flow-induced noise technical group induced noise.pdf · 2 overview • the mission of the...

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Flow-Induced Noise Technical Group

Center for Acoustics and Vibration

Spring Workshop

May 14, 2012

Presented by:

Dean E. Capone, Group Leader

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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.

• Research Areas

– Numerical simulations of high speed jet noise

– Experimental jet noise

– Marine renewable energy turbine noise

– Acoustic Detection of Cavitation

Numerical Simulations of High Speed Jet Noise

Philip J. Morris

Boeing/A. D. Welliver Professor

Department of Aerospace Engineering

CAV Workshop

May 2012

Jet Noise Research Projects

Noise from dual stream jets (Pratt & Whitney) – Swati Saxena (RA)

Noise reduction in supersonic jets (ONR) – Dr. Yongle Du & Nidhi Sikarwar (RA)

Nonlinear propagation of jet noise (Boeing) – Don Hyatt (RA)

LES for high speed jets (NAVAIR) – Dr. Yongle Du

Unsteady loading in nozzles with UAV applications (Pratt & Whitney) – Michael Lurie (RA)

Forward Flight Analysis of Single Stream Jet Mj = 0.9, TTR = 1.0, Mcf = 0.0 to 0.28

Q Iso-surfaces and FW-H surface

Potential core length comparison Centerline Turbulence Intensity

Centerline mean axial velocity OASPL (dB) variation with polar angle

Flow Visualization of Military- Style Nozzle Flows

Time-averaged solution

Experiment

Munday et al, 2008

Prediction

Baseline nozzle jet, Mj=1.56

Flow Visualization

Unsteady Jet Flow and Noise Radiation

Baseline, Mj=1.47 cold jet Baseline, Mj=1.47 hot jet

Color: Density gradient Gray: Time derivative of static pressure

Simulation of Bypass Cooling Flow

Preliminary reults of the Mj=1.47 jet with bypass cooling flow

Temperature Vorticity magnitude

Noise Source Identification Using Virtual Beamforming

Noise source locations

Mj=1.47, unheated jet

Experiment

Mj=1.47, unheated baseline jet

Nonlinear propagation from Distributed Noise Sources

2

2

2 212

: 0

( ): 0

( ): 0

( ) ( ): 0

: ( 1) ( )

u vContinuity

t x y

u u p uvx momentum

t x y

v uv v py momentum

t x y

E uE up vE vpEnergy

t x y

State p E u v

Initial and time dependent conditions can be enforced near the center of the domain to drive waves. This figure shows the result of Gaussian Distribution of pressure and density.

Numerical and Computational Approach

The system of equations is nonlinear. Without damping, shocks will inevitably be produced. To cope with the numerical issues this introduces, a non-oscillatory scheme is used. A distributed source can be used to approximate noise from a jet, with solution resolved in the plane normal to the jet axis These methods lend themselves to parallel computing, and is currently able to be run on nVidia graphics processing units via the CUDA programming language.

4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 50.94

0.96

0.98

1

1.02

1.04

1.06

1.0133

x 105

X: 4.673

Y: 1.013e+005

meters

Pre

ssure

(P

a)

Pressure

File: CAV Seminar May 2012.pptx

Aeroacoustic Experiments on

Supersonic Jets Exhausting from

Military-Style Nozzles

Russell Powers and Dennis K. McLaughlin

Department of Aerospace Engineering

Penn State University

Presented at CAV Seminar

May, 2012

File: CAV Seminar Apr 2010.pptx

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Technical approach

The Current Objectives are to examine several modifications to

supersonic nozzles to produce significant noise reduction.

Acoustic measurements are conducted in the anechoic

chamber: dimensions: 5 6 2.8 m, cut-off frequency: ~250 Hz.

Penn State High-Speed Jet Noise Facility

Helium canisters


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Technical approach Nozzle Design and Manufacture

- Nozzles Fabricated Using Rapid Prototyping Technology.

- Several different nozzles manufactured in this Study, which

use interior hard walled corrugations.


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Experimental Results Two Corrugations

- Results Shown for an over-expanded jet with

the nozzle pressure ratio = 3.0 and TTR = 3.0

- Narrowband spectra at several polar angles

- Shadowgraph images which show the

flow and shock structure within the jet


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Experimental Results Three Corrugations

- The variation of the overall sound pressure

level (OASPL) is shown in addition to

narrowband spectra.

- Notice the high frequency reduction at low

polar angles.

- Azimuthal directivity at low polar angles,

but very little difference in the sideline and

forward arc.

Successful

noise reduction


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Experimental Results Six Corrugations

- The variation of the overall sound pressure

level (OASPL) is shown in addition to

narrowband spectra.

- Notice the high frequency reduction at low

polar angles.

