Technical Challenges to Reducing Subsonic Transport ... · PDF fileTechnical Challenges to Reducing Subsonic Transport Perceived Noise ... Reduce aircraft drag . ... Reduce aircraft

1 1 Subsonic Fixed Wing Project Fundamental Aeronautics Program

Technical Challenges to Reducing Subsonic Transport Perceived Noise

AIAA Aerospace Sciences Meeting January 9-12, 2012

David P. Lockard, Christopher J. Miller

Technical Leads for Noise Subsonic Fixed Wing Project

[email protected] 757-864-6805

mailto:[email protected]


TC6 - Revolutionary tools and methods enabling practical design, analysis, optimization, & validation of technology solutions for vehicle system energy efficiency & environmental compatibility

TC4 - Reduce harmful emissions attributable to aircraft energy consumption

TC5 - Reduce perceived community noise attributable to aircraft with minimal impact on weight and performance

TC1 - Reduce aircraft drag with minimal impact on weight (aerodynamic efficiency)

TC2 - Reduce aircraft operating empty weight with minimal impact on drag (structural efficiency)

TC3 - Reduce thrust-specific energy consumption while minimizing cross-disciplinary impacts (propulsion efficiency)

SFW Strategic Thrusts & Technical Challenges

Reduce TSEC

Reduce OWE

Reduce Drag

Reduce Noise Reduce

Emissions

Economically Viable

Revolutionary Tools and Methods

Maintain Safety

Enable Advanced Operations

Energy Efficiency Thrust (with emphasis on N+3) Develop economically practical approaches to improve aircraft efficiency

Environmental Compatibility Thrust (with emphasis on N+3) Develop economically practical approaches to minimize environmental impact

Cross-Cutting Challenge (pervasive across generations)

Energy & Environment

TSEC

Clean

Weight

Drag

Noise

Tools


TC5 - Reduce perceived community noise attributable to aircraft with minimal impact on weight and performance Noise

Noise Prediction

Capabilities

Experimental Observations/

Simulations

Physical Insight

Constraints

Noise Reduction

Technology

Noise Source

Descriptions

weight cost

safety

maintenance

materials

performance

Approach


NASA Subsonic Transport System Level Metrics …. technology for dramatically improving noise, emissions, & performance

FAA/CLEEN NASA/ERA NASA SFW


N+3 Subsystem Concepts Goal-Driven Advanced Concepts 1. Tailored Fuselage

2. High AR Elastic Wing

3. Quiet, Simplified High-Lift

4. High Efficiency Small Gas Generator

5. Hybrid Electric Propulsion

6. Propulsion Airframe Integration

Near Term/Cross-cutting

7. Alternative Fuels

8. Tool Box (MDAO, Systems Modeling, Physics-Based)

SFW N+3 Opportunities from Goal-Driven Advanced Concepts broadly applicable …….

Noise

Noise

Noise

Tools


The Cost of Noise

AIP funds, fiscal years 1982-2007 Funding (millions)

Mitigation measures for residences $1,903 Land acquisition $2,170 Noise monitoring system $170 Mitigation measures for public buildings $703 Noise compatibility plan $87

PFC funds, fiscal years 1992-2007 Multiphase $1,283 Land acquisition $481 Soundproofing $1,018 Monitoring $31 Planning $15

Grand total $7,861

Airport Improvement Program (AIP) and Passenger Facilities Charge (PFC) Investments for Noise-Related Purposes through Fiscal Year 2007

Source: GAO-08-216T, “AVIATION AND THE ENVIRONMENT: Impact of Aviation Noise on Communities Presents Challenges for Airport Operations and Future Growth of the National Airspace System,” Oct, 2007.

Many airports use other funding sources for noise mitigation activities.

8 billion has been spent on noise mitigation, much more than has been spent on affecting the source.


