2015 Volume 10 Issue 2 Pages JFST0015
In this research, an inexpensive aerodynamic shape optimization of airfoil is performed for Darrieus type vertical axis wind turbine (VAWT). Computational fluid dynamics (CFD) evaluations of various airfoil shapes are treated inexpensively by considering the apparent flow velocity magnitudes and apparent angles of attack at multiple positions of VAWT airfoil, which includes some assumptions as two dimensional steady flows and no consideration about flow interactions between blade airfoils. Global optimal shapes are efficiently explored by using a Kriging response surface model approach. An optimal VAWT airfoil is obtained by the maximization of a proposed objective function. Since our objective function for this design optimization of VAWT airfoil can be primary decomposed into the terms of thrust force and pitching moment, another multi-objective optimization of thrust/pitching moment coefficients is also performed for detailed discussions about the obtained optimal airfoil. Analysis of variance is performed on the Kriging response surface model to extract design knowledge in this design optimization problem. The obtained optimal airfoil achieves a significant improvement in the aerodynamic performance compared with an existing airfoil. Finally, expensive unsteady CFD simulations are performed for the obtained airfoils, that take into account unsteady flow interactions between three blade airfoils. The results of the unsteady CFD simulations validate the effectiveness of the proposed aerodynamic shape optimization approach for VAWT airfoil.
