Aeroacoustic Optimization of VTOL Rotor Blades
Matthew Clarke, Emilio Botero
Abstract
View Video Presentation: https://doi.org/10.2514/6.2023-0209.vid Increased interest in urban air mobility has seen various efforts to design air transportation systems with smaller or even indistinguishable acoustic footprints. With many proposed concepts opting for open rotors, attention has accordingly been placed on the optimization of rotor blades. Unfortunately, many of the existing design tools are either sufficiently accurate but very slow or very fast but lack the required accuracy to facilitate design optimization. To address this emergent need, we present an inexpensive but suitably accurate approach for designing low-noise rotors for vertical and short takeoff and landing aircraft. This approach employs elliptic functions to parameterize the spanwise properties of the rotor blade and takes advantage of recent advances in numerical computation, notably GPU acceleration and automatic differentiation. To demonstrate the versatility of this proposed approach, two design studies representing the most common scenarios of rotor blade operation are explored. The first is that of a lift-rotor which is primarily used for hover while the second is of a prop-rotor which operates in a wide range of flight conditions. Preliminary findings show that this approach can successfully generate optimal planforms in two orders of magnitude less time than the traditional parameterization approach with guaranteed smoothness of sectional properties.