Instability over a Porous Liner in a Duct with...
Transcript of Instability over a Porous Liner in a Duct with...
Instability over a Porous Liner in a Duct with Flow
Yves AuréganLaboratoire d'Acoustique de l'Université du Mans
CNRS, Le Mans Université
Tuesday December 5th
17:00 18:00 Welcome of participants
18:00 20:00 Visit of Le Mans circuit
20:00 21:00 Dinner
Wednesday December 6th
08:00 08:30 Welcome of participants
08:30 09:00 Opening ceremony
Session: Characterisation of Porous M aterials
09:00 09:45 Keynote LecturePhotoacoustic determination of mechanical properties at microstructure
level
CHRIST GLORIEUX (KUL, Belgium)
09:45 10:05 Charac 126 - Laboratory and In Situ Sound Absorption Measurement under a
Synthetized Diffuse Acoustic Field: a Case Study on Five Materials
O. ROBIN, C.K. AMEDIN, A. BERRY, N. ATALLA, O. DOUTRES, F. SGARD
10:05 10:25 Charac 217 - Vibration damping properties of porous materials L. ROULEAU, A. GUINAULT, J.-F. DEU
10:25 10:55 Coffee break
10:55 11:15 Charac 312 - Micro- to Macro-scale Investigations of Anisotropy and Local
Boundary Stiffness Variations in Open-cell Lightweight Foams
P. GORANSSON, J. CUENCA, E. LUNDBERG, L. MANZARI
11:15 11:35 Charac 4
62 - SLaTCoW (Spatial LAplace Transform for COmplex Wavenumber
recovery) method for frequency / complex wavenumber dispersion
relation recovery
A. GESLAIN, L. SCHWAN, J.-P. GROBY, V. ROMERO-GARCIA, S. RAETZ, A.
DUCLOS, N. BOECHLER
11:35 11:55 Charac 535 - Elastic characterization of a porous layer in a sandwich structure L. LEI, J.D. CHAZOT, N. DAUCHEZ
11:55 12:15 Charac 663 - Round Robin test on elastic properties of poro- and viscoelastic
materials for vibro-acoustic applications
P. BONFIGLIO, et al.
12:15 13:30 Lunch
13:30 13:50 Poster 10(charac), 48(charac), 68(charac), 9(models)
13:50 14:10 Charac 760 - Characterization of poroelastic materials through interface scattering
and propagation models
S. BOURGUIGNON, N. BOUHLEL, A. DUCLOS, J.P. GROBY
14:10 14:30 Charac 864 - Characterizing rigid frame porous materials with deterministic and
statistical inversion
M. NISKANEN, J.P. GROBY, A. DUCLOS, O. DAZEL, J.C. LE ROUX, N.
POULAIN, T. HUTTUNEN, T. LÄHIVAARA
14:30 14:50 Charac 939 - Efficient simulation of dispersion envelope of poro-elastic media J. RODENAS, F. CHEVILLOTTE, F.-X. BÉCOT, L. JAOUEN
14:50 15:20 Coffee break
15:20 15:40 Poster 30(models), 32(models), 70(models), 22(materials)
Laboratoire d’Acoustiquede l’Universté du Maine
5th SAPEMSymposium on the Acoustics of Poro-Elastic MaterialsDecember 6-7-8, 2017LE MANS, FRANCE
presented by Joachim Golliard
Instability over a Porous Line in a Duct with Flow Y. Aurégan (presented by J. Golliard)
5th SAPEMDecember 2017, Le Mans, France
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Position of the problem (Not so new)
0
Attenuation(dB/m)
M=0
M=0.12
Negative attenuation= Amplification
Instability over a Porous Line in a Duct with Flow Y. Aurégan (presented by J. Golliard)
5th SAPEMDecember 2017, Le Mans, France
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Position of the problem (experimental amplification)
Brandes and RonnebergerAIAA Conference, Berlin, 1995
4000
M=0.26
M=0
2000 30000.001
0.01
0.1
1
10Transmission T+
Frequency (Hz)
0.14
0.15
0.16
0.17
2000 3000 4000
Pressure drop
Frequency (Hz)p+
R+ p+ T+ p+M
Amplification
Instability over a Porous Line in a Duct with Flow Y. Aurégan (presented by J. Golliard)
5th SAPEMDecember 2017, Le Mans, France
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Position of the problem (experimental amplification)
Size of pores: 1× 1×65 mm400 channels/inch2
H=15 mm
L=100 mm0 500 1000 1500 2000 2500 3000
10-3
10-2-
10-1
1
frequency (Hz)
abs(
T+)
M=0M=0.1M=0.2M=0.3
p+ T+ p+
Amplification
Y. Aurégan and M. LerouxExperimental evidence of an instability over an impedance wall in a duct with flowJournal of Sound and Vibration Vol: 317 Pages: 432–439 2008
Instability over a Porous Line in a Duct with Flow Y. Aurégan (presented by J. Golliard)
5th SAPEMDecember 2017, Le Mans, France
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Position of the problem
Some theoretical references:
Brian Tester J. Sound and Vib., 1973 ( ”strange modes” )
Börje Nilsson and Olle Brander J. Inst. Maths Applics, 1980 (amplification in bulk-reacting lining)
Sjoerd Rienstra Wave Motion, 2003 (systematic classification)
Edward Brambley and Nigel Peake Wave Motion, 2006
…
Instability over a Porous Line in a Duct with Flow Y. Aurégan (presented by J. Golliard)
5th SAPEMDecember 2017, Le Mans, France
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Position of the problemParticle Image Velocimetry
(PIV)Unstable mode visualisation
Laser
sheet
Liner
Camera
80 mm
20 mm
25 mm
80 mm
x
z
y
Flow
Incident wave
Instability over a Porous Line in a Duct with Flow Y. Aurégan (presented by J. Golliard)
5th SAPEMDecember 2017, Le Mans, France
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Position of the problem Unstable mode visualisation
v (m/s)
0
20
-20
LDV measurements
u (m/s)100
0
u=U+ut+u’
U
u’
ut
David Marx, Yves Aurégan, Hélène Bailliet, Jean-Christophe ValièrePIV and LDV evidence of hydrodynamic instability over a liner in a duct with flowJournal of Sound and Vibration (2010)
Instability over a Porous Line in a Duct with Flow Y. Aurégan (presented by J. Golliard)
5th SAPEMDecember 2017, Le Mans, France
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Instablemode
Mode continuum
Acousticalmodes
Position of the problem
u’ v’
Unstable mode visualisation
Instability over a Porous Line in a Duct with Flow Y. Aurégan (presented by J. Golliard)
5th SAPEMDecember 2017, Le Mans, France
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What happens when, instead of locally-reacting linings,
porous bulk-reacting linings are used?
