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Centre d'Études techniques de l'Équipement de l'Est

Ministère de l'Écologie, de l'Énergie, du Développement durable et de l'Aménagement du Territoire

Thèse de doctorat,

université du Maine

Spécialité acoustique

Characterization of the

acoustic emission of vehicles

by equivalent point sources

F. Golay

Advisory committee:C. Ayrault LAUMG. Dutilleux LRSL. Simon LAUM

Introduction: urban noise

Emission

Reception

1Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

Introduction: urban noise

Emission

Reception

1Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

Introduction: urban noise

Emission

Reception

1Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

Introduction: urban noise

Emission

Reception

propagation

1Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

Introduction: research on emission

I modeling in France: [Guide du Bruit, 1972],[NMPB, 2008] [Dutilleux, AAuA, 2010]

I numerous emission models with signi�cantdi�erences

I need of additional indicators to LAeq inurban context (near �eld 6= far �eld)

2Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

Introduction: research on emission

I modeling in France: [Guide du Bruit, 1972],[NMPB, 2008] [Dutilleux, AAuA, 2010]

I numerous emission models with signi�cantdi�erences

I need of additional indicators to LAeq inurban context (near �eld 6= far �eld)

2Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

Introduction: research on emission

I modeling in France: [Guide du Bruit, 1972],[NMPB, 2008] [Dutilleux, AAuA, 2010]

I numerous emission models with signi�cantdi�erences

I need of additional indicators to LAeq inurban context (near �eld 6= far �eld)

2Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

Introduction: problem statement

S(~v = ~cst)

S(~v = ~cst) Sei

y

z

x

Mj(~v = ~0)

d<10 m

Emission• NSe

• (xSe , ySe , zSe)i• |Ai |2

PSDj

3Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

Introduction: problem statement

S(~v = ~cst) Sei

y

z

x

Mj(~v = ~0)

d<10 m

Emission• NSe

• (xSe , ySe , zSe)i• |Ai |2

PSDj

3Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

Introduction: problem statement

S(~v = ~cst) Sei

y

z

x

Mj(~v = ~0)

d<10 m

Emission• NSe

• (xSe , ySe , zSe)i• |Ai |2

PSDj

3Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

Introduction: problem statement

S(~v = ~cst) Sei

y

z

x

Mj(~v = ~0)

d<10 m

Emission• NSe

• (xSe , ySe , zSe)i• |Ai |2

PSDj

propagation

3Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

Introduction: problem statement

S(~v = ~cst) Sei

y

z

x

Mj(~v = ~0)

d<10 m

Emission• NSe

• (xSe , ySe , zSe)i• |Ai |2

PSDj

propagation−1

3Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

Table of contents

State of the art

Model improvements

Source height

Méthode Énergétique de Caractérisation de Source(MÉCS)

4Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Table of contents

State of the artEmission modelsPropagation modelsMeasurements methods

Model improvements

Source height

MÉCS

5Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Emission models

I 2 sorts of modelsI reference (physical): more

complex, a lot of input data

I engineering (heuristicapproach): less complex, a fewinput data

I vehicles are modeled bypoint sources

I number of sourcesI source heightI emission spectra (function

of vehicle, v ,. . . )

I numerous engineering modelswith di�erent characteristics

6Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Emission models

I 2 sorts of modelsI reference (physical): more

complex, a lot of input dataI engineering (heuristic

approach): less complex, a fewinput data

I vehicles are modeled bypoint sources

I number of sourcesI source heightI emission spectra (function

of vehicle, v ,. . . )

I numerous engineering modelswith di�erent characteristics

6Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Emission models

I 2 sorts of modelsI reference (physical): more

complex, a lot of input dataI engineering (heuristic

approach): less complex, a fewinput data

I vehicles are modeled bypoint sources

I number of sourcesI source heightI emission spectra (function

of vehicle, v ,. . . )

I numerous engineering modelswith di�erent characteristics

6Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Emission models

I 2 sorts of modelsI reference (physical): more

complex, a lot of input dataI engineering (heuristic

approach): less complex, a fewinput data

I vehicles are modeled bypoint sources

I number of sourcesI source heightI emission spectra (function

of vehicle, v ,. . . )

I numerous engineering modelswith di�erent characteristics

6Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Emission models

I 2 sorts of modelsI reference (physical): more

complex, a lot of input dataI engineering (heuristic

approach): less complex, a fewinput data

I vehicles are modeled bypoint sources

I number of sourcesI source heightI emission spectra (function

of vehicle, v ,. . . )

I numerous engineering modelswith di�erent characteristics

6Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Propagation models: �xed sources

I harmonic point sources

I �at ground

I homogeneous: Rudnick's model

hij(f ) =− ω4π

1

Rde κR

d

+Q

R re κR

r

I discontinuity of impedance: Rasmussen's model

I ground impedance: Delany-Bazley-Miki's modelI meteorological e�ects neglected

SM

Rd

R rθg

0 5 000 10 000

−20

−10

0

f [Hz]

DSP

[dB]

7Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Propagation models: �xed sources

I harmonic point sourcesI �at ground

I homogeneous: Rudnick's model

hij(f ) =− ω4π

1

Rde κR

d

+Q

R re κR

r

I discontinuity of impedance: Rasmussen's model

I ground impedance: Delany-Bazley-Miki's modelI meteorological e�ects neglected

SM

Rd

R rθg

0 5 000 10 000

−20

−10

0

f [Hz]

DSP

[dB]

7Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Propagation models: �xed sources

I harmonic point sourcesI �at ground

I homogeneous: Rudnick's model

hij(f ) =− ω4π

1

Rde κR

d

+Q

R re κR

r

I discontinuity of impedance: Rasmussen's model

I ground impedance: Delany-Bazley-Miki's modelI meteorological e�ects neglected

SM

Rd

R rθg

0 5 000 10 000

−20

−10

0

f [Hz]

DSP

[dB]

7Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Propagation models: �xed sources

