Impact of optimized variable rotor speed and active blade twist control on helicopter blade–vortex interaction noise and environmental impact

Combined variable rotor speed and active blade twist helicopter technologies have the potential to reduce environmental acoustic impact of modern rotorcraft. This paper explores aeroacoustics, ground noise combined rotors, optimized for simultaneous mitigation source NOx emissions. An integrated approach is employed including free-wake aeroelastic modeling time-domain aeroacoustic formulations fundamentally based on Acoustic Analogy. The overall method incorporated into a multi-disciplinary design space exploration surrogate-model-assisted optimization algorithm. developed framework deployed towards devising optimal control representative twin-engine light operating in realistic descent trajectory. obtained schedules achieve reductions up 7 dB with concurrent 11%, relative conventional rotor. proposed provides new insight wake behavior blade–vortex interactions, as well footprint concepts.