Stability of Hypersonic Boundary Layer on Porous Wall with Regular Microstructure
A. Fedorov and V. KozlovMoscow Institute of Physics and Technology, Zhukovski, 140180, Russia
A. Shiplyuk, A. Maslov, A. Sidorenko and E. BurovInstitute of Theoretical and Applied Mechanics, Novosibirsk, 630090, Russia
N. MalmuthRockwell Scientific Company, Thousand Oaks, California 91360, USA
AIAA 2003-4147
This effort was supported by the European Office of Aerospace Research and Development under the International Science and Technology Center (ISTC) partner grant No. 1863.The authors are grateful to Dr. John Schmisseur and Dr. Steven Walker for support of this research project.
Speaker Could Not Present due to Visa Problems. Paper is Available. Here, a Brief Summary by the Session Chair
3 4 5 6 7 8 9 10 11 120
1x106
2x106
3x106
4x106
5x106
Re tr
H0, MJ/kg
Caltech* experiments confirm the theoretical concept† of hypersonic laminar flow control
black squares - solid wallopen circles - porous wallarrowed circles - flow is totally laminar
Ultrasonically absorptive coating with equally-spaced cylindrical blind micro-holes was able to increase laminar run on a sharp hypersonic cone more than twice
Sharp cone model with porous surface
Summary of Caltech data (H0 is total enthalpy)
Perforated sheet with blind cylindricalholes:
• hole diameter 60 microns• hole depth 500 microns• spacing 100 microns
~100 holes per 1 mm2
*Rasheed, A., Hornung, H.G., Fedorov, A.V., and Malmuth, N.D., AIAA J., 40, No. 3, 2002.†Fedorov & Malmuth et al., AIAA J., 39, No. 4, 2001
1 mm
ITAM stability experiments on felt-metal coating agree well with LST*
*Fedorov A., Shiplyuk, A., Maslov, A., Burov, E., and Malmuth, N., AIAA Paper No. 2003-1270, 2003;JFM, Vol. 479, 2003, pp. 99-124.
Felt-metal coating of 0.75 mm thickness
Felt-metal coating of 0.75 mm thickness
0 100 200 300f, kHz
0.0
0.5
1.0
1.5
2.0
2.5
A
12
first mode second mode
0 100 200 300f, kHz
0.0
0.5
1.0
1.5
2.0
2.5
A
12
0 100 200 300f, kHz
0.0
0.5
1.0
1.5
2.0
2.5
A
12
0 100 200 300f, kHz
0 100 200 300f, kHz
0.0
0.5
1.0
1.5
2.0
2.5
A
12
first mode second mode
For natural disturbancesUAC stabilizes the second mode and destabilizes fow-frequency disturbances (first mode?)
For natural disturbancesUAC stabilizes the second mode and destabilizes fow-frequency disturbances (first mode?)
200 240 280 32030
405060708090
100100
200
300
400500600700
theory, porous theory, solid exp., porous exp., solid
A
X, mm
Theory
Experiment
porous
solid
200 240 280 32030
405060708090
100100
200
300
400500600700
theory, porous theory, solid exp., porous exp., solid
A
X, mm
Theory
Experiment
porous
solid
Amplitudes of artificially excited wave packet of 280 kHz agree well with LST
Amplitudes of artificially excited wave packet of 280 kHz agree well with LST
Objectives
• Perform theoretical and experimental studies of porous coating of regular microstructure
• Include gas rarefaction effect in theoretical model of acoustic absorption
• Conduct stability measurements of natural and artificially excited disturbances
• Compare LST predictions with experiment
Porous coating is similar to UAC of Caltech experiments*
Stainless steel sheet perforated withequally spaced cylindrical holes:
• Diameter 50 µm on face side• Spacing 100 µm • Depth 450 µm• Porosity 20%
Stainless steel sheet perforated withequally spaced cylindrical holes:
• Diameter 50 µm on face side• Spacing 100 µm • Depth 450 µm• Porosity 20%
2r0
s
s
h
s
Side view
Top view
perforated sheet
solid backing
holes
2r0
s
s
h
s
Side view
Top view
perforated sheet
solid backing
holes
Back side, d= 64 µmFace side, d= 50 µm
Pores are conical, taper angle~0.9°
*Rasheed, A., Hornung, H.G., Fedorov, A.V., and Malmuth, N.D., AIAA J., 40, No. 3, 2002.