I harmonic point sourcesI �at ground

I homogeneous: Rudnick's model

hij(f ) =− ω4π

1

Rde κR

d

+Q

R re κR

r

I discontinuity of impedance: Rasmussen's model

I ground impedance: Delany-Bazley-Miki's modelI meteorological e�ects neglected

SM

RdRd

R rθg

0 5 000 10 000

−20

−10

0

f [Hz]

DSP

[dB]

7Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Propagation models: �xed sources

I harmonic point sourcesI �at ground

I homogeneous: Rudnick's model

hij(f ) =− ω4π

1

Rde κR

d

+Q

R re κR

r

I discontinuity of impedance: Rasmussen's model

I ground impedance: Delany-Bazley-Miki's modelI meteorological e�ects neglected

SM

RdRd

R rR rθg

0 5 000 10 000

−20

−10

0

f [Hz]

DSP

[dB]

7Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Propagation models: �xed sources

I harmonic point sourcesI �at ground

I homogeneous: Rudnick's model

hij(f ) =− ω4π

1

Rde κR

d

+Q

R re κR

r

I discontinuity of impedance: Rasmussen's model

I ground impedance: Delany-Bazley-Miki's modelI meteorological e�ects neglected

SM

RdRd

R rR rθg

0 5 000 10 000

−20

−10

0

f [Hz]

DSP

[dB]

7Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Propagation models: �xed sources

I harmonic point sourcesI �at ground

I homogeneous: Rudnick's model

hij(f ) =− ω4π

1

Rde κR

d

+Q

R re κR

r

I discontinuity of impedance: Rasmussen's model

I ground impedance: Delany-Bazley-Miki's modelI meteorological e�ects neglected

SM

RdRd

R rR rθg

0 5 000 10 000

−20

−10

0

f [Hz]

DSP

[dB]

7Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Propagation models: �xed sources

I harmonic point sourcesI �at ground

I homogeneous: Rudnick's model

hij(f ) =− ω4π

1

Rde κR

d

+Q

R re κR

r

I discontinuity of impedance: Rasmussen's model

I ground impedance: Delany-Bazley-Miki's modelI meteorological e�ects neglected

SM

RdRd

R rR rθg

0 5 000 10 000

−20

−10

0

f [Hz]

DSP

[dB]

7Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Propagation models: movingsources

I no need to take into accountmovement to compute Leq[van der Heijden and van Son,1982]

I heuristic approach based onRudnick's model, addingDoppler and convection e�ects[Li et al., 1998]

I Doppler Weyl Van der Polequation [Buret et al., 2006]

8Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Propagation models: movingsources

I no need to take into accountmovement to compute Leq[van der Heijden and van Son,1982]

I heuristic approach based onRudnick's model, addingDoppler and convection e�ects[Li et al., 1998]

I Doppler Weyl Van der Polequation [Buret et al., 2006]

8Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Propagation models: movingsources

I no need to take into accountmovement to compute Leq[van der Heijden and van Son,1982]

I heuristic approach based onRudnick's model, addingDoppler and convection e�ects[Li et al., 1998]

I Doppler Weyl Van der Polequation [Buret et al., 2006]

8Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Measurements methods: reference

I acoustic arraysI sound intensity measurementI Equivalent Source Method

⇒ Not suitable for everyday outmeasurements:

I a lot of microphonesI data acquisitionI post-processing

I phase calibrationI is phase relevant outdoors near a

real source?

9Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Measurements methods: reference

I acoustic arraysI sound intensity measurementI Equivalent Source Method

⇒ Not suitable for everyday outmeasurements:

I a lot of microphonesI data acquisitionI post-processing

I phase calibrationI is phase relevant outdoors near a

real source?

9Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Measurements methods: reference

I acoustic arraysI sound intensity measurementI Equivalent Source Method

⇒ Not suitable for everyday outmeasurements:

I a lot of microphonesI data acquisitionI post-processing

I phase calibrationI is phase relevant outdoors near a

real source?

9Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Measurement methods: engineering

I Standard Pass-By methodI CPX methodI source height measurement,

two-microphone methodI transfer function matrix

⇒ none is adapted for a dynamicindicator

10Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Measurement methods: engineering

I Standard Pass-By methodI CPX methodI source height measurement,

two-microphone methodI transfer function matrix

⇒ none is adapted for a dynamicindicator

10Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

State of the art: conclusion

I emission models: numerous with di�erentparameters

I propagation models:I assume harmonic point sourceI no simple expression of the pressure produced by

a moving source

I existing measurement methods:I not applicable to dynamic indicatorsI often deal only with one equivalent source

I need for a new methodI easy measurementI easy post-processingI adapted to dynamic indicators

11Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

State of the art: conclusion

I emission models: numerous with di�erentparameters

I propagation models:I assume harmonic point sourceI no simple expression of the pressure produced by

a moving source

I existing measurement methods:I not applicable to dynamic indicatorsI often deal only with one equivalent source

I need for a new methodI easy measurementI easy post-processingI adapted to dynamic indicators

11Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Table of contents

State of the art

Model improvementsBroadband sourcesOne harmonic moving source

Source height

MÉCS

12Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Broadband sources: measurement problems

Remarks from measurements

I di�erences betweenmeasurement and model

I localized at the interferencesminima

Loss of coherence due to

I turbulenceI model de�ned for harmonic

sourcesI uncertainties on geometrical

parameters

0 500 1 000 1 500 2 000

−40

−20

0

20

f [Hz]

Att21[dB]

13Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Broadband sources: measurement problems

Remarks from measurements

I di�erences betweenmeasurement and model

I localized at the interferencesminima

Loss of coherence due to

I turbulenceI model de�ned for harmonic

sourcesI uncertainties on geometrical

parameters0 500 1 000 1 500 2 000

−40

−20

0

20

f [Hz]

Att21[dB]

13Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Broadband sources: measurement problems

Remarks from measurements

I di�erences betweenmeasurement and model

I localized at the interferencesminima

Loss of coherence due to

I turbulenceI model de�ned for harmonic

sourcesI uncertainties on geometrical

parameters0 500 1 000 1 500 2 000

−40

−20

0

20

f [Hz]

Att21[dB]

13Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Broadband noise: theory

PSD(f ) =1

2

∣∣∣Pd (f )∣∣∣2 + |P r (f )|2 + 2 τcoh Re(P

d P r )

with

τcoh =

0 if (R r − Rd )/c > TI

1 if R r ≈ Rd

T′I

TIotherwise.

and

T′I = TI −

R r − Rd

c

pd

pr

TI

T′I

14Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Broadband noise: theory

PSD(f ) =1

2

∣∣∣Pd (f )∣∣∣2 + |P r (f )|2 + 2 τcoh Re(P

d P r )

with

τcoh =

0 if (R r − Rd )/c > TI

1 if R r ≈ Rd

T′I

TIotherwise.

and

T′I = TI −

R r − Rd

c

pd

pr

TI

T′I

14Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Broadband noise: theory

PSD(f ) =1

2

∣∣∣Pd (f )∣∣∣2 + |P r (f )|2 + 2 τcoh Re(P

d P r )

with

τcoh =

0 if (R r − Rd )/c > TI

1 if R r ≈ Rd

T′I

TIotherwise.

and

T′I = TI −

R r − Rd

c

pd

pr

TI

T′I

14Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Broadband noise: theory

PSD(f ) =1

2

∣∣∣Pd (f )∣∣∣2 + |P r (f )|2 + 2 τcoh Re(P

d P r )

with

τcoh =

0 if (R r − Rd )/c > TI

1 if R r ≈ Rd

T′I

TIotherwise.

and

T′I = TI −

R r − Rd

c

tpd

pr

TI

T′I

14Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Broadband noise: theory

PSD(f ) =1

2

∣∣∣Pd (f )∣∣∣2 + |P r (f )|2 + 2 τcoh Re(P

d P r )

with

τcoh =

0 if (R r − Rd )/c > TI

1 if R r ≈ Rd

T′I

TIotherwise.

and

T′I = TI −

R r − Rd

c

t

tpd

pr

TI

T′I

14Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Broadband noise: theory

PSD(f ) =1

2

∣∣∣Pd (f )∣∣∣2 + |P r (f )|2 + 2 τcoh Re(P

d P r )

with

τcoh =

0 if (R r − Rd )/c > TI

1 if R r ≈ Rd

T′I

TIotherwise.

and

T′I = TI −

R r − Rd

c

t

tpd

pr

TI

T′I

14Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Broadband noise: theory

PSD(f ) =1

2

∣∣∣Pd (f )∣∣∣2 + |P r (f )|2 + 2 τcoh Re(P

d P r )

with

τcoh =

0 if (R r − Rd )/c > TI

1 if R r ≈ Rd

T′I

TIotherwise.

and

T′I = TI −

R r − Rd

c

t

tpd

pr

TI

T′I

14Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Broadband noise: theory

PSD(f ) =1

2

∣∣∣Pd (f )∣∣∣2 + |P r (f )|2 + 2 τcoh Re(P

d P r )

with

τcoh =

0 if (R r − Rd )/c > TI

1 if R r ≈ Rd

T′I

TIotherwise.

and

T′I = TI −

R r − Rd

c

t

tpd

pr

TI

T′I

14Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Broadband noise: theory

PSD(f ) =1

2

∣∣∣Pd (f )∣∣∣2 + |P r (f )|2 + 2 τcoh Re(P

d P r )

with

τcoh =

0 if (R r − Rd )/c > TI

1 if R r ≈ Rd

T′I

TIotherwise.

and

T′I = TI −

R r − Rd

c

t

tpd

pr

TI

T′I

14Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Broadband noise: simulations

SM

zS 1 m2 m yz

0 1 000 2 000 3 000 4 000 5 000

30

40

50

60

70

f [Hz]

PSD

[dB]

Simulation: broadband

15Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Broadband noise: simulations

SM

zS=0.1 m 1 m2 m yz

0 1 000 2 000 3 000 4 000 5 000

30

40

50

60

70

f [Hz]

PSD

[dB]

Simulation: broadband

15Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Broadband noise: simulations

SM

zS=0.1 m 1 m2 m yz

0 1 000 2 000 3 000 4 000 5 000

30

40

50

60

70

f [Hz]

PSD

[dB]

Simulation: broadband

Model: harmonic

15Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Broadband noise: simulations

SM

zS=0.1 m 1 m2 m yz

0 1 000 2 000 3 000 4 000 5 000

30

40

50

60

70

f [Hz]

PSD

[dB]

Simulation: broadband

Model: harmonic

Model: broadband

15Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: layout

M

S(τd )

~v

source pathS(τ r ) S(t)

x

yz

Rd (τd )R r (τ r )

S(tCPA)

16Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: layout

M

S(τd )

~v

source path

S(τ r ) S(t)

x

yz

Rd (τd )R r (τ r )

S(tCPA)

16Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: layout

M

S(τd )

~v

source path

S(τ r ) S(t)

x

yz

Rd (τd )R r (τ r )

S(tCPA)

16Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: layout

M

S(τd )

~v

source path

S(τ r )

S(t)

x

yz

Rd (τd )R r (τ r )

S(tCPA)

16Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: layout

M

S(τd )

~v

source path

S(τ r )

S(t)

x

yz

Rd (τd )

R r (τ r )

S(tCPA)

16Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: layout

M

S(τd )

~v

source pathS(τ r ) S(t)

x

yz

Rd (τd )R r (τ r )

S(tCPA)

16Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: existing model

I Temporal Model for one Moving Source (MTSM),Doppler Weyl van der Pol equation

p(t) =− ωA4π

×

CdeκR

d

Rd+ C r Q(w r )

eκRr

R r

︸ ︷︷ ︸pd

︸ ︷︷ ︸pr

I movement e�ects:

I convection e�ectI Doppler e�ect

17Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: existing model

I Temporal Model for one Moving Source (MTSM),Doppler Weyl van der Pol equation

p(t) =− ωA4π

×

CdeκR

d

Rd+ C r Q(w r )

eκRr

R r

︸ ︷︷ ︸pd

︸ ︷︷ ︸pr

I movement e�ects:

