"IGF::OT::IGF" OTHER FUNCTIONS: 1. TASK ORDER TITLE: PROPULSION/AIRFRAME NOISE SCATTERING PREDICTION DEVELO…

Public award description

"IGF::OT::IGF" OTHER FUNCTIONS: 1. TASK ORDER TITLE: PROPULSION/AIRFRAME NOISE SCATTERING PREDICTION DEVELOPMENT AND STUDY 2. PURPOSE, OBJECTIVE, AND BACKGROUND OF WORK TO BE PERFORMED: THE PURPOSE OF THIS EFFORT IS TO IMPROVE AND VALIDATE A TURBOMACHINERY NOISE SCATTERING PREDICTION CAPABILITY IN SUPPORT OF THE ENVIRONMENTALLY RESPONSIBLE AVIATION (ERA) PROJECT. AN UNDERSTANDING AND ABILITY TO PREDICT TURBOMACHINERY NOISE DIFFRACTION OF A HYBRID WING BODY (HWB) AIRCRAFT CONFIGURATION IS REQUIRED. THE OBJECTIVE OF THIS EFFORT IS TO ADVANCE THE TURBOMACHINERY NOISE SCATTERING PREDICTION CAPABILITY FOR USE AND IMPLEMENTATION WITHIN NASA S AIRCRAFT NOISE PREDICTION PROGRAM2 (ANOPP2) AND TO PROVIDE PREDICTIONS TO SUPPORT THE ERA EXPERIMENTAL EFFORT OF THE HWB CONFIGURATION KNOWN AS THE N2A-EXTE. THE IMPROVED SHIELDING METHOD SHALL BE APPLIED TO CANONICAL PROPULSION SYSTEM INSTALLATIONS (TURBOFAN AND OPEN ROTOR) MOUNTED ON TOP OF A LIFTING SURFACE OR ATTACHED TO A CYLINDRICAL FUSELAGE TO EXPLORE METHOD CAPABILITY AND SHIELDING POTENTIAL OF SUCH INSTALLATIONS. BACKGROUND IN A PREVIOUS NRA EFFORTS (NASA CONTRACT NUMBER NNL07AA54C ACOUSTIC PREDICTION METHODOLOGY AND TEST VALIDATION FOR AN EFFICIENT LOW-NOISE HYBRID WING BODY SUBSONIC TRANSPORT ), THE CONTRACTOR CONDUCTED COMPUTATIONAL, THEORETICAL WORK ON NOISE SHIELDING FOR THE HWB PLANFORM, WITH EMPHASIS ON DEVELOPMENT OF A METHODOLOGY FOR PREDICTIVE MODELS FOR TURBOMACHINERY NOISE SCATTERING. THE MOTIVATION FOR THAT EFFORT WAS TO MEET THE NEED TO DEVELOP ULTRA-QUIET AIRCRAFT TO MEET NASA S N+2 AND EVENTUALLY N+3 NOISE GOALS OF 42 AND 71 DB, RESPECTIVELY, RELATIVE TO FAA STAGE 4 BASELINE. THE HWB DESIGN PROVIDES PLANFORM AREA FOR SHIELDING OF BOTH FORWARD-EMITTING TURBOMACHINERY SOURCES AND AFT-EMITTING JET NOISE SOURCES. IN ANOTHER EFFORT ( NASA CONTRACT NUMBER NNL13AA00B PROPULSION/ARIFRAME NOISE SCATTERING PREDICTION DEVELOPMENT AND STUDY ) TURBOMACHINERY NOISE SHIELDING WAS INVESTIGATED AND A PHYSICS-BASED PREDICTIVE TOOL BASED ON DIFFRACTION INTEGRAL WAS DEVELOPED TO ACCOUNT FOR BASIC SHIELDING AND THE EFFECT OF DIFFERENT EDGE GEOMETRIES. THE TOOL IS KNOWN AS DIM2 (DIFFRACTION INTEGRAL METHOD2). THE DIM2 TOOL WAS USED TO ASSESS NOISE SHIELDING FOR AN HWB CONFIGURATION. IN ADDITION A FORMULATION TO ACCOUNT FOR REFLECTIONS OF NOISE SOURCES FROM FUSELAGE SURFACES WAS DEFINED. TO PROPERLY INTEGRATE THE ENGINE WITH THE AIRFRAME FOR TURBOMACHINERY NOISE SCATTERING THE EFFECT OF REFLECTIONS MUST BE ACCOUNTED AS WELL AS SHIELDING MUST BE CONSIDERED. IN ADDITION TO ALLOW FOR SUCH A PREDICTIVE CAPABILITY TO BE USED WITHIN ANOPP2, IT MUST ALLOW FOR THE MODELING AND CONSIDERATION OF DIFFERENT NOISE SOURCES AS WELL AS AIRFRAME CONFIGURATIONS. THIS CURRENT EFFORT IS TO FURTHER DEVELOP THE FORMULATION THAT ACCOUNTS FOR REFLECTION TO BE APPLICABLE TO FULL RANGE OF AIRCRAFT CONFIGURATIONS/SOURCES AND IMPLEMENT WITHIN DIM2. IN ADDITION THE SOURCES FOR DIM2 ARE TO BE EXTENDED TO INCLUDE OPEN ROTOR NOISE. THE DIM2 CODE IS TO BE MATURED TO A LEVEL THAT IS APPROPRIATE FOR USE WITHIN ANOPP2 AND FOR PERFORMING HWB SYSTEM STUDIES AS WELL AS CONVENTIONAL TUBE AND WING CONFIGURATIONS.. THIS TASK ORDER CONTINUES THE WORK EFFORT INITIATED AS TASK ORDER NNL11AC76T UNDER IDIQ CONTRACT, NNL08AA00B. PERIOD OF PERFORMANCE: 10/1/2013 - 8/31/2014