A new active absorption system and its performance to linear and non-linear waves

Andersen, Thomas Lykke; Clavero, María; Frigaard, Peter; Losada, Miguel Á.; Puyol, J.I.

doi:10.1016/j.coastaleng.2016.04.010

Cited by 43 publications

(34 citation statements)

References 10 publications

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“…Active absorption systems are based on linear wavemaker theory and their performance on nonlinear waves has not been studied until recently. The present paper extends the recent studies for nonlinear regular waves by Lykke Andersen et al (2016) to nonlinear bichromatic and irregular waves.…”

Section: Introductionsupporting

confidence: 77%

“…The method chosen by most laboratories is based on measurement of surface elevation in the nearfield and such system is also examined in the present paper. The tested system is the one presented in Lykke Andersen et al (2016) which is implemented in the AwaSys software, cf. Aalborg University (2018a).…”

Section: Applied Active Absorption Systemmentioning

confidence: 99%

“…Lykke Andersen et al (2016) showed that a causal digital FIR filter can be designed, and they provided an iterative filter design procedure. This procedure involves performance optimization in a desired frequency band, i.e.…”

Section: Applied Active Absorption Systemmentioning

confidence: 99%

See 2 more Smart Citations

Active Absorption of Nonlinear Irregular Waves

Andersen¹,

Clavero²,

Eldrup³

et al. 2018

Int. Conf. Coastal. Eng.

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In the present paper, the performance of active absorption systems based on nearfield surface elevation measurements is studied. Based on linear wavemaker theory the performance of such systems can easily be calculated for linear waves. A recent study demonstrated that bound superharmonics in regular waves is also well absorbed by such system and has a re-reflection similar to a linear component. However, the performance of active absorption systems on nonlinear irregular waves has never been studied. In the present paper the absorption of bound sub and superharmonics in bichromatic and irregular waves is examined based on new model tests. The conclusion is that also in irregular waves the bound harmonics are well absorbed by the studied active absorption system.

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Section: Introductionsupporting

confidence: 77%

Section: Applied Active Absorption Systemmentioning

confidence: 99%

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Active Absorption of Nonlinear Irregular Waves

Andersen¹,

Clavero²,

Eldrup³

et al. 2018

Int. Conf. Coastal. Eng.

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“…Simultaneously, active absorption of reflected waves was used in all tests [27]. Waves were generated based on the three parameters in the JONSWAP (JOint North Sea Wave Project) spectrum: significant wave height H m0 , peak period (T p ) and the peak enhancement factor γ (γ = 3.3 in all tests).…”

Section: Wave Characteristicsmentioning

confidence: 99%

Hydraulic Performance of an Innovative Breakwater for Overtopping Wave Energy Conversion

Iuppa

Contestabile²,

Cavallaro

et al. 2016

Sustainability

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Abstract:The Overtopping BReakwaterfor Energy Conversion (OBREC) is an overtopping wave energy converter, totally embedded in traditional rubble mound breakwaters. The device consists of a reinforced concrete front reservoir designed with the aim of capturing the wave overtopping in order to produce electricity. The energy is extracted through low head turbines, using the difference between the water levels in the reservoir and the sea water level. This paper analyzes the OBREC hydraulic performances based on physical 2D model tests carried out at Aalborg University (DK). The analysis of the results has led to an improvement in the overall knowledge of the device behavior, completing the main observations from the complementary tests campaign carried out in 2012 in the same wave flume. New prediction formula are presented for wave reflection, the overtopping rate inside the front reservoir and at the rear side of the structure. Such methods have been used to design the first OBREC prototype breakwater in operation since January 2016 at Naples Harbor (Italy).

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“…Thus, active absorption systems usually assume reflected waves to be head-on to the wavemaker. Examples of such systems are Milgram [1,2], Schäffer et al [3], and Lykke Andersen et al [4,5] for nearfield surface elevation feedback, Frigaard and Christensen [6] and Hald and Frigaard [7] for farfield surface elevation and/or particle velocity feedback, and Salter [8], Chatry et al [9] and Spinneken and Swan [10] for force feedback.…”

Section: Introductionmentioning

confidence: 99%

Influence of Spurious Waves on the Performance of Active Absorption Systems in Oblique Waves

Andersen

Eldrup

Frigaard

2020

JMSE

Self Cite

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Existing active absorption systems do not take into account the spurious waves caused by the segmentation of the wavemaker. Thus, the theoretical estimated performance curves for oblique waves are only valid for infinitely narrow segments. In the present paper, it is demonstrated that by ignoring the spurious waves, an unstable system might be designed for box-mode paddles (piecewise constant segmentation). For vertical hinged pistons (piecewise linear segmentation), the results are the opposite, as the stability of the system is improved at high frequencies when a finite paddle width is considered. It is also shown that finite discretization leads to a directional influence in the system, even for a pseudo-3D active absorption system. This effect is more pronounced for vertical hinged systems compared to box-mode paddles.

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A new active absorption system and its performance to linear and non-linear waves

Cited by 43 publications

References 10 publications

Active Absorption of Nonlinear Irregular Waves

Active Absorption of Nonlinear Irregular Waves

Hydraulic Performance of an Innovative Breakwater for Overtopping Wave Energy Conversion

Influence of Spurious Waves on the Performance of Active Absorption Systems in Oblique Waves

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