利用直接施力沉浸邊界（DFIB）法處理複雜幾何形狀的流固耦合問題，始終是一個複雜而困難的挑戰。 然而，對於可以用數學方程的形式表達的簡單幾何形狀，如圓柱體或球體，則相對容易處理。 但生活並不總是那麼容易。 因此，通過 STL 電腦圖檔在流場中呈現複雜的實體幾何形狀，將是現實世界應用中不可避免且必要的步驟。

不幸的是，只有極少數複雜幾何形狀的例子，如飛機、汽車或風力發電機葉片，受到科學家或工程師的興趣，在 DFIB 方法下進行 FSI 問題的模擬，以供自己的機密參考。 他們幾乎不可能公開分享這些有價值的信息。

同時，通過全尺寸風洞實驗來檢查所選 Fortran DFIB 求解器對於此類大型物體的有效性和驗證性變得不現實。

為了解決這些問題，這裡提出的重要步驟是，在參考文獻中特定的雷諾數和網格大小模擬一些著名和流行的幾何形狀，如圓柱體（固體結構）和空腔（流體環境），這些幾何形狀已被其他研究人員公開研究數據進行了很好的驗證。 分別通過選定的 Fortran DFIB 求解器重複此類模擬，是想證明實驗室研發的Fortran DFIB 求解器處理 FSI 問題的有效性和驗證性的好方法。

接著會從得到的有效性和驗證性基礎上，使用實驗室研發的Fortran DFIB 求解器處理對潛艇在流場中的複雜幾何形狀進行模擬，並提出模擬結果供審視。

To deal a complex geometry by direct forcing immersed boundary(DFIB) method for a fluid-structure interaction problem is always a complicate and difficult challenge. However, for a simple geometry which can be expressed in a form of mathematical equations like a cylinder or a sphere are relatively easy to deal with. But life is not always that easy. Therefore, to present a complex solid geometry by a STL file in a flow field would be an unavoidable and necessary step for a real world application.
Unfortunately, there are only very few examples like space shuttle , cars or blades of wind turbine were interested by scientists or engineers to perform FSI problems' simulations under DFIB method for their own confidential reference. It is almost impossible they will share this valuable information in public.
Meanwhile, to check the validity and validation of a selected Fortran DFIB solver for such big objects through a full size wind tunnel experiment become unrealistic.
In order to solve these problems, important steps proposed here are to simulate some famous and popular geometries like cylindrical cylinder(solid structure) and cavity(fluid environment) which are well-validation by other researchers with public announced data. To repeat such simulations by a selected Fortran DFIB solver(Tiger-F program developed by NTUST CFD lab) are good methods to testify Fortran DFIB solver's validity and validation to deal with FSI problems.
In the end, a simulation of complex geometry of submarine in a flow field will be performed at Reynolds number 10,000 and at defined grid sizes to present its simulation result for review.
After all, a new method for adaptive mesh refinement, ray-casting, $\eta$ of VOS, to judge a point inside a triangle will be presented for review.

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