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Performance improvement of a supercritical airfoil by a multi-point optimized shock control channel

Nejati, A ; Sharif University of Technology | 2018

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  1. Type of Document: Article
  2. DOI: 10.1007/s10494-017-9878-y
  3. Publisher: Springer Netherlands , 2018
  4. Abstract:
  5. A shock control channel (SCC) is a flow control method introduced here to control the shock wave/boundarylayer interaction (SWBLI) in order to reduce the resulting wave drag in transonic flows. An SCC transfers an appropriate amount of mass and momentum from downstream of the shock wave location to its upstream to decrease the pressure gradient across the shock wave and as a result the shock-wave strength is reduced. Here, a multi-point optimization method under a constant-lift-coefficient constraint is used to find the optimum design of the SCC. This flow control method is implemented on a RAE-2822 supercritical airfoil for a wide range of off-design transonic Mach numbers. The RANS flow equations are solved using Roe’s averages scheme and a gradient-based adjoint algorithm is used to find the optimum location and shape of the SCC. The solver is validated against experimental works studying effect of cavities in transonic airfoils. It is shown that the application of an SCC improves the average aerodynamic efficiency in a range of off-design conditions by 13.2% in comparison with the original airfoil. The SCC is shown to be an effective tool also for higher angle of attack at transonic flows. 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. © 2017, Springer Science+Business Media B.V., part of Springer Nature
  6. Keywords:
  7. Multi-point adjoint optimization ; Shock control channel ; Shock wave ; Supercritical airfoil ; Aerodynamics ; Airfoils ; Angle of attack ; Boundary layers ; Drag ; Drag reduction ; Flow control ; Optimization ; Shock absorbers ; Transonic flow ; Adjoint optimizations ; Aerodynamic efficiency ; Flow control methods ; Off design condition ; Optimization algorithms ; Shock control ; Supercritical airfoils ; SWBLI ; Shock waves
  8. Source: Flow, Turbulence and Combustion ; Volume 100, Issue 3 , 2018 , Pages 675-703 ; 13866184 (ISSN)
  9. URL: https://link.springer.com/article/10.1007%2Fs10494-017-9878-y