Frequency-Response and Frequency-Domain Models

Encyclopedia of Systems and Control ◽

10.1007/978-1-4471-5102-9_236-1 ◽

2014 ◽

pp. 1-10

Author(s):

Abbas Emami-Naeini ◽

J. David Powell

Keyword(s):

Frequency Response ◽

Frequency Domain ◽

Domain Models

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Frequency-Response and Frequency-Domain Models

Encyclopedia of Systems and Control ◽

10.1007/978-3-030-44184-5_236 ◽

2021 ◽

pp. 851-859

Author(s):

Abbas Emami-Naeini ◽

Christina M. Ivler ◽

J. David Powell

Keyword(s):

Frequency Response ◽

Frequency Domain ◽

Domain Models

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Frequency-Response and Frequency-Domain Models

Encyclopedia of Systems and Control ◽

10.1007/978-1-4471-5058-9_236 ◽

2015 ◽

pp. 479-486

Author(s):

Abbas Emami-Naeini ◽

J. David Powell

Keyword(s):

Frequency Response ◽

Frequency Domain ◽

Domain Models

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Seakeeping Tests of a FOWT in Wind and Waves: An Analysis of Dynamic Coupling Effects and Their Impact on the Predictions of Pitch Motion Response

Journal of Marine Science and Engineering ◽

10.3390/jmse9020179 ◽

2021 ◽

Vol 9 (2) ◽

pp. 179

Author(s):

Giovanni Amaral ◽

Pedro Mello ◽

Lucas do Carmo ◽

Izabela Alberto ◽

Edgard Malta ◽

...

Keyword(s):

Frequency Domain ◽

Offshore Wind ◽

Offshore Wind Turbine ◽

Dynamic Coupling ◽

Coupling Effects ◽

Mooring Lines ◽

Scaled Model ◽

Wave Basin ◽

Domain Models ◽

Catenary System

The present work highlights some of the dynamic couplings observed in a series of tests performed in a wave basin with a scaled-model of a Floating Offshore Wind Turbine (FOWT) with semi-submersible substructure. The model was moored by means of a conventional chain catenary system and an actively controlled fan was used for emulating the thrust loads during the tests. A set of wave tests was performed for concomitant effects of not aligned wave and wind. The experimental measurements illustrate the main coupling effects involved and how they affect the FOWT motions in waves, especially when the floater presents a non-negligible tilt angle. In addition, a frequency domain numerical analysis was performed in order to evaluate its ability to capture these effects properly. The influence of different modes of fan response, floater trim angles (changeable with ballast compensation) and variations in the mooring stiffness with the offsets were investigated in the analysis. Results attest that significant changes in the FOWT responses may indeed arise from coupling effects, thus indicating that caution must be taken when simplifying the hydrodynamic frequency-domain models often used as a basis for the simulation of FOWTs in waves and in optimization procedures for the design of the floater and mooring lines.

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