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Aerodynamic Control of Slender Bodies from Low to High Angles of Attack through Flow Manipulation

Lopera, Javier
http://rave.ohiolink.edu/etdc/view?acc_num=toledo1177504352

Abstract Details

2007, Doctor of Philosophy in Engineering, University of Toledo, Mechanical Engineering.
This dissertation presents experimental investigations of several novel active flow control methodologies that have been implemented for aerodynamic control and maneuvering of slender bodies at low and high angles of attack through flow manipulation. For low angles of attack, a U.S. Army Smart Cargo projectile was examined. For high angles of attack a U.S. Air Force countermeasure concept projectile termed DEX (Destructive Expendable) was examined. Low angle of attack control was attempted using two novel separation control techniques: reconfigurable porosity and miniature deployable spoilers. Results show that significant aerodynamic forces are generated by implementing reconfigurable porosity and can be effectively used to steer and maneuver air vehicles. Porous patterns with a “saw-tooth” configuration seem to be the most effective in generating consistent control forces over a wide range of angles of attack. Miniature deployable spoilers successfully demonstrated their ability in producing both positive and negative pitch and yaw controls by modulating the spoiler height and length when used on the boattail and Aero Control Fins (ACFs) of a projectile. The effect of aftbody strake parameters such as shape, locations (axial and azimuthal), deployment height, and number of strakes implemented was examined on a short blunt-nose projectile. Large yaw control authority was attained for á > 40 deg. The largest yaw control authority was produced by a rectangular-shaped strake. A robust closed-loop feedback controller was successfully tested using dynamic wind tunnel experiments to control the coning motion of a projectile. The controller showed good control authority and was capable of attaining and maintaining the commanded roll angle with a tolerance of ± 10 deg. A study was conducted to gain some insights into the fluid mechanics of short blunt-nose bodies of revolution at high angles of attack. Off- and on-surface flow visualization records are collected to study the effects of two blunt noses: a hemispherical nose and an elliptical nose with 33% ellipticity. It was found that the elliptical-nose results in flow behaviors typical of a blunt-nose, while the hemispheric-nose results in behaviors that are akin to a pointed-nose. An explanation for the contrasting behaviors is provided.
T. Ng (Advisor)
269 p.
active flow control; aerodynamic control; slender bodies; blunt bodies; high angle of attack; forebody vortex control; coning motion; strakes; flowfield

Recommended Citations

Citations

  • Lopera, J. (2007). Aerodynamic Control of Slender Bodies from Low to High Angles of Attack through Flow Manipulation [Doctoral dissertation, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1177504352

    APA Style (7th edition)

  • Lopera, Javier. Aerodynamic Control of Slender Bodies from Low to High Angles of Attack through Flow Manipulation. 2007. University of Toledo, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=toledo1177504352.

    MLA Style (8th edition)

  • Lopera, Javier. "Aerodynamic Control of Slender Bodies from Low to High Angles of Attack through Flow Manipulation." Doctoral dissertation, University of Toledo, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1177504352

    Chicago Manual of Style (17th edition)

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© 2007, all rights reserved.
This open access ETD is published by University of Toledo and OhioLINK.