scholarly journals Attenuation and directional spreading of ocean wave spectra in the marginal ice zone

2016 ◽  
Vol 790 ◽  
pp. 492-522 ◽  
Author(s):  
Fabien Montiel ◽  
V. A. Squire ◽  
L. G. Bennetts
Keyword(s):  
Wave Field ◽  
Wave Energy ◽  
Scattering Problem ◽  
Ocean Wave ◽  
Thin Elastic Plate ◽  
Linear Potential ◽  
Wave Spectra ◽  
Water Ice ◽  
Marginal Ice Zone ◽  
Ice Floes

A theoretical model is used to study wave energy attenuation and directional spreading of ocean wave spectra in the marginal ice zone (MIZ). The MIZ is constructed as an array of tens of thousands of compliant circular ice floes, with randomly selected positions and radii determined by an empirical floe size distribution. Linear potential flow and thin elastic plate theories model the coupled water–ice system. A new method is proposed to solve the time-harmonic multiple scattering problem under a multidirectional incident wave forcing with random phases. It provides a natural framework for tracking the evolution of the directional properties of a wave field through the MIZ. The attenuation and directional spreading are extracted from ensembles of the wave field with respect to realizations of the MIZ and incident forcing randomly generated from prescribed distributions. The averaging procedure is shown to converge rapidly so that only a small number of simulations need to be performed. Far-field approximations are investigated, allowing efficiency improvements with negligible loss of accuracy. A case study is conducted for a particular MIZ configuration. The observed exponential attenuation of wave energy through the MIZ is reproduced by the model, while the directional spread is found to grow linearly with distance. The directional spreading is shown to weaken when the wavelength becomes larger than the maximum floe size.

scholarly journals Reflection and transmission of ocean wave spectra by a band of randomly distributed ice floes

2015 ◽  
Vol 56 (69) ◽  
pp. 315-322 ◽  
Author(s):  
Fabien Montiel ◽  
Vernon A. Squire ◽  
Luke G. Bennetts
Keyword(s):  
Wave Spectrum ◽  
Ocean Wave ◽  
Wave Spectra ◽  
Ensemble Averaging ◽  
Ice Dynamics ◽  
Reflection And Transmission ◽  
Directional Wave ◽  
Ice Edge ◽  
Ice Floes ◽  
Edge Band

AbstractA new ocean wave/sea-ice interaction model is proposed that simulates how a directional wave spectrum evolves as it travels through an arbitrary finite array of circular ice floes, where wave/ ice dynamics are entirely governed by wave-scattering effects. The model is applied to characterize the wave reflection and transmission properties of a strip of ice floes, such as an ice edge band. A method is devised to extract the reflected and transmitted directional wave spectra produced by the array. The method builds upon an integral mapping from polar to Cartesian coordinates of the scattered wave components. Sensitivity tests are conducted for a row of floes randomly perturbed from a regular arrangement. Results for random arrays are generated using ensemble averaging. A realistic ice edge band is then reconstructed from field experiment data. Simulations show good qualitative agreement with the data in terms of transmitted wave energy and directional spreading. In particular, it is observed that short waves become isotropic quickly after penetrating the ice field.

scholarly journals Modelling wave-induced sea ice break-up in the marginal ice zone

2017 ◽  
Vol 473 (2206) ◽  
pp. 20170258 ◽  
Author(s):  
F. Montiel ◽  
V. A. Squire
Keyword(s):  
Stress Field ◽  
Wave Scattering ◽  
Scattering Problem ◽  
Three Dimensional ◽  
Field Studies ◽  
Ocean Wave ◽  
Wave Forcing ◽  
Marginal Ice Zone ◽  
Break Up ◽  
Wave Induced

A model of ice floe break-up under ocean wave forcing in the marginal ice zone (MIZ) is proposed to investigate how floe size distribution (FSD) evolves under repeated wave break-up events. A three-dimensional linear model of ocean wave scattering by a finite array of compliant circular ice floes is coupled to a flexural failure model, which breaks a floe into two floes provided the two-dimensional stress field satisfies a break-up criterion. A closed-feedback loop algorithm is devised, which (i) solves the wave-scattering problem for a given FSD under time-harmonic plane wave forcing, (ii) computes the stress field in all the floes, (iii) fractures the floes satisfying the break-up criterion, and (iv) generates an updated FSD, initializing the geometry for the next iteration of the loop. The FSD after 50 break-up events is unimodal and near normal, or bimodal, suggesting waves alone do not govern the power law observed in some field studies. Multiple scattering is found to enhance break-up for long waves and thin ice, but to reduce break-up for short waves and thick ice. A break-up front marches forward in the latter regime, as wave-induced fracture weakens the ice cover, allowing waves to travel deeper into the MIZ.

