潛艦是近代海洋軍事發展的重要元素，其推進性能及匿蹤性尤其重要，當柴電動力潛艦在柴油發電機運作時，需要上浮至呼吸管深度供其進、排氣。因此，本篇論文透過CFD(Computational Fluid Dynamics)軟體對潛艦做了兩種模擬: A部分針對穩態行駛的潛艦進行推進性能中的阻力預估，並與拖航水槽試驗數據進行比較，潛艦沒水深度考慮實驗中拖航深度及深水兩種情況，以瞭解拖航支架、自由液面以及兩者交互作用對阻力的影響；B部分針對潛艦水下排煙系統的匿蹤性進行評估，對於帆罩在呼吸管深度下的排氣進行局部模擬，觀測排煙時在特定船速下的氣泡上升、擴散、變形、與帆罩周圍流場的交互作用及在水面上形成的最大波高。兩部分皆利用流體體積法(VOF，Volume of Fluid)、SST (Shear Stress Transport) k-ω紊流模型和非結構性網格模擬考慮自由液面之兩相、不可壓縮、紊流黏性流場。

To consider Propulsion performance and stealth of the submarine, this thesis includes two parts of CFD simulations. In part A, the steady-state ship resistance is predicted for the submarine propulsion performance, and compared with towing tank data. To understand the effect of towing strut and free surface, and their interaction on ship resistance, the submerged depth in the experiment and deep-water condition are considered. In part B, to evaluate the stealth effectiveness of the underwater exhaust system, the simulation focused on the region around submarine sail, submerged exhaust (port) and snorkel mask. At certain ship speed, the travel, diffusion, deformation of exhaust bubble, the interaction with the flow field around the sail, and the maximum height on the water surface are observed.

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