Faglige interesser
Bølgefenomener, spesielt overflatebølger på vann, havbølger og ekstreme bølger. Ved hjelp av deterministisk og stokastisk analyse, laboratorieeksperimenter, numeriske simuleringer og feltobservasjoner studeres ulike problemstillinger rundt bølger.
Oppslag om freake krefter på neddykkede rørbruer hos titan.uio.no og Teknisk ukeblad (september 2022).
Informasjon om bachelor
Presentasjon av studieretning FA:Fluidmekanikk (18. oktober 2022).
Informasjon om master
Undervisning
vår 2023: MEK4100 og delvis MEK4320
høst 2022: MEK4350 og delvis MEK3230
vår 2022: MEK4100
høst 2021: MEK4350
vår 2021: MEK4320
Emneord:
Mekanikk,
Fluidmekanikk,
ikkelineære bølger,
freakbølger
Publikasjoner
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Bitner-Gregersen, E. M.; Gramstad, Odin; Trulsen, Karsten; Magnusson, Anne Karin; Støle-Hentschel, Susanne & Aarnes, Ole Johan
[Vis alle 7 forfattere av denne artikkelen]
(2024).
Rogue waves: Results of the ExWaMar project.
Ocean Engineering.
ISSN 0029-8018.
292.
doi:
10.1016/j.oceaneng.2023.116543.
Fulltekst i vitenarkiv
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Rogue waves, also known as freak waves, have received much attention in the scientific community as well as in media and the marine industry in the past two decades. Forecasts of extreme weather events have always been welcomed by the marine industry. Therefore, the development of warning criteria for rogue waves, being scientifically challenging forecast products, has also been encouraged. Such criteria would help mariners avoid sea states where rogue waves occur. The paper summarizes the main findings of the Norwegian research project ExWaMar dedicated to development of improved warning criteria for extreme and rogue waves. Three approaches for warning criteria for extreme and rogue waves based on information provided by the weather forecast are proposed. They include use of integrated wave parameters, coupling of a phase-averaged wave spectral model and phase-resolving wave model and application of Machine Learning methodology. Challenges related to development of warning criteria for rogue waves are discussed.
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Lawrence, Christopher; Trulsen, Karsten & Gramstad, Odin
(2022).
Extreme wave statistics of surface elevation and velocity field of gravity waves over a two-dimensional bathymetry.
Journal of Fluid Mechanics.
ISSN 0022-1120.
939,
s. 1–18.
doi:
10.1017/jfm.2022.227.
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Lawrence, Christopher; Trulsen, Karsten & Gramstad, Odin
(2021).
Statistical properties of wave kinematics in long-crested irregular waves propagating over non-uniform bathymetry.
Physics of Fluids.
ISSN 1070-6631.
33.
doi:
10.1063/5.0047643.
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Experimental and numerical evidence have shown that nonuniform bathymetry may alter significantly the statistical properties of surface elevation in irregular wave fields. The probability of “rogue” waves is increased near the edge of the upslope as long-crested irregular waves propagate into shallower water. The present paper studies the statistics of wave kinematics in long-crested irregular waves propagating over a shoal with a Monte Carlo approach. High order spectral method is employed as wave propagation model, and variational Boussinesq model is employed to calculate wave kinematics. The statistics of horizontal fluid velocity can be different from statistics in surface elevation as the waves propagate over uneven bathymetry. We notice strongly non-Gaussian statistics when the depth changes abruptly in sufficiently shallow water. We find an increase in kurtosis in the horizontal velocity around the downslope area. Furthermore, the effects of the bottom slope with different incoming waves are discussed in terms of kurtosis and skewness. Finally, we investigate the evolution of kurtosis and skewness of the horizontal velocity over a sloping bottom in a deeper regime. The vertical variation of these statistical quantities is also presented.
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Støle-Hentschel, Susanne; Nieto Borge, Jose Carlos & Trulsen, Karsten
(2021).
The deconvolution as a method to deal with gaps in ocean wave measurements.
Ocean Engineering.
ISSN 0029-8018.
219.
doi:
10.1016/j.oceaneng.2020.108373.
