Optimization of multi-foil based on RBF mesh deformation method and modified particle swarm optimization algorithm

This paper applies the Bezier and B-spline parameterization methods and particle swarm optimization (PSO) algorithm and radial basis function (RBF) mesh deformation method to multi-foil optimization based on the computational fluid dynamic (CFD) method and mesh generation technique, and the results are validated by wind tunnel tests. Comparing the definitions and properties of the Bezier curve and B-spline, the latter is found to be better than the former in description abilities and local supporting characteristics. The optimization results of three complex functions show that the convergence rate and result of the modified PSO (MPSO) algorithm is better than the original PSO algorithm. A robust, less time-consuming RBF mesh deformation method is built, which is fit for the mesh variation variation in multi-foil optimization. Two-element and three-element multi-foils are optimized by the MPSO algorithm, which increases the maximum lift coefficient and stall angle of attack of the multi-foil. The increase of maximum lift coefficient of the two-element foil is 4.1% (with Bezier) and 4.46% (with B-spline). The increase of the three-element foil is 6.74%. Therefore, it is shown that the B-spline parameterization method is better than Bezier for two-element multi-foil optimization, and the optimization process is valid and reliable.