CONTINUOUS DIGITAL SIMULATION OF THE SECOND-ORDER SLOWLY VARING WAVE DRIFT FORCE

A discussion is given on practical aspects of digital representation in time of the slowly oscillatory second-order wave drift force from a known force spectrum. The emphasis is placed on the computational efficiency and on the suitability of the simulation to a numerical integration of an equation of motion using a variable integration step size, where the force acts as the excitation of motion. The effect of approximating the original spectrum by a white spectrum is discussed. A sensitivity analysis is made to the range of frequencies of the spectra. The force time record is obtained by first generating at equal time intervals a discrete time series which possesses the desired random characteristics, and then by extending the discrete series into a continuously available digital record using a sin(x)/x-type interpolation. Various numerical tests are illustrated with plots. Superiority of the fast Fourier transform over the cosine series is demonstrated in terms of the spectral contents preservation.

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  • Corporate Authors:

    Society of Naval Architects and Marine Engineers

    601 Pavonia Avenue
    Jersey City, NJ  USA  07306-2907
  • Authors:
    • Oppenheim, B W
    • Wilson, P A
  • Publication Date: 1980-9

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Filing Info

  • Accession Number: 00319833
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Oct 27 1980 12:00AM