結論 - 流體注入對圓柱尾流渦漩的影響與其流場控制研究(II)Effect of Unsteady Fluid Mass Injection on the Vortex Shedding f

於圓柱後方(0°角)穩定注入動量時，圓柱後方之尾流結構將被破壞，尾流場中沒有明顯的渦漩剝離之固定頻率出現。隨著注入動量增加，尾流的區域跟著縮減，分離點將延後發生，隨著動量干擾角度的增加，動量的干擾將阻擋從上游通過圓柱的流體，阻礙上游流體的能量傳遞至圓柱後方，而圓柱後方受尾流影響的區域也會增加，若持續增加注入的動量會擴大尾流區的範圍。

在穩定吸出動量時，圓柱後方流場將與注入動量時產生相當大的差異。首先在0°角(於圓柱後方)吸出動量，在圓柱後方會出現一週期

性的均勻流場，造成尾流流場的範圍擴大。但是當動量吸出的角度改至60°時，由實驗結果中可以看到圓柱後方只剩下一剪力層存在，若增加動量的干擾，則可以降低此剪力層的振幅及出現的頻率，而其所影響的範圍也會隨之減小。若持續增加動量的吸出，則流場將變的更為均勻，但是如果將動量吸出的角度增加到90°時，所形成的尾流對

流場的影響又會增加，不過其影響的範圍也會隨著干擾量的增加而減小。

以升力阻力而言，穩定地從0°角注入會降低阻力，也降低升力係數上下起伏的振幅；反之動量的吸出會增加阻力的平均值，並且增加

阻力升力上下起伏的振幅。以消除尾流後的渦流結構而言，動量從 0

°角注入的效果最好。

當有週期性的動量注入-吸出時，阻力係數有明顯週期性的變化，

注入-吸出的振幅越大，阻力係數的起伏振幅也越大，其尖峰值與動量注入的尖峰值有相位落差（約180°），二者的週期相同。升力係數基本上為零，這是由於週期性的動量注入破壞了原來的渦流結構。

不同頻率的動量注入，阻力係數以相同於動量干擾的頻率，做週期性的變化，因此動量干擾的頻率，為主宰流場振盪的頻率。在相同的注入振幅下，阻力係數上下變動的振幅均相同，升力係數均為零。。

誌謝

本計畫的執行感謝國科會給予贊助，使本計畫在實驗設備及研究人力上，不至於因為經費的問題而困窘，在研究方面也更能夠專心一意的前進，在此再次表達最高的謝意。

參考文獻

Adrian R. J., Dynamic Ranges of Velocity and Spatial Rsolution of Particle Image Velocimetry, Meas. Sci. Technol. 8, 1393-1398, 1997.

Baldassarre A., Lucia M. De, Nesi P. and Rossi F., A Vision-Based Particle Tracking Velocimetry, Real-Time Imaging 7, 145-158, 2001 Academic Press.

Blevins,R.D. 1990, “Flow-Induce Vibration”, Second Edition,Van Nostrand Reinhold.

Chyu,C.K. and Rockwell,D., “Near-Wake Structure of an Oscillating Cylinder: Effect of Controlled Shear-Layer Vortices,” Journal of Fluid Mechanics, Vol.322, pp.21-40,1996.

Cimbala,J.M. and Park,W.J., “Experimental Investigation of the Turbulent Structure in the Wake of a Two-Dimensional Airfoil,”

Journal of Fluid Mechanics, Vol.213, pp.479-509, 1990.

Dunham J. , A Theory of Circulation Control by Slot-blowing, Applied to a Circular Cylinder, Journal of Fluid Mechanics, vol. 33, part 3, pp.

495-514, 1968.

Fujisawa N., Kawaji Y. and Ikemoto K. , Feedback Control of Vortex Shedding from a Circular Cylinder by Rotational Oscillations, Journal of Fluids and Structures, vol. 15, pp. 23-37, 2001.

