Numerical Simulation of Parametric Rolling in Regular Waves
Date Issued
2006
Date
2006
Author(s)
Wu, Ming-Yu
DOI
zh-TW
Abstract
Parametric rolling is an unstable phenomenon, which can rapidly induce large roll angles if significant pitch motions are also coupled with them. In the case of occurrences of the rolling in phase with pitching motions, high loads can be introduced into the containers and their lashing system. It is known that post-Panamax containerships are susceptible to this condition and cause damage and lost of containers overboard. It is thus an important issue regarding the increasing size of containerships with a huge number of containers (more than 8,000 TEU) to be designed and built in the next years. In head or stern seas the irregular wave surface accompanied by the pitch and heave motions of the ship results in a time-varying underwater hull geometry. This variation in the geometry, in turn, gives rise to time-varying changes in the metacentric height GM. Under some cases with certain combinations of the ratios of the wavelength to the ship length and the natural period of roll to the wave encounter period the parametric resonance will occur. This paper presents results from the numerical simulation of the parametric rolling, which is described with the Mathieu equation. For simplicity, only regular waves conditions are considered.
Subjects
船舶穩度
參數橫搖運動
Mathieu方程式
縱搖及起伏
Ship Stability
Parametric Rolling
Mathieu Equation
Type
thesis