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This work introduces the deconvolution as a technique to reconstruct missing information in data. While the method was originally developed for ocean waves, it will be useful in a wider range of applications where gaps in data may alter the statistics or spikes have to be eliminated without removing extreme values. For the application to ocean waves, it is estimated that gaps as long as half of the peak period may be reconstructed well. It is possible to reconstruct data of longer gaps, however, in total the amount of missing points should be less than 50% of all points and the missing data should not be clustered.
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Lawrence, Christopher; Gramstad, Odin & Trulsen, Karsten
(2020).
Variational Boussinesq model for kinematics calculation of surface gravity waves over bathymetry.
Wave motion.
ISSN 0165-2125.
100.
doi:
10.1016/j.wavemoti.2020.102665.
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Many of the widely used models for description of nonlinear surface gravity waves, in deep or shallow water, such as High Order Spectral Method (HOSM) and Boussinesq-type equations, rely on the elimination of the vertical coordinate from the basic three-dimensional Euler equations. From a numerical point of view such models are often computationally efficient, which is one of the main reasons that many such models are frequently used in studies on nonlinear surface waves.
While surface-based models provide the time-evolution of surface quantities, typically the surface elevation η and velocity potential at the surface φ , they do not directly provide the water particle kinematics in the fluid interior. However, in many practical applications information about the water-particle kinematics is crucial. The present paper presents a new method for the calculation of water-particle kinematics, from information about surface quantities. The presented methodology is a non-perturbative approach based on the fully nonlinear Variational Boussinesq model, and can be applied to wave propagation over both constant and variable water depth. The proposed method is validated on several cases, including Stokes waves, a solitary wave, and irregular waves over flat bottom. We have carried out new laboratory experiments of regular waves over a shoal with measurements of the horizontal velocity specifically taken for validation of the method. We also employ recent laboratory experiments for validation of statistical properties of wave kinematics of long crested irregular waves propagating over a shoal.
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Trulsen, Karsten; Raustøl, Anne; Jorde, Stian & Rye, Lisa Bæverfjord
(2020).
Extreme wave statistics of long-crested irregular waves over a shoal.
Journal of Fluid Mechanics.
ISSN 0022-1120.
882.
doi:
10.1017/jfm.2019.861.
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We report laboratory experiments of long-crested irregular water surface waves propagating over a shoal. For a sufficiently shallow shoal we find that the surface elevation can have a local maximum of skewness and kurtosis above the shallower part of the shoal close to the edge on the incoming side, and a local minimum of skewness over the downward slope on the lee side of the shoal. We find that the horizontal fluid velocity can have a local maximum and minimum of skewness at the same locations as those for the surface elevation. However, the kurtosis of the horizontal fluid velocity can have a local maximum over the downward slope on the lee side of the shoal, different from the location of the maximum of kurtosis of the surface elevation.
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Magnusson, Anne Karin; Trulsen, Karsten; Bitner-Gregersen, Elzbieta M.; Aarnes, Ole Johan & Malila, Mika Petteri
(2019).
“Three Sisters” Measured as a Triple Rogue Wave Group.
I ASME, . (Red.),
ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering. Volume 3: Structures, Safety, and Reliability.
The American Society of Mechanical Engineers (ASME).
ISSN 978-0-7918-5878-3.
doi:
%20https:/doi.org/10.1115/OMAE2019-96837.
Vis sammendrag
On November 30, 2018, our attention was caught when analyzing wave profile time series measured by a platform mounted wave sensor (a SAAB REX radar) at Ekofisk, central North Sea. The 20-minute time series had not only one, but three consecutive waves with individual heights that all were more than twice the significant wave height, the two last of them being almost equally high with a factor 2.35 to the significant wave height of 4m (from 4σ(η), over 20 minutes).
Counting three rogue waves in one sequence seems to be very rare. In this study we analyze how the shape is evolving in space and time using linear and non-linear propagation methods developed by Mark Donelan [1,2] and Karsten Trulsen [3,4]. Weather conditions and characteristics of the sea state with the ‘Three Sisters’ (named the “Justine Three Sisters”) are presented. It is found that the Three Sisters occurred in a crossing sea condition, with wind sea and swell coming from directions 60 degrees apart, with about same frequency, but very different energy.
