flow-induced noise technical group noise tech group 2015.pdfflow-induced noise technical group ......

CAV Workshop May 5-6, 2015 1

Flow-Induced Noise Technical Group

Center for Acoustics and Vibration Spring Workshop

May 6, 2015 Presented by:

Michael L. Jonson


Overview

• The mission of the Flow-Induced Noise Group of the Center for Acoustics and Vibration is the understanding and control of acoustic noise and structural vibration induced by fluid flow.

• Topical Research Area Presentation – Mr. Russell Powers: Fluidic Insert Noise for

Tactical Aircraft

2


Task 3: Helicopter Icing Physics Modeling and Detection

PIs: Palacios, Kinzel, Brentner [email protected], [email protected], [email protected]

Graduate Students:

Yiqiang Han – PhD Candidate Dave Hanson – PhD Candidate

Baofeng Cheng – PhD Candidate

Point of Contact: Eric Kreeger

Tom Thompson


Acoustics Part Background • From experience we know the noise changes as

ice accretes on the blades • The thickness and loading noise will vary as ice

accretes noticeably • Surface roughness due to ice accretion is

expected to affect broadband noise.

Objectives • Understand the acoustic signature of:

– Varying surface roughness – Varying ice shapes

• Use acoustics for prediction/detection of rotor ice severity

– Determine the ice-induced surface roughness through noise measurements

– CFD can be used with PSU-WOPWOP to compute the changes in noise due to ice accretion

Vertical Lift Research Center of Excellence Task 3: Helicopter Icing Physics Modeling and Detection


Frequency (Hz)

SP

L(d

B)

0 4000 8000 12000 16000 20000 240000

20

40

60

80 Grit 16Grit 24Grit 36Grit 60Grit 80Grit 100clean bladesBG Noise

RPM 400

Broadband Noise related to icing Most likely sources

Strongly impacted by icing

Broadband noise changes due to different surface roughness (sand paper):

Sand paper used to represent ice


Purpose: • Show broadband noise can be used for ice detection • Develop a correlation between the surface roughness and the broadband

noise level

Broadband Noise Test


Frequency (Hz)So

un

dp

ress

ure

leve

l,d

B(P

a2 /Hz

re20

µPa)

0 6000 12000 18000 2400035

40

45

50

55

60

clean bladescase 15 (smooth)case 12 (rough)

RPM 450

Case 15

Case 12

Different surface roughness cases can be distinguished in the high frequencies

Broadband Noise Test Actual ice used in roughness detection


Total absolute mean deviation 11.2%

Correlation of broadband noise with surface roughness

Validation points: 7.6%

Broadband Noise Test


8.5 ft/s 8.5 ft/s

Noise from Pulsating of Supercavities

Prepared for

The 2015 ONR 6.1 Program Review Panel Prepared by

Grant M. Skidmore Timothy A. Brungart Jules W. Lindau Michael E. Moeny Steven D. Young April 22, 2015

Photograph of a pulsating supercavity in the ARL Penn State 0.305 m water tunnel. The inset is a computational simulation of the subject pulsating supercavity.


Introduction • Enveloping an undersea vehicle in a gaseous bubble or cavity provides an order of magnitude reduction in drag and correspondingly higher speeds than a fully wetted vehicle - Injecting gas into the cavity generates a ventilated supercavity - Under certain conditions, the ventilated supercavity can become unstable and pulsate or undergo periodic oscillations in size

Introduction

Supercavitating Torpedo Schematic from Popular Science Magazine

Noise from Pulsating Supercavities


8.5 ft/s

Experimental Setup

Flow Dir.

Static Tap


Flow

• Rearward facing truncated cone cavitator with embedded static and dynamic pressure sensor - Senses cavity pressure

• Experiments performed in ARL Penn State 0.305 m water tunnel - Hydrophone mounted on water tunnel window


8.5 ft/s

Results & Discussion – Noise • Cavity interior pressure and noise vary sinusoidally and in-phase with time

• Spectrum level of cavity interior press. is 20 dB greater than that measured by window hydrophone > Due to spherical spreading of sound waves from cavity interface

20 dB



8.5 ft/s

• Acoustic pressure, p(r,t), from fluctuating volume or monopole source is given by

dt

crtd

rtrp

)/(

4),(

−=

ξπρ

• Assuming time harmonic motion of the interface we get

)/(22

ˆ2

),( crtfjr eu

r

afjtrp −= πρπ

• Substituting measured values of f, a, r and into (2) gives ru

(1)

