Improving robustness of adjoint-based airfoil optimization design

By introducing the line search method, the robustness of the adjoint-based airfoil optimization design method is improved. For a given objective function, its corresponding adjoint equations, boundary conditions and the gradient expression in the body-fitted coordinate system are derived. In the optimization process, the gradient of the objective function is obtained by solving the flow equations and the adjoint equations, and for the traditional adjoint-based optimization method, a constant step is used, while in this research, the line search method is introduced to obtain the optimal step. The results illustrate that it can automatically find the optimal step, and overcome the restriction imposed by the choice of user-defined constant step, which is used in the traditional adjoint-based optimization method, thus improving the robustness of the adjoint-based airfoil optimization design method.