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Støle-Hentschel, Susanne; Trulsen, Karsten; Rye, Lisa Bæverfjord & Raustøl, Anne
(2018).
Extreme wave statistics of counter-propagating, irregular, long-crested sea states.
Physics of Fluids.
ISSN 1070-6631.
30(6).
doi:
10.1063/1.5034212.
Fulltekst i vitenarkiv
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Støle-Hentschel, Susanne; Seemann, Jörg; Nieto Borge, Jose Carlos & Trulsen, Karsten
(2018).
Consistency between Sea Surface Reconstructions from Nautical X-Band Radar Doppler and Amplitude Measurements.
Journal of Atmospheric and Oceanic Technology.
ISSN 0739-0572.
35,
s. 1201–1220.
doi:
10.1175/JTECH-D-17-0145.1.
Fulltekst i vitenarkiv
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Trulsen, Karsten
(2018).
Rogue Waves in the Ocean, the Role of Modulational Instability, and Abrupt Changes of Environmental Conditions that Can Provoke Non Equilibrium Wave Dynamics.
I Velarde, Manuel G.; Tarakanov, Roman Yu. & Marchenko, Alexey V. (Red.),
The Ocean in Motion.
Springer.
ISSN 978-3-319-71934-4.
s. 239–247.
doi:
10.1007/978-3-319-71934-4_17.
Fulltekst i vitenarkiv
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Simanesew, Abushet; Krogstad, Harald E; Trulsen, Karsten & Nieto Borge, Jose Carlos
(2018).
Bimodality of directional distributions in ocean wave spectra: A comparison of data-adaptive estimation techniques.
Journal of Atmospheric and Oceanic Technology.
ISSN 0739-0572.
35(2),
s. 365–384.
doi:
10.1175/JTECH-D-17-0007.1.
Fulltekst i vitenarkiv
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Naaijen, Peter; Trulsen, Karsten & Blondel-Couprie, Elise
(2014).
Limits to the extent of the spatio-temporal domain for deterministic wave prediction.
International Shipbuilding Progress.
ISSN 0020-868X.
61(3-4),
s. 203–223.
doi:
10.3233/ISP-140113.
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Gramstad, Odin; Zeng, Huiming; Trulsen, Karsten & Pedersen, Geir Kleivstul
(2013).
Freak waves in weakly nonlinear unidirectional wave trains over a sloping bottom in shallow water.
Physics of Fluids.
ISSN 1070-6631.
25(12).
doi:
10.1063/1.4847035.
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Trulsen, Karsten; Zeng, Huiming & Gramstad, Odin
(2012).
Laboratory evidence of freak waves provoked by non-uniform bathymetry.
Physics of Fluids.
ISSN 1070-6631.
24(9).
doi:
10.1063/1.4748346.
Fulltekst i vitenarkiv
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Gramstad, Odin & Trulsen, Karsten
(2011).
Fourth-order coupled nonlinear Schrödinger equations for gravity waves on deep water.
Physics of Fluids.
ISSN 1070-6631.
23(6).
doi:
10.1063/1.3598316.
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Toffoli, Alessandro; Gramstad, Odin; Trulsen, Karsten; Monbaliu, Jaak; Bitner-Gregersen, Elzbieta & Onorato, Miguel
(2010).
Evolution of weakly nonlinear random directional waves: laboratory experiments and numerical simulations.
Journal of Fluid Mechanics.
ISSN 0022-1120.
664,
s. 313–336.
doi:
10.1017/S002211201000385X.
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Socquet-Juglard, Herve; Dysthe, Kristian; Trulsen, Karsten; Krogstad, Harald E. & Liu, Jingdong
(2005).
Probability distributions of surface gravity waves during spectral changes.
Journal of Fluid Mechanics.
ISSN 0022-1120.
542,
s. 195–216.
doi:
10.1017/S0022112005006312.
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Trulsen, Karsten
(2005).
Spatial evolution of water surface waves,
Fifth International Symposium on Ocean Wave Measurement and Analysis. WAVES 2005.
IAHR Secretariat.
