A ROLL MOTION MODEL FOR SHIPS IN QUARTERING WAVES

In this paper, a frequently used nonlinear single-degree-of- freedom roll equation is modified to allow stochastic restoring and exciting moments. This modification is made by introducing an approximate representation of the first order GZ-variation. The obtained roll equation is used to investigate the pure loss of stability and period bifurcation phenomena, which may typically occur at low frequency of encounter in quartering waves. Numerical examples in regular and irregular waves are given for a ro/ro passenger ferry. In regular waves, comparison with experimental roll time series shows that the roll characteristics can be quite closely captured with the presented mathematical model for some parameter value combinations in the vicinity of the nominal experimental parameter values. However, the great sensitivity to small changes of parameters points out the difficulties of making generalised conclusions. Finally, simulation examples at different ship speeds in irregular waves are given.

  • Supplemental Notes:
    • Royal Inst of Technology, Sweden, Dept of Vehicle Engng, Naval Architecture, rpt 9615, 1996, p C1 [27 p, 16 ref, 14 fig]
  • Authors:
    • Palmquist, M
  • Publication Date: 1996

Language

  • English

Subject/Index Terms

Filing Info

  • Accession Number: 00728262
  • Record Type: Publication
  • Source Agency: British Maritime Technology
  • Files: TRIS
  • Created Date: Nov 4 1996 12:00AM