The Noise Problem

Sources: GAO-08-216T, FAA, Art Explosion, Corel Draw


LAX Noise Exposure Contours (3Q 2010)

Landing 65 dB CNEL

• Community Noise Exposure Levels (CNEL) – Weighted average of sound levels over 24 hours

Includes # of flights, so noise affects capacity

• Large area exposed to 65 dB levels on approach – Airframe is a major contributor to landing noise – Must simultaneously decrease airframe and propulsion

noise sources to achieve overall reduction

Source: http://www.lawa.org/welcome_lax.aspx?id=1090

Takeoff

65

Airport Property


WHAT ARE WE TRYING TO DO? • Discover, explore, and develop technology concepts to reduce the community

noise of future aircraft systems while maintaining system-level benefits to energy efficiency and environmental compatibility

WHY? • Community noise annoyance continues to increase and more stringent

regulations are forthcoming

HOW DOES THIS GET DONE, AT PRESENT? • Conventional turbofan engines, pod-mounted on tube-and-wing airframes, with

bypass ratios (BPR) limited to ~12 • Vehicle choice limits shielding, BPR limits jet noise reduction and propulsive

efficiency, current liner practice limits attainable treatment effectiveness • Many turbulence generating bluff bodies (e.g., landing gear) and vortex

generating edges (e.g., flaps)

Challenge: Reduce Perceived Noise

WHAT IS NEW ABOUT OUR APPROACH? • New technologies to increase propulsive efficiency, reduce noise, and increase treatment

effectiveness couple with vehicle layouts that add shielding • Smoother, more aerodynamic airframe components to reduce noise source regions &

strength • Revolutionary and new enabling technologies for embedded, hybrid/electric, distributed

propulsion • Techniques to understand, analyze, and predict performance of unconventional and

revolutionary designs

IF WE SUCCEED, WHAT DIFFERENCE DO WE THINK IT WILL MAKE? • Practical approaches to retaining aircraft efficiency and emissions while reducing noise


Quiet, Simplified High-Lift System

Focus: Develop noise prediction and reduction technology for takeoff and landing configurations. Technical Content: Slat Noise: • Structural development of cove and gap fillers • Source description using experiments and computations Flap Noise: • Structural development of flexible side-edge link Landing Gear Noise: • Advancing the state of the art in unsteady flow simulations Circulation Control: • Quantification of noise from flow control devices installed on realistic

configurations


Slat Noise

• Source characterization – 3-element high-lift system

• Experimental testing • Unsteady numerical simulations

• Noise Reduction Devices

– Structural aspects of implementations • Slat cove filler (SCF) • Slat gap filler (SGF)

Deployed Retracted

Superelastic Rib SCF


Flap Noise Task

• Turbulent wake/airfoil interaction experiments – Characterizing turbulence characteristics on noise generation

• Noise Reduction Devices

– Structural aspects of practical implementations

• FlexSEL (Flexible Side-Edge Link) Flap


Gear Noise Task

• Gulfstream G550 Nose Landing Gear – Extensive experimental database – Unsteady numerical simulations

• Source characterization • Noise Prediction

Viscous surface

Outflow plane

Radiation condition

Radiation condition


Alternative High-Lift Systems

• NFAC (40x80 tunnel at NASA Ames) test data analysis of a circulation control airplane concept – Provides baseline acoustic data on the noise produced by

circulation control devices on a large-scale model

NRA CESTOL test in 40x80 New array system and acquisition/system (Optinav) developed for NFAC tests (CESTOL NRA and Lockheed Martin/AFRL Speed Agile).


High Efficiency Small Gas Generator (I)

Focus: Develop an understanding of the core noise generation process and implement noise reduction technology to minimize the source and propagation.

Technical Content: Understanding Core-Noise Sources: • NRA: “Acoustic Database for Core-Noise

Sources,” Don Weir/PI; Bill Schuster/Co-I (Honeywell Aerospace)

• NRA: “Measurement and Modeling of Entropic Noise Sources in a Single Stage Low-Pressure Turbine,” Daniel Bodony/PI (University of Illinois Urbana Champaign); Scott Morris/Co-I (University of Notre Dame)

Unsteady P & T


High Efficiency Small Gas Generator (II)

Technical Content (continued): Ceramic Matrix Composite Liners for Core: • High-temperature light-weight liners for broadband attenuation • Fundamental research on effectiveness of core liners (TRL 2-3) • TRL 4 demonstration Source Evaluation: • Flame tubes, sector combustor rigs, turbine rigs, and real engines Physics-Based Prediction using URANS/LES

Flow

Notional cross section of variable-depth liner


Core Noise-Source Example

Entropy scattered into noise by a turbine stator (NRA, UIUC, Bodony)