ISSN 9078046023.
Vis sammendrag
Weakly nonlinear phase-resolving modeling of the spatial evolution of water surface wave trains is capable of predicting the deterministic evolution of long-crested waves over a substantial number of wavelengths. The extension of this capability to directionally distributed waves is discussed. Application to long wave tanks are given.
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Krogstad, Harald E; Liu, Jingdong; Socquet-Juglar, Herve; Dysthe, Kristian & Trulsen, Karsten
(2004).
Spatial Extreme Value Analysis of Nonlinear Simulations of Random Surface Waves.
I ASME, . (Red.),
23rd International Conference on Offshore Mechanics and Arctic Engineering, Volume 2.
The American Society of Mechanical Engineers (ASME).
ISSN 0-7918-3744-0.
doi:
10.1115/OMAE2004-51336.
Vis sammendrag
The paper first recalls the Slepian Model Representation and a theorem of V. I. Piterbarg as generic tools for analyzing the spatial characteristic of ocean waves. We then consider numerical simulations of random surface gravity waves carried out in space and time by means of the modified nonlinear Schrödinger equation. It is shown that the extreme waves in the simulations are steeper and more asymmetric than predicted by the Gaussian theory. Moreover, the reconstructed wave fields shows extreme crest heights well in excess of what is expected from the Gaussian theory.
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Trulsen, Karsten
(2003).
Real time deterministic ocean wave forecasting using weakly nonlinear wave evolution theory,
MekIT'03, Second national conference on Computational Mechanics, Trondheim 8-9 May 2003.
Tapir Akademisk Forlag.
ISSN 82-519-1868-5.
s. 371–390.
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Selezov, Igor; Avramenko, Olga; Kharif, Christian & Trulsen, Karsten
(2003).
High-order evolution equation for nonlinear wave-packet propagation with surface tension accounting.
Comptes rendus de l'Académie des sciences. Série IIb, Mécanique.
ISSN 1620-7742.
331,
s. 197–201.
doi:
10.1016/S1631-0721(03)00043-3.
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Trulsen, Karsten & Teigen, Per Steinar
(2002).
Wave scattering around a vertical cylinder: Fully nonlinear potential flow calculations compared with low order perturbation results and experiment,
21ST International Conference on Offshore Mechanics and Arctic Engineering.
American Society of Mechanical Engineers (ASME).
ISSN 0-7918-3599-5.
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Trulsen, Karsten & Stansberg, Carl Trygve
(2001).
Spatial evolution of water surface waves: Numerical simulation and experiment of bichromatic waves.
I Chung, Jin S.; Prevosto, Marc & Mizutani, Norimi (Red.),
The Proceedings of The Eleventh (2001) International Offshore and Polar Engineering Conference.
International Society of Offshore and Polar Engineers (ISOPE).
ISSN 1-880653-54-0.
s. 71–77.
Vis sammendrag
The modified nonlinear Schrödinger (MNLS) equation for spatial evolution of weakly nonlinear water surface waves is shown to yield good comparisons with experimental measurements of bichromatic waves in a long tank. While linear theory does not predict neither the phase velocity nor the evolution of the envelope well, the cubic nonlinear Schrödinger (NLS) equation improves the prediction of the phase velocity but not the modulation of the envelope. The MNLS equation predicts both the evolution of individual wave crests and the modulation of the envelope over longer fetch, and thus permits accurate forecasting of individual ocean wave crests over a fetch of several tens of wavelengths.
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Teigen, Per Steinar & Trulsen, Karsten
(2001).
Numerical investigation of nonlinear wave effects around multiple cylinders.
I Chung, Jin S.; Prevosto, Marc & Mizutani, Norimi (Red.),
The Proceedings of The Eleventh (2001) International Offshore and Polar Engineering Conference.
International Society of Offshore and Polar Engineers (ISOPE).
ISSN 1-880653-54-0.
s. 369–378.
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Trulsen, Karsten
(2001).
Simulating the spatial evolution of a measured time series of a freak wave.
I Olagnon, Michel & Athanassoulis, Gerassimos (Red.),
Rogue waves 2000.
Editions Ifremer.
