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標題: | 大型貨櫃船於規則波中參數橫搖之數值模擬 Numerical Simulation of Parametric Rolling in Regular Waves |
作者: | Ming-Yu Wu 吳明祐 |
指導教授: | 郭真祥 |
關鍵字: | 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, |
出版年 : | 2006 |
學位: | 碩士 |
摘要: | 參數橫搖運動為一不穩定之現象,當它與顯著的縱搖運動結合在一起時,會快速導致大橫搖角度的發生,由於橫搖與縱搖同時發生,在貨櫃船上會造成貨櫃及其牢繫系統極高的負荷,此種現象在大型的 post-Panamax 貨櫃船特別容易發生,導致貨櫃的損壞及從船上掉落。基於參數橫搖運動可能產生的損害而且對於許多即將於未來幾年交船的貨櫃船而言,此一議題無疑顯得格外重要。當船舶處於頂浪或隨浪的情況下,不規則的波面(wave surface)加上縱搖及起伏(heave)運動導致 隨著時間(相當於波峰或波谷沿著船體縱向遊走時的不同位置)產生忽大忽小顯著的變化,若遭遇週期等於船舶本身自然橫搖週期的一半時,極端的橫搖運動就有可能發生。本論文旨在展示針對大型貨櫃船(8200TEU)於規則波中之計算結果,使用之工具是利用Mathieu equation所自行建立之時間域的數值模擬計算程式,由所得結果可做為評估大型貨櫃船產生參數橫搖運動危險性的的指標,提供貨櫃船設計時的參考。 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. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/32845 |
全文授權: | 有償授權 |
顯示於系所單位: | 工程科學及海洋工程學系 |
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