Boundary element analysis on the fuselage scattering of drone noise

Multi-rotor powered drones and urban mobility vehicles (UMV) have received considerable attention over recent years and attracted ever-increasing interest in their aerodynamic noise. Physics-based prediction tools for aerodynamic noise are of importance to facilitate quiet drone designs. In this work, a boundary element method (BEM) based solver is employed to evaluate the scattering of the rotor noise of a flying drone fuselage. The possible non-uniqueness of the solution is tackled using a Combined Helmholtz Interior integral Equation Formulation (CHIEF). The proposed method is applied to evaluate the noise scattering by a realistic fuselage configuration. Results suggest that the fuselage can visibly redirect propeller noise radiation at low frequencies because of wave diffractions. The fuselage can also affect the sound field by wave reflections at high frequencies, producing an apparent noise reduction.