Aerodynamic shape optimization by considering geometrical imperfections using polynomial chaos expansion and evolutionary algorithms

Abstract

Uncertainties, in the form of either non–predictable shape imperfections (manufacturing uncertainties) or flow conditions which are not fixed (environmental uncertainties) are involved in all aerodynamic shape optimization problems. In this paper, a workflow for performing aerodynamic shape optimization under uncertainties, by taking manufacturing uncertainties into account is proposed. The uncertainty quantification (UQ) for the objective function is carried out based on the non–intrusive Polynomial Chaos Expansion (niPCE) method which relies upon the CFD software as a black–box tool. PCE is combined with an evolutionary algorithm optimization platform. CAD–free techniques are used to control the shape and simultaneously generate shape imperfections; next to this, a morphing/smoothing tool adapts the CFD mesh to any new shape. In the cases presented in this paper, all CFD evaluations are performed in the OpenFOAM environment.