High-fidelity LES calculation: • Plane wave incident entropy

disturbance • Colors are unsteady pressure

(green is Δp=0) • Black lines are entropy levels • Shows scattering of entropy

into noise • Mechanism strongest at

trailing edge • Indirect noise may become

more important for emerging core designs


Propulsion Airframe Integration Focus: Develop noise prediction and reduction capabilities for closely coupled propulsion/airframe systems. Technical Content: Inflow Distortion: • Predict duct mode sound power levels for a fan ingesting circumferentially asymmetric flow • Experimental data sets for validation Jet-Flap/Surface Interaction: • Jet-surface interaction experiments • Open-rotor noise prediction assessment and improvement • Shielding

Low-Drag Duct Liners: • Design multi-degree-of-freedom liners • Impedance eduction • NRA: "Diagnostic Techniques to Elucidate the Aerodynamic Performance of Acoustic Liners,” Mark Sheplak (U of Florida)


Installed Fan/Inflow Distortion (I) • Fan inflow distortion tone noise being studied computationally

and experimentally with the goal of predicting tone noise generated by embedded engines

• Goldstein, Dittmar and Gelder theory extended to predict tone noise generated by circumferentially asymmetric inflow distortions

• ANCF test rig being used to collect validation data – Highly configurable 4-foot diameter ducted fan – In-duct & far-field acoustics, flow measurements – Auxiliary system for generating artificial noise sources – Low speed: (variable)

Flow separation

Advanced Noise Control Fan ANCF @ GRC/AAPL

Flow

Flow


NASA GRC BASS code development • General-purpose, high-order, nonlinear

Computational AeroAcoustics (CAA)/Large-Eddy Simulation (LES) solver

• Current focus is rotor-stator interaction • Synthetic turbulence method being evaluated to

reduce computational cost of simulations • Completion expected in 2014

Downstream Wake TKE

BASS Experiment

Incoming Wake TKE

Using a boundary condition to specify inflow turbulence (matched to experiment), BASS correctly convects the wakes downstream.

Installed Fan/Inflow Distortion (II)


Jet/Surface Interaction Noise Experiments

• Noise created by the high-speed jet exhaust striking or passing near a solid surface – Difficult to predict accurately with current tools/codes – Experimental data is limited or unavailable – Conducting fundamental experiments of a jet near a flat surface for

development of noise prediction codes

Boeing 787

Simple geometry where complexity increases with choice of surface

position and jet exit condition

• Phased array • Far-field mics

Flow

Nozzle


Jet-Surface Interaction Experiments

• Canonical experiments for code development


Wind Tunnel Data LINPROP Predictions

Open Rotor Noise Prediction

• Aerodynamic Assessment – Tools: NASA’s TURBO, Numeca’s FINE/Turbo – Take-off & cruise conditions – Axisymmetric inflow

• Acoustic Assessment using CFD blade loads – Frequency domain (LINPROP, QPROP) – Time domain (ASSPIN)

• NASA Wind Tunnel Data – NASA 9x15 (take-off) – NASA 8x6 (cruise)

GE Historical Blade Set (F31/A31)

1st Loading Harmonic (TURBO)

Tip vortex induced loading

Reasonable prediction of low order tones and interactions


Liner Technology

• Pursue in-situ drag measurement capability via in-house and external development

• Develop and implement instrumented Curved Duct Test Rig (CDTR) test section for impedance eduction

• Design multi-degree-of-freedom liners and test in the LaRC Liner Test Facility (LTF)

• Design and conduct component tests of 2nd generation Over the Rotor (OTR) and Soft Vane (SV) fan noise reduction concepts

OTR SV

Curved Duct Test Rig

Gracing Flow Impedance Tube

Liner Test Facility (LTF)

Two-layer liner


Analysis Methods & Tools Focus: Develop fundamental, high-fidelity tools and methods specifically for noise sources and acoustic propagation geared towards assessing community noise impacts and enabling the design and analysis of noise reduction technologies. Technical Content: Physics-Based Source Simulation: • Model assessment for acoustics (e.g., Hybrid RANS/LES) • Benchmark problems for Airframe Noise Computations (BANC) workshops ANOPP2: • Framework Development to allow mixed-fidelity noise prediction • Incorporation of improved noise source and propagation models Shielding: • NRA: “Fast and Efficient Computation of Acoustic Scattering and its Application

to Aircraft Noise Prediction,” Fang Hu (Old Dominion University) • Fast-scattering code development, Tinetti and Dunn (Old Dominion University)


• https://info.aiaa.org/tac/ASG/FDTC/DG/BECAN_files_/BANCII.htm • Inquiry: [email protected], [email protected]

