Shape Parametrization Using Freeform Deformation

Abstract

Shape parametrization has been identified as an import issue in aerodynamic design optimization based on high-fidelity CFD-methods. For given shapes, which are available as CAD-models, post-parametrization method, based on freeform deformation, has been established to simplify and to automate the generation of geometrical variants to be used for CFD analyses. To create the necessary deformation lattices, structured grid generation techniques of a grid generation system, developed at DLR, are utilized. As this grid generation system has the salient feature to store and to replay a sequence of processes with different parameter settings, modifications of shapes, given by polygonal curves and surfaces can be performed instantly. The present freeform deformation method has reached a state, where it can be integrated into design loops to handle a variety of shape optimization tasks. In two examples the applicability of the method for aerodynamic wing design and detailed design of a wing tip is demonstrated.