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The influence of leading-edge tubercles on airfoil performance at low reynolds numbers

Sudhakar, S and Venkatakrishnan, L and Ramesh, ON (2020) The influence of leading-edge tubercles on airfoil performance at low reynolds numbers. In: AIAA Scitech 2020 Forum, 6-10 January 2020, Orlando; United States.

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Official URL: https://dx.doi.org/10.2514/6.2020-2219


An experimental investigation is carried out to study the influence of leading-edge undulations (tubercles) on Selig S1223 (S1223) and NACA-4415 airfoils at low Reynolds numbers. The influence of airfoil geometry on the effectiveness of tubercles and their ability to improve aerodynamic performance is investigated using flow field and force measurements. The tests are conducted at Reynolds numbers of 100,000, 150,000 and 200,000. Aerodynamic characteristics are measured using a force balance for angles of attack ranging from-6� to 24� . Velocity flow fields over both airfoils are measured using 2D-particle image velocimetry at selected angles of attack. The tubercles on the S1223 airfoil resulted in a delayed stall, increased lift and decreased drag at Reynolds number of 100,000 and 150,000 when compared to the baseline. Additionally, the modified airfoil eliminated the hysteresis loop at Re=150,000. At Re=200,000, for the modified Selig airfoil, the elimination of hysteresis loop is observed without much decrease in the lift or increase in the drag penalty. The velocity field for the modified S1223 airfoil shows attached flow at post-stall angles of attack of the baseline for Reynolds number 100,000 and 150, 000, which results in an improved aerodynamic performance by the modified airfoil. Additionally, the flow field on the modified airfoil is the same at increasing and decreasing phases of the angles of incidence, ascertaining for the absence of the hysteresis loop in aerodynamic characteristics for all Reynolds number considered here. However, for the modified NACA-4415 airfoil, while the hysteresis loop is eliminated, no significant improvement in lift and drag characteristics or stall angles are observed. © 2020, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

Item Type: Conference Paper
Publication: AIAA Scitech 2020 Forum
Publisher: American Institute of Aeronautics and Astronautics Inc, AIAA
Additional Information: cited By 0; Conference of AIAA Scitech Forum, 2020 ; Conference Date: 6 January 2020 Through 10 January 2020; Conference Code:237189
Department/Centre: Division of Mechanical Sciences > Aerospace Engineering(Formerly Aeronautical Engineering)
Date Deposited: 04 Nov 2020 11:19
Last Modified: 04 Nov 2020 11:19
URI: http://eprints.iisc.ac.in/id/eprint/67010

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