ISSN 2-84433-063-0.
s. 265–273.
Vis sammendrag
Proceedings of a Workshop organized by Ifremer and held in Brest, France 29-30 November 2000 within the Brest SeaTechWeek 2000.
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Trulsen, Karsten; Gudmestad, Ove Tobias & Velarde, Manuel G.
(2001).
The nonlinear Schrödinger method for water wave kinematics on finite depth.
Wave motion.
ISSN 0165-2125.
33(4),
s. 379–395.
doi:
10.1016/S0165-2125(00)00077-9.
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Trulsen, Karsten; Kliakhandler, Igor L; Dysthe, Kristian & Velarde, Manuel G.
(2000).
On weakly nonlinear modulation of waves on deep water.
Physics of Fluids.
ISSN 1070-6631.
12(10),
s. 2432–2437.
doi:
10.1063/1.1287856.
Vis sammendrag
We propose a new approach for modeling weakly nonlinear waves, based on enhancing truncated amplitude equations with exact linear dispersion. Our example is based on the nonlinear Schrödinger (NLS) equation for deep-water waves. The enhanced NLS equation reproduces exactly the conditions for nonlinear four-wave resonance (the "figure 8" of Phillips) even for bandwidths greater than unity. Sideband instability for uniform Stokes waves is limited to finite bandwidths only, and agrees well with exact results of McLean; therefore, sideband instability cannot produce energy leakage to high-wave-number modes for the enhanced equation, as reported previously for the NLS equation. The new equation is extractable from the Zakharov integral equation, and can be regarded as an intermediate between the latter and the NLS equation. Being solvable numerically at no additional cost in comparison with the NLS equation, the new model is physically and numerically attractive for investigation of wave evolution.
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Trulsen, Karsten; Stansberg, Carl Trygve & Velarde, Manuel G.
(1999).
Laboratory evidence of three-dimensional frequency downshift of waves in a long tank.
Physics of Fluids.
ISSN 1070-6631.
11,
s. 235–237.
doi:
10.1063/1.869915.
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Trulsen, Karsten
(1999).
Wave Kinematics Computed With the Nonlinear Schrödinger Method for Deep Water.
Journal of Offshore Mechanics and Arctic Engineering.
ISSN 0892-7219.
121,
s. 126–130.
doi:
10.1115/1.2830077.
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Trulsen, Karsten; Temmos, Jean-Marc; Dysthe, Kristian; Gudmestad, Ove Tobias & Velarde, Manuel G.
(1998).
The Schrödinger method for water wave kinematics.
I Zhang, Jun (Red.),
Ocean wave kinematics, dynamics and loads on structures.
American Society of Civil Engineers.
ISSN 0-7844-0336-8.
s. 76–83.
Vis sammendrag
Proceedings of the 1998 international OTRC symposium, April 30-May 1, 1998, Houston, Texas.
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Trulsen, Karsten
(1998).
Crest pairing predicted by modulation theory.
Journal of Geophysical Research (JGR).
ISSN 0148-0227.
103(C2),
s. 3143–3147.
doi:
10.1029/97JC03284.
Vis sammendrag
Crest pairing of water surface waves is a consequence of linear dispe rsion alone and is predicted by the linear Schrodinger equation for t he slow evolution of a wave train. Linear theory also explains why cr est pairing is observed in front of a wave group. The role of nonline arity is to redistribute sufficient energy to the sidebands such that the linear dispersive mechanism can become effective. There is also quantitative agreement with experimental observations for the propaga tion of a wave group faster than the linear group velocity.
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Trulsen, Karsten & Dysthe, Kristian
(1997).
Water wave kinematics computed with nonlinear Schrödinger theory.
I Chakrabarti, Subrata; Kinoshita, T & Maeda, Hisaaki (Red.),
OMAE 1997: Proceedings of the 16th international conference on Offshore Mechanics and Arctic Engineering. Volume 1 - Part B.
The American Society of Mechanical Engineers.
ISSN 0-7918-1799-7.
s. 7–18.
Vis sammendrag
Presented at the 16th international conference on offshore mechanics and arctic engineering, Yokohama, Japan, April 13-17, 1997.
