NASA Glenn Research Center utilizes specialized instrumentation to analyze airflow and sound, including particle image velocimetry, Raman spectroscopy, and hotwire anemometry. These tools provide data essential for the global aviation noise reduction community to validate theoretical models and noise prediction software.
Engineers at the center developed rotating microphone rake procedures in the 1990s to measure modal content in turbofan engine tones. These systems have been deployed across various test environments, ranging from the Advanced Noise Control Fan Rig and the 9- by 15-Foot Low Noise Wind Tunnel to full-scale ground tests.
The facility operates an Array48 microphone system, which identifies noise sources in scale-model jet flows and full-scale military engines like the F404. Researchers also employ hotwire probes and Laser Doppler Velocimeters to record air velocity between rotor and stator components, helping to visualize disturbances and mitigate engine noise.
Research activities are conducted at the Glenn Research Center at Lewis Field in Cleveland and the Neil Armstrong Test Facility in Sandusky, Ohio. These sites support ongoing efforts to record detailed velocity measurements and refine noise mitigation strategies for aviation propulsors.
