Quantcast Table 8A Objectives and Key Acoustic Results of Model Studies

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Table 8A
Objectives and Key Acoustic Results of Model Studies
Miramar Model Study (October 1975) [3]
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OBJECTIVES
RESULTS
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1.  Verify acoustical performance of a
1. Exhaust noise of an F-14 in
full-scale hush-house for F-14
maximum afterburner was
aircraft.
predicted to meet the 85 dBA
criteria at 250 ft.
2.  Provide design information for
future hush-house and test cell
2. a) A method was developed
designs.
to predict a jet sound power
spectrum based on jet total
temperature nozzle pressure
ratio, and nozzle diameter.
b) The division of
acoustic energy between the
interior and exterior of the
hush-house depends strongly
on the axial distance between
the jet and the augmenter
entrance.  Increasing this
distance resulted in more
energy in the interior, and
less energy entering the
augmenter.
c) Augmenter attenuation
as a function of axial posi-
tion of the acoustic lining
in the augmenter was found to
be approximately independent
of position, except that
little attenuation occurred
at low frequencies in the
upstream end of the augmenter
(at least partly because low
frequencies are generated
farther downstream in the
jet) and little attenuation
occured at high frequencies
in the downstream end of the
augmenter.
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