Burley, Casey L.

Olson, Erik D.

Thomas, Russell H.

NASA Technical Reports Server

1 
National Aeronautics and Space Administration 
www.nasa.gov 
Status of Hybrid Wing Body 
Community Noise Assessments
Russell H. Thomas, Casey L. Burley, and Erik D. Olson
NASA Langley Research Center, Hampton, VA   USA
Presented at the AIAA Aerospace Sciences Meeting
Special ERA Session
Orlando, Florida
January 6, 2011
https://ntrs.nasa.gov/search.jsp?R=20110011922 2019-08-30T15:50:34+00:00Z
Introduction
Acknowledgments:
      Mr. Craig Nickol, Dr. Frank Gern, Mr. Jeff Berton, NASA
      PAA Experimental Data on separate task: Dr. Michael Czech, Dr.   
Leon Brusniak, Mr. Ronen Elkoby and the LSAF Team, The 
Boeing Company
      Mr. John Rawls Jr., Lockheed Martin Engineering Services
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PAA Definition: Aeroacoustic effects associated with the integration of 
the propulsion and airframe systems (acoustic and flow interactions) 
3 
Outline
•  NASA N+2 Noise Goal Roadmap
•  HWB with BPR 7 Turbofan (ref: AIAA 2010-3913 Thomas, Burley, and Olson)
•  Assessment Process Including PAA Experiment
•  HWB Configurations
•  System Noise Impacts
•  Summary & Future Directions – HWB with UHB Turbofan
•  Current Study In Progress – HWB with Open Rotor
•  LSAF PAA Experiment 
•  Assessment Process
•  Summary
Initial System Noise 
Assessment, sets 
Stage 4 –42dB Goal 
Simple Shielding 
Experiment 
Basic Concept 
Selection > Hybrid 
Wing Body (HWB) 
Broaden Technology Path, 
Refined Methods, 
Increasing Confidence 
Industry Partnerships Key 
     Pathfinding 
Technology Development 
 Maturation 
HWB Aeroacoustic 
Experiments: 
•  Large-scale, high fidelity 
integrated HWB aircraft systems 
•  Low Noise Levels 
Multi-Disciplinary HWB 
Aircraft Concept Design: 
•  Absence of prior validation and 
acoustic prediction methods 
HWB Aircraft System Prediction Methods: 
•  Interaction effects methods  
•  Validation Experiments 
•  Vehicle Definition and Computational Capabilities 
2009 Preliminary 
with LSAF Data 
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System Noise 
Assessments 
AIAA 2010-3913 
with LSAF Data 
2005 Pathfinding with 
Limited Data
2012 High Fidelity 
with 14 by 22
2011 with Open Rotor 
LSAF PAA data
Engine Options for HWB: 
•  BPR 7 Turbofan 
•  BPR 10 Turbofan 
•  Ultra High BPR Turbofan 
•  Open Rotor Engine Types 
Review 2010 Assessment - Aircraft Models and 
Framework
5 
Both aircraft use equivalent technology levels and are sized for 
same payload, same 7500 NM mission, meet FAA airworthiness 
standards, and same GE90-like engine used on both aircraft
SOA HWB
Aircraft System Noise Prediction Method
•  NASA Aircraft Noise Prediction Program (ANOPP-Lv 27)
•  SOA and HWB flight definition from FLOPS
•  GE90-like relative engine noise sources match data (ref. Gliebe, 2003)
•  Total SOA prediction calibrated to match EPNL data for this aircraft
ANOPP 
Aircraft Flight Definition
Source Noise
Jet: ST2JET
Fan: Boeing method
Duct Treatment: GE
Core: SAE
Airframe: Boeing, Fink (t.e.)
PAA Effects
Propagation & Noise Metrics
FLight OPtimization System (FLOPS)
Numerical Propulsion System 
Simulation (NPSS)
Experimental 
Data from 
LSAF (ref AIAA 
2010-3912)
EPNL predicted at FAR 36 locations
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Flight Path Profiles
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Approach Takeoff
HWB Experiment Improves Basic 
Understanding of Aeroacoustic Sources 
and Parameters:
•  Effects from Verticals and Elevons
•  Jet-Airframe shielding including source 
modification
•  Broadband point source shielding with 
flow effect
Technology and Experimental Data for Key PAA Effects
Ref: Czech, Thomas, and Elkoby, “Propulsion Airframe 
Aeroacoustics Integration Effects for a Hybrid Wing 
Body Aircraft Configuration,” AIAA 2010-3912
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Effect of Pylon Orientation Relative to Observer
“Crown Pylon” position
“Keel Pylon” position
Effect of pylon on key jet noise source 
included through experimental information
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SPL difference between crown pylon and 
keel position (from ref AIAA 2010-3912)
Crown rel. to Keel at Cutback Crown rel. to Keel at Sideline 
    20              25             30             35
10*log(f), Hz
    20              25               30              35
10*log(f), Hz
Em
is
si
on
 A
ng
le
, d
eg

