The 12th International Conference on Hydrodynamics
18 – 23 september 2016, Egmond aan Zee, The Netherlands
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EXPERIMENTAL STUDY OF FREAK WAVE FORMATION IN IRREGULAR WAVE TRAINS PROPAGATING IN WATER OF CONSTANT DEPTH


Go-down ichd2016 Tracking Number 133

Presentation:
Session: Linear and-linear waves III
Room: Room 1
Session start: 10:30 Wed 21 Sep 2016

Maciej Paprota   mapap@ibwpan.gda.pl
Affifliation:

Wojciech Sulisz   sulisz@ibwpan.gda.pl
Affifliation:


Topics: - Linear and non-linear waves and current, - Ocean and atmosphere dynamics

Abstract:

ABSTRACT Laboratory experiments were conducted to study a formation of freak waves in irregular wave trains propagating in water of constant depth. The experiments were conducted in a wave flume at the water depth of 0.3 m. Irregular waves were generated by a programmable wavemaker. A JONSWAP wave spectrum and a random phases method were applied to compose irregular wave trains. The wave steepness is modified by multiplying the calculated wavemaker paddle displacement by an amplification factor. Resistant-type wave gauges installed along the wave flume were used to record free-surface oscillations. The application of a common definition of a freak wave of height exceeding twice the significant wave height resulted in a considerable number of wave cases for which the freak wave was registered. The results show that typical wave parameters including significant wave height, peak period, mean wave direction, etc. are sufficient to describe a sea state for engineering applications [1]. However, these parameters cannot be applied to predict freak waves. A detailed analysis confirms that typical wave parameters are rather of limited applicability in the studies of extreme waves and wave events. In order to study the freak wave phenomenon and the complex nature of extreme waves, a wide set of tools was applied to obtain spectral and statistical parameters of freak-wave-prone sea states. ACKNOWLEDGEMENTS Financial support for this study was provided by the National Science Centre, Poland, and the Institute of Hydro-Engineering of the Polish Academy of Sciences in Gdańsk, Poland, under the contract No. UMO-2012/05/13/ST8/01833. REFERENCES [1] W. Sulisz, M. Paprota, "Analysis of wave parameters in extreme wave records", Proc. of the 12th International Congress of the International Maritime Association of the Mediterrenean, Lisbon, Portugal, Vol. 2, pp. 1153-1158 (2015)