船舶の大振幅運動時の非線形特性に関する研究(第2報) : 横揺れ固有周期および非線形流体力の影響

概要

論文の詳細を見る
The purposes of the study are to investigate non-linear features in large amplitudes of ship motions experimentally and to clarify the mechanism of these features. In the first report, a new non-linear feature of ship motions in high waves was presented. In heavy beam seas, large amplitude rolling motion occurs not only in frequency region of the roll resonance but also in wide frequency region higher than the resonant frequency, and a kind of jump phenomena of rolling motion appears. The cause of these phenomena is that drift motion induced by high waves changes encounter frequency and shifts roll resonance to higher frequency. Roll natural period of the model ship used in the experiments are close to heave natural period. There is quite a possibility that a roll natural frequency influences on the non-linear features in the rolling motion in heavy beam seas. In this paper, additional experiments are carried out to investigate relation between roll natural frequency and roll-resonance-shifting to higher frequency, and to confirm a kind of jump phenomena of rolling motion. The experiments show that roll-resonance-shifting to higher frequency is significant with increasing roll natural frequency. This phenomenon is induced by increasing drifting velocity due to increasing roll natural frequency. A non-linear feature of heaving motion is also confirmed near heave natural frequency. In the experiment, the model ship is knocked to induce jump phenomena during the measurement of ship motions in heavy beam seas. The results show that two modes of ship motions appear with different encounter frequencies for the same regular wave. To reveal the reason of the non-linear features shown in the experiments, non-linear hydrodynamic characteristics in the motion equations for drifting and roll-heave-sway coupling motion are investigated.
社団法人日本船舶海洋工学会の論文

船舶の大振幅運動時の非線形特性に関する研究(第2報) : 横揺れ固有周期および非線形流体力の影響

スポンサーリンク

概要

著者

関連論文

スポンサーリンク