SPL
•  Effect of pylon orientation 
increases with power setting 
•  Azimuthal orientation of pylon 
has up to 8dB effect in aft arc 
PAA Technology Effects on System Noise Levels
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+2D -1D 
Baseline, Engines 
1D downstream of 
trailing edge Simple Shielding, 
engines move 2D 
upstream 
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Jet noise changes with chevrons 
Peak source location 
changes 
•  Chevrons relocate peak sources towards the 
nozzle exit except at very low frequencies 
•  Movement of sources with chevrons is 
favorable for shielding 
Spectral changes with Chev2 
 Aggressive design 
High frequency 
increase 
Low frequency 
reduction 
SPL
SPL
Spectral changes with Chev1 
Mild design 
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Shielding Effectiveness 
Normalized jet noise EPNdB vs X/D 
Sideline conditionCutback condition
•  Jet noise EPNdB varies significantly as a function of engine location. Isolated 
nozzle is the reference. 
•  The baseline nozzle with pylon offers reductions of ~1 to 2dB of EPNdB 
•  Shielding effectiveness significantly enhanced with the chevron nozzle 
•  Jet noise EPNdB decreased by up to 5dB at x/D=2 and cutback power 
Increasing slope 
means more noise 
reduction with the 
same surface area 
PAA Technology Effects on System Noise Levels
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Baseline, engines 
1D downstream of 
trailing edge 
Simple Shielding, 
engines move 2D 
upstream 
2D, chevrons to 
reduce jet source & 
increase shielding 
effectiveness 
Vertical 
Pylon at 
Keel 
Chevrons 
PAA Technology Effects on System Noise Levels
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Favorable 
directivity of 
jet from 
strong effect 
crown pylon 
Acoustic liner 
added to 
crown pylon 
for aft fan 
attenuation 
Pylon at 
Crown 
Keel Pylon Crown Pylon 
Pylon rotated from keel to 
crown position 
PAA Technology Effects on System Noise Levels
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Baseline, Engines 
1D downstream of 
trailing edge 
Simple Shielding, 
Engines move 2D 
upstream 
Chevrons  reduce 
source & increase 
shielding 
effectiveness (same 
area, more noise 
reduction) 
Active Pylon 
adds more jet 
shielding 
effectiveness, 
elevons add 
more aft fan 
shielding 
Favorable 
directivity of 
jet from 
strong effect 
crown pylon 
Acoustic liner 
added to 
crown pylon 
for aft fan 
attenuation 
Projection from more 
advanced crown 
pylon, chevrons, quiet 
landing gear 
EPNL Impacts of HWB Configurations 
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•  HWB configuration results in a new distribution between 3 cert points
•  Technology reduces all 3 cert points without changing basic distribution
Perspective on 42.4 dB Cumulative Level
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From AIAA 2009-3144         
Note: Included a BPR 16 engine 
SOA HWB 
An integrated systems approach key to achieving NASAʼs 
N+2 goal of 42 dB
Technology that 
reduces noise sources 
and relocates sources 
to be more effectively 
shielded 
Simple shielding from 
moving engines 
upstream on aircraft 
Lower noise of baseline 
HWB from: simple 
shielding of inlet noise, 
lower approach speed, 
absence of flap noise, 
flight path effects 
Sound Exposure Level (SEL) Contour
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SOA 
HWB 
Impact is a 66% reduction in ground area
For a simulated 
certification procedure 
(FAR 36) takeoff and 
landing 
Summary of 2010 Assessment of HWB with BPR 7  
(from ref AIAA 2010-3913 Thomas, Burley, and Olson)
•  A rigorous HWB system noise assessment with key elements: 
–  NASA ANOPP system noise method
–  NASA updated HWB aircraft model and flight path
–  Boeing/NASA PAA LSAF (2009) experimental results
•  42.4 dB cumulative assessed on the HWB with relatively near term 
technologies:
–  Existing GE90-like engine (BPR 7)
–  PAA chevron nozzle and crown pylon technology configurations
–  Acoustic liner applied on the crown pylon
–  Quiet landing gear technology
–  Reduced approach flight speed  
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Results in higher confidence assessment 
compared to earlier pathfinding assessments
Future Directions – HWB with UHB Turbofan
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Assess with new 
technology higher 
BPR engines
