Title page for ETD etd-08082000-13180002

Type of Document Master's Thesis
Author Miranda, Sergio
Author's Email Address smiranda@vt.edu
URN etd-08082000-13180002
Title Active Control of Separated Flow over a Circular-Arc Airfoil
Degree Master of Science
Department Engineering Mechanics
Advisory Committee
Advisor Name Title
Telionis, Demetri P. Committee Chair
Hendricks, Scott L. Committee Member
Mook, Dean T. Committee Member
  • flow control
  • airfoil
  • wind tunnel testing
  • vortex flow
Date of Defense 2000-05-08
Availability unrestricted

An experimental study of active control of fully separated flow over a symmetrical circular-arc airfoil at high angles of attack was performed. The experiments were carried out in a low-speed, open circuit wind tunnel. Angles of attack from 10 to 40 degrees were tested. Low-power input, unsteady excitation was applied to the leading or trailing edge shear layers. The actuation was provided by the periodic oscillation of a 4-percent-chord flap placed on the suction side of the airfoil and facing the sharp edge. Vortex-shedding frequencies were measured and harmonic combinations selected as the applied actuator frequencies.

Pressure measurements over the airfoil show that the control increased the normal force coefficient by up to 70%. This supports the idea of vortex capture in the time-averaged sense, enhancing the lift on the airfoil by managing the shear layer roll up.

The results indicate the viability of the control of large-scale flow fields by exploiting the natural amplification of disturbances triggered by small-scale actuators.

The application of flow control on sharp-edged aircraft wings could lead to improved maneuverability, innovative flight control and weight reduction. These can be achieved by inexpensive, low-power, rugged actuators.

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