airframe noise Archives - Colin Gordon Associates

Research tagged "airframe noise"

Microphone Array Assessment of an Isolated, 26%-scale, High-fidelity Landing Gear

An aeroacoustic study of a 26 pct.-scale landing gear model was conducted in a 7-by 10-foot using a phased microphone array. The incorporation of complex parts via stereo lithography produced a model that can mimic full-scale details down to 3 mm. These details include the contours, brake cylinders, bolt holes, and wheel hubs that appear […]...

Airframe Noise Study of a CRJ-700 Aircraft Model in the NASA Ames 7- by 10-Foot Wind Tunnel No. 1

An acoustic and aerodynamic study was made of a 7 pct. scale unpowered Bombardier CRJ-700 aircraft model in the NASA Ames 7 by 10 Foot Wind Tunnel No. 1 for the purpose of identifying and attenuating airframe noise sources. Simulated landing, takeoff and approach configurations were evaluated at Mach 0.22 and 0.26. With a phased […]...

Acoustics

Aeroacoustic Study of Flap-tip Noise Reduction using Continuous Moldline Technology

B. L. Storms, J. A. Hayes, S. M. Jaeger, and P. T. Soderman, “Aeroacoustic Study of Flap-tip Noise Reduction using Continuous Moldline Technology,” AIAA 2000-1976, 6th AIAA/CEAS Aeroacoustics Conference, Lahaina, HI, June 12-14, 2000....

Effects of Distributed Source Coherence on the Response of Phased Acoustic Arrays

Phased acoustic arrays have been used successfully to locate propulsive and nonpropulsive aeroacoustic sources with the array located both in a moving wind-tunnel stream and in still air. Multiple or distributed sources may vary over the full range in coherence level, particularly when local reflections are present. A constant contour level integration boundary is defined […]...

Acoustics

Effect of Surface Treatment on Array Microphone Self-noise

A method for reducing the flow-induced self-noise of acoustic array microphones was demonstrated in a wind tunnel. Unsteady boundary-layer flow in the wind tunnel induces large pressure fluctuations on exposed, flush-mounted microphone diaphragms, reducing the signal-to-noise capability of microphone arrays. Two important steps were take to reduce this background noise. First, the microphones were recessed […]...

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Research tagged "airframe noise"

Microphone Array Assessment of an Isolated, 26%-scale, High-fidelity Landing Gear

Airframe Noise Study of a CRJ-700 Aircraft Model in the NASA Ames 7- by 10-Foot Wind Tunnel No. 1

Aeroacoustic Study of Flap-tip Noise Reduction using Continuous Moldline Technology

Effects of Distributed Source Coherence on the Response of Phased Acoustic Arrays

Effect of Surface Treatment on Array Microphone Self-noise

Calibration of Microphone Arrays for Phased Array Processing

Acoustic Array Measurements of 1995 High-Lift Engine Aeroacoustic Technology Test in Ames 40- by 80-Foot Wind Tunnel

Acoustic Measurements of a Model Semi-span Symmetry-Plane

Reduction of Background Noise in the NASA Ames 40- by 80-Foot Wind Tunnel

Two-Dimensional Sound Intensity Analysis of Jet Noise

On the Prediction of Far Field Computational Aeroacoustics of Advanced Propellers

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