2013/4/6
1
Unsteady Pressure-Sensitive Paint
Techniques for Dynamic Wind-
Tunnel Testing
Keisuke ASAI ([email protected])
Dept. of Aerospace Engineering
Tohoku University
Sendai, Japan
Workshop on Next Generation Transport Aircraft March 29, 2013, Mary Gates Hall, UW Campus
Prof. Martin Gouterman
Visit to University of Washington in 1995
2013/4/6
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UW: Birthplace of Pressure-Sensitive Paint
"Oxygen Quenching of Luminescence of Pressure Sensitive Paint for Wind Tunnel Research," M.
Gouterman, J. Chem. Ed., 74, 697 (1997).
"Luminescent Barometry for Aerodynamic Measurements," J. Gallery, M. Gouterman, J. B. Callis, G. E.
Khalil, B. G. McLachlan, and J. H. Bell, Rev. Sci. Instrum., 65, 712 (1994).
"Sub-Millisecond Response Times of Oxygen Quenched Luminescent Coatings," A. Baron, J. D. S.
Danielson, M. Gouterman, J. R. Wan, J. B. Callis, and B. G. McLachlan, Rev. Sci. Instrum., 64, 3394 (1993).
"Video Luminescent Barometry: The Induction Period," R. H. Uibel, G. E. Khalil, M. Gouterman, J.
Gallery, and J. B. Callis, AIAA Paper No. 93-0179, 31st Aerospace Sciences Meeting, Reno, NV
(January 1993).
University of Washington Department of Chemistry
Dr. Kavandi served as a mission specialist on
STS-91 (June 2-12, 1998), STS-99 (February
11-22, 2000) and STS-104/ISS Assembly Flight
7A (July 12-24, 2001).
Dr. Kavandi currently serves as Director, Flight
Crew Operations, NASA Johnson Space Center.
.
In 1986, while still working for Boeing, she was
accepted into graduate school at the University
of Washington, where she began working
toward her doctorate in analytical chemistry.
She has obtained Doctorate in Analytical
Chemistry from the University of Washington -
Seattle in 1990
Her doctoral dissertation involved the
development of a pressure-indicating coating
that uses oxygen quenching of porphyrin
photoluminescence to provide continuous
surface pressure maps of aerodynamic test
models in wind tunnels. Her work on pressure
indicating paints has resulted in two patents.
.
Astronaut Janet L. Kavandi -mission specialist
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Pressure- and Temperature-Sensitive Paints
・Pressure-Sensitive Paint [PSP]
・Temperature-Sensitive Paint [TSP]
model
Excitation light Emission light
PSP or TSP
Oxygen/thermal
Quenching gas molecule
Example of molecular sensors
(metal complex compound)
Excitation
light
Excited singlet state (S1)
Triplet state (T1)
Intersystem crossing
Ground state (S0)
Oxygen quenching A
dso
rptio
n
Th
erm
al q
uen
ch
ing
Flu
ore
sc
en
ce
Th
erm
al q
uen
ch
ing
Ph
osp
ho
res
ce
nce
Excited oxygen
Jablonsky energy-level diagram
Principle of measurement
Oxygen quenching → PSP
Thermal quenching → TSP
N N
NN
Pt
CH2CH3 CH2CH3
CH2CH3
CH2CH3
CH2CH3CH2CH3
H3CH
2C
H3CH
2C
Demo of PSP Response : Oxygen quenching
O2
N2
UV illumination
PSP: Platinum Porphyrine + TLC Plate
Stern-Volmer
Relationship
]O[1 200 qkI
I
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Pressure Sensitive Paint (1st Generation)
Sensor: Platinum Octaethylporphyrin (PtOEP)
Binder: Polydimethylsiloxyan (PDMS)
N N
NN
Pt
CH2CH3 CH2CH3
CH2CH3
CH2CH3
CH2CH3CH2CH3
H3CH
2C
H3CH
2C
380nm 650nm
PtOEP
Absorption/emission spectra
I ref
/I
T=20degC
P/Pref
Pressure
Stern-Volmer
Equation
Washington Univ. (USA)
PSP
Calibration
Imaging Method
painted model
CCD camera
bandpass filter
