Frequency analysis of surface pressures on an airfoil after stall

K. E. Swalwell, J. Sheridan, W. H. Melbourne

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

43 Citations (Scopus)


At high angles of attack airfoils can be considered as bluff bodies and their shedding frequency can be important to designers if it becomes too close to the natural frequency or a harmonic of the natural frequency of the object. This paper details the results from a thick, symmetric airfoil, a NACA 0021 section, at a Reynolds number of 2.70 × 105. At high angles of attack shedding frequencies were found in both the lift and the drag. The main frequency was at half the frequency of the secondary frequency as would be expected for a bluff body although the asymmetry in the wake caused both frequencies to be present in the lift and drag. These frequencies could be scaled by the width of the chord normal to the freestream such that the Strouhal number was nearly constant with angle of attack. The major shedding peak occurred at an angle of attack of 50 degrees, predominately in the lift.

Original languageEnglish
Title of host publication21st AIAA Applied Aerodynamics Conference
PublisherAmerican Institute of Aeronautics and Astronautics
ISBN (Print)9781624100925
Publication statusPublished - 1 Dec 2003
Event21st AIAA Applied Aerodynamics Conference 2003 - Orlando, FL, United States of America
Duration: 23 Jun 200326 Jun 2003

Publication series

Name21st AIAA Applied Aerodynamics Conference


Conference21st AIAA Applied Aerodynamics Conference 2003
Country/TerritoryUnited States of America
CityOrlando, FL

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