- 學位論文
應用計算流體力學方法探討船舶流體動力係數及操縱性能之研究
Study on Hydrodynamic Coefficients and Maneuverability of a Ship by Applying CFD Method
摘要
本文研究重點著重於使用計算流體力學的方法，進行船舶在靜水面上流體動力係數的求取，並探討船舶的安定性能及迴旋性能。首先透過六自由度耦合船舶運動方程式，分析平面操船運動中，船舶所受之慣性力及流體力，經由方程式聯立求解得到以船舯為原點的反應模式以及相關的安定性和迴旋性指標，進而整理出解析操縱性能所需的流體動力導數；透過計算流體力學軟體ANSYS -FLUENT，模擬直線航行、斜航試驗、迴旋臂試驗、等加速度運動、舵力試驗等，計算並分析相關的流體動力係數；以日本海上技術安全研究所(NMRI)對油輪KVLCC1船模所作的一系列實驗作為數值驗證的依據，來確認本研究數值方法模擬的可行性以及流體動力導數分析的準確性。 油輪在安定性能上普遍呈現不安定，由本研究的模擬計算和分析結果發現，KVLCC1亦為不安定；在有螺槳作動下，對於船舶的安定性能和迴旋性能皆有提升的作用，也使舵的失速角有延後的現象。
並列摘要
The present study focuses on the development of a CFD method to calculate the hydrodynamic coefficients of a ship running in calm water, and so its maneuverability including directional stability and turning ability can be analyzed. Firstly, maneuverability related hydrodynamic coefficients are derived via hydrodynamic modeling of horizontal planar motions, and the stability indices are derived via responsive modeling. Then the CFD software ANSYS-FLUENT is applied to simulate these maneuver motions including straight forward motion, oblique towing test, rotating arm test, constant accelerating test, and rudder force test, and to obtain the corresponding hydrodynamic forces as well as hydrodynamic coefficients. The experimental data of a tanker KVLCC1 of a series of model tests carried out by National Maritime Research Institute (NMRI) of Japan are adopted for the validation of the present CFD method. In general, tankers may have not sufficient directional stability. In the present numerical study, it is also shown that the KVLCC1 tanker is unstable in direction as expected. Besides, CFD simulations also indicate that both directional stability and turning ability are improved, and the occurrence of ruder stall delayed due to the effects of rotating propeller.