@article{b540b8e8d80d44d68fd84c45c2f44959,
title = "Boundary layer ingestion benefit of the D8 transport aircraft",
abstract = "This paper presents the experimental assessment of the aerodynamic benefit of boundary layer ingestion for an advanced design civil transport aircraft, the D8 {"}double bubble,{"} carried out from 2010 to 2015 as part of a NASA N + 3 Phase 2 Program. A back-to-back comparison of non-boundary layer ingesting and boundary layer ingesting versions of the D8 was conducted using 1:11-scale powered models in the NASA Langley 14- by 22-foot subsonic tunnel. The aerodynamic benefit of boundary layer ingestion, as quantified by the difference in mechanical flow power required with boundary layer ingestion relative to the non-boundary layer ingesting case, was measured using two different methods to be 8.6% at the simulated cruise condition when the same propulsors are used on the two configurations. The benefit is found to be insensitive to the various modeling and processing assumptions. A detailed error analysis shows that the benefit has an uncertainty fraction of 0.21 and a 95% confidence interval fraction of 0.035, thus giving high confidence to these results. This work represents the first measurement of boundary layer ingestion performance improvements for a realistic civil aircraft configuration and provides a proof-of-concept for the use of boundary layer ingestion to improve fuel efficiency of subsonic transports.",
author = "Alejandra Uranga and Mark Drela and Greitzer, {Edward M.} and Hall, {David K.} and Titchener, {Neil A.} and Lieu, {Michael K.} and Siu, {Nina M.} and C{\'e}cile Casses and Huang, {Arthur C.} and Gatlin, {Gregory M.} and Hannon, {Judith A.}",
note = "Funding Information: This work was supported by the NASA Fundamental Aeronautics Program, Fixed Wing Project, through Cooperative Agreement Number NNX11AB35A. We emphasize that the authors are only part of the extended collaboration that is an enabling feature of this project. In this regard, we are pleased to acknowledge contributions from the rest of the Massachusetts Institute of Technology (MIT) N 3 team: this includes Elise van Dam from Delft University of Technology, the 13 MIT undergraduate students who completed internships with the project, and our partners at Aurora Flight Sciences and Pratt and Whitney, especially the insights on propulsion-airframe integration contributed by Wes Lord. From NASA Langley, we thank Scott Anders for his guidance and valuable suggestions. We benefited enormously from the expertise and enthusiasm of the staff of the NASA Langley 14-by 22-foot subsonic tunnel, in particular Jim Byrd and Les Yeh who served as test engineers during the two experimental campaigns. We would also like to acknowledge Shishir Pandya from NASA Ames for his work on numerical simulations. We are most appreciative of the strong interest, support, and useful input contributed by the NASA Fixed Wing Project management, especially Rub{\'e}n del Rosario, Richard Wahls, and Kim Pham. We thank Harold Youngren of Aerocraft, Inc. who was instrumental in performing the computational fluid dynamics studies during the model design phase. We also wish to thank the many people who offered technical feedback, in particular, Publisher Copyright: Copyright {\textcopyright} 2017 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.",
year = "2017",
doi = "10.2514/1.J055755",
language = "English (US)",
volume = "55",
pages = "3693--3708",
journal = "AIAA journal",
issn = "0001-1452",
publisher = "American Institute of Aeronautics and Astronautics Inc. (AIAA)",
number = "11",
}