A discrete correction scheme for envelope approach of wave group statistics
Guizheng, Z.; Xuren, H.; Delun, X. (2004). A discrete correction scheme for envelope approach of wave group statistics. : 225-230
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Authors | | Top |
- Guizheng, Z.
- Xuren, H.
- Delun, X.
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Abstract |
The existence of empty envelope excursions (EEE) brings error to the envelope approach of wave group statistics, whichidentifies wave group by envelope upcrossing of a critical level. A group number correction scheme is suggested in this paper toexclude EEE from wave group statistics. To this end, the Ditlevson and Lindgren [J. Sound Vib. 122 (1988) 571] theory aboutthe fraction of empty excursion envelopes (FEEE) is examined to see if it fits for ocean waves. The sea waves are simulatedwith Monte Carlo method and with P-M and JONSWAP spectrums. The values of FEEE of the simulated waves areinvestigated and compared with the theory of Ditlevson and Lindgren. The comparison shows that, at the second-orderapproximation, theoretical predictions of FEEE are close to those derived from simulations. This approximate analyticalexpression of FEEE is then employed to form a group number correction scheme. Comparisons between numerical andtheoretical results of wave group properties show that this correction scheme is quite effective. |
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