Abstract
Wave energy devices are often located in intermediate or shallow water close to the free water surface where the wave exposure is extreme. The structures typically consist of large thin curved plates, spherical shells, or cylindrical structures which are sensitive to pressure loads. The lack of proper methods to calculate design pressure distributions has led to structural failures such as buckling in the shells in wave energy prototypes.
As a step towards understanding the complex loading from high order non-linear waves, this paper presents a practical approach to estimate wave excitation forces accounting for both non-linearity and diffraction effects. The method is validated by laboratory experiments using a hemispherical point absorber with a 6-axis force transducer, but the technique is believed to be applicable for most types of submerged or semi-submerged floating devices.
The applied method is based on calculation of a peak force coefficient defined as experimentally measured forces on the structure divided by forces estimated by the chosen theoretical method. Methods used include an integration of the undisturbed wave pressure over the surface of the structure, corresponding to the Froude-Krylov force, and a numerical solution to linear potential diffraction theory. Since the two methods have mutual limitations in describing higher order waves and diffraction, a combination of the two will be introduced.
As a step towards understanding the complex loading from high order non-linear waves, this paper presents a practical approach to estimate wave excitation forces accounting for both non-linearity and diffraction effects. The method is validated by laboratory experiments using a hemispherical point absorber with a 6-axis force transducer, but the technique is believed to be applicable for most types of submerged or semi-submerged floating devices.
The applied method is based on calculation of a peak force coefficient defined as experimentally measured forces on the structure divided by forces estimated by the chosen theoretical method. Methods used include an integration of the undisturbed wave pressure over the surface of the structure, corresponding to the Froude-Krylov force, and a numerical solution to linear potential diffraction theory. Since the two methods have mutual limitations in describing higher order waves and diffraction, a combination of the two will be introduced.
Originalsprog | Engelsk |
---|---|
Titel | 10th ewtec 2013 European Wave and Tidal Energy Conference Series : Proceedings of the 10th European Wave and Tidal Energy Conference |
Redaktører | Peter Frigaard, Jens Peter Kofoed, AbuBakr S. Bahaj, Lars Bergdahl, Alain Clément, Daniel Conley, Antonio F. O. Falcão, Cameron MacLeod Johnstone, Lucia Margheritini, Ian Masters, António José Sarmento, Diego Vicinanza |
Antal sider | 9 |
Udgivelsessted | Aalborg |
Forlag | Technical Committee of the European Wave and Tidal Energy Conference |
Publikationsdato | 2013 |
Status | Udgivet - 2013 |
Begivenhed | European Wave and Tidal Energy Conference - Aalborg, Danmark Varighed: 2 sep. 2013 → 5 sep. 2013 Konferencens nummer: 10 |
Konference
Konference | European Wave and Tidal Energy Conference |
---|---|
Nummer | 10 |
Land/Område | Danmark |
By | Aalborg |
Periode | 02/09/2013 → 05/09/2013 |
Navn | European Wave and Tidal Energy Conference Series |
---|---|
Nummer | 10 |
Bibliografisk note
The proceedings is published on a usb.Emneord
- WEC
- Hemispherical point absorber
- wave loads
- Wave regimes
- Non-linear diffraction