I convection e�ectI Doppler e�ect

17Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: existing model

I Temporal Model for one Moving Source (MTSM),Doppler Weyl van der Pol equation

p(t) =− ωA4π

×

CdeκR

d

Rd+ C r Q(w r )

eκRr

R r

︸ ︷︷ ︸pd

︸ ︷︷ ︸pr

I movement e�ects:

I convection e�ectI Doppler e�ect

17Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: existing model

I Temporal Model for one Moving Source (MTSM),Doppler Weyl van der Pol equation

p(t) =− ωA4π

×

CdeκR

d

Rd+ C r Q(w r )

eκRr

R r

︸ ︷︷ ︸pd

︸ ︷︷ ︸pr

I movement e�ects:I convection e�ect

I Doppler e�ect

17Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: existing model

I Temporal Model for one Moving Source (MTSM),Doppler Weyl van der Pol equation

p(t) =− ωA4π

×

CdeκR

d

Rd+ C r Q(w r )

eκRr

R r

︸ ︷︷ ︸pd

︸ ︷︷ ︸pr

I movement e�ects:I convection e�ectI Doppler e�ect

17Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: simpli�ed model

p

l

=− ωA4π

×

CdeκR

d

Rd+ C r Q(w r )

eκRr

R r

I a lot of variables are function of timeI simpli�cation on time intervals Il with

I either constantI or linear approximation

pl (t) ≈− ω A

4π×

{C̃dl

e(µdlt+νd

l)

Rdl

+ C̃ rl Ql

e(µrlt+νr

l)

R rl

}

18Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: simpli�ed model

p

l

=− ωA4π

×

CdeκR

d

Rd+ C r Q(w r )

eκRr

R r

I a lot of variables are function of time

I simpli�cation on time intervals Il with

I either constantI or linear approximation

pl (t) ≈− ω A

4π×

{C̃dl

e(µdlt+νd

l)

Rdl

+ C̃ rl Ql

e(µrlt+νr

l)

R rl

}

18Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: simpli�ed model

pl =− ωA4π

×

CdeκR

d

Rd+ C r Q(w r )

eκRr

R r

I a lot of variables are function of timeI simpli�cation on time intervals Il with

I either constantI or linear approximation

pl (t) ≈− ω A

4π×

{C̃dl

e(µdlt+νd

l)

Rdl

+ C̃ rl Ql

e(µrlt+νr

l)

R rl

}

18Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: simpli�ed model

pl =− ωA4π

×

Cdl

eκRd

Rdl

+ C rl Q(w r

l )eκR

r

R rl

I a lot of variables are function of timeI simpli�cation on time intervals Il with

I either constant

I or linear approximation

pl (t) ≈− ω A

4π×

{C̃dl

e(µdlt+νd

l)

Rdl

+ C̃ rl Ql

e(µrlt+νr

l)

R rl

}

18Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: simpli�ed model

pl =− ωA4π

×

Cdl

eκRdl

Rdl

+ C rl Q(w r

l )eκR

rl

R rl

I a lot of variables are function of timeI simpli�cation on time intervals Il with

I either constantI or linear approximation

pl (t) ≈− ω A

4π×

{C̃dl

e(µdlt+νd

l)

Rdl

+ C̃ rl Ql

e(µrlt+νr

l)

R rl

}

18Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: simpli�ed model

pl =− ωA4π

×

Cdl

eκRdl

Rdl

+ C rl Q(w r

l )eκR

rl

R rl

I a lot of variables are function of timeI simpli�cation on time intervals Il with

I either constantI or linear approximation

pl (t) ≈− ω A

4π×

{C̃dl

e(µdlt+νd

l)

Rdl

+ C̃ rl Ql

e(µrlt+νr

l)

R rl

}

18Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: simpli�ed model

pl =− ωA4π

×

Cdl

eκRdl

Rdl

+ C rl Q(w r

l )eκR

rl

R rl

I a lot of variables are function of timeI simpli�cation on time intervals Il with

I either constantI or linear approximation

pl (t) ≈− ω A

4π×

{C̃dl

e(µdlt+νd

l)

Rdl

+ C̃ rl Ql

e(µrlt+νr

l)

R rl

}

18Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: numerical results ofa worst case

−10 −5 0 5 1020

30

40

50

60

xS(t) [m]

Lpl[dB]

2 000 3 000 4 000 5 000

−50

−25

0

25

50

f [Hz]

PSD

[dB]

XS(t), f = 3010 Hz

M

2 mv = 130 km/h

19Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: numerical results ofa worst case

−10 −5 0 5 1020

30

40

50

60

xS(t) [m]

Lpl[dB]

2 000 3 000 4 000 5 000

−50

−25

0

25

50

f [Hz]

PSD

[dB]

XS(t), f = 3010 Hz

M

2 mv = 130 km/h

19Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: numerical results ofa worst case

−10 −5 0 5 1020

30

40

50

60

xS(t) [m]

Lpl[dB]

Model

2 000 3 000 4 000 5 000

−50

−25

0

25

50

f [Hz]

PSD

[dB]

XS(t), f = 3010 Hz

M

2 mv = 130 km/h

19Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: numerical results ofa worst case

−10 −5 0 5 1020

30

40

50

60

xS(t) [m]

Lpl[dB]

Model

Simpli�ed model

2 000 3 000 4 000 5 000

−50

−25

0

25

50

f [Hz]

PSD

[dB]

XS(t), f = 3010 Hz

M

2 mv = 130 km/h

19Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: numerical results ofa worst case

−10 −5 0 5 1020

30

40

50

60

xS(t) [m]

Lpl[dB]

Model

Simpli�ed model

2 000 3 000 4 000 5 000

−50

−25

0

25

50

f [Hz]

PSD

[dB]

XS(t), f = 3010 Hz

M

2 mv = 130 km/h

19Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: numerical results ofa worst case

−10 −5 0 5 1020

30

40

50

60

xS(t) [m]

Lpl[dB]

Model

Simpli�ed model

2 000 3 000 4 000 5 000

−50

−25

0

25

50

f [Hz]PSD

[dB]

