Freak Wave Events Within the Second Order Wave Model

Bitner‐Gregersen, Elzbieta M.; Hagen, Øistein

doi:10.1115/omae2004-51410

Cited by 12 publications

(9 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Sea states with increasing wave steepness, k p H s /2, in which rogue waves occurred in nature (see Reference [26]), were used in simulations, assuming a unidirectional wave field. For completion, two additional sea states with k p H s /2 = 0.13, 0.14, were also included.…”

Section: Set-up Of Numerical Simulationsmentioning

confidence: 99%

Challenges in Description of Nonlinear Waves Due to Sampling Variability

Bitner‐Gregersen

Gramstad

Magnusson

et al. 2020

JMSE

Self Cite

View full text Add to dashboard Cite

Wave description is affected by several uncertainties, with sampling variability due to limited number of observations being one of them. Ideally, temporal/spatial wave registrations should be as large as possible to eliminate this uncertainty. This is difficult to reach in nature, where stationarity of sea states is an issue, but it can in principle be obtained in laboratory tests and numerical simulations, where initial wave conditions can be kept constant and intrinsic variability can be accounted for by changing random seeds for each run. Using linear, second-order, and third-order unidirectional numerical simulations, we compare temporal and spatial statistics of selected wave parameters and show how sampling variability affects their estimators. The JONSWAP spectrum with gamma peakedness parameters γ = 1, 3.3, and 6 is used in the analysis. The third-order wave data are simulated by a numerical solver based on the higher-order spectral method which includes the leading-order nonlinear dynamical effects. Field data support the analysis. We demonstrate that the nonlinear wave field including dynamical effects is more sensitive to sampling variability than the second-order and linear ones. Furthermore, we show that the mean values of temporal and spatial wave parameters can be equal if the number of simulations is sufficiently large. Consequences for design work are discussed.

show abstract

Section: Set-up Of Numerical Simulationsmentioning

confidence: 99%

Challenges in Description of Nonlinear Waves Due to Sampling Variability

Bitner‐Gregersen

Gramstad

Magnusson

et al. 2020

JMSE

Self Cite

View full text Add to dashboard Cite

show abstract

“…However, the question arises as to why exceptionally large waves occur in the open ocean away from nonuniform currents or a special type of bathymetry? During the last 30 years, various mathematical models of freak wave phenomena have been developed and many laboratory experiments conducted, so that great progress has been achieved in the understanding of the physical mechanisms involved (Dysthe 1979, Lo & Mei 1985, Trulsen & Dysthe 1997, Onorato et al 2000, 2001, Kharif & Pelinovsky 2003, Kurkin & Pelinovsky 2004, Bitner-Gregersen & Hagen 2004. In particular, the following mechanisms, based on the linear or non-linear description of wave mechanics, are the principal potential sources of extreme wave generation: dispersion enhancement of transient wave groups, spatial focusing of waves, wavecurrent interaction.…”

Section: Development Of Extreme Wavesmentioning

confidence: 99%

Morphological, genetic, chemical and ecophysiological characterisation of two Microcystis aeruginosa isolates from the Vistula Lagoon, southern Baltic

Mazur‐Marzec¹,

Browarczyk-Matusiak²,

Forycka³

et al. 2010

OCEANOLOGIA

View full text Add to dashboard Cite

The motion of water due to surface waves is the most dynamic factor observed in the marine environment. In this review various aspects of the wave modelling of non-linear, steep surface waves and their role in the atmosphere-ocean interaction are discussed. Significant improvements in wave forecasting have been made in the last ten years. This is to a large extent related to substantial progress in the description of wind forcing and other processes, as well as to the more efficient use of satellite observations and assimilation methods. One striking observation is the increasing variety and complexity of models in which more physical processes are implemented, greater precision and resolution achieved and extended ranges of applicability demonstrated. However, in order to evaluate the applicability of particular models, comparison with high quality experimental data, collected in nature or under laboratory conditions, is necessary. Notation lista -wave amplitude, constant a 1 -functionThe complete text of the paper is available at http://www.iopan.gda.pl/oceanologia/

show abstract

“…[1], Magnusson et al [2], Bitner-Gregersen and Magnusson [3], Krogstad et al [4], Kharif et al [5]). The most famous measurement is perhaps the Draupner wave, also called Newyear wave (Haver and Andersen [6]) measured on Jan. 1, 1995 from the Draupner platform operated by Statoil in the North Sea.…”

Section: Introductionmentioning

confidence: 98%

The Andrea Wave Characteristics of a Measured North Sea Rogue Wave

Magnusson

Donelan

2013

Journal of Offshore Mechanics and Arctic Engineering

View full text Add to dashboard Cite

Wave profiles have been measured with a system of four Optech lasers mounted on a bridge at the oil production site Ekofisk in the central North Sea since 2003, operated by ConocoPhitlips. A double rogue wave was measured on Nov. 9, 2007 in a storm crossing the North Sea and named Andrea following a forecasting procedure betM>een the Norwegian Meteorological Institute and ConocoPhillips. This wave, named here the "Andrea wave," is comparable in height and characteristics to the well known Newyear wave (or Draupner wave) measured in 1995 by Statoil. Front steepness is higher. That the same profile is measured by all four lasers is a good indication that the shape of the wave has been captured correctly, but one may still ask if this crest is that of blue, green, or white water. That is, how much of the height is related to presence of foam or sea spray? We attempt to answer this using the information of intensity of the return signals, which has been related to wave breaking and sea spray in recent studies by Toffoli et al. (2011, "Estimating Sea Spray with a Laser Altimeter," J. Atmos. Oceanic Technol., 28(9), pp. 1177-1183. Measurements of the average intensity of the return signal do not indicate presence of sea spray in the incoming part of the wave, but high intensity of return after the passage of the crest indicates presence of sea spray or foam on the parts of the waves exposed to winds. Cameras following the sea surface at measuring position with information on the return signal as given here would most probably increase our understanding of what is measured. Exceedance probability of crests and heights show a deviation from the second order distribution as given by Forristall (2000, "Wave Crests Di.stributions: Observations and Second-Order Theory," J. Phys. Oceanogr. 30(8), pp. 1931-1943 for the one percent highest waves in an apparently stable 3 h period including the Andrea wave. The deviation already starts at crestlHsfactors around 1.0.

show abstract

Freak Wave Events Within the Second Order Wave Model

Cited by 12 publications

References 0 publications

Challenges in Description of Nonlinear Waves Due to Sampling Variability

Challenges in Description of Nonlinear Waves Due to Sampling Variability

Morphological, genetic, chemical and ecophysiological characterisation of two Microcystis aeruginosa isolates from the Vistula Lagoon, southern Baltic

The Andrea Wave Characteristics of a Measured North Sea Rogue Wave

Contact Info

Product

Resources

About