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The application of the gradient-based adjoint multi-point optimization of single and double shock control bumps for transonic airfoils

Mazaheri, K ; Sharif University of Technology | 2015

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  1. Type of Document: Article
  2. DOI: 10.1007/s00193-015-0591-2
  3. Publisher: Springer New York LLC , 2015
  4. Abstract:
  5. A shock control bump (SCB) is a flow control method which uses local small deformations in a flexible wing surface to considerably reduce the strength of shock waves and the resulting wave drag in transonic flows. Most of the reported research is devoted to optimization in a single flow condition. Here, we have used a multi-point adjoint optimization scheme to optimize shape and location of the SCB. Practically, this introduces transonic airfoils equipped with the SCB which are simultaneously optimized for different off-design transonic flight conditions. Here, we use this optimization algorithm to enhance and optimize the performance of SCBs in two benchmark airfoils, i.e., RAE-2822 and NACA-64A010, over a wide range of off-design Mach numbers. All results are compared with the usual single-point optimization. We use numerical simulation of the turbulent viscous flow and a gradient-based adjoint algorithm to find the optimum location and shape of the SCB. We show that the application of SCBs may increase the aerodynamic performance of an RAE-2822 airfoil by 21.9 and by 22.8 % for a NACA-64A010 airfoil compared to the no-bump design in a particular flight condition. We have also investigated the simultaneous usage of two bumps for the upper and the lower surfaces of the airfoil. This has resulted in a 26.1 % improvement for the RAE-2822 compared to the clean airfoil in one flight condition
  6. Keywords:
  7. Drag reduction ; Shock control bump ; Single- and multi-point adjoint optimization ; Transonic airfoil
  8. Source: Shock Waves ; 2015 ; 09381287 (ISSN)
  9. URL: http://link.springer.com/article/10.1007%2Fs00193-015-0591-2