Funes-Gallanzi, High Accuracy Measurement of Unsteady Flows Using Digital Particle Velocimetry, Optics & Technology, vol. 30, pp.

349-359, 1998.

Gopalkrishnan,R., Triantafyllou,M.S., Triantafyllou, G.S. and Barrett,D.,

1994, “Active Vorticity Control in a Shear Flow Using a Flapping Foil,” Journal of Fluid Mechanics, Vol.274,pp.1-21.

Govardhan R. and Williamson C. H. K., Mean and Fluctuating Velocity Fields in the Wake of a Freely-Vibrating Cylinder, Journal of Fluids and Structures, vol. 15, pp. 489-501, 2001.

Green,R.B. and Gerrard,J.H., “Vorticity Measurements in the Near Wake of a Circular Cylinder at Low Reynolds Numbers.” Journal of Fluid Mechanics, Vol.246, pp.675-691, 1993.

Gunzburger,M.D. and Lee,H.C., “Feedback Control of Karman Vortex Shedding, ” , Journal of applied mechanics, Transactions of the ASME, Vol.63, pp.828-835, 1996.

Gursul,I., Srinvas,S. and Batta,G., “Active Control of Vortex Breakdown over a Delta Wing,” AIAA Journal,Vol.33, pp.1743-1745, 1995.

Hover F. S., Tvedt H. and Triantafyllou M. S., Vortex-Induced Vibrations of a Cylinder with Tripping Wires, J. Fluid Mech. vol. 448, pp.

175-195, 2001.

Igarashi,T. and Itoh,S., “Drag Reduction of a Square Prism (1st Report, Flow Control around a Square Prism Using a Small Vortex Shedder),”

Transactions of JSME, Vol.59, pp.3701-3707, 1993.

Kazuyuki Fujimura, Hiroaki Yoshizawa, Reima Iwatsu, Hide S. Koyama, and Jae Min Hyun, “Velocity Measurements of Vortex Breakdown in an Enclosed Cylinder,” Journal of Fluids Engineering, Transactions of the ASME, Vol.123, pp. 604-611, 2001.

Keane R. D., Adrian R. J. and Zhang Y., Super-Resolution Particle Imaging Velocimetry, Meas. Sci. Technol, 6, 754-768, 1995.

Kim M. J., Bekok A. and Kihm K. D., Electro-Osmosis-Driven

Micro-Channel Flows: A Comparative Study of Microscopic Particle Image Velocimetry Measurements and Numerical Simulations, Experiments in Fluids, vol. 33, pp. 170-180, 2002.

Lee,S.J. and Kim,H.B., “Effect of Surface Protrusions on the near Wake of a Circular Cylinder,” Journal of Wind Engineering and Industrial Aerodynamics Progress in Bluff Body Aerodynamics Proceedings of the 1996 3rd International Colloquium on Bluff Body Aerodynamics and Applications Jul 28-Aug 1, Vol.69-71, pp.351-361, 1996.

Lienhard,J.H. “Synopsis of Lift, Drag and Vortex Frequency Data for Rigid Circular Cylinders,” Washington State University, College of Engineering, Research Division Bulletin pp.300, 1966.

Lin J. -C., Towfighi J. and Rockwell D., Near-wake of a Circular Cylinder: Control by Steady and Unsteady Surface Injection, Journal of Fluids and Structures, 9, 659-669, 1995.

Lin, Yang Y. and Rockwell D., Flow Past Two Cylinders in Tandem:

Instantaneous and Averaged Flow Structure, Journal of Fluids and Structures, 16(8), 1059-1071, 2002.

Mathelin L., Bataille F. and Lallemand A., Near Wake of a Circular Cylinder Submitted to Blowing – II Impact on the Dynamics, International Journal of Heat and Mass Transfer, 44, 3709-3719, 2001.

Mathelin L., Bataille F. and Lallemand A., The Effect of Uniform Blowing on the Flow Past a Circular Cylinder, Journal of Fluids Engineering, 124, 452-464, 2002.