Immediately after:

High-Fidelity Simulations

BANC-II Workshop, Colorado Springs, CO, June 7-8, 2012

https://info.aiaa.org/tac/ASG/FDTC/DG/BECAN_files_/BANCII.htm




ANOPP2 Aircraft Flight Definition

Source Noise Jet: ST2JET Core: GECOR (SAE) Airframe: Boeing OR: CRPFAN, Py-ASSPIN PAA Effects scattering & installation

Propagation & Noise Metrics

FLOPS

Numerical Propulsion System Simulation (NPSS)

LSAF Data & ANOPP2 module prediction

EPNL predicted at FAR 36 locations

ANOPP2 – Community Noise Prediction

• ANOPP2 validation of system with emphasis on scattering methods

• Assessment of noise goals for N+3 as well as N & N+2 configurations

• PAA Technology Effects on System Metrics

SOA HWB/OR HWB/GE90

N N+2 N+3

Mixed-fidelity framework that includes the current semi-empirical ANOPP models and assumptions but allows for adding modules that can handle aircraft components with a range of fidelity up to Computational AeroAcoustic (CAA) methods


Summary

• Ground-based efforts to mitigate the impact of aircraft noise are expensive and have not resolved the problem – Many people are still exposed to high noise levels near airports – The impact of aircraft noise limits airport capacity

• NASA SFW is focused on enabling substantially quieter future

aircraft while simultaneously improving other performance goals (such as fuel burn) by developing technologies and tools needed to predict and reduce noise from these aircraft

David P. Lockard Technical Lead for Noise

Subsonic Fixed Wing Project [email protected] 757-864-6805



References (I) Choudhari, M., Lockard, D., Khorrami, M., and Mineck, R.,“Slat Cove Noise,” presented at Inter-noise 2011, Osaka, Japan, 5 Sept. 2011. Kang, J. H., Siochi, E. J., Penner, R. K., and Turner, T. L., “AC Electric Field Activated Shape Memory Polymer Composite,” Southeastern Regional Meeting of ACS(SERMACS), Richmond, VA, 28 Oct. 2011. Bridges, J., and Wernet, M. P., (NASA Glenn Research Center), “PIV Measurements of Transonic Internally-Mixed Dual-Stream Jets,” 17th AIAA/CEAS Aeroacoustic Conference, June 6-9, 2011, Portland, Oregon, AIAA-2011-2786. Bozak, R., and Henderson, B., (NASA Glenn Research Center), “Aeroacoustic Experiments with Twin Jets.” 17th AIAA/CEAS Aeroacoustic Conference, June 6-8, 2011, Portland, Oregon, AIAA-2011-2790. Elliott, D. M., (NASA Glenn Research Center), “Initial Investigation of the Acoustic of a Counter Rotating Open Rotor Model with Historical Baseline Blades in a Low Speed Wind Tunnel,” 17th AIAA/CEAS Aeroacoustic Conference, June 6-8, 2011, Portland, Oregon, AIAA-2011-2760. Gerhold, C., Jones, M., Brown, M., and Howerton, B., “Report on Recent Upgrades to the Curved Duct Test Rig at NASA Langley Research Center,” AIAA-2011-2896. Henderson, B., (NASA Glenn Research Center), “A PIV Study of Slotted Air Injection for Jet Noise Reduction,” 17th AIAA/CEAS Conference, June 6-8, 2011, AIAA-2011-2898. Hixon, R., Sescu, A., and Sawyer, S., “Towards the Prediction of Noise from Realistic Rotor Wake/Stator Interaction Using Computational Aeroacoustics,” accepted for publication in Journal of Sound and Vibration, 2011. Horne, W., “Initial Assessment of Acoustic Source Visibility with a 24-element Microphone Array in the Arnold Engineering Development Center 80-by-120-Foot Wind Tunnel at NASA Ames Research Center,” AIAA-2011-2723. Hultgren, L. S., (NASA Glenn Research Center), “Full-Scale Turbofan-Engine Turbine-Transfer Function Determination Using Three Internal Sensors,” 17th AIAA/CEAS Aeroacoustic Conference, June 6-8, 2011, Portland, Oregon, AIAA-2011-2912 (Documents the completion of SFW.08.13.001.)


