NASA Logo
+ NASA Homepage
+ About Us– Testing+ Analysis+ Collaboration+ Education+ Contact Us

Find Out More
To find out if one of our Phased Arrays can be used for your test, contact:

James E. Bridges

Gary G. Podboy

Special Instrumentation
PHASED ARRAY MICROPHONES
Phased Array

Eighty microphones of a cage array encircle the plume region of a nozzle in the Nozzle Acoustic Test Rig.

Pinpointing noise sources
Like a police officer might find fugitives hiding in the dark using night vision goggles which detect the thermal infrared light from their bodies, engineers can use phased array systems to pinpoint noise sources.

In a phased array system, microphones are placed in a 1D, 2D or 3D arrangement and when sound measurements from these microphones are properly processed, noise sources can be pinpointed.

NASA Glenn has developed a 16-microphone linear array and an 80-microphone cage array which have been used to find the noisy spots in the plumes of different nozzle concepts tested in the rigs of the AeroAcoustic Propulsion Lab.

A 63-microphone spiral-ring array has also been used to hunt down fan noise sources in tests in the 9’ x 15’ Low Speed Wind Tunnel.

NASA engineers have even stepped beyond the gates of the Glenn Research Center, and applied their expertise to identify noise sources in static engine tests for General Electric and Honeywell Engines and Systems using linear, 2D, and cage array systems.

Phased array data can be used to target noise sources, giving engineers clues to help them apply treatment where it is most needed.

TESTING FACILITIES
+ 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
SPECIAL INSTRUMENTATION
+ Particle Image Velocimetry
+ Rotating Microphone Rake
– Phased Array Microphones
+ Rotor Alone
+ Rayleigh Scattering
+ Hotwire, Hotfilm, and Laser    Doppler Velocimetry
Spacer
FirstGov - Your First Click to the US Government

+ NASA Privacy Statement, Disclaimer,
   and Accessibility Certification

+ Download Adobe Reader

Click to visit the NASA Homepage

NASA Official: E. Brian Fite
Last Updated: July 8, 2008


+ GRC Home