Numerical investigation of passive separation control for airfoil at low Reynolds number conditions

A. Gross, Hermann F Fasel

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


Direct numerical simulations were employed for investigating two different passive flow control strategies for a modified NACA 643-618 airfoil at a chord based Reynolds number of Re=64,200 and an angle of attack of α = 8.64deg. 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 a roughness Reynolds number of Rek = 446 that were mounted near the leading edge and a scalloped leading edge with serration amplitudes of 5% and 0.5% of the chord were considered. Both strategies reduce flow separation and enhance performance. The flow physics are, however, different. The roughness elements are large enough to induce local flow separation resulting 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 mid-chord. 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)
Title of host publication41st AIAA Fluid Dynamics Conference and Exhibit
Publication statusPublished - 2011
Event41st AIAA Fluid Dynamics Conference and Exhibit 2011 - Honolulu, HI, United States
Duration: Jun 27 2011Jun 30 2011


Other41st AIAA Fluid Dynamics Conference and Exhibit 2011
CountryUnited States
CityHonolulu, HI


ASJC Scopus subject areas

  • Fluid Flow and Transfer Processes
  • Energy Engineering and Power Technology
  • Aerospace Engineering
  • Mechanical Engineering

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