Effect of leading-edge curvature on separation control: A comparison of two NACA airfoils

D. Greenblatt, I. Wygnanski

Research output: Contribution to conferencePaper

3 Scopus citations

Abstract

Static stall and its control by periodic excitation were studied under incompressible conditions on a NACA 0012 airfoil, where excitation was achieved by means of independently employed two-dimensional leading-edge slots, inclined at 45° and 90° to the chord respectively, as well as a slot located in the airfoil aft region. In contrast to trailing-edge type stall of the NACA 0015, the NACA 0012 stall was controlled by a bubblebursting mechanism, giving rise to intervals of alternating partial-attachment and separation, but with no regular frequency. Separation was controlled by attaching the flow downstream of the bubble without eliminating the bubble itself. The combination of low excitation amplitudes with relatively high frequencies was found to be effective for controlling stall, as was the combination of high amplitudes with low frequencies. Large harmonic content at the higher amplitudes was believed to be responsible for this apparent anomaly. The 45° leading-edge slot was more effective for controlling stall than the 90° slot and excitation near the leading-edge was more effective than excitation from the aft portion of the airfoil. Lift augmentation resulting from generation of a "virtual surface", in the absence of natural separation, was found to be considerably inferior to lift augmentation that exploits separation control.

Original languageEnglish (US)
DOIs
StatePublished - 2002
Externally publishedYes
Event40th AIAA Aerospace Sciences Meeting and Exhibit 2002 - Reno, NV, United States
Duration: Jan 14 2002Jan 17 2002

Other

Other40th AIAA Aerospace Sciences Meeting and Exhibit 2002
CountryUnited States
CityReno, NV
Period1/14/021/17/02

ASJC Scopus subject areas

  • Space and Planetary Science
  • Aerospace Engineering

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    Greenblatt, D., & Wygnanski, I. (2002). Effect of leading-edge curvature on separation control: A comparison of two NACA airfoils. Paper presented at 40th AIAA Aerospace Sciences Meeting and Exhibit 2002, Reno, NV, United States. https://doi.org/10.2514/6.2002-411