Multidisciplinary Design Framework for Low Noise Propulsors

In this Phase II STTR, Whisper Aero is proposing an adaptable multidisciplinary design framework for low noise propulsors. It will incorporate the newest industry-standard and open source propulsive design tools across aerodynamics, acoustics, powertrain, and structures disciplines for synthesizing ideal propulsors for Group I, II, and III UAS. In Phase I, Whisper Aero successfully incorporated medium-fidelity aerodynamic design tools, state-of-the-art vortex particle methods, and industry standard low-Reynolds number cascade aerodynamics analysis tools into one framework with tonal and broadband acoustic prediction codes. The results of Phase I were substantiated by a successful prototype propulsor build and test in a companion “eQ Propulsor” AFWERX STTR, validating Whisper Aero’s ability to rapidly integrate new and industry standard aeroacoustic design and analysis tools towards developmental hardware. Further expansion of this capability will enable the Air Force and its industry base to more rapidly design and field novel propulsors and airframes with reduced acoustic signature. Whisper Aero will further expand the framework in Phase II to include structures and powertrain disciplines required to comprehensively navigate key thrust, power, and weight tradeoffs and to allow designers to identify and minimize any non-aero-induced sources of noise and vibration. Whisper Aero will delve deeper into medium- and higher- fidelity aerodynamic methods that will explore low Reynolds Number transition models, GPU enabled solvers, and viscous vortex-based methods. Additional tonal and broadband acoustics models will be tightly coupled with these aerodynamic advancements for proper assessment of rotor and stator geometries and then validated using acoustic cameras at BYUs flow-through anechoic facility. Ultimately, these capabilities will prepare the team to evaluate full airframes with multiple propulsors and advanced integrations as a follow-on Phase III activity.