Modi,V.J., Dobric,A. and Yokomizo,T., “Effect of Momentum Injection on the Fluid Dynamics of Bluff Bodies,” Proceedings of the Third (1993) International Offshore and Polar Engineering Conference, Part

3 (of 4) Jun 6-11, 1993 Singapore, pp.501-513, 1993.

Munshi,S.R., Modi,V.J. and Yokomizo,T., “Effect of Momentum Injection on the Drag Reduction and Flow-Induced Instabilities of a Square Prism,” International Journal of Offshore and Polar

Engineering, Vol.6, No.3, pp.161-170, 1996.

Munshi S. R., Modi V. J. and Yokomizo T., Aerodynamics and dynamics of rectangular prisms with momentum injection, Journal of Fluids and Structures, vol. 11, pp. 873-892, 1997.

Munshi,S.R., Modi,V.J., and Yokomizo,T., “Drag Reduction and Vibration Control of a Spar-Type Cylindrical Structure through Boundary-Layer Control,” Proceedings of the International Offshore and Polar Engineering Conference Proceedings of the 1998 8th

International Offshore and Polar Engineering Conference. Part 3 (of 4) May 24-29 , Vol.3, 1998 Montreal, pp.415-423, 1998.

Oshima H. and Ramaprian B. R., The Use of Particle Image Velocimetry to Study Vortex Shedding Behind a Cylinder, Fluid Measurement and Instrumentation Forum FED-Vol. 108, ASME 1991.

Richard D. Keane and Ronald J. Adrian, Optimization of Particle Image Velocimeters. Part 1: Double Pulsed Systems, Meas. Sci. Technol. 1, 1202-1215, 1990.

Sahjendra N. Singh, James H. Myatt, Gregory A. Addington, Siva Banda, and James K. Hall, 2001, “Optimal Feedback Control of Vortex

Shedding Using Proper Orthogonal Decomposition Models,” Journal of Fluids Engineering, Transactions of the ASME, Vol.123,

pp.612-618.

Sakamoto,H., Tan,K. and Haniu,H., “An Optimum Suppression of Fluid

Forces by Controlling a Shear Layer Separated form a Square Prism,”

Journal of Fluids Engineering, Transactions of the ASME, Vol.113, pp.183-189, 1991.

Sakamoto,H. and Haniu,H., “Optimum Suppression of Fluid Forces Acting on a Circular Cylinder,” Journal of Fluids Engineering, Transactions of the ASME, Vol.116, pp.221-222, 1994.

Sakamoto,H., Tan,K., Takeuchi,N. and Haniu,H., “Suppression of Fluid Forces Acting on a Square Prism by passive Control,” Journal of Fluids Engineering, Transactions of the ASME, Vol.119, pp.506-511, 1997.

Shafiqul Islam M., Haga K., Kaminaga M., Hino R. and Monde M., Experimental Analysis of Turbulent Flow Structure in a Fully Developed Rib-Roughende Rectangular Channel with PIV, Experiments in Fluids, vol. 33, pp. 296-306, 2002.

Soria J., An Investigation of the Near Wake of a Circular Cylinder Using a Video-Based Digital Cross-Correlation Particle Image Velocimetry Technique, Experimental Thermal and Fluid Science, 12:221-233, 1996.

Strykowski,P.J., and Sreenivasan,K.R., “The Control of Vortex Shedding behind Circular Cylinder at Low Reyolds Numbers”, Proceeding of 5th Symp. on Turbulent Shear Flows, Cornell University, 1985.

Strykowski,P.J., and Sreenivasan,K.R., “On the Formation and

Suppression of Vortex Shedding at Low Reynolds Numbers,” Journal of Fluid Mechanics, Vol.218, pp.71-107, 1990.

Strouhal,V. “Uber enie Besondere Art der Tonerregung,” Annalen der Physik und Chemie(Leipzig), pp.217-251, 1878.

