Numerical investigation of separation for airfoils

A. Gross, H. F. Fasel

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

4 Scopus citations


Separation deteriorates airfoil performance and is generally undesirable. In this paper turbulent separation from two different airfoils is investigated. The first airfoil is a modified NACA 643-618 airfoil. At a chord based Reynolds number of Re=322,000 and for an angle of attack of α = 13.2deg a laminar separation bubble forms near the leading edge and the flow separates turbulent at about mid-chord. For these conditions "coarse" grid direct numerical simulations and unsteady hybrid simulations based on a one-equation renormalization group turbulence model and the filter-based Reynolds-averaged Navier- Stokes model were carried out. The direct simulation was found to suffer from insufficient grid resolution. Results obtained from the hybrid simulations provide an adequate match with the experimental reference data at much reduced computational cost. A procedure for "seeding" turbulence velocity fluctuations in areas where the grid resolution increases in the streamwise direction was found to have no effect on the mean flow data. The second airfoil is a generic laminar airfoil. For Re=2,630,000 and α = 23deg the flow separates near quarterchord. Unsteady Reynolds-averaged Navier-Stokes simulations show a curved separation line which is indicative of stall cells. Attempts to explain the spanwise wavelength of the unsteady and steady spanwise flow structures remained unsuccessful.

Original languageEnglish (US)
Title of host publication41st AIAA Fluid Dynamics Conference and Exhibit
PublisherAmerican Institute of Aeronautics and Astronautics Inc.
ISBN (Print)9781600869471
StatePublished - 2011
Event41st AIAA Fluid Dynamics Conference and Exhibit 2011 - Honolulu, HI, United States
Duration: Jun 27 2011Jun 30 2011

Publication series

Name41st AIAA Fluid Dynamics Conference and Exhibit


Other41st AIAA Fluid Dynamics Conference and Exhibit 2011
Country/TerritoryUnited 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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