Reduction in Spectral Intensity

For the lower angles tested, fences are seen to be effective in reducing the over all spectral intensity.  At the higher angles of attack, there is a rise in the broad-band turbulence.  The spectral peak is still moderately reduced, but not to the extent seen at lower angles.  It is important to note that the spectral peak intensity is plotted on a log scale.

F-15 Tail Buffet Alleviation Results
Introduction:    Spectral Amplification:    Centrifugal Instabilities:
Reduced Frequency Scaling:    Linear Peak Frequency/Velocity Slopes:    Models Tested:
Empirical Peak Frequency Data:    Surface Fence Tests:    Reduction in Spectral Intensity:
Reductions Over all Angles:    Comparison with Flight Tests:    Summary:
Future F-15 Wind Tunnel Tests: