My observations from the Tuesday, 8 March 2016 kite testing in BSU Wind Tunnel Lab, in the 2X2 foot test section:

 

1. Small kites respond to wind speed change very differently depending on configuration and kite flexibility.

 

2. The frequency of kite oscillation is aperiodic for most configurations with low dihedral.

 

3. The frequency of kite oscillation appears to to kick in a threshold wind speed and increased with wind speed (see CrossBreed range from 76 at

0.9 m/s to 124 at 1.5 m/s).

 

4. The angle of the tether with the horizon did not exceed 63 degrees for any of the kites tested, it appeared kites with higher aspect ratio (wingspan to chord length) had higher tether angles.

 

5. The angle of the tether with the horizon appeared to decrease after a threshold wind speed.

 

6. Judging from our experiment with tinsel to show streamlines of flow over the kite, it is clear that forces on the kite do not behave according to Newtonian Law (third one in particular) rather conventional aerodynamic forces of pressure gradient and shear stress should be applied.

 

7. Reynolds Numbers for the experiments ranged from 2000 to 20,000, based on a kinematic viscosity of air a sea-level T=283K(10C) and kite length dimensions (chord length) ranging from 0.02 to 0.1 m.

 

8. Wind speeds for all tests ranged from 0.9 to 4.8 m/s.

 

Interesting stuff,

 

Robert Hellstrom

Bridgewater State University