On the representation of normalized wave spectra

Article type: Research Article

Authors: Ferdinande, V.

Affiliations: “Dienst voor Scheepsbouwkunde”, State University of Ghent, Belgium

Abstract: An analysis of the non-dimensional representation of the uni-directional wave energy spectrum is developed. The standard I.T.T.C./I.S.S.C. spectrum formula proves to be one of the correctly derived formulations, but the assessment of the characteristic period and the significant wave height can be criticized. For an available collection of wave spectra, gathered by Ceberena on the North Atlantic, the best adapted Bretschneider expression is formulated. As even this formula does not give satisfaction in matching the average of the actual measured spectra, there is little hope of arriving at any proper mathematical spectrum formulation in the future. Therefore, a general procedure is proposed, which may lead to a representative curve of dimensionless spectral densities versus frequency. This curve for a given sea area, with indication of standard deviations, might be a better base for deriving realistic wave spectra of known visual heights and periods, and therefore be a better tool for the short-term and long-term prediction of ship responses.

DOI: 10.3233/ISP-1977-2427902

Journal: International Shipbuilding Progress, vol. 24, no. 279, pp. 306-318, 1977