Tang,S., “Suppression of Vortex Shedding Inspired by a

Low-Dimensional Model,” Journal of Fluids and Structures, Vol.14, pp.443-468, 2000.

Tao,J.S. and HUANG,X.Y., “A Flow Visualization Study on Feedback Control of Vortex Shedding from a Circular Cylinder,” Journal of Fluids and Structures, Vol.10, pp.965-970, 1996.

Tennekes,H. and Lumle,J.L., “A First Course in Turbulence,” The MIT Press Cambridge, Massachusetts, and London, England, 1972

Tomboulides,A.G., “Direct and Large-Eddy Simulation of Wake Flows:

Flow Past a Sphere ,” Ph.D. Thesis, Department of Mechanical and Aerospace Engineering, Princeton University, 1993.

Unal M. F., Lin J. –C and Rockwell D., Force Prediction by PIV Imaging:

A Momentum-Based Approach, Journal of Fluids and Structures, vol.

11, pp. 965-971, 1997.

Von Karman,T., “Uber den Mechanismuss des Windersstandes den ein bewegter Korper in einen Flussigkeit Erfahart,” Nachrichten der K.

Gesellschaft der Wissenschaften zu Gottingen, pp.547-556, 1912.

Weaver,D.S., and El-Kashlan,M., “On the Number of Tube Rows Required to Study Cross-flow Induced Vibrations in Tube Banks,”

Journal of Sound and Vibration, Vol.75, pp.265-273, 1981.

Yannick Delaunay and Lambros Lambros Kaiktisis, “Control of Cylinder Wakes Using Base Mass Transpiration,” Physics of Fluids, Vol.13, pp.3285-3302, 2001.

1 2 4 3

5

7 9 10

11

12 13 14 6

8

1 . 儲水槽 2 . 管路 3 . 排水閥門 4 . 金屬軟管 5 . 抽水馬達 6 . 變頻器 7 . 浮子式流量計 8 . 濾網 9 . 漸擴段 1 0 . 整流箱 1 1 . 漸縮段 1 2 . 蜂巢式整流器 1 3 . 皮托管 1 4 . 測試段

圖 2.1-1 封閉式水循環系統

Flow

Flow In

Pitot Tube

圖 2.1-2 測試段立體圖

Water in

圖 2.1-3 圓柱動量干擾示意圖

圖 2.1-4 動量干擾之狹縫角度改變圖

Momentum Injection Flow

Flow

Momentum Injection Cylinder

Slot Angleθ

DC Motor

Flow

M t

圖 2.1-5 穩定動量注入/吸入方式

圖 2.1-6 往復式運動機構

Connect to Water Tank Connect to

Cylinder

Signal In

f 2 f ₁

d 1

d 2

圖 2.2-1 PIV 系統設備圖

圖 2.2-2 雷射經透鏡聚焦過程

DANTEC 55L90A

Lens module

Light sheet CCD

PC

Flow Test

section

Cylindrical lens

X Y

Lens 2 Lens 1

loop on I = 2 ~ n

圖 2.2-3 分析程式流程圖 Read two digital images

Divide images to interrogation regions

Shift I

th

, ( I = 1 ~ n ) interrogation with it’s relative

one to find max correlation C

max _I

UseC

max _I

to calculate I

th

interrogation’s flow velocity

Get whole fluid field

1 2 3 4

Resolution of interrogation (pixel × pixel)

圖 2.2-4 不同的 interrogation resolution 比較圖(兩張圖由人工位移(x, y): (5, 10) pixels)

Resolution of interrogation (pixel × pixel)

圖 2.2-5 不同的 interrogation resolution 比較圖(兩張圖由人工位移(x, y): (30, 20) pixels)

圖 2.2-6 Single particle 在不同情形下通過光頁之灰階分佈 (From Baldassarre, Lucia Nesi and Rossi, 2001)

(a)

(c)

(b) (e)

(d)

