Document
9x15 Low Speed Wind Tunnel
Improvement Update and Plans
David Stephens
NASA Glenn Research Center, Acoustics Branch
This work has been funded by the - NASA Advanced Air Transport Technology Project - NASA Aeronautics Evaluation and Test Capabilities Project
9x15 Wind Tunnel Upgrades
Complementary but discrete improvements
1. Add fairings and acoustic turning vanes to turn 2
2. Add acoustic baffles downstream of doors 1 & 2
3. Replace test section, uniform deep acoustic absorber, new flow surface, remove
slots, lengthen by 5 feet
4. Reshape diffuser and add acoustic treatment
5. Add acoustic turning vanes to turn 3
1 2 3 4 5
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Turn 2
Turn 2
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12 m (40 feet) 3 m (10 feet)
Test Section (2016)
Test Section (2016)
.
-
. . .
Test Section
. . . . .
2.7 x 4.5 m (9 x 15 feet) .. . . . . .
. .
. .
. . . . - . .
- /
. . . . .
Upstream
Diffuser
Acoustic Results PRELIMINARY
. .
Downstream
~• ..•
Diffuser
'" 6.4 x 5.8 m (21 x 19 feet)
Turn 3
-
-
Piggyback During Integrated System Test
• Other upgrades
• Tunnel control system • Steady - state data system • Pressure measurement system
• Operation over full
tunnel range
demonstrated
• Pressure drop and gain
balance
• Improved temperature
uniformity
How’d we do, Mach 0.1?
Mach 0.10 Mach 0.10 2016, Single White Floor Mic 2018, Single White Floor Mic PRELIMINARY PSD, dB PRELIMINARY 50 1/3 Octave Level, dB 45 2016, Single White Floor Mic 2018, Single White Floor Mic
0 40 -
3 4 3 4 10 10 10 10 Frequency, Hz Frequency, Hz
How’d we do, Mach 0.2?
20 dB axis shift from previous slide Mach 0.20 Mach 0.20 2016, Single White Floor Mic PRELIMINARY 2018, Single White Floor Mic PSD, dB 70 PRELIMINARY 1/3 Octave Level, dB 65 2016, Single White Floor Mic 2018, Single White Floor Mic
60 20 -
3 4 3 4 10 10 10 10 Frequency, Hz Frequency, Hz
Total Noise Reduction
• Frequency dependent
........
Mach 0.10 ......
Mach 0.15
• 12 dB at 630 Hz
PRELIMINARY Mach 0.20
• 8 dB at 50 kHz ---
• Tunnel Speed Dependent
• 4 - 10 dB at 2 kHz
• 5 - 11 dB at 7 kHz
Noise Reduction, dB
3 4
10 10
Frequency, Hz
Implications for Fan Testing
• Frequency
dependence good
match for fan noise
• ADP fan will be
tested in Fall 2019
at multiple tunnel
dB
Mach numbers
70 M=0.20, 2018 ........
ADP Aft (126º emitted) Third Octave Sound Pressure Level, - ADP Broadside (89º emitted) ADP Forward (23º emitted) One 100 1000 10000 Frequency, Hz 1 1 1j f ' 1' If /' J ,:,,\, , ,', , I ~::\, ,,,,~ I I II I I ,, ,, ,, ,, ,
Next Steps
I 11 1I I I I I 11 I
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• Finish installing diffuser
boxes
• Low Boom Flight
Demonstrator in 8x6
• Summer maintenance
......
. . . . . .
. . . . . .
•••••••
shutdown
• • • ••• • • • • • • •••••• •••••• ••••••
• Anechoic quality testing
•••••• •••••• •••••• ••••••
(no flow)
••••••
• Calibration of 9x15
• New Microphone Traverse
• ADP Fan Test
Questions?
Summary
The 9 - by 15 - Foot Low Speed Wind Tunnel (9x15 LSWT) at NASA Glenn
Research Center was built in 1969 in the return leg of the 8 - by 6 - Foot
Supersonic Wind Tunnel (8x6 SWT). The 8x6 SWT was completed in
1949 and acoustically treated to mitigate community noise issues in
1950. This treatment included the addition of a large muffler
downstream of the 8x6 SWT test section and diffuser.
The 9x15 LSWT was designed for performance testing of V/STOL aircraft
models, but with the addition of the current acoustic treatment in 1986
the tunnel been used principally for acoustic and performance testing
of aircraft propulsion systems. The present document describes the
status of the acoustic upgrade as of early 2019.