illumination source
PC with digitizing
board
● Excitation: Xe arc, LED
● Emission: CCD camera
PSP/TSP measurement system (imaging)
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Wind-off image
Iref
Wind-on image
I
T correction T correction
Pressure 0.4
0.5
0.6
0.7
0.8
P/Pt
ref
ref
P
PTBTA
TPI
TPI )()(
),(
),(
Image
registration
Processing of PSP images
Pressure map(pseudo color )
Normalization
Stern-Volmer
Relationship
Image
registration
Iref / I (ratioing)
Wind-off image Iref Wind-on image I
MITSUBISHI REGIONAL JET (MRJ)
JAXA PSP systems applied to develop MRJ
Both high-speed (transonic) and low-speed
* Estimate load on the main wings
* Validate aerodynamic model
Experimental Results@TWT1 (M=0.8, AoA=4deg)
Application of PSP Technique to a
Domestic Civil Aircraft Development
K. Mitsuo, et al.
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Flow around Shuttle Cock (U= 30 m/s)
Collaboration with Akita Univ.
60 deg 90 deg
a = 0 deg 20 deg 30 deg
Model Painted with PSP
Surface Pressure Distribution over World Cup Soccer Balls (2012)
smooth
-3
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
-3
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
2004
Application to Sport Aerodynamics
-3
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
2010
Prof. Seo (Yamagata Univ.)
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- Karman vortex cause undesirable
periodic forcing during the high winds
- It is important for engineers to account
for the possible effects of vortex
shedding when designing a wide range
of structures
(tall building, bridge, chimney, etc)
A Kármán vortex street is a term used in fluid dynamics for a repeating pattern of swirling vortices caused
by the unsteady separation of flow of a fluid over bluff bodies. It is named after the engineer and fluid
dynamicist, Theodore von Kármán[1] and is responsible for such phenomena as the "singing" of
suspended telephone or power lines, and the vibration of a car antenna at certain speeds.
commons.wikimedia.org
Theodore von Kármán
Unsteady Flow: Kármán Vortex Street
Tacoma Narrows Bridge collapse
(Nov., 7, 1940)
Requirements for fast PSP
Fast response time
High luminescent intensity Thickness
O2
O2
O2
O2
O2
O2 O2
O2
A key is
“Porous Binder”
mD
h2
Time
constant Diffusion of O2
(Dm)
Fast-responding PSP
O2 O2
O2 O2
O2
O2
(ex) silicone polymer (Poly(DMS))
Dm=O(10-10)m2/sec
h=10mm = O(1)sec
Faster response thinner
lower intensity and SNR
h Diffusion Theory
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Silica-gel thin-layer chromatography plate (TLC-PSP)
Fast Response PSP
Anodized-aluminum (AA-PSP)
Polymer/ceramic (PC-PSP)
Ultra fine ceramic powder
1 mm
Anodized aluminum
(Asai et al., 1997)
Polymer/ceramic
(Scroggin et al., 1999)
Ultra fine ceramic powder
(Kameda et al., 2008)
Porous materials for fast-response PSP
Frequency characteristics of PC-PSP
- The amplitude attenuation starts at about 1 kHz and it reaches -3 dB at the
frequency of 3.8 kHz.
- The phase delay increases in the frequency range over 1 kHz.
- Frequency response of PC-PSP is that of 1st order system of which time constant
is determined by luminescent lifetime of sensor molecules
Amplitude characteristics Phase delay characteristics
3 dB attenuation
-6
-5
-4
-3
-2
-1
0
1
100 1000 10000
h=20mm
h=30mm
h=300mm
Gai
n[d
B]
Frequency[Hz]
-60
-50
-40
-30
-20
-10
0
100 1000 10000
Phas
e sh
ift[
deg
.]
