flowpac acoustics research scott c. morris thomas j. mueller
TRANSCRIPT
Overview
• Basic and applied research• Mix of theoretical, computational, and
experimental capabilities• Experimental tools include:
– Anechoic Wind Tunnel (AWT)– Phased Microphone Array– Laser vibrometry– Particle Image Velocimetry
NDTE Dual Array Cross-spectra (Scaled)
St = fyf/U
ref
10-2 10-1 100 101
Adj
uste
d S
PL
(dB
): S
PL 0
+ 5
0log
10(U
ref 0
/Ure
f)
-60
-40
-20
0
20
40
60
80
Uref = 69ft/s Uref = 75ft/s Uref = 80ft/s Uref = 85ft/s Uref = 90ft/s Uref = 100ft/s
Experimental Approach:
Acoustic TheoryLES calculations
Hot-wire & PIV measurements
Far field signature
Boundary Conditions
Unsteady wall pressure
ijijijijs SSP 2
Beamforming Results(Example SPL map)
Uref = 69 ft/s
Array #1z = 42 in.
Test section boundary
Model trailing edge location
Flow: L to R
Inlet noise
Trailing edge noise
Collector noise
Acoustic spectra: 3 regions
101
102
103
104
10-11
10-10
10-9
10-8
10-7
10-6
10-5
10-4
10-3
10-2
Frequency (Hz)
Gp 1p 1
Pressure Auto-Spectral Density for Array #1
69 ft/s75 ft/s80 ft/s85 ft/s90 ft/s95 ft/s100 ft/s
Low frequency
Vortex shedding
Broadband
PIV Experimental Setup
Trailing Edge12-bit CCD Cameras
Nd YAG Lasers
Lasers Sheet
Camera view areas
Flow