Loading...

Aerodynamic Optimization of Transonic Airfoils and Wings by Using Shock Control Bump, Suction and Blowing with Adjoint Method

Nejati, Ashkan | 2014

809 Viewed
  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 48076 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Mazaheri, Karim
  7. Abstract:
  8. Shock control bump (SCB) and suction and blowing are flow control methods used to control the shock wave/boundary layer interaction (SWBLI) in order to reduce the resulting wave drag in transonic flows. A SCB uses a small local surface deformation to reduce the shock-wave strength, while suction decreases the boundary-layer thickness and blowing delays the flow separation. Here, a single-point, a multi-point, and a robust optimization method are used to find the optimum design of SCB and suction and blowing. The flow control methods are used separately or together on two transonic airfoils i.e.; RAE-2822 and NACA-64A010 for a wide range of off-design transonic Mach numbers. The RANS flow equations are solved using Roe’s averages scheme and SST-k-ω turbulence model, and a gradient-based adjoint algorithm is used to find the optimum location and shape of all devices. A three-dimensional bump model with eleven parameters is introduced, and it is optimized by using both single and multi-point optimization procedures. To study how the SCB may improve the performance of a real wing, the transonic flow is simulated around the ONERA-M6 wing with two 3D bumps with different shapes. It is shown that the simultaneous application of blowing and SCB (hybrid blowing/SCB) improves the average aerodynamic efficiency at off-design conditions by 18.2 % in comparison with the clean airfoil, while this increase is only 16.9 % for the hybrid suction/SCB. The hybrid usage of all three methods improves the average aerodynamic performance by 22.1 %. We have also studied the SWBLI and how the optimization algorithm makes the flow wave structure and interactions of the shock wave with the boundary layer favorable
  9. Keywords:
  10. Shock Wave ; Drag Reduction ; Shock Control Bump ; Robust Optimization ; Blowing ; Suction ; Transonic Airfoil ; Mulfi-Point Optimization ; Gradient-Based Adjoint Algorithm

 Digital Object List

 Bookmark