Frequnecy[Hz]
PtTFPP, T=20℃, P=100 kPa
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• Time-series PSP images are acquired with a CMOS high-speed camera under continuous excitation.
• Acquisition timing of every camera image and reference signal (phase information) are measured simultaneously.
• After image acquisition, PSP images are sorted by phases of filtered reference signal (ex. BP, POD) and averaged.
• This technique yields a series of high-SNR instantaneous pressure images.
Ref sensor
Excitation
light
Camera
Data Logger
Pressure variation
Continuous excitation
Image acquisition
Acquisition timing Time-series
PSP images (Yorita, et al, AIAA Paper 2010-307)
Conditional Image Averaging (1)
Application to flow around square cylinder
100 m
m Lateral plate
100 m
m
Square cylinder model
Pressure Transducer
H
D
z y x
W
x/D = 0.5 z/H = 0.5
PSP 3-D Square Cylinder
• Free-stream velocity : 50 m/s (Re=1.4x105)
• Incidence angle : 0 degree
-1.0
-0.5
0
0.5
1.0
0 0.01 0.02 0.03 0.04 0.05
Am
pli
tud
e [k
Pa]
Time [sec]
Experimental condition
Pressure variation on lateral side surface
Time-series pressure transducer data Amplitude spectrum
f ≈ 150 Hz
Turn table (PSP)
• Height H = 100 mm
• Width W = 40 mm
• Length L = 40 mm
* One high-frequency pressure transducer is provided
on the center point of the side surface
100
101
0 100 200 300 400 500Am
pli
tude
spec
tral
den
sity
Frequency [Hz]
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Time-series pressure image
(Raw images)
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5x 10
-3
1.005
1.000
0.995
Phase-averaged pressure image
(Conditional image averaging)
PP /
Time-resolved pressure map
Application to flow around square cylinder
38/19 Japanese-German Seminar on Molecular Imaging Technology for Interdisciplinary Research Feb.21 (Tue) – Feb. 24 (Fri), 2012
0 - 45 45 - 90 90 - 135 135 - 180
180 - 225 225 - 270 270 - 315 315 - 360
Phase
[deg]
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5x 10
-3
1.005
1.000
0.995
- The pressure variations on the side surface were successfully visualized.
- High fluctuating-pressure regions appear at the bottom rear part.
- The PSP data are in good agreement with the pressure transducer data.
0.996
0.998
1.000
1.002
1.004
0 60 120 180 240 300 360
PSPPressure transducer
Pre
ssu
re r
atio
P/P
ref
Phase [degrees]
Comparison with pressure transducer
PP /
Application to flow around square cylinder
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200 400 600 800
100
200
300
400
500
600
700
95
96
97
98
99
100
x =
)(/ _ UnsteadyPP aveon
)(_ SteadyP aveon
Turn table (PSP)
Application of conditional image sampling
2D unsteady pressure distribution on a ground plane (V=50m/sec)
The peak frequency is 150 Hz and the pressure
amplitude is on the order of several hundred Pa.
Absolute pressure variation P
“Hybrid Flight Simulator”
6 DoF eqs. of motion
(Flight Dynamics)
Manipulator control
(Servo compensation)
air data
Intertia
Control
Motion
table
Motion analysis (PC)
model
attitude
(real time)
Attitude
Deformation
Servo
balance
6 DoF
Robot
Manipulator
Imaging Camera
CFRP model
HEXA
Parallel Robot
Interface
Optical
Model
Deformation
Optical
Model
Attitude
Pressure
Sensitive
Paint
3D
Meas.
Schematic
Optical
Model
Deformation
Optical
Model
Attitude
Pressure
Sensitive
Paint
3D
Meas.
