IGF::OT::IGF TASK ORDER - STATEMENT OF WORK (SOW) TASK TITLE: DESIGN OF TRANSONIC JUNCTURE FLOW MODEL 1.0 I…

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IGF::OT::IGF TASK ORDER - STATEMENT OF WORK (SOW) TASK TITLE: DESIGN OF TRANSONIC JUNCTURE FLOW MODEL 1.0 INTRODUCTION/BACKGROUND: THE GOAL OF THE REVOLUTIONARY COMPUTATIONAL AEROSCIENCES SUB-PROJECT OF THE AERONAUTICAL SCIENCES PROJECT IN FUNDAMENTAL AERONAUTICS PROGRAM IS TO IMPROVE PREDICTIVE CAPABILITY OF TURBULENT SEPARATED FLOWS. NASA HAS PARTICIPATED WITH OTHER NATIONAL AND INTERNATIONAL ORGANIZATIONS IN A SERIES OF WORKSHOPS TO EVALUATE THE STATE OF THE ART IN COMPUTATIONAL FLUID DYNAMICS (CFD) PREDICTIVE CAPABILITY FOR AEROSPACE VEHICLES. ONE OF THESE WORKSHOPS THAT STARTED IN 1999 IS THE AMERICAN INSTITUTE OF AERONAUTICS AND ASTRONAUTICS (AIAA) DRAG PREDICTION WORKSHOP (DPW) SERIES. THE ORGANIZING COMMITTEE OF DPW SERIES IDENTIFIED PREDICTION OF TURBULENT SEPARATED JUNCTURE FLOW AS A CRITICAL ISSUE FOR IMPROVING THE PREDICTIVE CAPABILITY OF TRANSONIC AEROSPACE VEHICLES. FIVE WORKSHOPS OVER MORE THAN A DECADE DEMONSTRATE THAT THE UNCERTAINTY IN SEPARATION PREDICTION IS AFFECTED BY THE GRID TOPOLOGY, GRID DENSITY, AND TURBULENCE MODEL. HOWEVER, THERE IS INSUFFICIENT EXPERIMENTAL DATA TO DETERMINE WHICH PREDICTIONS OF THE SEPARATION REGION ARE CORRECT AND WHY OTHER PREDICTIONS ARE NOT CORRECT. MODERN AEROSPACE VEHICLES HAVE MANY JUNCTURE REGIONS. AIRPLANES HAVE SIMILAR JUNCTURE FLOWS AT THE WING-BODY, HORIZONTAL TAIL-BODY, VERTICAL TAIL-BODY, WING-PYLON, NACELLE-PYLON, AND FLAP TRACK FAIRING-WING JUNCTURES. NEXT GENERATION CONFIGURATIONS SUCH AS THE TRUSS-BRACED WING HAVE EVEN LARGER JUNCTURE REGIONS. THE ABILITY TO PREDICT THE ONSET AND PROGRESSION OF SEPARATION FLOW IN THESE JUNCTURE REGIONS IS CRITICAL TO ACCURATE PREDICTION OF FORCES AND MOMENTS AND THEREFORE CRITICAL TO DESIGN OF FUEL EFFICIENT AND QUIET AIRCRAFT. ADDITIONALLY, SPACE LAUNCH VEHICLES HAVE SIMILAR JUNCTURE REGIONS. THE DPW ORGANIZING COMMITTEE DISCUSSED THE DEVELOPMENT OF A UNIT TEST PROBLEM TO PROVIDE VALIDATION DATA FOR CFD PREDICTIONS OF THE JUNCTURE FLOW. THE ORGANIZING COMMITTEE IDENTIFIED A CONFIGURATION WITH A LIGHTLY LOADED, SHORT WING SPAN THAT COULD BE SCALED LARGE ENOUGH TO ALLOW ACCURATE MEASUREMENTS OF THE MEAN AND TURBULENT FLOW IN THE SEPARATION REGION. THE VALIDATION TEST WOULD UTILIZE A COMMERCIALLY AVAILABLE INTERNALLY MOUNTED LASER DOPPLER VELOCIMETRY (LDV) SYSTEM TO MEASURE THE FLOW NEAR THE FUSELAGE AND WING SURFACES IN THE SEPARATED REGION, STATIC PRESSURE PORTS, AND UNSTEADY PRESSURE MEASUREMENTS. THE WING WOULD BE DESIGNED TO HAVE A PRESSURE GRADIENT SIMILAR TO NASAS COMMON RESEARCH MODEL (CRM) GEOMETRY, WHICH IS AN OPEN GEOMETRY REPRESENTATIVE OF MODERN IN-SERVICE COMMERCIAL TRANSPORT AIRCRAFT. FURTHER, THE VALIDATION TEST CONFIGURATION WOULD HAVE TWO PLANES OF SYMMETRY: LEFT-RIGHT AND TOP-BOTTOM ALLOWING MULTIPLE ROTATION ANGLES IN THE EXPERIMENTAL TEST MATRIX TO PROVIDE ESTIMATES OF TUNNEL EFFECTS. MULTIPLE PLANES OF SYMMETRY ARE POWERFUL TOOLS FOR VALIDATION EXPERIMENTS. THE VALIDATION TEST WILL BE DESIGNED WITH FOUR FLOW TYPES: 1) ATTACHED FLOW, 2) INCIPIENT SEPARATION, 3) SMALL WING-BODY SEPARATION, AND 4) LARGE SCALE SEPARATION. BOEING, AS PART OF THE DPW ORGANIZING COMMITTEE, DEVELOPED A DESIGN OF A JUNCTURE FLOW MODEL. THIS FIRST DESIGN WAS DETERMINED TO BE INSUFFICIENT TO MOUNT THE INTERNAL INSTRUMENTATION, AND BOEING SUBSEQUENTLY PROVIDED AN UPDATED DESIGN TO THE DPW ORGANIZING COMMITTEE. ANALYSIS OF THIS MODEL AT NASA LANGLEY IDENTIFIED THAT THE MODEL DID NOT PROVIDE THE FOUR FLOW TYPES, THE FUSELAGE WAS TOO NARROW TO ACCOMMODATE THE INTERNAL INSTRUMENTATION AND TRAVERSE SYSTEM, AND THE EXIT AREA OF THE FUSELAGE WAS TOO SMALL TO ACCOMMODATE ALL OF THE INSTRUMENTATION CABLING THAT WAS REQUIRED. THE WORK DESCRIBED IN THIS TASK ORDER IS REQUIRED TO ESTABLISH AN OPEN, PUBLIC-DOMAIN GEOMETRY FOR THE OUTER MOLD LINE OF THE JUNCTURE FLOW MODEL THAT ADDRESSES THE ISSUES WITH THE PREVIOUS DESIGN. THE JUNCTURE MODEL SHALL BE DESIGNED WITH A THINNER WING TO USE ANGLE OF ATTACK TO