Sharp-cone model tested in the T-326 wind tunnel of ITAM
Base part with the porous coating
Perforated sheet was tensed onto the model to avoid cavities
UAC
Spectra of Natural Disturbances on Solid and Porous Sides (M=5.95, T0=390K, Tw/T0=0.80-0.84)
Solid side Porous side
0 100 200 300 400 500f, kHz
10
100
Ampl
itude
ReeX *10-6
2.282.552.842.963.243.523.794.284.544.784.99
0 100 200 300 400 500f, kHz
10
100
Ampl
itude
ReeX *10-6
2.222.502.783.063.343.623.904.274.554.805.06
Porous coating stabilizes the second mode and weakly affects the first mode
Porous coating stabilizes the second mode and weakly affects the first mode
Low-frequency fist mode High-frequency second mode
Stabilization effect
-4 0 4β, rad/deg
0
200
400
600
800
1000
Ampl
itude
ReeX *10 -6
2.222.773.353.914.475.05
-20 -10 0 10 20θ, deg
0
10
20
30
40
50
Ampl
itude
ReeX *10-6
2.222.773.353.914.475.05
Artificially Excited Wave Packets in Boundary Layer on Porous Walls
Amplitude vs. circumferential angle β-spectra
Dominant component of artificially excited wave packet is two-dimensional wave of β=0
Dominant component of artificially excited wave packet is two-dimensional wave of β=0
frequency 275 kHz
Phase Speeds and Amplitudes of Natural and Artificial Disturbances
Phase speeds of artificially excited wave packets Amplitude growth of artificial and natural
disturbances
Natural disturbances of high frequency are predominantly 2-D waves of the second mode.Natural disturbances of high frequency are predominantly 2-D waves of the second mode.
120 160 200 240 280 320X, mm
0.8
0.84
0.88
0.92
0.96
1
C x/U
e
1234
frequency 275 kHz
2 3 4 5 6ReeX*10-6
10
100
A 0
123
A/A 0
2 3 4 5 6ReeX*10-6
10
100
A 0
123
A/A 0
Solid side,artificial
Porous side,natural
Porous side,artificial
For Kn<1, gas rarefaction increases performance of porous coating
0 100 200 300 400 5000,00
0,03
0,06
0,09T-326, Tw=Tad, Re1=20.E+6 1/m, r=25 mkm, s=100 mkm
solid h=inf, Kn=0 h=inf, Kn=0.395, Au=Ae=1.
σ, 1
/mm
X, mmMaximum (versus frequency) growth rate of second mode
Me=5.3T0=390K
Me=5.3T0=390K
solid wall
porous wall, Kn=0
porous wall, Kn=0.4
Amplification of Artificial and Natural Disturbances of 275kHz(Experiment and LST)
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
10
100
exp.: natural, porous wall exp.: artificial, porous wall exp.: natural, solid wall LST, solid wall LST, porous wall, r=25 µm LST, porous wall, r=28.5 µm
A/A 0
ReeXx10-6
nonlinear effect (?)
Theory agrees well with experiment on both porous and solid wallsTheory agrees well with experiment on both porous and solid walls
actual pore
average pore
Conclusions• Experimental and theoretical studies of hypersonic boundary
layer stability were performed for ultrasonically absorptive coatings (UAC) of regular microstructure
• Under natural conditions, UAC stabilizes the second mode and weakly affects the first mode that is consistent with theoretical predictions
• Natural disturbances of high-frequency band are predominantly 2-D waves of the second mode
• UAC stabilizes high-frequency wave packets of second-mode instability
• Theoretical predictions of second-mode growth agree well with experiment for both solid and porous walls
• For Kn<1, gas rarefaction increases UAC performance