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Trulsen, Karsten & Dysthe, Kristian
(1997).
Freak waves - A three-dimensional wave simulation,
Twenty-First Symposium on Naval Hydrodynamics.
The National Academies Press.
ISSN 0-309-05879-1.
s. 550–560.
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Se alle arbeider i Cristin
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Magnusson, Anne Karin; Trulsen, Karsten; Bitner-Gregersen, Elzbieta M.; Aarnes, Ole Johan & Malila, Mika Petteri
(2019).
“Three Sisters” Measured as a Triple Rogue Wave Group.
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Simanesew, Abushet; Krogstad, Harald E; Trulsen, Karsten & Nieto Borge, Jose Carlos
(2015).
Frequency dependence of directional characteristics of ocean wave spectra.
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Trulsen, Karsten
(2013).
Bølgebeistene.
[Avis].
Aftenposten Junior.
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Gramstad, Odin & Trulsen, Karsten
(2008).
Can swell increase the number of freak waves in a wind-sea?
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Trulsen, Karsten
(2005).
Spatial evolution of directionally distributed water surface waves: numerical simulation and experiment.
Vis sammendrag
Weakly nonlinear phase-resolving modeling of the spatial evolution of water surface wave trains is capable of predicting the deterministic evolution of long-crested waves over a substantial number of wavelengths. The extension of this capability to directionally distributed waves is discussed. Application to long wave tanks are given.
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Jenkins, Alastair David; Magnusson, Anne Karin; Niedermeier, Andreas; Monbaliu, Jaak; Toffoli, Alessandro & Trulsen, Karsten
(2004).
Rogue waves and extreme events in measured time-series.
Vis sammendrag
We report on the wave time-series data used in the MAXWAVE project, with sample time series and statistics of wave height, crest height, and trough depth. Data are included from the Ekofisk and Draupner oil fields, and from Belgian coastal waters. As well as extreme value analysis, wavelet analysis has been were performed. Studies were also made of buoy time series transformed by quasi-Lagrangian correction of the buoy motion, and of laser time series propagated to other locations with up to 220 m separation from the original measurement location using linear and nonlinear techniques.
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Krogstad, Harald E.; Socquet-Juglard, Herve; Liu, Jingdong; Dysthe, Kristian B. & Trulsen, Karsten
(2004).
Spatial extreme value analysis of nonlinear simulations of random surface waves.
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Trulsen, Karsten
(2004).
Transversal crest and group modulation of extreme waves.
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Socquet-Juglard, Herve; Dysthe, Kristian; Trulsen, Karsten; Krogstad, Harald E & Liu, Jingdong
(2004).
Distribution of extreme waves by simulations.
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Socquet-Juglard, Herve; Dysthe, Kristian B.; Trulsen, Karsten & Krogstad, Harald E.
(2003).
Evolution of a directional spectrum of random surface graviy waves.
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Krogstad, Harald E; Dysthe, Kristian B.; Trulsen, Karsten; Socquet-Juglard, Hervé & Liu, Jingdong
(2003).
Spectral evolution and extreme value analysis of non-linear numerical simulations of narrow band random surface gravity waves.
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Socquet-Juglard, Herve; Dysthe, Kristian B.; Trulsen, Karsten; Liu, Jingdong & Krogstad, Harald E.
(2003).
Spectral evolution and extreme value analysis of non-linear numerical simulations of narrow band random surface gravity waves.
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Dysthe, Kristian & Trulsen, Karsten
(2001).
The evolution of an evolution equation.
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Trulsen, Karsten; Temmos, Jean-Marc; Dysthe, Kristian; Gudmestad, Ove Tobias & Velarde, Manuel G.
(1998).
The Schrödinger method for water wave kinematics.
Vis sammendrag
The Schrödinger method is developed for computation of water wave kinematics on finite depth, and is applied to laboratory experimental data for irregular waves.
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Trulsen, Karsten & Stansberg, Carl Trygve
(1998).
Laboratory evidence of frequency downshift in three-imensional waves in a wave tank.
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Se alle arbeider i Cristin
Publisert
14. apr. 2020 13:13
- Sist endret
28. apr. 2023 14:35