the secondary crests received energy from the currents, in addition to those of the magnitude of the maximum crest and the adjacent secondary crests. When opposing currents enhance to a certain level, a dynamic equilibrium between the energy of waves and currents would be achieved, in which the proportion of the linear components to their own is almost equivalent to that in the non-current state, revealing that the majority of nonlinearity generated by wave–current interaction is blocked at that time. These findings can promote an understanding of nonlinear characteristics due to wave–current interactions.

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“…In addition to theoretical predictions, traditional numerical methods were also available, such as the commonly used high-order spectral method [15]. Taking full nonlinearity into account, the numerically simulated results were closer to real values, but they took a long time to simulate and process [16,17]. The above methods could neither quickly nor accurately predict the occurrence probability of freak waves under a given application.…”

Section: Introductionmentioning

confidence: 99%

Prediction of the Occurrence Probability of Freak Waves in Unidirectional Sea State Using Deep Learning

Zhou,

Wang,

Ding

et al. 2023

JMSE

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Predicting extreme waves can foresee the hydrodynamic environment of marine engineering, critical for avoiding disaster risks. Till now, there are barely any available models that can rapidly and accurately predict the occurrence probability of freak waves in a given state. This paper develops a trained model based on the Back Propagation (BP) neural network, with wave parameters of unidirectional sea state fed into the model, such as significant wave height, wave period, spectral type, and the intermodal distance of the peak frequencies. A rapid and accurate model optimized for predicting the occurrence probability of freak waves in a unidirectional sea state, from unimodal to bimodal configuration, is achieved by iterating to reduce accumulation errors. Compared to the regression and least-squares boosting trees, the optimized model performs much better in accurately predicting the occurrence probability of freak waves. Irrespective of whether in unimodal or bimodal sea state, this optimized model is competitive in calculation accuracy compared to theoretical models such as Rayleigh prediction and MER prediction, improved by at least 41%. The established model based on the BP neural network can quickly predict the threshold of freak waves in a given sea state, guiding practical engineering applications.

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Quantitative prediction of the freak wave occurrence probability in co-propagating mixed waves

Cited by 10 publications

References 22 publications

Nonlinear statistical characteristics of the multi-directional waves with equivalent energy

Nonlinear statistical characteristics of the multi-directional waves with equivalent energy

Influence of uniform currents on nonlinear characteristics of double-wave-group focusing

Prediction of the Occurrence Probability of Freak Waves in Unidirectional Sea State Using Deep Learning

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