Hybrid B-Spline-Targets Airfoil Parametrization with a Direct Link to CAD-Based Aircraft Geometry

Abstract

This work presents an airfoil parameterization method, called hybrid b-spline--targets (HBT), that enables a human designer or an optimization algorithm to separately control airfoil overall thickness, nose radius, camber distribution, and thickness distribution, while at the same time preserving a standard b-spline representation of the airfoil lower and upper surface in a CAD system, by means of an implicit parameter transformation external to the CAD system. The parametrization methodology, direct and inverse transformation between HBT and b-spline parameters, and an optimization demonstration with both types of parameters on a transonic wing-body transport aircraft configuration with RANS flow modeling are presented.