The ultra-low Reynolds number airfoil wake

Md Mahbub Alam, Y. Zhou, Hongxing Yang, H. Guo, J. Mi

Research output: Journal article publicationJournal articleAcademic researchpeer-review

119 Citations (Scopus)


Lift force and the near wake of an NACA 0012 airfoil were measured over the angle (α) of attack of 0°-90° and the chord Reynolds number (Rec), 5.3 × 103-5.1 × 104, with a view to understand thoroughly the near wake of the airfoil at low- to ultra-low Rec. While the lift force is measured using a load cell, the detailed flow structure is captured using laser-Doppler anemometry, particle image velocimetry, and laser-induced fluorescence flow visualization. It has been found that the stall of an airfoil, characterized by a drop in the lift force, occurs at Rec≤ 1.05 × 104but is absent at Rec= 5.3 × 103. The observation is connected to the presence of the separation bubble at high Recbut absence of the bubble at ultra-low Rec, as evidenced in our wake measurements. The near-wake characteristics are examined and discussed in detail, including the vortex formation length, wake width, spanwise vorticity, wake bubble size, wavelength of K-H vortices, Strouhal numbers, and their dependence on α and Rec.
Original languageEnglish
Pages (from-to)81-103
Number of pages23
JournalExperiments in Fluids
Issue number1
Publication statusPublished - 1 Jan 2010

ASJC Scopus subject areas

  • Computational Mechanics
  • Mechanics of Materials
  • General Physics and Astronomy
  • Fluid Flow and Transfer Processes


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