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RESULT・INVESTIGATION

As a result of quantity of generation

Butterfly's wing -shaped（Flat board type）Blade

 Wind speed
(m/s)		  2  3  4  5  6  7
 Output
(mW)		  0  146  1098  2346  2302  2292

（　By WINCOM competition movie　）

Dragonfly's wing-shaped blade

 Wind speed
(m/s)		  2  3
  4  5  6  7
 Output
(mW)		  0  195  458  1385  2380  2331




Generation efficiency


We think about generation efficiency(CP). From the theor.

Cp＝２W/PAV

We substitute it for this expression.　P=1.165 (From Science chronological table、Air density-Temperature30℃) A=0.478 , V=2~7

 Wing speed
(m/s)		  Butterfly's (flat)blade
Generation efficiency(Cp)		  Dragonfly's blade
Generation efficiency(Cp)
 2  ０  8.76×10⁻²
 3  1.95×10⁻²  6.09×10⁻²
 4  6.17×10⁻²  7.78×10⁻²
 5  6.73×10⁻²  6.83×10⁻²
 6  3.83×10⁻²  3.96×10⁻²
 7  2.40×10⁻²  2.41×10⁻²





Consideration and summary

Consideration

①　（　Butterfly's(flat)wing blade　）
　We devised a wind tray area to be able to give output electricity even a little.(We made the leader of the blade big thickly.)But、The output in the low wind velocity（2m/s）was zero.
　
　The bestoutput is time of 5meters of wind velocity,and gradually falls down. We think that this is because the blurring of the blade increases when the wind velocity increases.We fixed a P.P boad with a bolt and were not able to bear 7m/s of wind velocity only in footing of the pipe for furniture.

When the hubdynamo gets the rating output, the system is such that the output no longer goes up.


②　（ Dragonfly's wing-shaped blade ）
　Dragonfly's wing-shaped blade exceeds butterfly's(flat board) wing-shaped blade by all output of the low wind velocity～high wind velocity.　The wind that hit a burr side of The Dragonfly's wing-shaped blade makes a small whirlpool with the photograph of the Reynolds number change on the blade surface as showed.This is because descent from air of the whole blade does a flow of the wind such as the NASA type.

　In addition, atomospheric pressure of the blade top surface becomes easy to fall and thereby thinks that even a breeze becomes easy to turn.So,We bent it jaggedly in comparison with butterfly's(flat) wing-shaped blade,rigidity added to doragonfly's-wing shaped blade. And It is thought that output electricity increased because the blurring of the blade decreased.

Summary

　As for the wing in the low Reynolds number area,the wing of the leading edge burr( the wing which lets a flow of the wind exfoliate once ) is higher in output electricity than costal round NASA wing.(This wing type which current NACA announces). It was written on a hydrodynamic book.

The wing of the insect is not streamlined and a leading edge is notched and is thin in unevenness, and there is surely a part having a sharp it.As for the wing type blade of the dragonfly which referred to this, the most effective result is obtained with the wind velocity of around 2～７m/s. After testing it with the wind velocity more than 8m/s, a blade began to bend, and the measurement continuation has become difficult.

Power to act on the object in the fluid has an inertial force and viscous power.　( inertial force = density of the object×speed×area, viscous force = surface area of the object×incline of the speed ) An object becomes small,and the moleculed of the expression indicating the Reynolds number decrease if speed becomes slow, and the effects of the inertial force decrease, and it is thought that effects of viscosity increase.

We cause turbulent flow like the golf ball with the dimple if we pay attention to viscous power, and it is thought that it is important whether you can delay exfoliation point .So, turbulent flow is easy to happen than the butterfly's wing-shaped blade,it is earlier, and the doragonfly's wing(flat blade)-shaped blade turns and thinks that output electricity is high.

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