Parametric study of evtol rotor acoustic design trades

A computational framework that couples the parametric aircraft geometry tool, OpenVSP with the acoustic prediction code, PSU-WOPWOP was developed and applied to evaluate the aerodynamic and acoustic effects of variations in the design and operating conditions of eVTOL rotors in hover. While reducing disk loading is beneficial for both acoustics and hover performance, most other design changes entail a tradeoff between noise and aerodynamic efficiency. Changes in twist and taper can reduce noise by shifting loading and blade volume inboard, where convective amplification of the acoustic sources is lower. However, these changes reduce aerodynamic efficiency. Acoustically-beneficial changes to taper, twist rate, and twist distribution are combined to design a low noise rotor. Compared to the baseline, a maximum noise reduction of approximately 7dB is achieved but power loading is reduced by 15%.