References (II) Hutcheson, F., Brooks, T., Burley, C., and Stead, D. “Measurement of the Noise Resulting from the Interaction of Turbulence with a Lifting Surface,” AIAA-2011-2907. Jameson, K., Marshall, D., Ehrmann, R., Paciano, E., Englar, R.J., and Horne, W. C., “Part 1: The Wind Tunnel Model Design and Fabrication of Cal Poly’s AMELIA 10 Foot Span Hybrid Wing-Body Low Noise CESTOL Aircraft,” Jan 2011, AIAA-2011-1306. Jameson, K., Marshall, D., Ehrmann, R., Paciano, E., Englar, R.J., and Horne, W. C., “Part 2: Preparation for Wind Tunnel Model Testing and Verification of Cal Poly’s AMELIA 10 Foot Span Hybrid Wing-Body Low Noise CESTOL Aircraft,” Jan 2011, AIAA-2011-1307. Jones, M., and Watson, W. “On the Use of Experimental Methods to Improve Confidence in Educed Impedance,” AIAA-2011-2865. Khavaran, A., (NASA Glenn Research Center), “Acoustic Investigation of Jet Mixing Noise in Dual Stream Nozzles,” 17th AIAA/CEAS Aeroacoustic Conference, June 6-8, 2011, Portland, Oregon, AIAA-2011-2701. Khavaran, A., and Frate, F., “An Aerodynamic and Acoustic Assessment of Convergent-Divergent Nozzles with Chevrons,” Jan 2011, AIAA-2011-976. Koch, L. D., (NASA Glenn Research Center), “Validation of the Predicted Circumferential and Radial Mode Sound Power Levels in the Inlet and Exhaust Ducts of a Fan Ingesting Distorted Inflow,” 17th AIAA/CEAS Aeroacoustic Conference, June 6-8, 2011, Portland, Oregon, AIAA-2011-2808. Lockard, D. P., “Summary of the Tandem Cylinder Solutions from the Benchmark Problems for Airframe Noise Computations-I Workshop,” AIAA-2011-353, Jan, 2011. Lockard, D., and Choudhari, M., “The Variation of Slat Noise with Mach and Reynolds Numbers,” AIAA-2011-2910. Lopes, L., and Burley, C., “Design of the Next Generation Aircraft Noise Prediction Program: ANOPP2,” AIAA-2011-2854. Miller, S., and Morris, P., “The Prediction of Broadband Shock-Associated Noise Including Propagation Effects,” AIAA-2011-2923. Nark, D., “Assessment of Radiated Fan Noise Prediction Capabilities using Static Engine Test Data,” AIAA-2011-2807. Palumbo, D., Boundary layer paper on results of Boeing/Gulfstream/NASA flight test submitted to JSV.


References (III) Redonnet, S., Lockard, D., Khorrami, M., and Meelan, C.,"CFD-CAA Coupled Calculations of a Tandem Cylinder Configuration to Assess Facility Installation Effects,” AIAA-2011-2841. Stephens, D. B., and Envia, E., (NASA Glenn Research Center), “Acoustic Shielding for a Model Scale Counter-Rotation Open Rotor,” 17th AIAA/CEAS Conference, June 6-8, 2011, Portland, Oregon, AIAA-2011-2940. Spalt, T., Fuller, C., Brooks, T., and Humphreys, W., “A Background Noise Reduction Technique Using Adaptive Noise Cancellation for Microphone Arrays,” AIAA-2011-2715. Tam, C. K. W., Ju, H., Jones, H. M., Watson, W. R. and Parrott, T. L. “Computational and Experimental Study of Resonators in Three Dimensions,” JSV, Vol.329 (2010), pp.5164-5193, November 2010. Vatsa, V., Lockard, D., Khorrami, M., “Application of FUN3D Solver for Aeroacoustic Simulation of a Nose Landing Gear Configuration,” AIAA-2011-2820. Watson, W., Jones, M., and Gerhold, C., “Implementation and Validation of an Impedance Eduction Technique,” AIAA-2011-2867. Hixon, R., Sescu, A., and Sawyer, S., “Vortical gust boundary condition for realistic rotor wake/stator interaction noise prediction using computational aeroacoustics,” Journal of Sound and Vibration, Vol. 330, No. 16, August 2011, pp. 3801-3817. Miles, J. H., “Estimation of signal coherence threshold and concealed spectral lines applied to detection of turbofan engine combustion noise,” Journal of the Acoustical Society of America, Vol. 129, Issue 5, May 2011, pp. 3068-3081.