Aerodynamic shape optimization of passenger car fender based on the FFD method

The research of this work focuses on optimizing the body fender of the CAERI AERO car model to decrease aerodynamic drag and improve aerodynamic performance. Five design regions of the body fender were selected and studied. The Free-Form Deformation (FFD) method was used to perform the mesh deformation process without re-modeling and re-gridding. The optimal Latin Hypercube Sampling method and Computational Fluid Dynamics (CFD) simulations are used to generate the sample points and obtain their responses. The relationships between the design variables and their responses, as well as the contributions of the main factors, were analyzed. After then, an optimization of decreasing drag using the Adaptive Simulated Annealing (ASA) algorithm was conducted based on the Radial Basis Function (RBF) model, and a set of convergent solution space sets is obtained. Finally, CFD simulations were performed on the ASA algorithm search results, and a comparison of the aerodynamic performance between the original fender and an optimal fender that selected from the solution spaces is presented. Using the FFD method and the surrogate model dramatically improves the computational efficiency in this study.