Numerical investigation of passive separation control for an airfoil at low-reynolds-number conditions

A. Gross, Hermann F Fasel

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Two different passive flow control strategies were investigated for a modified NACA 643-618 airfoil at a chord-based Reynolds number of Re = 64,200 and an angle of attack of α = 8.64 deg. For these conditions, the laminar boundary layer separates from the suction side, resulting in a loss of lift and a drag increase. Distributed roughness elements with roughness Reynolds numbers of Rek = 136 and 446 that were mounted near the leading edge and scalloped leading edges with serration amplitudes of 5 and 0.5% of the chord were considered. The large roughness elements and the scalloped leading edge reduce the flow separation and enhance performance. The flow physics are, however, different. For Rek = 446, the roughness elements result in high-frequency shedding. The shedding results in an accelerated transition of the separated boundary layer. For the scalloped leading edge with 5% serration amplitude, laminar separation bubbles are situated in the leading-edge troughs. The turbulent wedges that originate from these bubbles coalesce near midchord. For a serration amplitude of 0.5%, the separation line is deformed in the spanwise direction in a manner that is reminiscent of stall cells.

Original languageEnglish (US)
Pages (from-to)1553-1565
Number of pages13
JournalAIAA Journal
Volume51
Issue number7
DOIs
StatePublished - Jul 2013

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Airfoils
Reynolds number
Surface roughness
Laminar boundary layer
Flow separation
Angle of attack
Flow control
Drag
Boundary layers
Physics

ASJC Scopus subject areas

  • Aerospace Engineering

Cite this

Numerical investigation of passive separation control for an airfoil at low-reynolds-number conditions. / Gross, A.; Fasel, Hermann F.

In: AIAA Journal, Vol. 51, No. 7, 07.2013, p. 1553-1565.

Research output: Contribution to journalArticle

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