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To learn more about the capabilities of the Advanced Noise Control Fan Rig and to find out if it can be used for your test, please, contact:

Dan Sutliff

Testing Facilities

Honeycomb-shaped screens (left side of image) are used to create more uniform flow at the entrance to the fan rotating inside the Advanced Noise Control Fan Rig.  Controlled test conditions enable engineers to draw better conclusions from experimental data.

Trailing edge blowing: turning a promising concept into a proven noise reduction technology
Short duration tests had indicated fan noise could be reduced by blowing air through the trailing edge of the rotor blades. But it was clear that longer and more detailed tests in a continuous flow facility were needed. Hollow fan blades were constructed and installed in the Advanced Noise Control Fan Rig.

Both aerodynamic and acoustic measurements were taken since the goal was to reduce noise without sacrificing fan performance. Being able to readily change test parameters, and having access to special instrumentation like the Rotating Microphone Rake enabled engineers to study the problem more closely.

Not only do we now know that far field sound power levels can be reduced by as much as 10-12 dB using trailing edge blowing, but we also have learned a bit about why this is possible. Sharing what we’ve learned about the physics of noise helps whole industries to use and optimize these techniques for their products.

+ Aero-Acoustic Propulsion Lab
+ Small Hot Jet Acoustic
   Test Rig

+ Nozzle Acoustic Test Rig
– Advanced Noise Control
   Fan Rig

+ 9’x15’ Low Speed Wind Tunnel
+ Acoustical Testing Laboratory
+ Particle Image Velocimetry
+ Rotating Microphone Rake
+ Linear Microphone Array
+ Phased Array Microphones
+ Rayleigh Scattering
+ Hotwire, Hotfilm, and Laser    Doppler Velocimetry

Read more about other experiments conducted in the Advanced Noise Control Fan Rig

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NASA Official: Paula J. Dempsey, Ph.D.

Last Updated: March 22, 2019

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