Hot-Film

圖 2.3-1 熱膜測速儀探針(Hot-Film probe)流場量測分析流程 Anemometer

CTA 56C01

Data Acquisition

Data Output Analysis Hot-Film

圖 2.4-1 流場可視化設備流程

圖 2.5-1 應變規設備配置圖

Strain Gauge

電橋濾波器

&

放大器

IEEE 488 PC

電壓擷取系統

穩定動量噴/吸入系統往復動量噴吸入系統螢光染劑

整流區

測試圓管

雷射光頁(Laser-Light Sheet)

圖 2.5-2 固定支架示意圖

10cm

^up

=0.1611m/s, T=0.60sec, D=20mm, 水溫 30℃

X / D

Y/ D

(a) T = 0sec

(b) T = 1.0sec

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

圖 3.1-7 Continue.

(d) T = 3.0sec

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

圖 3.1-7 Continue.

(e) T = 4.0sec

(f) T = 4.8sec

-10 0 10 20 30

圖 3.1-7 Continue.

X/D X/D X/D X/D

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 Hot-Film probe located at X/D=3.5, Y/D=1.0

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

-3 -2 -1 0 1 2 3

1.0

Re=1600 , X/D=3.5

_j

_up

-3 -2 -1 0 1 2 3

Re=2400 , X/D=3.5 U

_j

_up

1.0

Re=3200 , X/D=3.5

_j

^m

=520 mm/s.

(a) T = 0sec

(b) T = 1.0sec

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

圖 3.2-17 Continue.

(d) T = 3.0sec

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

圖 3.2-17 Continue.

(e) T = 4.0sec

(f) T = 5.0sec

-10 0 10 20 30

圖 3.2-17 Continue.

U (mm/s)

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

-3 -2 -1 0 1 2 3

-20 -10 0 10 20 30

U V

Vel o ci ty ( mm/ s)

Y / D

圖 3.2-18 (a) At Re = 465,

U _∞

= 22.1 mm/s, 0°角動量注入 Q = 0.2 L/min (b) 速度分佈圖 at (X/D)≈2.

(a)

(b)

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

-3 -2 -1 0 1 2 3

-20 -10 0 10 20 30

U V

Vel o ci ty ( m m /s)

Y / D

圖 3.2-19 (a) At Re = 465,

U _∞

= 22.1 mm/s, 0°角動量注入 Q = 0.5 L/min (b) 速度分佈圖 at (X/D)≈2.

(b) (a)

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

圖 3.2-22 Re=465 60°動量注入 Q=0.5 L/min 之圓柱後尾流場連續速度向量分佈圖,週期 5 sec. 狹縫噴出速度為 U

^m

=520 mm/s.

(a) T = 0 sec

(b) T = 1.0 sec

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

圖 3.2-22 Continue.

(d) T = 3.0 sec

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

圖 3.2-22 Continue.

(e) T = 4.0 sec

(f) T = 5.0 sec

-20 -10 0 10 20 30

圖 3.2-22 Continue.

X/D = 1 X/D = 2 X/D = 3 X/D = 4

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

-3 -2 -1 0 1 2 3

-20 -10 0 10 20 30

U V

Ve lo ci ty ( m m /s)

Y / D

圖 3.2-23 (a)At Re = 465,

U _∞

= 22.1 mm/s, 60°角動量注入 Q = 0.2 L/min(b)速度分佈圖 at (X/D)≈2.

(a)

(b)

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

圖 3.2-25 Re=465 90°動量注入 Q=0.5 L/min 之圓柱後尾流場連續速度向量分佈圖,週期 5 sec. 狹縫噴出速度為 U

^m

=520 mm/s.

(a) T = 0

(b) T = 1.0 sec

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

圖 3.2-25 Continue.

(d) T = 3.0 sec

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

圖 3.2-25 Continue.

(e) T = 4.0 sec

(f) T = 5.0 sec

-20 -10 0 10 20 30

圖 3.2-25 Continue.

