Representative models of the nonlinear behaviour of floating platforms are essential for their successful design, especially in the emerging field of wave energy conversion where nonlinear dynamics can have substantially detrimental effects on the converter efficiency. The spar buoy, commonly used for deep-water drilling, oil and natural gas extraction and storage, as well as offshore wind and wave energy generation, is known to be prone to experience parametric resonance. In the vast majority of cases, parametric resonance is studied by means of simplified analytical models, considering only two degrees of freedom (DoFs) of archetypical geometries, while neglecting collateral complexity of ancillary systems. On the contrary, this paper implements a representative 7-DoF nonlinear hydrodynamic model of the full complexity of a realistic spar buoy wave energy converter, which is used to verify the likelihood of parametric instability, quantify the severity of the parametrically-excited response, and evaluate its consequences on power conversion efficiency. It is found that the numerical model agrees with expected conditions for parametric instability from simplified analytical models. The model is then used as a design tool to determined the best ballast configuration, limiting detrimental effects of parametric resonance while maximizing power conversion efficiency.

Numerical investigation of parametric resonance due to hydrodynamic coupling in a realistic wave energy converter / Giorgi, Giuseppe; Gomes, Rui P. F.; Bracco, Giovanni; Mattiazzo, Giuliana. - In: NONLINEAR DYNAMICS. - ISSN 0924-090X. - (2020). [10.1007/s11071-020-05739-8]

Numerical investigation of parametric resonance due to hydrodynamic coupling in a realistic wave energy converter

Giorgi, Giuseppe;Bracco, Giovanni;Mattiazzo, Giuliana
2020

Abstract

Representative models of the nonlinear behaviour of floating platforms are essential for their successful design, especially in the emerging field of wave energy conversion where nonlinear dynamics can have substantially detrimental effects on the converter efficiency. The spar buoy, commonly used for deep-water drilling, oil and natural gas extraction and storage, as well as offshore wind and wave energy generation, is known to be prone to experience parametric resonance. In the vast majority of cases, parametric resonance is studied by means of simplified analytical models, considering only two degrees of freedom (DoFs) of archetypical geometries, while neglecting collateral complexity of ancillary systems. On the contrary, this paper implements a representative 7-DoF nonlinear hydrodynamic model of the full complexity of a realistic spar buoy wave energy converter, which is used to verify the likelihood of parametric instability, quantify the severity of the parametrically-excited response, and evaluate its consequences on power conversion efficiency. It is found that the numerical model agrees with expected conditions for parametric instability from simplified analytical models. The model is then used as a design tool to determined the best ballast configuration, limiting detrimental effects of parametric resonance while maximizing power conversion efficiency.
File in questo prodotto:
File Dimensione Formato  
GIORGI Numerical investigation of parametric resonance due to hydrodynamic coupling in a realistic wave energy converter 2020.pdf

accesso aperto

Tipologia: 2a Post-print versione editoriale / Version of Record
Licenza: Creative commons
Dimensione 2.94 MB
Formato Adobe PDF
2.94 MB Adobe PDF Visualizza/Apri
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11583/2836399