Computational efficient and high fidelity optimization of rotor blade geometry

Abstract

This paper explains a computationally efficient and high fidelity optimization method. CFD technique to get aerodynamic solution and optimization technique to obtain optimized blade geometry are weakly coupled. The base CFD code herein is a structured grid solver, rFlow3D, which has intensively been developed for helicopter applications at Japan Aerospace Exploration Agency. The rFlow3D is a highly versatile CFD code that can numerically simulate flows around helicopter in a wide range of flow conditions, considering trimming and blade elastic deformation. For optimization, Genetic Algorithm is combined with Kriging model. Blade geometry is expressed with a few parameters by interpolating cubic spline. In this study, blade geometry optimization is conducted assuming hovering UAVs. And the optimal blade geometry is reasonably predicted, showing uniform induced velocity distribution on the rotor plane. As a next step, we plan to conduct multi-objective optimization of blade geometry, considering both forward flight and hovering in the near future.