Non-linear roll motions of a frigate-type trimaran

Adrian S. Onas, Raju Datla

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

12 Scopus citations

Abstract

Two nonlinear roll damping models using a roll decrement and an energy method are considered. The objective is to use experimental hydrodynamics to validate the numerical prediction of nonlinear roll motions in waves. Reasonably good fits are obtained with 1 DOF mathematical model of the roll motion augmented by a viscous roll damping term. Variability of side hull longitudinal stagger, transverse spacing and speed on roll damping is examined. Forced roll experiments are employed to study the effect of roll excitation frequency on roll response and nonlinear roll damping. Screening of parametric roll resonance is carried-out at wave encounter frequencies generating nonlinear coupled roll-pitch motions. A dynamic stability study follows and the unstable regions are identified on the Ince-Strutt diagram. This investigation reveals that trimaran vessels, which normally benefit from high transverse stability, can in fact encounter seaways that can cause significantly large or resonant roll motions and also wave trapping. The nonlinear roll damping models were in good agreement with the experimental analysis for the frequency domain roll response and time domain parametric roll resonance.

Original languageEnglish
Title of host publication11th International Conference on Fast Sea Transportation, FAST 2011 - Proceedings
EditorsTodd J. Peltzer
Pages607-614
Number of pages8
ISBN (Electronic)9780985066000
StatePublished - 2011
Event11th International Conference on Fast Sea Transportation, FAST 2011 - Honolulu, United States
Duration: 26 Sep 201129 Sep 2011

Publication series

Name11th International Conference on Fast Sea Transportation, FAST 2011 - Proceedings

Conference

Conference11th International Conference on Fast Sea Transportation, FAST 2011
Country/TerritoryUnited States
CityHonolulu
Period26/09/1129/09/11

Keywords

  • Forced roll
  • Nonlinear restoring
  • Parametric roll resonance
  • Roll damping
  • Wave trapping

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