Experiments on uni-directional and nonlinear wave group shoaling

The ComFLOW wave model has been employed to study the impact of nonlinear wave groups on cylindrical monopiles. Four nonlinear wave groups are selected from fully nonlinear waves generated by a 2D ComFLOW model, representing wave groups with the largest or the second largest crest heights, the largest wave height and a wave group consisting of consecutive large waves. These four wave groups are used to investigate the wave loads on the foundation and the platform in a 3D ComFLOW model. Model results show that the maximum wave loads on the foundation and the platform by nonlinear wave groups are determined by their individual wave crest height. This study presents a relationship between platform level and wave impact on the platform, as the vertical force on the platform is the combination of buoyancy force (if inundated) and wave impact force due to wave run-up. Results also show that wave loads on the foundation and wave impact on the platform decrease as the wave period increases from 13s to 16s (typical wave period at German Bight). A wave group can cause a larger wave load on the foundation and the platform than regular waves, considering a regular wave height equal to the maximum wave height, regardless of the associated wave period (period of individual wave or peak period).

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Nonlinear Wave Group Evolution in Shallow Water

Journal of Waterway Port Coastal and Ocean Engineering ◽

10.1061/(asce)0733-950x(2000)126:5(221) ◽

2000 ◽

Vol 126 (5) ◽

pp. 221-228 ◽

Cited By ~ 17

Author(s):

E. Kit ◽

L. Shemer ◽

E. Pelinovsky ◽

T. Talipova ◽

O. Eitan ◽

...

Keyword(s):

Shallow Water ◽

Nonlinear Wave ◽

Wave Group ◽

Group Evolution

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Numerical Study on Nonlinear Wave-Ice-Interaction

Volume 8: Polar and Arctic Sciences and Technology; Petroleum Technology ◽

10.1115/omae2019-95116 ◽

2019 ◽

Author(s):

Moritz Hartmann ◽

R. U. Franz von Bock und Polach ◽

Sören Ehlers ◽

Norbert Hoffmann ◽

Miguel Onorato ◽

...

Keyword(s):

Wave Propagation ◽

Nonlinear Wave ◽

Numerical Study ◽

Wave Interaction ◽

Parameter Study ◽

Wave Group ◽

Nonlinear Wave Propagation ◽

Level Ice ◽

Definition Of ◽

The Impact

Abstract This paper investigates the fundamental question of nonlinear wave-ice interaction under level ice focusing on nonlinear wave propagation and dispersion of waves. Therefore, numerical investigations are performed to verify theoretically if nonlinearity takes place under level ice and if this can lead to intense wave events far away from the ice edge in order to provide an explanation for observed real-world ice break-ups. Therefore, nonlinear wave-ice interaction as well as the impact of the ice characteristics on this interaction will be investigated. The direct numerical simulations of the nonlinear wave propagation under solid ice are performed within the Nonlinear Schrödinger Equation (NLSE) framework. The Peregrine breather solution is applied to represent exact solutions of the NLSE for a nonlinear wave group. The application of such a nonlinear wave group is predestined for the verification of occurring nonlinear wave-wave interaction below the ice sheet. For the definition of wave and ice parameters in the simulation setup, the results of the presented parameter study are used. The parameters are analyzed regarding relevant characteristics of nonlinear wave-ice interaction and wave propagation. By assuming constraints with respect to physical consistency, the parameter range for the NLSE simulations can be narrowed. The scope of this investigation is to provide a better understanding of the ice conditions required to observe nonlinear wave effects under level ice.

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On Determining the Onset and Strength of Breaking for Deep Water Waves. Part I: Unforced Irrotational Wave Groups

Journal of Physical Oceanography ◽

10.1175/1520-0485-32.9.2541 ◽

2002 ◽

Vol 32 (9) ◽

pp. 2541-2558 ◽

Cited By ~ 83

Author(s):

Jin-Bao Song ◽

Michael L. Banner

Keyword(s):

Growth Rate ◽

Nonlinear Wave ◽

Deep Water ◽

Water Waves ◽

Wave Group ◽

Two Dimensional ◽

Wave Groups ◽

Average Growth ◽

Deep Water Waves

Abstract Finding a robust threshold variable that determines the onset of breaking for deep water waves has been an elusive problem for many decades. Recent numerical studies of the unforced evolution of two-dimensional nonlinear wave trains have highlighted the complex evolution to recurrence or breaking, together with the fundamental role played by nonlinear intrawave group dynamics. In Part I of this paper the scope of two-dimensional nonlinear wave group calculations is extended by using a wave-group-following approach applied to a wider class of initial wave group geometries, with the primary goal of identifying the differences between evolution to recurrence and to breaking onset. Part II examines the additional influences of wind forcing and background shear on these evolution processes. The present investigation focuses on the long-term evolution of the maximum of the local energy density along wave groups. It contributes a more complete picture, both long-term and short-term, of the approach to breaking and identifies a dimensionless local average growth rate parameter that is associated with the mean convergence of wave-coherent energy at the wave group maximum. This diagnostic growth rate appears to have a common threshold for all routes to breaking in deep water that have been examined and provides an earlier and more decisive indicator for the onset of breaking than previously proposed breaking thresholds. The authors suggest that this growth rate may also provide an indicative measure of the strength of wave breaking events.

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