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Experimental Measurement of Aerodynamic Characteristics of a Projectile at Subsonic and Supersonic Regims

Jaberi, Amin | 2015

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 47018 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Soltani, Mohammad Reza; Farahani, Mohammad
  7. Abstract:
  8. A projectile was tested in a wind tunnel at various free sream Mach numbers and angles of attack. The tests were carried out at the transonic wind tunnel of the Imam Hussein University.The experiments were performed at subsonic and supersonic speeds and at different angles of attack. The aerodynamic behavior of the model was investigated using force and moment measurements. The results showed that in the range of measured angles of attack the separation did not occurr and variations of lift coefficient remained linear for all Mach numbers except for a free stream Mach number of 2.0. For this Mach number, the asymmetric bow shock makes a pressure difference between leeward and windward sides, which increases the lift coefficient nonlinearly. Moreover, the force measurements revealed that drag coefficient increased as the free stream Mach number approached unity. However, for supersonic Mach numbers drag reduced slightly. The static margin results showed that the projectile is statically stable for all Mach numbers except for Mach number of 2.0. For this Mach number, the aerodynamic center of the model moves aft and gets closer to the body aerodynamic center.Finally, the shock waves structure and their formation process were carefully examined via shadowgraphs images. The shadowgraph visualization showed that the first normal shock appears right after the parabola-cylinder junction. By increasing the free stream Mach number, other shock waves forms at corners. As the free stream Mach number becomes supersonic, a normal shock wave is established upstream. This primary shock wave splits into two shock waves at higher Mach numbers and forms the bow shock wave and two oblique shocks over the body
  9. Keywords:
  10. Wind Tunnel ; Force Measurement ; Axisymmetric Body ; Shadowgraphy Visualization

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