X/D = 1 X/D = 2 X/D = 3 X/D = 4

X / D

0 1 2 3 0.00

0.05 0.10 0.15 0.20

A m pl it ude

Frequency (Hz)

圖 3.2-28 Re = 465, 0°動量注入 Q=0.5 L/min 之流場頻譜圖, 在 X=2.6D, Y=0.5D 處

0 1 2 3

0.00 0.05 0.10 0.15 0.20

A m p litu d e

Frequency (Hz)

圖 3.2-29 Re = 465, 60°動量注入 Q=0.5 L/min 之流場頻譜圖, 在 X=2.6D, Y=0.8D 處

0 1 2 3 0.00

0.05 0.10 0.15 0.20

A m p litu d e

Frequency (Hz)

圖 3.2-30 Re = 465, 90°動量注入 Q=0.5 L/min 之流場頻譜圖, 在 X=2.6D, Y=0.8D 處

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 probe located at X/D=3.5, Y/D=1.0

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

(a) T = 0sec

(b) T = 1.6sec

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

圖 3.3-17 Continue.

(d) T = 4.8sec

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

圖 3.3-17 Continue.

(e) T = 6.4sec

(f) T = 8.0sec

-10 0 10 20 30

圖 3.3-17 Continue.

X/D X/D X/D X/D

X / D

(f) T = 3.3sec

-10 0 10 20 30

圖 3.3-22 Continue.

X/D X/D X/D X/D

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

-3 -2 -1 0 1 2 3

-20 -10 0 10 20 30

U V

V e lo c ity (m m /s )

Y / D

圖 3.3-23 (a) At Re = 465,

U _∞

= 22.1 mm/s, 60°角動量吸出 Q = 0.2 L/min (b) velocity distribution at (X/D)≈2.

(a)

(b)

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

-3 -2 -1 0 1 2 3

-20 -10 0 10 20 30

U V

Ve lo c it y ( m m /s)

Y / D

圖 3.3-24 (a) At Re = 465,

U _∞

= 22.1 mm/s, 60°角動量吸出 Q = 0.5 L/min (b) velocity distribution at (X/D)≈2.

(a)

(b)

X / D

(f) T = 3.8sec

-10 0 10 20 30

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

-3 -2 -1 0 1 2

-20 -10 0 10 20 30

U V

V e lo ci ty ( m m /s)

Y / D

圖 3.3-26 (a) At Re = 465,

U _∞

= 22.1 mm/s, 90°角動量吸出 Q = 0.2 L/min (b) velocity distribution at (X/D)≈2.

(a)

(b)

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

-3 -2 -1 0 1 2

-20 -10 0 10 20 30

U V

V e lo c ity (m m /s )

Y / D

圖 3.3-27 (a) At Re = 465,

U _∞

= 22.1 mm/s, 90°角動量吸出 Q = 0.5 L/min (b) velocity distribution at (X/D)≈2.

(a)

(b)

0 1 2 3 0.00

0.05 0.10 0.15 0.20

A m p litu d e

Frequency (Hz)

圖 3.3-28 Re = 465, 0°動量吸出 Q=0.5 L/min 之流場頻譜圖, 在 X=2.6D, Y=0.5D 處

0 1 2 3

0.00 0.05 0.10 0.15 0.20

A m pl it ude

Frequency (Hz)

圖 3.3-29 Re = 465, 60°動量吸出 Q=0.2 L/min 之流場頻譜圖, 在 X=2.6D, Y=0.8D 處

0.13 Hz

0.27 Hz

0 1 2 3 0.00

0.05 0.10 0.15 0.20

A m p litu d e

Frequency (Hz)

圖 3.3-30 Re = 465, 90°動量吸出 Q=0.5 L/min 之流場頻譜圖, 在 X=2.6D, Y=0.8D 處

0.26 Hz

time = 0 sec (a)

time = 0.39 sec (b)

time = 0.78 sec (c)

time = 1.18 sec (d)

time = 1.57 sec (e)

time = 1.95 sec (f)

time = 2.35 sec (g)

time = 2.74 sec (h)

time = 3.13 sec (i)

