Understanding Vibration of an Airplane Wing in a Wind Tunnel

[wizkidder]

Hello all.

I have a question about a wing model...

The model I have is an airplane wing (airfoil) in a wind tunnel. The wing is supported at the quarter-chord length and the wing body is free to move.

My model is in the time domain with an oscillatory force at 20 Hz applied to the wing. When I look at the results, I see an oscillating signal for the displacement of the wing.

Then I use this data in MATLAB for signal processing. The force on the wing has a frequency of 20 Hz, but the frequency of the vibration ranges from 48 to 68 Hz. Why do I get a range for the vibration, when the force on the wing is oscillating at 20 Hz?

Thanks guys!

 

[mugaliens]

Hello all.

I have a question about a wing model...

The model I have is an airplane wing (airfoil) in a wind tunnel. The wing is supported at the quarter-chord length and the wing body is free to move.

Twin boom?

My model is in the time domain with an oscillatory force at 20 Hz applied to the wing. When I look at the results, I see an oscillating signal for the displacement of the wing.

Then I use this data in MATLAB for signal processing. The force on the wing has a frequency of 20 Hz, but the frequency of the vibration ranges from 48 to 68 Hz. Why do I get a range for the vibration, when the force on the wing is oscillating at 20 Hz?

Thanks guys!

Forces do not have frequencies... Need input!