XS(t), f = 3010 Hz

M

2 mv = 130 km/h

19Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source: numerical results ofa worst case

−10 −5 0 5 1020

30

40

50

60

xS(t) [m]

Lpl[dB]

Model

Simpli�ed model

2 000 3 000 4 000 5 000

−50

−25

0

25

50

f [Hz]PSD

[dB]

XS(t), f = 3010 Hz

M

2 mv = 130 km/h

19Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Model improvements

I Broadband sourceI heuristic approachI numerical validation

I Moving harmonic sourceI simpli�ed temporal modelI numerical validation

20Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Model improvements

I Broadband sourceI heuristic approachI numerical validation

I Moving harmonic sourceI simpli�ed temporal modelI numerical validation

20Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Model improvements

I Broadband sourceI heuristic approachI numerical validation

I Moving harmonic sourceI simpli�ed temporal modelI numerical validation

20Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Table of contents

State of the art

Model improvements

Source heightFixed sourcesMoving source heightFixed vehicles, motor switched on

MÉCS

21Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Fixed source height: statement ofthe problem

Emission• NSe

• (xSe , ySe , zSe)i• |Ai |2

PSDjPSDjAtt21

propagation−1

22Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Fixed source height: statement ofthe problem

Emission• NSe

• (xSe , ySe , zSe)i• |Ai |2

PSDj

PSDjAtt21

propagation−1

22Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Fixed source height: statement ofthe problem

Emission• NSe

• (xSe , ySe , zSe)i• |Ai |2

Emission• NSe

• (xSe , ySe , zSe)i• |Ai |2

PSDj

PSDjAtt21

propagation−1

22Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Fixed source height: statement ofthe problem

Emission• NSe

• (xSe , ySe , zSe)i• |Ai |2

Emission• NSe

• (xSe ,ySe ,zSe)i• |Ai |2

PSDj

PSDjAtt21

propagation−1

22Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Fixed source height: statement ofthe problem

Emission• NSe

• (xSe , ySe , zSe)i• |Ai |2

Emission• NSe

• (xSe ,ySe ,zSe)i• |Ai |2

PSDj

PSDjAtt21

propagation−1

22Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Fixed source height: synoptic

Measurement

Modelling

choose zS ∈ Z

AttMod21

(f )

AttMes21

(f )

Cost F (zS)

zopt

23Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Fixed source height: synoptic

Measurement Modelling

choose zS ∈ Z

AttMod21

(f )AttMes21

(f )

Cost F (zS)

zopt

23Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Fixed source height: synoptic

Measurement Modelling

choose zS ∈ Z

AttMod21

(f )AttMes21

(f )

Cost F (zS)

zopt

23Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Fixed source height: synoptic

Measurement Modelling

choose zS ∈ Z

AttMod21

(f )AttMes21

(f )

Cost F (zS)

zopt

23Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Fixed source height: synoptic

Measurement Modelling

choose zS ∈ Z

AttMod21

(f )AttMes21

(f )

Cost F (zS)

zopt

23Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Fixed source height: measurementresults (1/2)

0 0.5 1

0

0.5

1

Real height [m]

Computedheight[m

]

1SH

24Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Fixed source height: measurementresults (1/2)

0 0.5 1

0

0.5

1

Real height [m]

Computedheight[m

]

1SH

24Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Fixed source height: measurementresults (1/2)

0 0.5 1

0

0.5

1

Real height [m]

Computedheight[m

]

1SH

24Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Fixed source height: measurementresults (1/2)

0 0.5 1

0

0.5

1

Real height [m]

Computedheight[m

]

1SH

3SH

24Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Fixed source height: measurementresults (1/2)

0 0.5 1

0

0.5

1

Real height [m]

Computedheight[m

]

1SH

3SH

1SD

24Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Fixed source height: measurementresults (1/2)

0 0.5 1

0

0.5

1

Real height [m]

Computedheight[m

]

1SH

3SH

1SD

3SD

24Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Fixed source height: measurementresults for one point source (2/2)

0 1 2

5

10

zS [m]

Fcost

[dB]

0 2 000 4 000

−40

−20

0

20

f [Hz]

Att21[dB]

measurement

model

25Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Fixed source height: measurementresults for one point source (2/2)

0 1 2

5

10

zS [m]

Fcost

[dB]

0 2 000 4 000

−40

−20

0

20

f [Hz]

Att21[dB]

measurement

model

25Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source height: theory

Emission• NSe

• (xSe(t),ySe ,zSe)i• |Ai |2

Att21(t)

Three models tested:

I �xed sources (near tCPA)

I slow moving sources(without Doppler andconvection e�ects)

I moving sources, fromsimpli�ed temporal model

S(t) S(tCPA)

v

M1

M2

xy

z

26Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source height: theory

Emission• NSe

• (xSe ,ySe ,zSe)i• |Ai |2

Emission• NSe

• (xSe(t),ySe ,zSe)i• |Ai |2

Att21

Att21(t)

Three models tested:

I �xed sources (near tCPA)

I slow moving sources(without Doppler andconvection e�ects)

I moving sources, fromsimpli�ed temporal model

S(t) S(tCPA)

v

M1

M2

xy

z

26Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source height: theory

Emission• NSe

• (xSe(t),ySe ,zSe)i• |Ai |2

Att21(t)

Three models tested:

I �xed sources (near tCPA)

I slow moving sources(without Doppler andconvection e�ects)

I moving sources, fromsimpli�ed temporal model

S(t) S(tCPA)

v

M1

M2

xy

z

26Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source height: theory

Emission• NSe

• (xSe(t),ySe ,zSe)i• |Ai |2

Att21(t)

Three models tested:

I �xed sources (near tCPA)

I slow moving sources(without Doppler andconvection e�ects)

I moving sources, fromsimpli�ed temporal model

S(t) S(tCPA)

v

M1

M2

xy

z

26Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source height: theory

Emission• NSe

• (xSe(t),ySe ,zSe)i• |Ai |2

Att21(t)

Three models tested:

I �xed sources (near tCPA)I slow moving sources

(without Doppler andconvection e�ects)