圖 3.4-1 在 Re=800, f

^os

=0.3HZ 之往復動量圓柱尾流流場觀測，

其中 U

^slit

^up

=4.97, 水溫 30℃

time = 0 sec (a)

time = 0.17 sec (b)

time = 0.39 sec (c)

time = 0.58 sec (d)

time = 0.79 sec (e)

time = 0.98 sec (f)

time = 1.19 sec (g)

time = 1.38 sec (h)

time = 1.58 sec (i)

圖 3.4-2 在 Re=1600, f

^os

=0.3HZ 之往復動量圓柱尾流流場觀測，

其中 U

^slit

^up

=2.49, 水溫 30℃

time = 0 sec (a)

time = 0.13 sec (b)

time = 0.26 sec (c)

time = 0.40 sec (d)

time = 0.52 sec (e)

time = 0.65 sec (f)

time = 0.79 sec (g)

time = 0.92 sec (h)

time = 1.05 sec (i)

圖 3.4-3 在 Re=2400, f

^os

=0.3HZ 之往復動量圓柱尾流流場觀測，

其中 U

^slit

^up

=1.65, 水溫 30℃

time = 0 sec (a)

time = 0.10 sec (b)

time = 0.20 sec (c)

time = 0.31 sec (d)

time = 0.39 sec (e)

time = 0.51 sec (f)

time = 0.61 sec (g)

time = 0.72 sec (h)

time = 0.81 sec (i)

圖 3.4-4 在 Re=3200, f

^os

=0.3HZ 之往復動量圓柱尾流流場觀測，

其中 U

^slit

^up

=1.24, 水溫 30℃

time = 0 sec (a)

time = 0.78 sec (b)

time = 1.57 sec (c)

time = 2.35 sec (d)

time = 3.21 sec (e)

time = 3.91 sec (f)

time = 4.68 sec (g)

time = 5.45 sec (h)

time = 6.23 sec (i)

圖 3.4-5 在 Re=800, f

^os

=0.5HZ 之往復動量圓柱尾流流場觀測，

其中 U

^slit

^up

=4.97, 水溫 30℃

time = 0 sec (a)

time = 0.24 sec (b)

time = 0.46 sec (c)

time = 0.71 sec (d)

time = 0.95 sec (e)

time = 1.19 sec (f)

time = 1.43 sec (g)

time = 1.67 sec

在文檔中流體注入對圓柱尾流渦漩的影響與其流場控制研究(II)Effect of Unsteady Fluid Mass Injection on the Vortex Shedding from a Circular Cylinder and Its Control (II) (頁 58-174)

結論

誌 謝

參考文獻

1

2 4 3

5

7

9 10

11

12

13 14 6

8

Flow In

Pitot Tube

Flow

Momentum Injection Cylinder

Slot Angleθ

DC Motor

Connect to Water Tank Connect to

Cylinder

Signal In

f 2 f 1

d 1

d 2

DANTEC 55L90A

Lens module

Light sheet CCD

PC

Flow Test

section

Cylindrical lens

X Y

Lens 2 Lens 1

loop on I = 2 ~ n

th

max I

max I

th

1 2 3 4

Resolution of interrogation (pixel × pixel)

Resolution of interrogation (pixel × pixel)

Strain Gauge

&

IEEE 488 PC

電壓擷取系統

10cm

3cm 2cm

固定端 應變規黏貼處 受力

up

up

up

up

X / D

Y/ D

1 2 3 4

0 1 2 3 4

0 1 2 3 4

0 5 10 15 20 25

Vel o ci ty ( m m /s)

Y / D

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

X / D

Y/ D

0 1 2 3 4

-2 -1 0 1 2

誌謝

f 2 f ₁

max _I

max _I

固定端應變規黏貼處受力

^up

^up

^up

^up

_j

_up

_j

_up

_j

_up

_j

_up

_j

_up

_j

_up

^m

U _∞