(2)

1.1712

),(log20 =

trppkdB (re 1x10-6 Pa at 22.4 cm)

171.5 dB Measured with Window Hydrophone


Results & Discussion – Noise


8.5 ft/s

• Lump from Eq. 2 together to form complex pressure amplitude

• Evaluate on interface to obtain expression for radiated sound pressure

• Given/assuming pressure inside cavity is uniform and constant across interface

(3)

ruafj ˆ2 2ρπ

A

)/(2ˆ

),( crtfjer

Atrp −= π

The radiated sound pressure from pulsating supercavity can be obtained simply from a pressure sensor inside the cavity and accounting for

spherical spreading from the interface!




8.5 ft/s

20 dB dB

cm

cm8.19

4.22

3.2log20 −=

Spherical spreading of sound waves from interface to window hydrophone location

accounts for nominal 20 dB offset measured

• When the spectrum level of the cavity interior pressure was varied up to 20 dB during experiments aimed at suppressing pulsation noise, the spectrum level of the radiated noise varied commensurately

We have shown conclusively that the cavity interior pressure can be used as a measure of the radiated noise from a pulsating supercavity!




8.5 ft/s

• The noise from pulsating supercavities is at least 40 dB greater than that generated by comparable twin vortex and re-entrant jet cavities


40 dB



Summary

• Experimentally explored ventilated supercavity pulsation and its noise

• Noise from pulsating supercavities at least 40 dB greater than noise from comparable re-entrant jet and twin vortex supercavities - Pulsating supercavity is monopole sound source

• Pulsating supercavity interior pressure spectrum level related to radiated noise spectrum level through spherical spreading of sound waves from the interface - Cavity interior pressure can be used as a measure of radiated noise from pulsating supercavity


Fluidic Insert Noise Reduction for Tactical Aircraft

Russell W. Powers, Dennis K. McLaughlin, Phillip J. Morris

May 6, 2015 | University Park, PA

1

Presented at the 2015 CAV Workshop

Aircraft carrier crews are in close proximity to the loud supersonic exhaust jets of military aircraft.

State of the art hearing protection cannot bring the noise levels down to safe levels for an all day work environment.

Forward flight affects the noise generation mechanisms and can affect possible noise reduction methods.

2

Motivation – The Jet Noise Problem

PSU High Speed Jet Aeroacoustics Facility

3

• Compressed Air Supply (195 psig)

• Dnoz ~ 2.2 cm (~ 1/35 Scale)

• Rmic = 180 cm

• R/D ~ 80

• Capacity of the heated jet

simulation via helium/air mixture

jets

Fluidic Inserts for Noise Reduction

4

Replicate the mechanical inserts with precisely distributed nozzle blowing.

Produced with low injection mass flow rate ratios, less than 5% of the core jet’s mass flow

Static BBSAN Acoustic Comparisons Far-field microphone measurements

Average OASPL delta for polar angles from 90 to 130 degrees

The noise benefit dependence will be shown for three different injection parameters

Cold jet measurements for a larger range of conditions will be shown first.

Followed by helium-air mixture

Noise Benefit parameter dependence

5

IPR 𝒎 𝒓𝒂𝒕𝒊𝒐 𝒋𝒓𝒂𝒕𝒊𝒐

6 6

3FID06B

3FID06V

𝑗𝑟𝑎𝑡𝑖𝑜,1 = 𝑉1,𝑡ℎ 𝑚 𝑖𝑛𝑗,1,𝑚𝑒𝑎𝑠

𝑚 𝑐𝑜𝑟𝑒,𝑡ℎ𝑉𝑒𝑥𝑖𝑡,𝑡ℎ

NPR = 3.0

Mj = 1.36

TTR = 1.0

Still collapses between nozzles

for noise reduction when plotted

against momentum flux ratio

Static BBSAN Reduction vs 𝒋𝒓𝒂𝒕𝒊𝒐

7

0.6 0.8 1 1.2 1.4 1.6

0.4

0.5

0.6

0.7

0.8

0.9

j2 Downstream Momentum Flux Ratio (%)

j 1 U

pstr

eam

Mo

men

tum

Flu

x R

ati

o (

%)

Peak Noise, Downstream Direction (40o - 60

o)

O

AS

PL

(A

ve

rag

ed

)

-4

-3

-2

-1

0

1

2

7

3FID06B

3FID06V

NPR = 3.0 | Mj = 1.36

TTR = 3.0

- Significantly Higher Reductions than for Cold Jets

- Trends are still observable, but not as concrete as for BBSAN reduction

- For further examination, two specific conditions are plotted as narrowband spectra.

