- 學位論文
水下滑翔機加裝CTD之流體動力分析
Hydrodynamic Analysis of Underwater Glider with Installation of CTD
摘要
水下滑翔機是近年來新研發的自主式水下載具。它可以長時間、長距離的在水下運動，並且蒐集許多海洋物理資料。其中負責資料蒐集的裝置稱做CTD偵測器。 現有的CTD偵測器大都安裝在一側的機翼下方，而流體動力係數對於水下滑翔機的運動和操控性能有著決定性的影響。因為幾何形狀的改變對流體動力係數影響很大，所以如何正確地估算水下滑翔機在安裝CTD偵測器前後流體動力係數改變，對於掌握水下滑翔機的動態性能是相當重要的！ 本研究使用計算流體力學軟體FLUENT。首先以美國DTNSRDC對於4621軸對稱潛體的實驗報告做模擬驗證工作，在確認了計算所使用的數值方法及網格建置方式後，接著進行水下滑翔機針對有無CTD偵測器在-25度到+25度不同攻角下低速穩態滑行時，其周圍流場的分析與流體動力係數的計算。
並列摘要
Autonomous Underwater Glider is a new invention of Autonomous Underwater Vehicle (AUV) in recent years. Underwater Glider has long duration and long range, especially for an apparatus is called CTD sensor that could also collect many physical data of the ocean. Most of CTD sensors are placing for underneath one side of wing of underwater glider therefore the dynamic characteristics of an underwater glider depends on its hydrodynamic coefficients significantly. The variety of geometry has extremely effect to hydrodynamic coefficients, so it is important to estimate or analyze the difference between hydrodynamic coefficients which has the set of CTD sensor or not of underwater glider. The computation of fluid dynamics software “FLUENT” is used for this study. In order to make sure the numerical approaches and mesh arrangement in determining the hydrodynamic coefficients of an underwater glider are appropriate. The first stage is using the data of 4621 axial symmetric submerged body reported by DTNSRDC to simulate the hydrodynamic coefficients. As the result of 4621 simulation is closed to experimental data, then we can use the same numerical approaches and mesh arrangement to calculate the hydrodynamic coefficients of underwater glider at angles of pitch from -25 to +25 degrees which has CTD sensor or not.