- 學位論文
高速三體船在規則波中的運動及阻力性能之研究
The Research of Motion and Resistance in the Regular Wave for the High-speed Trimaran
摘要
「三體船」是一種由三個細長船體構成的船型，中間較寬的主船體提供主要排水量，左右側船體則在幾何特徵上提供大甲板的載重空間並有助於減緩橫搖運動。其在中高速度航行穩定性優於單體船及雙體船的特性，近年來逐漸開始受到世界的矚目進而開始積極的投入研究及製造，包括美英兩國的海軍也陸續將三體船列為新一代戰艦的船型。三體船船型的優點很多，細長體的設計能切開水面而減少阻力，而在中高速航行時三個船體的設計能有效降低興波阻力；然而細長的船體卻也容易在頂浪的情況之下降低運動性能。在過去的研究結果顯示，其縱向運動性能約能介於單體船及雙體船之間，而穿浪式雙體船的發展卻打破了這項排序，與其不相上下。但若探究其人員暈船率，穿浪式雙體船也因其中央船體的設計造成額外的垂向加速度，降低了人員暈船率的表現。穿浪式雙體船的不完美，也使得三體船在運動性能的研究上存有探討的空間。 本研究以商用CFD軟體Star-CCM+來模擬研究三體船在規則波浪中航行的運動及阻力性能，並加裝固定式及主動式兩種控制模式之T型穩定翼來探究其在規則波中頂浪時的運動及阻力性能，並站在使用者及乘客的立場看待其運動性能的影響；站在營運者及設計者的立場看待其阻力性能的表現。 由模擬結果發現，當波長為船長的1.5倍時裸船體的縱搖運動反應振幅運算子(Pitch RAO)約為Austal公司在加裝駕駛控制系統(Ride Control System)[1]穩定翼情況下之計算結果的5倍。對此，本研究也設計了固定式及主動式兩種控制模式來針對穩定翼對縱搖及起伏運動的影響進行探討，並對此兩種控制模式之下穩定翼所造成的阻力進行分析以探究其利弊。結果顯示，裝置穩定翼後平均總阻力上升約4% ~5%；縱搖及起伏運動性卻能降低約63%及47%。
並列摘要
This research applies the commercial CFD code Star-CCM+ to simulate the heave and pitch motions of a trimaran running in regular heading waves. A 102m high-speed trimaran designed by Austal Corporation in Australia was selected as our simulation target. This trimaran is equipped with RCS (Ride Control System) T-foils at the transoms of the side hulls and near the bow position of the main hull to reduce vertical motions. Comparing to the simulation results from Austal Corporation, the pitch motion of the bare hull was about five times larger at the wavelength equal to 1.5 times of the length overall. Thus we tried to add fixed and passive T-foils onto the trimaran and recomputed in the same wave condition. The results showed that the pitch motion was reduced about 48% after the T-foils were added, but still large discrepancy compared to active-controlled one. Because of that, we tried to control the T-foils at the transoms of the side hulls to make the larger lifting force against the pitch motion. The results showed that the pitch motion was reduced about 63% after the control of the side-hull T-foils were conducted.