跳到主要內容

臺灣博碩士論文加值系統

(44.211.26.178) 您好!臺灣時間:2024/06/16 00:26
字體大小: 字級放大   字級縮小   預設字形  
回查詢結果 :::

詳目顯示

: 
twitterline
研究生:陳建葳
論文名稱:旋轉自由落體能量演進之探討
論文名稱(外文):A study of energy evolution for the spinning free-fall object
指導教授:林源堂
口試委員:劉明山吳進源
口試日期:2015-06-26
學位類別:碩士
校院名稱:逢甲大學
系所名稱:機械與電腦輔助工程學系
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:2015
畢業學年度:103
語文別:中文
論文頁數:136
中文關鍵詞:花形圓錐旋轉自由落體軸向阻力周向阻力
外文關鍵詞:Floral coneRotating free-fall bodyAxial dragCircumferential drag
相關次數:
  • 被引用被引用:1
  • 點閱點閱:277
  • 評分評分:
  • 下載下載:18
  • 收藏至我的研究室書目清單書目收藏:0
本文以實驗記錄花瓣與花托面積比為2:1、2.5:1及3:1之花形圓錐自由落下的過程,探討空氣阻力對旋轉自由落體的影響。
實驗結果顯示旋轉自由落體承受之空氣阻力有軸向阻力和周向阻力二種,軸向阻力由空氣流經樣本表面之壓力和剪力的軸向分量合成,周向阻力由空氣流經表面之剪力產生,其對中心軸之扭矩使花形圓錐產生旋轉運動,錐角較大之花形圓錐,慣性矩也較大,致使轉速減慢,終端速度較小,以延長滯空時間。由動量分析知相同花瓣數和面積比之花形圓錐的軸向阻力遠小於周向阻力,錐角越大,周向阻力增加較軸向阻力劇烈;面積比增大,軸向阻力幾無增加,周向阻力則些微增加。由能量演進分析得知花形圓錐自由落體下降之起始位能轉換成處於不同高度之線動能、轉動動能、軸向阻力消耗能及周向阻力消耗能,相同花瓣數及面積比之花形圓錐下降時,其位能減少,線動能、轉動動能、軸向阻力及周向阻力消耗能增加,隨錐角增加,線動能減少,轉動動能先增加後減少,軸向阻力消耗能隨而些微減少,周向阻力消耗能則會增大。由此推測旋轉運動產生之周向阻力可有效增加自由落體之空氣阻力。
This paper record the falling process of floral cone which used the ratio of petal and torus 2:1, 2.5:1, and 3:1 to clarify the impact of the air resistance acted on the rotating free-fall object.
Results show that both the axial drag and the circumferential drag acted on rotating free-fall object, the axial drag combined by the axial components of the shear forces and pressure forces on the surface of the objects the circumferential drag comes from the shear force,the circumferential drag the hich generated torque to the axis of the floral cone cause the floral cone rotating. Using the floral cone with larger cone angles and moment of inertia to extend the time of the falling process because the cone rotated slowly and the terminal velocity is very small. The analysis of momentum reveals that the axial drag of the floral cone with the same number of the petal and the ratio of area is smaller than circumferential drag. With bigger cone angle, the circumferential drag will increase more than axial drag. As the ratio of area getting bigger, there is no increasing of the axial drag and circumferential drag.
According to the analysis of energy, the initial potential energy of the floral cone in the free-fall process transfer to linear kinetic energy, rotating energy, axial dissipated energy and the circumferential dissipated energy. When the floral cone with same number of petal and the ratio of area falls to ground, the potential energy, linear kinetic energy, rotating energy, axial dissipated energy and the circumferential dissipated energy will increase. As long as increasing the cone angle, linear kinetic energy will decrease, rotating energy will increase at beginning then start to decrease, axial dissipated energy will decrease a little bit and circumferential dissipated energy will be bigger. It concludes that the circumferential drag caused by rotating motion will increase the air drag effectively during the process of free-fall.
誌 謝 i
摘 要 ii
Abstract iii
圖 表 目 錄 vi
第一章 緒論 1
1-1 前言 1
1-2 文獻回顧 2
1-3 研究動機與目的 5
第二章 動量守恆與能量守恆 6
2-1 圓錐自由落體運動原理 6
2-2 花形圓錐自由落體動量守恆與能量守恆 8
第三章 實驗設備與量測方法 27
3-1 實驗設備 27
3-2 量測方法 40
第四章 實驗結果與討論 47
4-1 花形圓錐滯空時間的變化 49
4-2 花形圓錐落下速度變化 54
4-3 花形圓錐落下加速度的變化 58
4-4 花形圓錐落下時軸向總空氣阻力的變化 62
4-5 花形圓錐落下時軸向剪力阻力的變化 67
4-6 花形圓錐落下時軸向壓力阻力的變化 71
4-7 花形圓錐落下時角速度的變化 75
4-8 花形圓錐落下時角加速度的變化 80