Liner = Porous material
Grazing flow
Incident wave
Instability over a Porous Line in a Duct with Flow Y. Aurégan (presented by J. Golliard)
5th SAPEMDecember 2017, Le Mans, France
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Porous bulk-reacting lining
Melamine foam samples used for the testing
0 1000 2000 3000 40000
0.2
0.4
0.6
0.8
Frequency (Hz)
|T+|
M=0.2
M=0
First experiments with Melamine foam
Skeleton vibrations ?
Hydrodynamic instability ?
Instability over a Porous Line in a Duct with Flow Y. Aurégan (presented by J. Golliard)
5th SAPEMDecember 2017, Le Mans, France
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0 500 1000 1500 2000 2500 30000
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Frequency (Hz)
|T+|
M=0
M=0.2
M=0.3
Porous bulk-reacting liningNew experiments with metallic foam
Skeleton vibrations
Hydrodynamic instability
metallic foam RECEMAT
RCMPL-NC-4753.05pores : 0.4 mm
Instability over a Porous Line in a Duct with Flow Y. Aurégan (presented by J. Golliard)
5th SAPEMDecember 2017, Le Mans, France
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Porous bulk-reacting lining
x
11 microphones
x x
Instability over a Porous Line in a Duct with Flow Y. Aurégan (presented by J. Golliard)
5th SAPEMDecember 2017, Le Mans, France
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Unstable mode visualisationParticle Image Velocimetry
(PIV)
20 mm
Laser
sheet
Liner
Camera
80 mm
20 mm
25 mm
80 mm
x
z
y
Flow
Incident wave
Instability over a Porous Line in a Duct with Flow Y. Aurégan (presented by J. Golliard)
5th SAPEMDecember 2017, Le Mans, France
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Unstable mode visualisation
Instability over a Porous Line in a Duct with Flow Y. Aurégan (presented by J. Golliard)
5th SAPEMDecember 2017, Le Mans, France
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Unstable mode visualisation
Instability over a Porous Line in a Duct with Flow Y. Aurégan (presented by J. Golliard)
5th SAPEMDecember 2017, Le Mans, France
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Unstable mode visualisation: Mean flow
0 20 40 60 80 1000
2
4
6
8
10
U (m/s)
y (m
m)
Mean axial velocity
x= -5 mm
x= 75 mm
Mean transverse velocity
Instability over a Porous Line in a Duct with Flow Y. Aurégan (presented by J. Golliard)
5th SAPEMDecember 2017, Le Mans, France
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Unstable mode visualisation: Fluctuating velocity
1220 Hz, u’ 1220 Hz, v’
1500 Hz, u’ 1500 Hz, v’
u’
u’
v’
v’
Instability over a Porous Line in a Duct with Flow Y. Aurégan (presented by J. Golliard)
5th SAPEMDecember 2017, Le Mans, France
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Unstable mode visualisation: Mode identification
acoustic
Hyrodynamicconvective unstable
Hyrodynamicstatic unstable
Instability over a Porous Line in a Duct with Flow Y. Aurégan (presented by J. Golliard)
5th SAPEMDecember 2017, Le Mans, France
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Unstable mode visualisation: Mode identification
Hydro convected Hydro convected
Hydro static Hydro static
Acoustic
+
+
=Total
Acoustic
+
+
=Total
u’
Measurement Measurement
v’
Instability over a Porous Line in a Duct with Flow Y. Aurégan (presented by J. Golliard)
5th SAPEMDecember 2017, Le Mans, France
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Unstable mode visualisation: Detachment of the hydrodynamic wave
50 60 70 800
5
10
x (mm)y (
mm
)
50 60 70 800
5
10
0
1
2
3
0
1
2
3
(a)
(b)
fundamental
second harmonic
axial velocity u’
Instability over a Porous Line in a Duct with Flow Y. Aurégan (presented by J. Golliard)
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Conclusions
Unstable convective mode can exist over a porous liner.
This mode is responsible of oscillation in the transmission coefficient in the flow direction.
These oscillations correspond to wave interference mechanism between acoustic and hydrodynamic modes
The flow through the material can lead to unsteady flow separation near the trailing end of the material.
➠ Modelisation not so easy …