Static Peak Noise Reduction TTR = 3

𝑗𝑟𝑎𝑡𝑖𝑜,1 = 𝑉1,𝑡ℎ 𝑚 𝑖𝑛𝑗,1,𝑚𝑒𝑎𝑠

𝑚 𝑐𝑜𝑟𝑒,𝑡ℎ𝑉𝑒𝑥𝑖𝑡,𝑡ℎ

Static Fluidic Insert Noise Reduction

-6 -4 -2 0 2

30

36

40

43

46

50

55

60

65

70

80

85

90

93.5

100

105

110

115

OASPL (dB)

Po

lar

an

gle

(D

eg

ree

),

3FID06B

3FID06V

8

0.01 0.1 1 10

120

120

120

120

120

Strouhal Number

SP

L p

er

un

it S

t (d

B//(2

0

Pa

2))

30

40

60

90

120

Gen1B Baseline

3FID06B

3FID06V

20 dBM

j = 1.36

NPR = 3

TTR = 3.0

3 Fluidic Inserts

2 Injectors Each

Φ = 60°

D = 2.25 cm

Md =1.65

Mf = 0

NPR = 3.0

Mj =1.36

TTR = 3.0

Signal Analysis

9

20 30 40 50 60 70 80

120

122

124

126

128

130

132

Polar Angle, , (deg)

OA

SP

L d

B

ref

20

P

a

Baseline

3FID06B

3FID06V

20 30 40 50 60 70 80

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9


Sk

ew

ne

ss

of

Pre

ss

ure

, S

k{p

(t)}

Baseline

3FID06B

3FID06V

20 30 40 50 60 70 80

0.5

1

1.5

2

2.5


Sk

ew

ne

ss

of

Pre

ss

ure

De

riv

ati

ve

, S

k{p

(t)/t}

Baseline

3FID06B

3FID06V

OASPL Sk{p(t)} Sk{δp/dt}

- Noise reduction for helium-air jets are significantly larger (2-3 times) than for cold jets

- Possible reason could be that the heated jets are said to “crackle”, which is observed as high amplitude positive spikes in the pressure signal.

10

Initial Forward Flight Measurements

Typical non-injection forward

flight configuration

Original piping design and

delivery system

Second generation

air delivery system

Streamlined outer shroud

Noise Reduction with Forward Flight

11

-6 -4 -2 0 2

30

36

40

43

46

50

55

60

65

70

80

85

90

93.5

100

105

110

115

OASPL (dB)

Po

lar

an

gle

(D

eg

ree

),

3FID06B

3FID06V

0.01 0.1 1 10

120

120

120

120

120

Strouhal Number

SP

L p

er

un

it S

t (d

B//(2

0

Pa

2))

36

50

60

90

115

20 dB

Gen1B Baseline

3FID06B

3FID06V

Mj = 1.36

NPR = 3

TTR = 3.0M

f = 0.17

3 Fluidic Inserts

2 Injectors Each

Φ = 60°

D = 2.25 cm

Md =1.65

Mf = 0.17

NPR = 3.0

Mj =1.36

TTR = 3.0

12

Fluidic Inserts for Rectangular Nozzles In prior research all injector geometries have been equally spaced

azimuthally in axisymmetric nozzles.

The 4FIA nozzle has been designed as a Aspect Ratio 2, CD Rectangular nozzle with fluidic inserts.

13

Unsteady Velocity Measurements and Simulations

RANS Mach Number

RANS Turbulent Kinetic Energy

14

Noise Reduction with a Simulated Carrier Deck

Far-Field Microphones

Near-Field Edge Microphones

Surface Flush Mounted Microphones

Unsteady Pressure Sensors in the Flow

Acknowledgements The lead author would like to thank the Department of Defense for the SMART Scholarship

award, with mentor Mr. Allan Aubert.

This work was partially supported by the Office of Naval Research (ONR) w/ project monitor Dr. B. Henderson.

The authors would also like to thank graduate students Alex Karns, Scott Hromisin and Leighton Myers for assistance in the laboratory experiments and Matt Kapusta for the Simulations.

Thanks the financial support from Defense University Research Instrumentation Program sponsored by ONR.

15

Questions?

