Investigation of transonic Reynolds number scaling on a twin-engine transport

M. M. Curtin*, D. R. Bogue t, and D.Om _Enabling Technology & ResearchBoeing Commercial AirplanesSeattle, WashingtonS. M. B. Rivers**, O. C. Pendergraft, Jr. tt, and .R.A. Wahls _Aerodynamics, Aerothermodynamics, and Acoustics CompetencyNASA Langley Research CenterHampton, VirginiaI. ABSTRACTThis paper discusses Reynolds number scaling foraerodynamic parameters including force and wingpressure measurements. A full-span model of theBoeing 777 configuration was tested at transonicconditions in the National Transonic Facility (NTF)at Reynolds numbers (based on meanaerodynamic chord) from 3.0 to 40.0 million. Datawas obtained for a tail-off configuration both withand without wing vortex generators and flapsupport fairings. The effects of aeroelastics wereseparated from Reynolds number effects byvarying total pressure and temperatureindependently. Data from the NTF at flightReynolds number are compared with flight data toestablish the wind tunnel/flight correlation. Theimportance of high Reynolds number testing andthe need for developing a process for transonicReynolds number scaling is discussed. This paperalso identifies issues that need to be worked forBoeing Commercial to continue to conduct futurehigh Reynolds number testing in the NTF.