Adjoint Optimization of a Wing Using the CSRT Method

Abstract

This paper will demonstrate the potential of the Class-Shape-Refinement-Transformation (CSRT) method for aerodynamically optimizing three-dimensional surfaces. The CSRT method was coupled to an in-house Euler solver and this combination was used in an optimization framework to optimize the ONERA M6 wing in transonic conditions. The gradients of the flow variables with respect to the design parameters were computed using an adjoint solver integrated in the Euler code. The optimization was performed by a trust region reflective algorithm. A two-step approach was used to optimize the wing. First, a “general” optimization was done using the Bernstein coefficients of the shape function. Second, a “regional” refinement was performed using the B-spline coefficients of the refinement function. It was shown that using this strategy a considerable improvement of the lift-to-drag ratio of 22 % could be achieved. This result proves that an adjoint optimization using the CSRT method is an effective way to improve transonic wing performance.