A Guide to NASA Glenn's Aero-Acoustic Research Facilities

• NASA Glenn Research Center operates world-class facilities to research aircraft engine aerodynamics and acoustics, focusing on reducing community noise and supporting aerospace missions.
• These laboratories provide controlled environments for testing scale engine models, validating noise-prediction codes, and developing advanced flow-measurement diagnostics.

Primary Research Facilities

• 9x15 Low-Speed Wind Tunnel (9x15 LSWT): Designed for studying engine aerodynamics during takeoff and landing; recent modifications reduced background noise and enhanced measurement precision.
• Aero-Acoustic Propulsion Laboratory (AAPL): A 65-foot radius geodesic dome featuring 17,000 fiberglass wedges that create an anechoic environment by preventing sound reflections.
• Small Hot Jet Acoustic Rig (SHJAR): Housed within the AAPL, this rig explores the relationship between nozzle geometry and noise, utilizing advanced techniques like Particle Image Velocimetry (PIV) and Rayleigh scattering.
• Nozzle Acoustic Test Rig (NATR): A free-jet wind tunnel that simulates flight conditions to evaluate noise-reduction concepts, such as chevron nozzles, before full-scale implementation.
• DGEN AeroPropulsion Research Turbofan (DART): Acts as a flexible testbed for multidisciplinary research, including engine controls, propulsion-noise sources, and installation effects.
• Acoustical Testing Laboratory (ATL): A versatile chamber used for measuring noise levels from International Space Station experiments, calibrating microphones, and testing aircraft engine liners.

Research Impacts

• Advances in noise-prediction methods allow engineers to design quieter, more efficient aircraft engines.
• Facilities enable the evaluation of concepts for future aircraft, including supersonic airliners, reducing the risk of regulatory or environmental non-compliance.
• The integration of flow diagnostics and acoustic measurements allows researchers to map noise sources directly to turbulence and jet flow characteristics, facilitating groundbreaking discoveries in jet noise theory.