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Noise Control Educational Resources by David Nelson
Key Technical Papers by David Nelson
A comparison of tonality
metrics for product noise evaluation, Noise Con 2008 Fan selection and
installation issues related to spaceflight hardware, Noise Con 2007 Cooling requirements,
chassis design, and fan noise, Noise Con 2007 Assessing the hidden
costs of spaceflight hardware installation effects, Fan Noise 2007 Residual loudness of
wind turbine noise in the presence of ambient sound, Wind Turbine 2007 Axial Fan Installation
Effects due to inlet flow distortions, Internoise 2006 Effect of Discharge Duct
Geometry on Centrifugal Fan Performance and and Noise Emission, with
William Butrymowicz and Chris Thomas, Noise Con 2005 An Automated System for
the Acoustical and Aerodynamic Characterization of Small Air Moving Devices,
with Jeff Schmitt and John Phillips, Noise Con 2005 Acoustic Demonstrations
II: Challenges to Speech Communication and Music Listening, with Beth
Cooper and Richard Danielson, Noise Con 2004 Noise Emission Testing
Requirements for Spaceflight Hardware, Noise Con 2003 A computer-based
acoustical measurement system for NASA Glenn Research Center, Noise Con
2003 Computer Sound Quality: Masking,
Prominence, and Loudness, with Anne Balant, Noise Con
2000. Noise and Vibration Isolation Design for a
Vibration Testing Laboratory, with Thomas
Stewart of Cisco Systems, Noise Con 2000. NASA Glenn Research Center Reduced-Noise Design Guide,
Internoise 99. . -
Low-frequency noise
transmitted through walls: loudness and A-weighted level, Noise Con
96. Proves that there is no such thing as a
"soundproof" partition.
On quantifying and using
the "diffraction effect" for cost- and performance-optimization of
sound absorption treatments, . Noise Con 90. Why is the sound absorption coefficient
sometimes greater than 1.00, and what does it mean? - Nonlinear Effects in Porous Materials (ARL). It had been
noted during aircraft noise abatement work in the 1970s that tuned nacelle
inlet liners did not work as well in flight as on the test bench. At
high amplitudes the flow resistance of the material becomes nonlinear, such
that r = r1 + r2 |u|, where u is the flow velocity and
r1 and r2 are flow resistance constants. The
flow resistance of the material may therefore be significantly higher in
flight than on a ground test bench using small signals, throwing off the
tuning of the resonators. The ramifications of this phenomenon in the
frequency domain are also interesting: for an initially pure sine wave, the
model predicts generation of odd harmonic components and accelerated decay
of the fundamental. In real life, several harmonics of the blade
passage tone are present initially. In this case, the model predicts
strongest generation of odd-harmonic components, weaker generation of
combination tones, and accelerated decay of the 1st and 2nd harmonics.
Links to other Acoustical Sites
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