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To find out if the Linear Microphone Array can be used for your test, contact:

David Stephens

Special Instrumentation
LINEAR MICROPHONE ARRAY
Linear Microphone Array

The linear microphone array mounted in the NASA Glenn 9’x 15’ Low Speed Wind Tunnel

Improving acoustic measurements
Making high-quality acoustic measurements in a Mach 0.2 flow is a challenging proposition. Think of how noisy a high-speed air flow can sound when you stick your head out a car window. Now imagine an air flow of 150 MPH! The NASA Glenn 9’ x 15’ Low Speed Wind Tunnel runs at these speeds to simulate an aircraft taking off or landing. Taking sound measurements at these speeds is challenging, and required special instrumentation. One instrument being used in the wind tunnel is the linear microphone array pictured above. This is a long, smooth panel with microphones embedded in groups of three at sixteen locations along its length. When used with statistical data processing methods, this can help eliminate the wind noise and improve measurements of the model being tested.

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
– Linear Microphone Array
+ Phased Array Microphones
+ Rayleigh Scattering
+ Hotwire, Hotfilm, and Laser    Doppler Velocimetry
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NASA Official: E. Brian Fite
Last Updated: June 16, 2011


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