非結構性網格較易處理複雜幾何外形且對可調性網格技巧之使用具有方便性，故其在計算流體力學之領域上實為重要。為著有效處理複雜幾何外形之問題，本文採用CATIA電腦輔助設計軟體提供所需的幾何外形。首先利用此軟體在外形上建構表面非結構性三角形網格以形成邊界網格，然後將邊界網格之資料轉換以結合劉與黃所發展之網格建立法。經由上述步驟，可在包含任何物體之區域中建立非結構性四面體網格。為有效且正確處理邊界層問題，本文也利用CATIA軟體在物體表面附近建立稜鏡型網格。將稜鏡型網格最外層之資料當成邊界網格，接著引用上述之結合步驟可完成稜鏡與四面體混合網格。為評估本方法之可行性，首先對包含不同翼展之NACA 0012雙葉片旋翼區域進行四面體網格及稜鏡與四面體混合網格之建立。然後在同心立方體、同軸圓管與同心圓球區域建構四面體網格。

The application of unstructured mesh in computational fluid dynamic becomes very important because of its availability of triangulating complicated geometry and its simplicity for use of adaptive mesh technique. To efficiently treat the problem with complicated geometry, the CAD software of CATIA is adopted in this paper to provide geometry which we need. Firstly, the CAD software of CATIA is used to create the unstructured triangular meshes on surfaces of geometry to form the boundary meshes, then the data of boundary meshes is transformed to combine with a mesh generation technique which was developed by Liu and Hwang. By using the above-mentioned procedure, the unstructured tetrahedral meshes are created in the domains which include any kinds of bodies. Also, CATIA is adopted to creat the prismatic meshes around the surfaces of bodies, so that the boundary-layer problems can be treated efficiently and exactly. By choosing the data of outside prismatic meshes as boundary meshes, the prismatic and tetrahedral hybrid meshes are accomplished when the above-mentioned combinative steps are used. To evaluate the feasibility of the present method, the tetrahedral meshes and the prismatic and tetrahedral hybrid meshes are firstly created in the regions which contain the two-blade rotor having the NACA 0012 airfoil and different values of span. Then the domains including concentric cubes, coaxial annular pipe and concentric spheres are divided into tetrahedral meshes respectively.

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