Two-Dimensional Gradient-Based Aerodynamic Shape Optimization with Two Geometry Parameterization Techniques using SU2 Code

The paper studies the effect of some shape parameterization techniques on automatic two-dimensional aerodynamic shape optimization using the discrete adjoint method. In this paper, the Hicks-Henne Bump Functions (HHBF) technique and the Free-form Deformation (FFD) control points technique are used to parameterize the shape of the NACA 0012 airfoil. First, this paper makes a full, detailed description of the shape optimization workflow, including Euler equations, geometry parameterization techniques, discrete adjoint method, gradient evaluation, optimization algorithm, and mesh deformation. Second, it explores how shape parameterization techniques are implemented in the optimization problem. Finally, the results are evaluated to compare the efficiency of the mentioned techniques. The results suggest that, in general, both techniques were shown to be equally effective as geometry parameterization methods for the shape optimization problem. However, it appears that the HHBF technique demonstrates better performance with fewer design iterations compared to that of FFD technique. On the other hand, FFD shows stability and a smoother decrease in drag values, while HHBF exhibits greater unsteadiness during the optimization process.