4-9 花形圓錐落下時周向阻力的變化 84
4-10 花形圓錐落下時扭阻力矩的變化 88
4-11 花形圓錐落下時能量高度線的變化 92
第五章 結論 110
參考文獻 113
1.J. R. Calvert., “Experiments on the low-speed flow past cones,” J. Fluid Mech. Vol. 27, Part 2, pp. 273-280, January. 1966.
2.P.eremenko,C.A.Mouton,and H.G.Hornung,“The Pressure Drag of Blunted Cones in Supersonic Flow,”AIAA , January. 2003.
3.C.Marchal,“General theory of Relativity:does a rapidly rotating body fall slower than a non-rotating body? ,”Physics Letters A, Vol.318, pp.241-250, 2003.
4.J.M. Wooning, A.H. Mooldijk,“Top angle and the maximum speed of falling cones,”Centre for Science and Mathematics Education, Utrecht University,1996.
5. Pirooz Mohazzabi, “Free fall and angular momentum,” Am. J. Phys. Vol. 67, No. 11, pp.1017-102, November. 1999.
6. H. Dumitrescu and V. Cardos, “Rotational Effects on the Boundary- Layer Flow in Wind Turbines”, AIAA Journal Vol 42, No.2, pp.408-411,2004.
7. A.E. van der Valk,A.H. Mooldijk & J.M. Wooning, “Top angle and the maximum speed of falling cones,” Centre for Science and Mathematics Education, Utrecht University, 1996.
8. Paul Gluck, “Air resistance on falling balls and balloons,” Phys. Teach. Vol. 41, pp. 178-180, March. 2003.
9. M. S. Greenwood, C. Hanna and J. W. Milton, “Air resistance acting on a sphere,” Phys. Teach. Vol. 24, pp. 153-159, March. 1986.
10. W. W. H. Yeung, “On the relationships among strouhal number, pressure drag, and separation pressure for block bluff-body flow,” J. of Fluid Engineering. Vol.132, February. 2010.
11. J. T. Kegelman, R. C. Nelson and T. J.Mueller, “The boundary layer on an axisymmetric body with and without spin,” AIAA , Vol. 21, No. 11, pp. 1485-1491, November. 1983.
12. KOHAMA. Y. , “Flow structures formed by axisymmetric spinning bodies,” AIAA , Vol. 23, No.9, pp.1445-1447, 1985.
13. L. M. Porter, A. Paull, D. J. Mee, and J. M. Simmons , “Shock Tunnel Measurements of Hypervelocity Blunted Cone Drag,” AIAA , Vol. 32, No.12, pp.2476-2477, 1994.
14. R. Kobayashi, Y. Kohama and M. Kurosawa, “Boundary-layer transition on a rotating cone in axial flow,” Journal of Fluid Mechanics, Vol. 127, pp.341-352, 1983.
15. R. Kobayashi and H. Izumi, “Boundary-layer transition on a rotating cone in still fluid,” Journal of Fluid Mechanics, Vol. 127, pp.353-365, 1983.
16. F. M. White, “Viscous Fluid Flow,” McGraw-Hill, Inc. 1911.
17. R. W. Fox, A. T. McDonald and P. J. Pritchard, “Introduction to fluid mechanics”, John Wiley & Sons, Inc., 2004.
18. 陳重軒, “自轉矩形花瓣阻力與效率之探討,” 逢甲大學機械工程研究所碩士論文,民國九十七年.
19. 周宗慶, “花形圓錐自由落體空氣阻力之探討,” 逢甲大學機械工程研究所碩士論文,民國九十八年.
20. 陳俊傑, “三角形花形圓錐自由落體空氣阻力之探討,” 逢甲大學機械工程研究所碩士論文,民國九十九年.
21. 許伯維, “旋轉自由落體空氣阻力之探討,” 逢甲大學機械工程研究所碩士論文,民國一百年.
22. 張智豪, “花形圓錐自由落體空氣阻力之探討,” 逢甲大學機械工程研究所碩士論文,民國一百零一年.
23. 石邦楷, “空氣阻力對旋轉自由落體之影響,” 逢甲大學機械工程研究所碩士論文,民國一百零二年.
24. 蔡亞婷, “不對稱之美---大葉桃花心木種子飛行軌跡的分析, ” 2012年臺灣國際科學展覽會優勝作品專輯.
連結至畢業學校之論文網頁點我開啟連結
註: 此連結為研究生畢業學校所提供,不一定有電子全文可供下載,若連結有誤,請點選上方之〝勘誤回報〞功能,我們會盡快修正,謝謝!
QRCODE
 
 
 
 
 
                                                                                                                                                                                                                                                                                                                                                                                                               
第一頁 上一頁 下一頁 最後一頁 top