A New Modified Harmony Search Optimization Algorithm for Evaluating Airfoil Shape Parameterization Methods and Aerodynamic Optimization

In this work, a modification has been made to increase the efficiency and convergence of the harmony search algorithm. Then, the capability of this amendment was investigated by applying it to the following aerodynamic problems for the first time. First, the methods of airfoil shape parametrization (Bezier curves, Parsec method, and NACA 4-digit airfoil) were investigated using an inverse optimization design by the present modified harmony search optimization algorithm. Then, inverse and direct optimization of an airfoil were carried out by the modified algorithm. Aerodynamic analysis of the problem was obtained using compressible Reynolds-Averaged Navier-Stokes (RANS) equations along with the Spalart-Allmaras turbulence model. Results showed that the Bezier curves and the Parsec method have higher flexibility than the NACA 4-digit airfoil. The Parsec method was introduced as the best approach, because of fewer control parameters. The inverse optimization results showed that the present airfoil shape optimization set can obtain the target shape with high accuracy. The Direct optimization with a maximum lift to drag ratio target function revealed that the shock waves significantly weaken at the optimum airfoil. Generally, the results obtained verify that using the modified harmony search algorithm together with the Parsec method provides a powerful tool for direct and inverse aerodynamic optimization.