Hybrid Fidelity Optimization of Efficient Airfoils and Rotors in Ultra-Low Reynolds Numbers Conditions

The unmanned aerial systems (UAS) design for flight in the Martian atmosphere is thriving. This paper discusses the aerodynamic optimization of airfoils and blades at ultra-low Reynolds number conditions. In the case of airfoils, the performance predictions are carried out using unsteady Computational Fluid Dynamics (CFD). We analyzed the influence of the Reynolds number on optimal geometries and proposed a globally efficient airfoil. We computed the polar of these airfoils to generate an aerodynamic database as they are necessary for rotor reduced-order models. This work focuses on optimizing and comparing two and 3-bladed rotors. We used the Blade Element Method (BEM) to generate efficient geometries employing a genetic algorithm and evaluated the resultant geometries with higher fidelity CFD simulations. Final refinement of the presented geometries is performed with a CFD adjoint optimization.