scholarly journals Modelling Ocean Waves and an Investigation of Ocean Wave Spectra for the Wave-to-Wire Model of Energy Harvesting

2021 ◽  
Vol 12 (1) ◽  
pp. 51
Author(s):  
Safdar Rasool ◽  
Kashem M. Muttaqi ◽  
Danny Sutanto
Keyword(s):  
Time Series ◽  
Energy Harvesting ◽  
Energy Conversion ◽  
Wave Energy ◽  
Ocean Waves ◽  
Ocean Wave ◽  
Wave Spectra ◽  
Wave Energy Conversion ◽  
Peak Period ◽  
Ocean Wave Energy

Ocean wave energy is an abundant and clean source of energy; however, its potential is largely untapped. Although the concept of energy harvesting from ocean waves is antiquated, the advances in wave energy conversion technologies are embryonic. In many major studies related to wave-to-wire technologies, ocean waves are considered to be regular waves with a fixed amplitude and frequency. However, the actual ocean waves are the sum of multiple frequencies that exhibit a particular sea state with a significant wave height and peak period. Therefore, in this paper, detailed modelling of the ocean waves is presented and different wave spectra are analyzed. The wave spectra will eventually be used for the generation of wave elevation time series. Those time series can be used for the wave-to-wire model-based studies for improved investigations into wave energy conversion mechanisms, mimicking the real ocean conditions.

scholarly journals Towards a three-dimensional model of wave–ice interaction in the marginal ice zone

2010 ◽  
Vol 662 ◽  
pp. 1-4 ◽  
Author(s):  
C. M. LINTON
Keyword(s):  
Three Dimensional ◽  
Ocean Waves ◽  
Wave Spectra ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
The Past ◽  
Marginal Ice Zone ◽  
Directional Wave ◽  
Ice Floes ◽  
Made In

Over the past forty or so years, considerable advances have been made in our understanding of the effects of ocean waves on sea ice, and vice versa, with observations, experiments and theory all playing their part. Recent years have seen the development of ever more sophisticated mathematical models designed to represent the physics more accurately and incorporate new features. What is lacking is an approach to three-dimensional scattering for ice floes that is both accurate and efficient enough to be used as a component in a theory designed to model the passage of directional wave spectra through the marginal ice zone. Bennetts & Williams (J. Fluid Mech., 2010, this issue, vol. 662, pp. 5–35) have brought together a number of solution techniques honed on simpler problems to provide just such a component.

scholarly journals Wave attenuation in a marginal ice zone due to the bottom roughness of ice floes

2011 ◽  
Vol 52 (57) ◽  
pp. 118-122 ◽  
Author(s):  
Alison L. Kohout ◽  
Michael H. Meylan ◽  
David R. Plew
Keyword(s):  
Attenuation Coefficient ◽  
Internal Waves ◽  
Wave Energy ◽  
Wave Scattering ◽  
Wave Attenuation ◽  
Viscous Drag ◽  
Physical Factors ◽  
Marginal Ice Zone ◽  
Rate Of Decay ◽  
Ice Floes

AbstractWave attenuation in a diffuse marginal ice zone (MIZ) is thought to be mainly a result of wave scattering. In a compact MIZ, additional physical factors are thought to be relevant. In this paper, we propose that viscous drag, form drag and energy lost to internal waves under the ice play a role in attenuating wave energy. We derive a relation for the wave attenuation due to drag. We combine the drag attenuation coefficient with the scattering attenuation coefficient and compare the result to experimental results for compact MIZs. We find that the combined scatter and drag (CSD) model improves the rate of decay of wave attenuation in compact ice fields, but fails to predict the ‘rollover’ seen at short periods.

scholarly journals Ocean Wave Energy Utilization using Magnetostrictive Vibrational Power Generator

2014 ◽  
Vol 70 (2) ◽  
pp. I_1306-I_1310
Author(s):  
Takehis SAITOH ◽  
Junpei WAGATSUM ◽  
Toshiyuki UENO ◽  
Shot KITA
Keyword(s):  
Wave Energy ◽  
Energy Utilization ◽  
Ocean Wave ◽  
Power Generator ◽  
Ocean Wave Energy
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