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研究生:陳泰元
研究生(外文):Tai-Yuan Chen
論文名稱:力元理論應用於紊流模式
論文名稱(外文):The applications of Force Element on Turbulence Model
指導教授:張建成張建成引用關係
指導教授(外文):Chien-Cheng Chang
口試委員:朱錦洲周逸儒王繼宗
口試委員(外文):Chin-Chou ChuYi-Ru ChouChi-Tsung Wang
口試日期:2013-07-16
學位類別:碩士
校院名稱:國立臺灣大學
系所名稱:應用力學研究所
學門:工程學門
學類:機械工程學類
論文種類:學術論文
論文出版年:2013
畢業學年度:101
語文別:中文
論文頁數:80
中文關鍵詞:力元理論紊流模式環繞機翼流場
外文關鍵詞:Force elementTurbulence ModelFlow around the wing
相關次數:
  • 被引用被引用:1
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本論文主要討論均勻入流流經物體之流場分析,並且探討流場結構與物體受力之關係。一般在討論物體的受力情形,其藉由計算物體表面的表面摩擦力以及表面壓力,並且利用表面積分計算出物體的升、阻力之情形,但此現象並不能描述流場中流體的物理結構對物體受力的影響,而本文使用Chang(1992)力元理論將分解出不可壓縮流流場中,各流體元素對物體所產生的受力貢獻。
此研究將力元理論引用至紊流模式,因此將輔助勢流與平均雷諾方程式作內積並取體積分,並且將導出升、阻力係數與表面摩擦項、體積渦度項與雷諾應力項之關係,藉由此觀點將可觀察出流場物理性質與物體受力之關係,並可藉此方法來判斷這些流場的型態,對於物體個貢獻是造成正貢獻升、阻力係數或是負貢獻升、阻力係數,則可利用此分析、設計,控制流場流體特性進而達到有利的流場應用。
本文的主題主要針對環繞NACA0015機翼且雷諾數為 的升、阻力之情形,利用兩種不同的紊流模式(1) 紊流模式與(2)雷諾應力模式來進行模擬,取得紊流場的的物理特性,並嵌入使用者自訂方程將計算力元分析。同時探討在不同攻角下以及不同的紊流強度下,在不同的情況下流體元素各別對物體的貢獻的大小及其影響。


The thesis analyzed flow field that uniform inflow flow through the objects, and discussed flow field structure and the total force that imposed on the objects. In general, using surface friction and surface pressure calculated force distribution of the objects. However, we made surface integral and calculated that the nature of flow field produced force, using Chang(1992) force element. The fluid property was analyzed and made force element composition.
The research employed force element and turbulence model. Besides, potential flow let Reynolds average equation inner product, and took volume integral, and produced lift or drag coefficient. The lift or drag coefficient was relate to surface friction, volume vorticity and Reynolds stress. So could use this method, got the nature of flow field and force distribution of objects. By this behavior, could judge flow field property that provided positive value or negative value for the objects. Besides, could change shape, got new flow field property and effectively provided positive lift.
The turbulence models, (1) k-epsilon turbulence model, (2) Reynolds model, were used to simulate lift or drag coefficient with NACA0015 airfoil and Reynolds number of . We got turbulence flow field property and used Ansys Fluent to compute the basic flow information and combining flow information with force element. Besides, we also made different angle of attack or turbulence intensity. Observing the fluid element influence and contribute to drag or lift coefficient.


口試委員會審定書 #
致謝 i
中文摘要 ii
ABSTRACT iii
CONTENTS iv
LIST OF FIGURES vii
LIST OF TABLES x
Chapter 1 緒論 1
1.1 前言 1
1.2 參考文獻 2
1.3 全文概述 7
Chapter 2 力元理論與控制方程 8
2.1 前言 8
2.2 輔助勢流 8
2.3 無因次控制方程式 9
2.4 力元理論 12
2.5 紊流模式 18
2.5.1 紊流模式-- 模式 19
2.5.2 紊流模式—雷諾應力模式 20
2.6 牆函數 23
Chapter 3 數值方法 25
3.1 簡介 25
3.2 網格產生 25
3.2.1 計算花費的時間 26
3.2.2 數值擴散 26
3.2.3 網格品質 27
3.3 流場計算 28
3.3.1 分離求解器 29
3.3.2 空間離散 30
3.3.3 時間離散 35
3.3.4 壓力─速度耦合關係的處理 38
3.4 使用者自訂方程式(UDF)介紹 42
3.4.1 網格資料結構 42
3.4.2 DEFINE 巨集( DEFINE Macros ) 45
3.4.3 使用者自訂標量(User Defined Scalar)與使用者自訂記憶體空間(User Defined Memory) 47
3.4.4 UDF執行流程 48
Chapter 4 模擬結果與討論 49
4.1 簡介 49
4.2 流場統御方程式與流場參數 50
4.2.1 流場統御方程式 50
4.2.2 流場參數 51
4.3 輔助勢流結果 52
4.4 數值結果驗證 54
4.5 紊流模式的比較 57
4.5.1 流場特性之比較 57
4.5.2 流場升、阻力係數 58
4.5.3 攻角分析 63
4.5.4 不同紊流強度 69
Chapter 5 結論 76
REFERENCE 78


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7.Hsieh, C. T., Kung, C. F., Chang, C. C., & Chu, C. C. (2010). Unsteady aerodynamics of dragonfly using a simple wing–wing model from the perspective of a force decomposition. Journal of Fluid Mechanics, 663, 233-252.
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9.Menter, F. R. (1994). Two-equation eddy-viscosity turbulence models for engineering applications. AIAA journal, 32(8), 1598-1605.
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16.蕭穎謙(1993) "環繞機翼之二維渦漩流的研究",國立臺灣大學應用力學研究所博士論文
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