I moving sources, fromsimpli�ed temporal model

S(t) S(tCPA)

v

M1

M2

xy

z

26Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source height: theory

Emission• NSe

• (xSe(t),ySe ,zSe)i• |Ai |2

Att21(t)

Three models tested:

I �xed sources (near tCPA)I slow moving sources

(without Doppler andconvection e�ects)

I moving sources, fromsimpli�ed temporal model

S(t) S(tCPA)

v

M1

M2

xy

z

26Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source height:results

0 20 40 60 800

0.5

1

1.5

1.31

v [km.h−1]

zOpt

S[m

]

�xed sources

S(t) S(tCPA)

v

M1

M2

2 m

2 m

dPer=2 m

xy

z

27Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source height:measurement results

0 20 40 60 800

0.5

1

1.5

1.31

v [km.h−1]

zOpt

S[m

]

�xed sources

S(t) S(tCPA)

v

M1

M2

2 m

2 m

dPer=2 m

xy

z

27Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source height:measurement results

0 20 40 60 800

0.5

1

1.5

1.31

v [km.h−1]

zOpt

S[m

]

�xed sources

S(t) S(tCPA)

v

M1

M2

2 m

2 m

dPer=2 m

xy

z

27Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source height:measurement results

0 20 40 60 800

0.5

1

1.5

1.31

v [km.h−1]

zOpt

S[m

]

�xed sources

slow moving sources

S(t) S(tCPA)

v

M1

M2

2 m

2 m

dPer=2 m

xy

z

27Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source height:measurement results

0 20 40 60 800

0.5

1

1.5

1.31

v [km.h−1]

zOpt

S[m

]

�xed sources

slow moving sources

moving sources

S(t) S(tCPA)

v

M1

M2

2 m

2 m

dPer=2 m

xy

z

27Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source height:measurements results, v = 73 km.h−1

0 2 44

6

8

10

12

1.31

zModS [m]

Fcost

[dB]

measurement

�xed sources

2 000 4 000

−20

0

20

f [Hz]

Att21[dB]

28Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source height:measurements results, v = 73 km.h−1

0 2 44

6

8

10

12

1.31

zModS [m]

Fcost

[dB]

measurement

�xed sources

slow moving sources

moving sources

2 000 4 000

−20

0

20

f [Hz]

Att21[dB]

28Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Moving source height:measurements results, v = 73 km.h−1

0 2 44

6

8

10

12

1.31

zModS [m]

Fcost

[dB]

measurement

�xed sources

slow moving sources

moving sources

2 000 4 000

−20

0

20

f [Hz]Att21[dB]

28Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Fixed vehicle source height:measurement results

29Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Fixed vehicle source height:measurement results

0 2 4

2

4

6

8

zS [m]

Fcost

Measurement

0 2 000 4 000

−10

−5

0

f [Hz]

Att21[dB]

Measurement

29Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Fixed vehicle source height:measurement results

0 2 4

2

4

6

8

zS [m]

Fcost

Measurement

0 2 000 4 000

−10

−5

0

f [Hz]

Att21[dB]

Measurement

29Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Fixed vehicle source height:measurement results

0 2 4

2

4

6

8

zS [m]

Fcost

Measurement

0 2 000 4 000

−10

−5

0

f [Hz]

Att21[dB]

Measurement

Model

29Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Source height: conclusion

I �xed sources:I theoryI numerical validationI experimental validation: mainly three sources

with discontinuity

I moving sources:I theoryI numerical simulationsI experimental validation

I measurement on �xed vehicles

30Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

Table of contents

State of the art

Model improvements

Source height

MÉCSTheoryNumerical validationLarge source simulation

31Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: problem statement

S

(~v = ~0)

Sei

yz

x

Mj(~v = ~0)

Emission• NSe

• (xSe , ySe , zSe)i• |Ai |2

PSDj

propagation−1

32Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: problem statement

S(~v = ~0) Sei

yz

x

Mj(~v = ~0)

Emission• NSe

• (xSe , ySe , zSe)i• |Ai |2

PSDj

propagation−1

32Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: problem statement

S(~v = ~0) Sei

yz

x

Mj(~v = ~0)

Emission• NSe

• (xSe , ySe , zSe)i• |Ai |2

PSDj

propagation−1

32Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: problem statement

S(~v = ~0) Sei

yz

x

Mj(~v = ~0)

Emission• NSe

• (xSe , ySe , zSe)i• |Ai |2

PSDj

propagation−1

32Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: problem statement

S(~v = ~0) Sei

yz

x

Mj(~v = ~0)

Emission• NSe

• (xSe , ySe , zSe)i• |Ai |2

PSDj

propagation−1

32Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: problem statement

S(~v = ~0) Sei

yz

x

Mj(~v = ~0)

Emission• NSe

• (xSe , ySe , zSe)i• |Ai |2

PSDj

propagation−1

32Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: synoptic

Measurement Modeling

choose e ∈ E

|Ai (f , e)|2

PSDModj (f )PSDMes

j (f )

Cost F (e)

eopt

Space E ofsolutions

I NSe

I

33Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: synoptic

Measurement Modeling

choose e ∈ E

|Ai (f , e)|2

PSDModj (f )PSDMes

j (f )

Cost F (e)

eopt

Space E ofsolutions

I NSe

I

33Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: synoptic

Measurement Modeling

choose e ∈ E

|Ai (f , e)|2

PSDModj (f )PSDMes

j (f )

Cost F (e)

eopt

Space E ofsolutions

I NSe

I (xSe , ySe , zSe)i

33Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: computation of |Ai(f , e)|2

Formulation ...

and LMS-solve

DSPMes ≈ |H(e)|2|A(e)|2

DSPMes1

(f1)...

DSPMesNM

(f1)......

DSPMes1

(fNf)

...DSPMes

NM(fNf

)

=

. . . . . . . . .

. . . . . . . . .

. . . . . . . . .

. . . hij(fk) . . .

. . . . . . . . .

. . . . . . . . .

. . . . . . . . .

