Numerical Study of Reverse Thrust Generation Using Co-Flow Jet

Daniel Perlin, Gecheng Zha

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

This paper studies a new reversed thrust generation method for airfoils by use of active flow control altered from the regular Co-Flow Jet (CFJ) airfoil. This reverse thrust is generated by a CFJ injection slot duct that is redirected to flow against the freestream flow direction, rather than injecting flow tangentially to the main flow behind the leading edge. Such an injection jet can disrupt the flow with considerable flow separation, thereby decreasing the lift coefficient (C1) and increasing the drag coefficient (Cd). Three configurations of the reverse thrust CFJ concept are derived from a CFJ-NACA 6421 CFJ airfoil to compare the performance characteristics and determine the most effective approach to achieving maximal Cdand minimal C1 with low energy expenditure. The three configurations studied include an injection slot directed upward, an injection slot directed directly outward against the freestream, and an injection slot directed downward. The regular CFJ airfoil and the baseline airfoil with no flow control are also simulated for comparison. All three configurations are simulated, along with a regular CFJ airfoil, at a jet momentum coefficient (Cµ) of 0.03, 0.1, 0.2, 0.3, and 0.4, at angles of attack between 0° and 70°, and at a Mach number M = 0.15. The results for the CFJ configurations are compared with the baseline NACA 6421 airfoil. It reveals the forward-facing injection to be the most effective configuration in general, particularly at high AoA, between 15° and 60°, and Cµ = 0.2~0.3, with inverse aerodynamic efficiencies Cd ⁄Cl increased by up to 993% compared with the baseline NACA 6421 airfoil. The forward injection also requires substantially lower CFJ power than the downward and upward injection. At low angles of attack, AoA = 0°~10°, downward injection appears to be more effective, using Cµ = 0.2~0.3, with Cd ⁄Cl increased by 330% to 480% compared with the baseline airfoil Cd ⁄Cl .

Original languageEnglish (US)
Title of host publicationAIAA SciTech Forum 2022
PublisherAmerican Institute of Aeronautics and Astronautics Inc, AIAA
ISBN (Print)9781624106316
DOIs
StatePublished - 2022
Externally publishedYes
EventAIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022 - San Diego, United States
Duration: Jan 3 2022Jan 7 2022

Publication series

NameAIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022

Conference

ConferenceAIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022
Country/TerritoryUnited States
CitySan Diego
Period1/3/221/7/22

ASJC Scopus subject areas

  • Aerospace Engineering

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