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