Keel pylon with weak 
acoustic effect
Crown pylon with 
strong acoustic effect
Acoustic liner on the 
crown pylon inside duct
Winglets 
instead of 
inboard 
verticals
PAA chevrons on 
fan nozzle and 
core nozzle
Quiet landing gear 
(fairings, spoilers, 
etc) (not shown)
•  Better suppression map with more realistic fan noise simulation
•  Flight path and aircraft model
•  Maturation of specific PAA and aircraft system technology targeted for noise reduction
Include elevon 
shielding
Critical step toward higher fidelity HWB aeroacoustic capabilities 
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Assessment of HWB with Open Rotor  
Boeing R&T Image 
Noise 
(cum below Stage 4) 
-60% -75% better than -75% 
-33%   -50%  better than -70% 
-33% -50%  exploit metro-plex* concepts 
N+1 = 2015** 
Technology Benefits Relative 
to a Single Aisle Reference 
Configuration 
N+2 = 2020** 
Technology Benefits Relative 
to a Large Twin Aisle 
 Reference Configuration 
N+3  = 2025** 
Technology Benefits 
LTO NOx Emissions 
 (below CAEP 6) 
Performance: 
Aircraft Fuel Burn 
Performance: 
Field Length 
-32 dB -42 dB -71 dB 
**Technology Readiness Level for key technologies = 4-6.  ERA will undertake a time phased approach, TRL 6 by 2015 for “long-pole” technologies 
*   Concepts that enable optimal use of runways at multiple airports within the metropolitan area  
ERA Goal 
Open Rotor Isolated Engine Fuel Burn Reduction 
Promise….with a Known Noise Challenge 
Is an integrated HWB/Open Rotor aircraft system another 
solution to meet the ERA goals simultaneously? 
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NASA Open Rotor System Noise Assessment 
Process Elements  
From AIAA 2009-3144         
Note: Included a BPR 16 engine 
SOA HWB BPR 7 
Turbofan 
HWB  
Open Rotor 
TBD 
1. Modernized Open Rotor 
Engine Model from GRC 
2. Aircraft Model from Boeing 
R&T task (Frank Gern TM) 
3. Results from NASA/Boeing Open 
Rotor PAA Experiment 
4. System Noise Assessment (Thomas, Burley, 
Olson, Gern, et al): 
•  certification points 
•  include technology options from experiment 
•  flight path variables 
Rigorous systems noise assessments a key to 
achieving NASAʼs N+2 goal of 42 dB 
simultaneously with other goals
NASA/Boeing Open Rotor PAA Experiment  
Experiment of open rotor PAA effects for both HWB and Tube-and-
Wing aircraft types in Boeing’s LSAF completed November 15, 2010 
Dr. Michael Czech, Boeing PI & Dr. Russ Thomas, NASA TM 
Objec&ves: 
•   Measure PAA eﬀects 
•   Study op&ons for increasing 
shielding eﬀec&veness 
•   Acquire data for system noise 
assessment and predic&on 
methods 
Instrumenta&on: 
•   Far Field Microphones 
•   Near Field Mic Traverse 
•   Flow Field Survey 
•   Phased Array Traverse 
•   Surface Unsteady Pressure 
Funded by the NASA Environmentally Responsible Aviation 
Project, Dr. Fay Collier, Project Manager 
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NASA/Boeing Open Rotor PAA Experiment  
Experimental Parameter Summary: 
•  rotor speed variation 
•  wind tunnel Mach variation 
•  rotor to airframe relative position, axial and vertical 
•  off-center and centerline positions 
•  inboard verticals, size and cant angle 
•  elevon deflection 
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Summary  
•  ANOPP System Noise Assessment Process for HWB Aircraft Assembled 
•  Engine System Model 
•  Aircraft System Model 
•  PAA Experimental Data for Key Aircraft Integration Effects 
•  Rigorous System Noise Assessment of HWB with BPR 7 Turbofan Completed in 2010 
•  Technology Path Developed 
•  42 dB Assessed Level with High Confidence on Critical Noise Sources 
•  Leads to High Fidelity 14 X 22 N2A HWB Experiment and Validation in 2012 
•  Key Elements in Progress Toward Assessment of HWB with Open Rotor 
•  Engine System Model    – In Progress by GRC Systems Team 
•  Aircraft System Model   – In Progress on Boeing R&T task 
•  PAA Open Rotor Experiment   – Completed on Boeing Task 
•  PAA Open Rotor Data Analysis   − Initiated 
•  ANOPP Based System Noise Process  – In Progress 
For HWB aircraft concept, there has been rapid progress in 
technology and assessments to meet the noise goal of the N+2 goals 
26 Your Title Here 
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Status of Hybrid Wing Body Community Noise Assessments

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