Propeller Noise Study for eVTOL Interior Noise Using Equivalent Acoustic Source Model

Propeller-driven propulsion systems are receiving renewed attention in aviation with emerging electric propulsion concepts. This creates a growing need for predictive tools to assess its impact on vehicle vibro-acoustic performance. However, directly coupling high-fidelity aeroacoustic simulations with detailed acoustic and structural models can become computationally impractical for engineering studies. This paper explores a workflow in which aeroacoustic sources are represented using the Equivalent Source Method (ESM) and coupled with vibro-acoustic models to estimate interior cabin noise of an electric vertical takeoff and landing (eVTOL) aircraft. A propeller configuration representative of such systems is simulated using compressible transient CFD, with far-field acoustic pressure obtained through the Ffowcs Williams-Hawkings (FW-H) analogy. An equivalent compact acoustic source representation of the propeller is then generated and used within a Boundary Element Method (BEM) acoustic model with a hierarchical solver to compute surface pressure fields on the aircraft. These pressure fields are idealized as acoustically diffuse in order to excite exterior panels in a Statistical Energy Analysis (SEA) model for interior cabin noise estimation. Results for the eVTOL examine how different methods can be used the predict interior acoustic response from mutual propellers.