. . . . . . . . .

|A1(f1, e)|2...

|ANS(f1, e)|2......

|A1(fNf, e)|2

...|ANS

(fNf, e)|2

34

Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: computation of |Ai(f , e)|2

Formulation ... and LMS-solve

DSPMes ≈ |H(e)|2|A(e)|2

DSPMes1

(f1)...

DSPMesNM

(f1)......

DSPMes1

(fNf)

...DSPMes

NM(fNf

)

=

. . . . . . . . .

. . . . . . . . .

. . . . . . . . .

. . . hij(fk) . . .

. . . . . . . . .

. . . . . . . . .

. . . . . . . . .

. . . . . . . . .

|A1(f1, e)|2...

|ANS(f1, e)|2......

|A1(fNf, e)|2

...|ANS

(fNf, e)|2

34

Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: con�gurations used fornumerical simulation

S1

S2

M1

M2

M3

M4

zS1

zS2

0.05 m0.45 m

0.5 m

0.5 m2 m

Hypotheses:• white noise • SNR 15 dB• uncertainties along X, Y, Z

35Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: con�gurations used fornumerical simulation

S1

S2

M1

M2

M3

M4

zS1

zS2

0.05 m0.45 m

0.5 m

0.5 m2 m

Hypotheses:• white noise • SNR 15 dB• uncertainties along X, Y, Z

35Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: con�gurations used fornumerical simulation

S1

S2

M1

M2

M3

M4

zS1

zS2

0.05 m0.45 m

0.5 m

0.5 m2 m

Hypotheses:• white noise • SNR 15 dB• uncertainties along X, Y, Z

35Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: con�gurations used fornumerical simulation

S1

S2

M1

M2

M3

M4

zS1

zS2

0.05 m0.45 m

0.5 m

0.5 m2 m

Hypotheses:• white noise • SNR 15 dB• uncertainties along X, Y, Z

35Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: con�gurations used fornumerical simulation

S1

S2

M1

M2

M3

M4

zS1

zS2

0.05 m0.45 m

0.5 m

0.5 m2 m

Hypotheses:• white noise • SNR 15 dB• uncertainties along X, Y, Z

35Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: numerical results (1/4)

S1

S2M1

M2

M3

M4

0 2 000 4 0000

2

4

6

Z1 Z2 Z3

e =(zS1 ,zS2)

Fcost

[dB]

0 5 100.4

0.5

0.6

0.7

0.8

e =(zS1 ,zS2)

z S[m

]

zSimS

36Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: numerical results (1/4)

S1

S2M1

M2

M3

M4

0 2 000 4 0000

2

4

6

Z1 Z2 Z3

e =(zS1 ,zS2)

Fcost

[dB]

0 5 100.4

0.5

0.6

0.7

0.8

e =(zS1 ,zS2)

z S[m

]

zSimS

36Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: numerical results (1/4)

S1

S2M1

M2

M3

M4

0 2 000 4 0000

2

4

6

Z1 Z2 Z3

e =(zS1 ,zS2)

Fcost

[dB]

0 5 100.4

0.5

0.6

0.7

0.8

e =(zS1 ,zS2)

z S[m

]

zSimS

36Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: numerical results (1/4)

S1

S2M1

M2

M3

M4

0 2 000 4 0000

2

4

6

Z1 Z2 Z3

e =(zS1 ,zS2)

Fcost

[dB]

0 5 100.4

0.5

0.6

0.7

0.8

e =(zS1 ,zS2)

z S[m

]

zSimS

zOptS

36Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: numerical results (2/4)

S1

S2M1

M2

M3

M4

0 2 000 4 000

75

80

85

90

f [Hz]

PSDj[dB]

Measurement

Model

0 2 000 4 00085

90

95

100

105

f [Hz]

Lw

i[dB]

measurement

model

37Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: numerical results (2/4)

S1

S2M1

M2

M3

M4

0 2 000 4 000

75

80

85

90

f [Hz]

PSDj[dB]

Measurement

Model

0 2 000 4 00085

90

95

100

105

f [Hz]

Lw

i[dB]

measurement

model

37Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: numerical results (2/4)

S1

S2M1

M2

M3

M4

0 2 000 4 000

75

80

85

90

f [Hz]

PSDj[dB]

Measurement

Model

0 2 000 4 00085

90

95

100

105

f [Hz]

Lw

i[dB]

measurement

model

37Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: numerical results (3/4)

S1

S2M1

M2

M3

M4

1 2 3 4 5 6 7 8 9 10

0

0.5

1

Con�guration

z Si[m

]

Simulated

38Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: numerical results (3/4)

S1

S2M1

M2

M3

M4

1 2 3 4 5 6 7 8 9 10

0

0.5

1

Con�guration

z Si[m

]

Simulated

NSe = 1

38Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: numerical results (3/4)

S1

S2M1

M2

M3

M4

1 2 3 4 5 6 7 8 9 10

0

0.5

1

Con�guration

z Si[m

]

Simulated

NSe = 1

NSe = 2

38Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: numerical results (3/4)

S1

S2M1

M2

M3

M4

1 2 3 4 5 6 7 8 9 10

0

0.5

1

Con�guration

z Si[m

]

Simulated

NSe = 1

NSe = 2

NSe = 3

38Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: numerical results (4/4)

S1

S2M1

M2

M3

M4

1 2 3 4 5 6 7 8 9 100

1

2

3

Con�guration

Fcost(e

opt)[dB] NSe = 1

0 2 000 4 00080

90

100

110

f [Hz]

Lw

i[dB]

�ctive source

39Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: numerical results (4/4)

S1

S2M1

M2

M3

M4

1 2 3 4 5 6 7 8 9 100

1

2

3

Con�guration

Fcost(e

opt)[dB] NSe = 1

0 2 000 4 00080

90

100

110

f [Hz]

Lw

i[dB]

�ctive source

39Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: numerical results (4/4)

S1

S2M1

M2

M3

M4

1 2 3 4 5 6 7 8 9 100

1

2

3

Con�guration

Fcost(e

opt)[dB] NSe = 1

NSe = 2

0 2 000 4 00080

90

100

110

f [Hz]

Lw

i[dB]

�ctive source

39Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: numerical results (4/4)

