SECOND-ORDER WAVEMAKER THEORY FOR IRREGULAR WAVES

This paper develops the full second-order wavemaker theory (including superharmonics as well as subharmonics) valid for rotational as well as translatory wave board motion. The primary goal is to obtain the second-order motion of the wave paddle required in order to get a spatially homogeneous wave field correct to second order, ie in order to suppress spurious free-wave generation. In addition to the transfer functions developed in the line of references on which the work is based, some new terms evolve. These are related to the first-order evanescent modes and accordingly they are significant when the wave board motion makes a poor fit to the velocity profile of the desired progressive wave component. This is, for example, the case for the high-frequency part of a primary wave spectrum when using a piston-type wavemaker. The transfer functions are given in a relatively simple form by which the computational effort is reduced substantially. This enhances the practical computation of second-order wavemaker control signals for irregular waves, and no narrow band assumption is needed. The software is conveniently included in a PC-based wave generation system. The validity of the theory demonstrated for a piston type wavemaker in a number of laboratory wave experiments for regular waves, wave groups and irregular waves.

  • Supplemental Notes:
    • Ocean Engng, v 23 n 1, Jan 1996, p 47 [42 p, 31 ref, 3 tab, 18 fig]
  • Authors:
    • Schaffer, H A
  • Publication Date: 1996

Language

  • English

Subject/Index Terms

Filing Info

  • Accession Number: 00718965
  • Record Type: Publication
  • Source Agency: British Maritime Technology
  • Files: TRIS
  • Created Date: Mar 27 1996 12:00AM