- Less azimuthal directivity than for three

corrugations

Acoustics for a river-current turbine

Erick Johnson, Matt Barone Sandia National Laboratories

Michael Jonson, John Fahnline

Pennsylvania State University, Applied Research Laboratory

Motivation

• Baseline noise evaluation

– Turbine designed through straight transfer of wind knowledge

– Grounding for future improvements

• What is the environmental impact?

– Marine animal communication/behavior

– Barotrauma

CHAMP (Combined HydroAcoustic Modeling Program)

• A Penn State model

– Used extensively in marine propulsion systems

• Requires modal (structural) and CFD analyses

Blade Rate Noise Turbulence Ingestion Noise

Motor Noise Flow Noise and BBVN

Wake Harmonic Analysis

Unsteady Forces and Moments

(UFAM)

Structural Acoustic Transfer Function

Inflow Turbulence Characteristics

Unsteady Force Spectrum (TING)

Finite-Element Analysis (NASTRAN)

Boundary Element Analysis (POWER)

CFD RANS

Electromagnetic FE analyses

Self-generated Turbulence Statistics (TBL, Vortex Shedding, tip flows)


EM force harmonic content




Machinery Noise

Gear meshing and bearing analyses

Tonal loads and enforced

displacements



Design Turbine: 3-bladed, stall regulated 5 m diameter rotor 0.6m diameter hub

Blade Material and Loading: Material Safety Factor = 2.5 Load Safety Factor = 1.5 Fiberglass/epoxy: E = 35 GPa σmax = 580 MPa

Max Thrust = 2.5 m/s (BEM)

Operating Conditions: Design Speed = 2.0 m/s

BEM (Blade Element-Momentum) Theory

• Approximate calculation for performance and loading of a turbine

– Relies on lift/drag tables for each foil

• Can be used to optimize a blade design from operating conditions

– Does not directly give stress results

– Still need manufacturability and hub attachment

Stress/Modal Results

28.91 Hz 65.60 Hz

80.51 Hz 151.91 Hz

Blade does not break! (at least not under static load)

Modal cont’d (1)

Mode # In Vacuo Interior Exterior

Both

Interior and

Exterior

1 29.2 Hz 24.1 Hz 12.5 Hz 12.0 Hz

2 65.9 Hz 57.5 Hz 61.4 Hz 59.9 Hz

3 154.0 Hz 68.9 Hz 34.2 Hz 32.1 Hz

4 183.2 Hz 109.5 Hz 69.7 Hz 64.1 Hz

5 266.7 Hz 208.4 Hz 160.8 Hz 178.3 Hz

6 391.5 Hz 182.7 Hz 117.7 Hz 106.3 Hz

7 416.7 Hz 257.3 Hz 183.3 Hz 158.3 Hz

8 444.6 Hz 475.3 Hz 361.6 Hz 393.9 Hz

Modal cont’d (2)

• Modal radiation efficiencies

– Decompose modes into monopole/dipole components

–

Monopole indicates a “breathing” of the blade

Acoustic results

0

20

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120

140

1 10 100

Sou

nd

Pre

ssu

re L

eve

l, d

B r

e 1

µP

a @

1m

in 1

Hz

ban

ds

Frequency, Hz

Total Noise

Leading Edge Forcing Function

Trailing Edge Forcing Function

Total noise: 128 dB re 1µPa @ 1m

By: Daniel Perlitz and Lee Thompson

August 23, 2011 The Pennsylvania State University-Applied Research Laboratory

The Pennsylvania State University

August 23,2011

Student Research Objective: Investigate acoustic localization techniques for cavitation.

Time Delays between Microphones in the Anechoic Chamber

Am

plitu

de

0.82 0.83 0.84 0.85

time(s)

time(s)

Microphone 1

Microphone 3

Microphone 2

Direct Signal Path

Reflected Signal Path


Preliminary testing in ARL’s anechoic chamber in air

Noise source location was determined using an array of three microphones

Time Delays between Microphones in the Anechoic Chamber

August 23,2011


August 23,2011

Processing of Acoustic Signals from a Reverberant Environment

A filter is used to eliminate spurious noise

The data is time-windowed to isolate the direct path signal

Produced cavitation with a cross flow rod in a twelve inch water tunnel Took images using a Basler A500K high speed camera


August 23,2011

baslerweb.com


Images are processed so that each bubble can be identified and analyzed

August 23,2011


August 23,2011

Minna Ranjeva developed a system to produce cavitation in a water tank using a laser

A lens focuses the laser beam and a mirror deflects it into the tank

Perform cavitation localization in the 12-inch diameter water tunnel Nozzle cavitation

Hydrofoil cavitation


August 23,2011

computationalfluiddynamics.com

Questions?

flow-induced noise technical group induced noise.pdf · 2 overview • the mission of the...

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