Parallel (HEXA)
Serial (PA10)
Next-Generation Dynamic Wind-Tunnel
Testing – Tohoku University, Japan
2013/4/6
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50/38
Application to Dynamic Wind-Tunnel Testing
U = 30 m/s AoA = 35 deg.
1-DoF Roll Oscillation
( f = 1 Hz, Df = ±30 deg )
Cp with temp correction
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2Cp with temp correction
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
1
Cp with temp correction
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
1
22
0
-2
-4
-6
-8
Cp
Without correction With correction
Ratio Iref/I without correction Ratio Iref/I with correction Ratio Iref/I with correction
Cp with temp correction
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2 1.04
1
0.98
1.02
0.96
0.94
Iref/I
Intensity ratio of Reference paint
Oscillated Delta Wing (Phase-lock Method + Binary PSP)
0
0.2
0.4
0.6
0.8
1
1.2
1.4
400 500 600 700 800
Rel
ati
ve
Inte
nsi
ty
Wave length [nm]
(Pressure CH)
PtTFPP
650nm (Reference CH)
BAM-G
518nm
51/38
Application to Dynamic Wind-Tunnel Testing
Time History of Cp
at x/c = 0.5 on Right Wing
Oscillated Delta Wing (Phase-lock Method + Binary PSP)
Cp with temp and def correction
-7
-6
-5
-4
-3
-2
-1
0
1
2
Cp with temp and def correction
-7
-6
-5
-4
-3
-2
-1
0
1
2
Cp with temp and def correction
-7
-6
-5
-4
-3
-2
-1
0
1
2
Cp with temp and def correction
-7
-6
-5
-4
-3
-2
-1
0
1
2
Cp with temp and def correction
-7
-6
-5
-4
-3
-2
-1
0
1
2
Cp with temp and def correction
-7
-6
-5
-4
-3
-2
-1
0
1
2
Cp with temp and def correction
-7
-6
-5
-4
-3
-2
-1
0
1
2
Cp with temp and def correction
-7
-6
-5
-4
-3
-2
-1
0
1
2
Cp with temp and def correction
-7
-6
-5
-4
-3
-2
-1
0
1
2
Cp with temp and def correction
-7
-6
-5
-4
-3
-2
-1
0
1
2
Cp with temp and def correction
-7
-6
-5
-4
-3
-2
-1
0
1
2
Cp with temp and def correction
-7
-6
-5
-4
-3
-2
-1
0
1
2
f 25deg f 0deg
f 25deg f 0deg
-8
-6
-4
-2
0
-30 -20 -10 0 10 20 30
Bi-PSP corr.Bi-PSP uncorr.Pressure Sensor
Cp
Roll Angle
1-DoF Roll Oscillation
( f = 1 Hz, Df = ±30 deg )
f 20deg f 20deg
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Unsteady PSP Technique: Next Step
Effects of wing flexibility on dynamic stability
54/38
Unsteady PSP Technique: Next Step
Effects of wing flexibility on dynamic stability
The failure occurred during a flight on the
Hawaiian island of Kauai on June 26, 2003.
September 08, 2004
NASA Releases Report on Crash of Helios Solar Plane
The National Aeronautics and Space Administration (NASA) released on September 3rd its final report on the crash of
Helios, a solar-powered "flying wing" that suffered structural failure and fell into the Pacific Ocean during a long-duration
test flight last summer. A review of the flight data concluded that atmospheric turbulence caused the plane's wing tips to
bend upward abnormally and then caused the entire wing to oscillate. The growing oscillations caused the Helios to gain
speed until it suffered a structural failure. The accident investigation board determined that the mishap resulted from the
inability to predict, using available analysis methods, the aircraft's increased sensitivity to turbulence following modifications
to allow long-duration flights. Specifically, the addition of a hydrogen-air fuel cell pod and two hydrogen storage tanks placed
significant loads along the length of the flying wing, reducing the safety margins for the aircraft. See the press release from
the NASA Dryden Flight Research Center or go directly to the full report