S1

S2M1

M2

M3

M4

1 2 3 4 5 6 7 8 9 100

1

2

3

Con�guration

Fcost(e

opt)[dB] NSe = 1

NSe = 2

NSe = 3

0 2 000 4 00080

90

100

110

f [Hz]

Lw

i[dB]

�ctive source

39Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: numerical results (4/4)

S1

S2M1

M2

M3

M4

1 2 3 4 5 6 7 8 9 100

1

2

3

Con�guration

Fcost(e

opt)[dB] NSe = 1

NSe = 2

NSe = 3

0 2 000 4 00080

90

100

110

f [Hz]

Lw

i[dB]

�ctive source

39Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: numerical results (4/4)

S1

S2M1

M2

M3

M4

1 2 3 4 5 6 7 8 9 100

1

2

3

Con�guration

Fcost(e

opt)[dB] NSe = 1

NSe = 2

NSe = 3

0 2 000 4 00080

90

100

110

f [Hz]

Lw

i[dB]

�ctive source

real sources

39Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: large source simulation

S

M1

M2

M3

M4

0.6 m0.9 m

0.05 m

0.45 m

0.5 m

0.5 m2 m

Hypotheses

I 50 sources modeling one large real sourceI di�erent spectraI uncertainties on localization

40Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: large source simulation

S

M1

M2

M3

M4

0.6 m0.9 m

0.05 m

0.45 m

0.5 m

0.5 m2 m

Hypotheses

I 50 sources modeling one large real sourceI di�erent spectraI uncertainties on localization

40Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: large source simulation results

S

M1

M2

M3

M4

0 2 4 6 8 100

0.2

0.4

0.6

0.8

1

Simulation

z S[m

]

41Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: large source simulation results

S

M1

M2

M3

M4

0 2 4 6 8 100

0.2

0.4

0.6

0.8

1

Simulation

z S[m

]

41Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: large source simulation results

S

M1

M2

M3

M4

0 2 4 6 8 100

0.2

0.4

0.6

0.8

1

Simulation

z S[m

]

Narrow bands

41Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: large source simulation results

S

M1

M2

M3

M4

0 2 4 6 8 100

0.2

0.4

0.6

0.8

1

Simulation

z S[m

]

Narrow bands

Third octave

41Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: conclusion

I theory:I inverse approachI LMS to compute |Ai (f )|2

I numerous simulations with two point sourcesI good agreement between measurement and

modelI stability of the best solution

I simulation of a large sourceI Fcost based on narrow bands gives often sources

near the groundI Fcost based on third octaves approaches physical

height

42Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: conclusion

I theory:I inverse approachI LMS to compute |Ai (f )|2

I numerous simulations with two point sourcesI good agreement between measurement and

modelI stability of the best solution

I simulation of a large sourceI Fcost based on narrow bands gives often sources

near the groundI Fcost based on third octaves approaches physical

height

42Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

State of the art Model improvements Source height MÉCS

MÉCS: conclusion

I theory:I inverse approachI LMS to compute |Ai (f )|2

I numerous simulations with two point sourcesI good agreement between measurement and

modelI stability of the best solution

I simulation of a large sourceI Fcost based on narrow bands gives often sources

near the groundI Fcost based on third octaves approaches physical

height

42Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

Conclusion (1/3)

S(~v = ~cst) Sei

y

z

x

Mj(~v = ~0)

d<10 m

Emission• NSe

• (xSe , ySe , zSe)i• |Ai |2

PSDj

propagation−1

43Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

Conclusion (2/3)

I improvements of modelsI for broadband noiseI for moving sources

I two-microphone method for height of sourceI numerical simulationsI moving sourcesI vehicles

I MÉCSI theoryI numerical validation

44Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

Conclusion (2/3)

I improvements of modelsI for broadband noiseI for moving sources

I two-microphone method for height of sourceI numerical simulationsI moving sourcesI vehicles

I MÉCSI theoryI numerical validation

Emission• NSe = 1• (xSe , ySe ,zSe)i• |Ai |2

Attj

propagation−1

44Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

Conclusion (2/3)

I improvements of modelsI for broadband noiseI for moving sources

I two-microphone method for height of sourceI numerical simulationsI moving sourcesI vehicles

I MÉCSI theoryI numerical validation

Emission• NSe

• (xSe , ySe , zSe)i• |Ai |2

PSDj

propagation−1

44Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

MECS: Perspectives

Optimization and validation of MÉCS

I microphone localizationI space solution reductionI other sources con�gurationsI LMS with positivity constraint

I Measurements

45Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

MECS: Perspectives

Optimization and validation of MÉCS

I microphone localizationI space solution reductionI other sources con�gurationsI LMS with positivity constraintI Measurements

45Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

MECS: Perspectives

Optimization and validation of MÉCS

I microphone localizationI space solution reductionI other sources con�gurationsI LMS with positivity constraintI Measurements

Theoritical improvements

I movementI broadband noiseI measurement in real conditionsI directivity

45Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

MECS: Perspectives

Optimization and validation of MÉCS

I microphone localizationI space solution reductionI other sources con�gurationsI LMS with positivity constraintI Measurements

Theoritical improvements

I movementI broadband noiseI measurement in real conditionsI directivity

45Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

MECS: Perspectives

Optimization and validation of MÉCS

I microphone localizationI space solution reductionI other sources con�gurationsI LMS with positivity constraintI Measurements

Theoritical improvements

I movementI broadband noiseI measurement in real conditionsI directivity

45Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

Acknowledgments

Close supervision

I Christophe AYRAULT, LAUMI Guillaume DUTILLEUX, LRSI Laurent SIMON, LAUM

Monitoring committee

I Fabienne ANFOSSO-LEDEE, LCPCI David ÉCOTIÈRE, LRSI Franck POISSON, SNCF

Other

I Charlotte, Thérèse, Auguste, Gustave. . .I

Chritophe H., Thierry F., Jean-Louis A., Loic T., Laurent B.46

Thesis 31/08/10, Le MansCharacterization of the acoustic emission of vehicles by equivalent point sources F. Golay

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Thank you for your

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