-6 -4 -2 0 2

30

36

40

43

46

50

55

60

65

70

80

85

90

93.5

100

105

110

115

OASPL (dB)

Po

lar

an

gle

(D

eg

ree

),

3FID06B

3FID06V

Extra Slides

16

17

Heated Jets -Comparing Penn State with NASA Data (Md

= 1.65, Mj = 1.36 ) Over-expanded

Spectra and OASPL comparison of

heat simulated jets (TTR = 2.6)

at PSU , D. McLaughlin, C-W. Kuo

heated jets (TTR = 2.5, Single Stream) at NASA, Bridges, Henderson

Out of Test Repeatability

0.01 0.1 1 10

120

120

120

120

120

Strouhal Number

SP

L p

er

un

it S

t (d

B//

(20

Pa

2))

30

40

60

90

120

20dB

NASA 2010 Deff ~4.5

PSU 2012 Deff = 0.708

PSU 2013 Deff = 0.885

PSU 2014 Deff = 0.885

18

• Several Different Lead Test

Conductors

• Additional and Replacement of

Microphones

• New Data Acquisition System

• Removal and Replacement of entire

Jet Plenum

Md = 1.65

NPR = 3.5 Mj = 1.47

TTR = 3

F404 Geometry

Components of Supersonic Jet Noise

19

0.01 0.1 1 10

120

120

120

120

120

Strouhal Number

SP

L p

er

un

it S

t (d

B//(2

0

Pa

2))

20 dB

30

40

60

90

120

20

Noise Reduction with Corrugated Inserts

Mj = 1.36 - Md = 1.65

Mj = 1.37 - Md = 1.64

Seiner et al. 1/10th Scale

Acoustic Results from Seiner et al.

-Moderate scale (1/10th)

-Heated Jets

21

0.01 0.1 1 10

120

120

120

120

120

Strouhal NumberS

PL

per

un

it S

t (d

B//

(20

Pa

2))

GEMd1.65 BaseD M

j1.36, TTR=3, Scaled R /D

j = 100

Mf = 0

Mf = 0.17

20dB

30

40

60

90

110

NPR = 3.0 - Mj =1.36

Over-Expanded ; Heat-simulated: TTR = 3.0

Reduction of Magnitude at low polar angles

Slight increase of the angle of peak noise direction

Little Effect on the sideline and upstream arc

The Effect of Forward Flight

fc = 41,562 Hz

22

Forward Flight Acoustics- 6Corrug

-6 -4 -2 0 2

30

40

50

60

70

80

90

100

110

OASPL (dB)

Po

lar

an

gle

(D

eg

ree

),

6Cor = 0

6Cor = 30

0.01 0.1 1 10

120

120

120

120

120

Strouhal Number

SP

L p

er

un

it S

t (d

B//

(20

Pa

2))

GEMd1.65 M

j1.36, TTR = 3, Scaled R /D

j = 100, M

f = 0.17

20dB

30

40

60

90

110

Baseline

6Corrug = 0

6Corrug = 30

0°

D = 1.80 cm

Md =1.65

Mf = 0.17

NPR = 3.0

Mj =1.36

TTR = 3.0

-6 -4 -2 0 2

20

30

40

50

60

70

80

90

100

110

OASPL (dB)

Po

lar

an

gle

(D

eg

ree

),

Mf = 0

Mf = 0.17

23

Conclusions – Forward Flight

Forward Flight measurements first conducted with hardwall corrugation nozzles

The piping delivery system for the fluidic inserts is currently being upgraded to accommodate forward flight experiments

Forward Flight does not negatively affect the noise reduction of the hardwall corrugation nozzle jet.

NPR = 3.0

Mj =1.36

TTR = 3.0

24

Nozzle Designs

3FID06B

3FID06V

𝐴𝑖𝑛𝑗𝐵

≈ 𝐴𝑖𝑛𝑗𝑉

𝐴𝑖𝑛𝑗,2 = 𝐴𝑖𝑛𝑗,1

𝐴𝑖𝑛𝑗,2 ≈ 2.5 𝐴𝑖𝑛𝑗,1

- Nozzle Designs are identical other than the injector port diameters noted

- Objective of separate nozzles was to keep overall injection area constant to better understand which injection parameter has the largest effect on noise reduction.

- Different hole areas allows for mass flow ratio to be kept constant while changing the injection pressures.

IPR? 𝑚 𝑟𝑎𝑡𝑖𝑜? Momentum flux?

flow-induced noise technical group noise tech group 2015.pdfflow-induced noise technical group ......

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