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Experimental Investigation of the Plasma Actuator Effects on the Aerodynamic Efficiency of a Cranked Wing at Low Speeds

Mahdavi Zafarghandi, Fatemeh | 2025

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 58369 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Soltani, Mohammad Reza; Ebrahimi, Abbas
  7. Abstract:
  8. Nowadays, many modern fighters have delta wings to improve efficiency and maneuverability. The sharp leading edge of the delta wings at subsonic speeds and at medium and high angles of attack, causes the formation of a pair of vortices at the leading edge, which, as a result, creates an additional lift called vortex lift that is used during landing and take-off and various maneuvers. Vortex breakdown and wake flow are undesirable phenomena that occur at subsonic speeds for delta wings, which are caused by adverse pressure gradients or free flow disturbances and can lead to a sudden decrease in lift force and nonlinear behavior of the pitching moment. These undesirable phenomena reduce the efficiency of the aircraft in landing and takeoff regimes. Therefore, a solution should be thought of to control these undesirable phenomena. In this research, experimental investigations were conducted on a cranked delta wing, which is one of the most useful delta wings in advanced military and civilian aircraft. There was no information about the flow characteristics on the mentioned wing and the behavior of this wing was investigated for the first time in this research. Surface pressure distribution measurement on cranked delta wing at subsonic speeds was carried in two parts. In the first part, baseline tests were performed to investigate the flow characteristics at low speeds on the cranked delta wing. In this part, the pressure distribution measurements on the surface of this type of wing were carried out under different conditions, and the results of the experiments were examined to study the vortex formation, vortex interactions, and vortex breakdown. In the second part, the effect of flow control was investigated by applying a pulsed dielectric barrier discharge plasma actuator to increase the aerodynamic performance of the wing at low speeds. In this part, the purpose of the experiments was to investigate the effect of flow control on the behavior of vortices and flow reattachment on the surface of a cranked wing. For this purpose, several experiments were conducted in the wind tunnel to investigate active flow control on a cranked delta half-wing model, and the pressure distribution on the wing surface was measured for both the plasma on case and the baseline case (plasma off) at different angles of attack for three different configurations and three different speeds. The best results of the flow control experiment were obtained in the first configuration and speed of 10 m/s. Thus, the pulsed plasma actuator was able to delay the outer vortex burst and the flow separation at high angles of attack. Also, by applying flow control, the suction force coefficient remained constant from about 20 degrees to 34 degrees angels of attack, and in the plasma on case, the deep stall angle of attack was delayed by about 6 degrees compared to the baseline case
  9. Keywords:
  10. Vortex Breakdown ; Flow Control ; Plasma Actuator ; Aerodynamic Efficiency ; Cranked Delta Wing ; Maneuverability

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