臺灣博碩士論文加值系統

在計算流體力學(CFD)的研究領域中，格點是佔一個很重要的部分，格點的多少和好壞影響了程式的計算時間和正確性。如何來建立一組格點較少、品質較好的格點就成為一個重要的課題。
欲建立以有限機翼為基底的三維體積格點，本論文採用C-O grid，可使用較少的格點而得到較佳的結果，而且C-O grid在翼尖處的格點分佈能較正確地傳遞流場的訊息。本論文所使用的軟體是個交談式的軟體，藉著對於曲線、面等的應用技巧來快速地建立我們所需要的格點。此格點為具有良好疏密性、省格點、省程式計算時間並且正交性佳的三維體積格點。
本論文共使用三種基底來建立三維體積格點。首先以翼剖面NACA0012、展弦比為6.6的機翼作為基底，來建立格點數為101×32×41的三維體積格點；其次以翼剖面NACA64A006、展弦比為2.2、漸縮比為0.203和有扭轉的機翼作為基底，來建立格點數為161×42×51的三維體積格點。以上格點經程式計算和既有的結果比較很接近，表示所建立的格點很好。最後以航太所的無人飛行載具計劃中的機翼作為基底，來建立格點數為161×42×51的黏滯三維體積格點。預測在馬赫數0.10和0.15下的一些空氣動力之數值結果並檢視其流場，可清楚看到邊界層的變化情形、分離和回流現象、分離線及翼尖渦流等。

An interactive grid generation technique is an important part of Computational Fluid Dynamics. The number and quality of grid can greatly affect the computation time and result of a computer code. The objective of this study is to fast build a less, better-quality grid for three-dimensional flow simulation.
This study used a three-dimensional volume grid of C-O type for a finite wing. The grid with less grid points still accurately resulted in a good numerical result. In addition, the C-O grid can reasonably present the flow field on the wing tip. Using an interactive grid generation technique, we can easily generate lines, surfaces and hence a three-dimensional volume grid. This grid possesses a proper grid distribution, less grid number, less computer time and grid orthogonality at the body surface or boundaries.
We also used three sets of wing databases to produce three three-dimensional volume grids. One is for a wing with a NACA0012 airfoil and an aspect ratio of 6.6, which has a 101×32×41 grid number; the other with a NACA64A006 airfoil, an aspect ratio of 2.2 and a taper ratio of 0.203, having a 161×42×51 grid number. The computed results of flow field on these two grids are close to the existing data. The third grid was generated for an unmanned aerial vehicle wing. The grid with 161×42×51 grid points was used for a viscous flow model. The predicted results at Mach numbers of 0.10 and 0.15 are presented, involving in the growth of boundary layer, the flow separation and backward flow, the separation lines, and the vortices on the wing tip.

中文摘要……………………………………………………………...I
英文摘要……………………………………………………………..II
目錄…………………………………………………………………..IV
圖目錄………………………………………………………………..V
第一章 緒論………………………………………………….1
第二章 三維體積格點建立的技巧及其理論分析…………..4
2-1線上格點的分布……………………………………….4
2-2二維格點的建立……………………………………….6
2-3三維格點的產生法…………………………………….9
2-4基本翼形的建立………………………………………10
2-5三維體積格點的建立…………………………………12
第三章 數值方法…………………………………………14
3-1薄層納維爾-史托克方程式………………………….14
3-2邊界條件………………………………………… . .16
第四章 結果與討論…………………………………… 18
4-1以NACA0012為翼剖面的機翼……………………..18
4-2以NACA64A006為翼剖面的機翼………………….20
4-3 以NACA23012為翼剖面的機翼…………………...22
第五章 結論與建議…………………………………….27
附錄A……………………………………………………29
參考文獻…………………

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