在有關拍撲翼的空氣動力性能分析的論文中，其中不乏數值模擬及實驗結果。然而這些文章只探討拍撲翼在靜止大氣下之行為模式，然而，在實際上，大氣是充滿擾動的。即使是小小的擾動，如亂流，也有可能造成微飛行器相當大的傷害。
　　本文以計算流體力學的方式，利用現有之FLUENT商用軟體及動態網格技術，並簡化拍撲翼之運動模式，在非穩態流場中，計算二維拍撲翼在滯空時的升力與推力變化。
　　最後，本文建立適當之亂流風場，考慮拍撲翼在滯空時可能遭受到的風場模擬，發現風場的變化確能造成拍撲翼升力的改變，當風速越大時，升力的改變越劇烈，隨著自由流方向的改變，其升力的大小亦隨之改變。
　　天候對拍撲翼的影響是一直存在的，在設計微飛行器時亦是須被考量在內的一點，本文對於相關的議題作了一個初步的結果，未來將以三維真實拍撲翼為考量，並考慮大雨可能造成的影響，以提供設計微飛行器的參考之一。

Numbers of studies about flapping wing aerodynamic performance have been published including experiment and simulation. But these researches only consider that flapping motion work under calm and clear atmospheric conditions. Small atmospheric disturbance, such as gust wind, could lead to flapping MAV (Micro Aerial Vehicle) great damage. 
In this thesis, using numerical method and employ FLUENT software as the flow solver, the motions of flapping wing are simplified and combine with the dynamic mesh technique. Thus, we could calculate the 2-D flapping wing aerodynamic parameters such as lift and thrust in unsteady flow.
Finally, we constructed the gust wind profile, and simulating the flapping behavior in gust wind conditions. We found that the lift did change with the wind speed. As wind speed gets large, the lift also change more violently. Lift also changes while directions of gust wind change.
Weather influence always exists, and must be considered in designing MAVs. This thesis made a preliminary study to the topics. In future, we can consider the real cases such as 3-D flapping wing and rain effects to provide more realistic the consideration of designing the MAVs.

CHAPTER 1 INTRODUCTION	1
CHAPTER 2 RESEARCH BACKGROUND	5
2-1	 LITERATURE REVIEW	5
2-2	 FLIGHT MECHANISM	8
2-3	 GUST WIND PHYSICS	12
CHAPTER 3 NUMERICAL MODELING	14
3-1	 PREPROCESSING	14
3-2	 MESH SYSTEM	17
3-3	 GOVERNING EQUATIONS	20
3-4	 NUMERICAL METHOD	22
3-5	 GUST WIND MODELING	27
3-6	 VERIFICATION	33
CHAPTER 4 RESULTS AND DISCUSSION	36
CHAPTER 5 CONCLUSION	51
REFERENCES	52
APPENDIX	55
 

Fig. 1.1  Reynolds number range for flight vehicles.	2
Fig. 2.2  Stoke plane inclined at an angle β to the horizontal.	8
Fig. 2.3  (a) The wing tip path viewed from the side. (b) The wingbeat viewed from above.	9
Fig. 2.4  The wingbeat of a bat.	10
Fig. 2.5  The downstroke of a vertical take-off by Pieris brassicae.	11
Fig. 3.1  The positions of flapping wing in one period.	14
Fig. 3.2  Grids and calculated field.	19
Fig. 3.3  Grids around the flapping wing.	19
Fig. 3.4  The solution loop of the segregated solver.	22
Fig. 3.5  1-D control volume.	24
Fig. 3.6  X direction real gust wind velocity.	28
Fig. 3.7  Y direction real gust wind velocity.	28
Fig. 3.8  T1 parameter in X direction.	29
Fig. 3.9  T1 parameter in Y direction.	29
Fig. 3.10  X direction gust wind model velocity.	31
Fig. 3.11  Y direction gust wind model velocity.	31
Fig. 3.12  T1 parameter in X direction.	32
Fig. 3.13  T1 parameter in Y direction.	32
Fig. 3.14  The mesh of impulsively started flow over a cylinder	34
Fig.3.15  Numerical result for velocity uθ(r) vs. r/R compared with theory.	35
Fig. 3.16  The velocity along the symmetry axis at different instant.	35
Fig. 4.1  Vorticity contour at 0.25T	39
Fig. 4.2  Vorticity contour at 0.5T	39
Fig. 4.3  Vorticity contour at 0.75T	39
Fig. 4.4  Vorticity contour at 1T	39
Fig. 4.5  Lift profile in first ten periods.	40
Fig. 4.6  Drag vs. period.	40
Fig. 4.7  Lift vs. period comparing with references.	41
Fig. 4.8  Wind magnitude vs. period in case 1.	42
Fig. 4.9  Wind speed in different direction in case 1.	42
Fig. 4.10  Lift vs. period in case 1.	43
Fig. 4.11  Drag vs. period in case 1.	43
Fig. 4.12  Mean lift per period in case 1.	44
Fig. 4.13  Mean drag per period in case 2.	44
Fig. 4.14  Wind magnitude vs. period in case 2.	45
Fig. 4.15  Wind speed in different direction in case 2.	45
Fig. 4.16  Lift vs. period in case 2.	46
Fig. 4.17  Drag vs. period in case 2.	46
Fig. 4.18  Mean lift per period in case 2.	47
Fig. 4.19  Mean drag per period in case 2.	47
Fig. 4.20  Wind magnitude vs. period in case 3.	48
Fig. 4.21  Wind speed in different direction in case 3.	48
Fig. 4.22  Lift vs. period in case 3.	49
Fig. 4.23  Drag vs. period in case 3.	49
Fig. 4.24  Mean lift per period in case 3	50
Fig. 4.25  Mean drag per period in case 3	50

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