本研究以設計驅逐艦聲納罩外形使其總阻力變小為首要目標。減阻效果定義為原型驅逐艦附加聲納罩與安裝新型聲納罩船型相比總阻力的減少率。模擬軟體為OpenFOAM 6，使用VOF (Volume of Fluid)法對空氣與水的雙相流進行計算，並利用k-ω SST(shear stress transport)模型對紊流進行模擬。研究條件採用無風浪的靜水環境，並以國立成功大學系統及船舶機電工程學系拖航水槽尺寸做為計算域，船模速度設為巡航船速1.755公尺/秒。
研究分成兩個階段。第一階段對原船型建立疏、中、密三套不同大小的網格，並各自進行阻力計算。計算結果與實驗測得阻力值進行比較，不同網格間模擬誤差的關係必須通過ITTC 7.5-03-01-01建議的驗證與確認(V&V，Verification & Validation)方法，確認具有足夠的可信度。第二階段利用通過V&V的網格設定對不同聲納罩外型進行模擬。透過將船體幾何變形-模擬的循環過程，不斷計算並找出具有最低阻力的外型。
最終我們提出拉長聲納罩的F系列與調整聲納罩後方坡度的Sa、Sb系列共三組設計。F系列具有最佳17.14%的減阻效果，但需要將聲納罩拉長7.28%倍的垂標間長。Sa系列具有最佳1.94%的減阻效果，調整後的坡度為16.023度。Sb系列具有最佳3.32%的減阻效果，調整後的坡度為15.285度。Sa和Sb的差異主要是聲納罩前緣的弧形。

The purpose of this study is to find a better sonar dome design which has lower total resistance compared to the prototype. In this research, the experimental environment is set up as calm water condition. The model speed is 1.765m/s, corresponding to 16 knots cruising speed for full scale ship. Ship motion is not considered. The CFD software that we used is OpenFOAM 6, the solver is interFOAM. The 3D model is built in Rhino 6. Three sonar dome geometries are proposed as the result of this study. F-0.45 has a longer sonar dome which has the same design concept with the bulbous bow of container ship, and it has 17.14% total resistance reduction. Sa-16.023 and Sb-15.285v are both having a sonar dome back slope change. The difference between them is the front edge profile. Without changing the front edge for the consideration of installing the original sonar equipment, Sa-16.023 has 1.94% resistance reduction. On the other hand, Sb-15.285v has a deformation on the front edge. We are not sure if the sonar equipment can fit in, but the 3.32% resistance reduction is the optimal result for S-series design.

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