Aeroacoustic Predictions of Mars Ingenuity Coaxial Helicopter Using High-Fidelity Computational Fluid Dynamics

The Mars Ingenuity helicopter, developed as part of NASA's Mars 2020 mission, represents a breakthrough in extraterrestrial flight by achieving powered, controlled flight on another planet. This study presents acoustic predictions of the Ingenuity helicopter in hover within the unique atmospheric conditions of Mars using high-fidelity computational fluid dynamics (CFD) simulations. Utilizing NASA’s OVERFLOW CFD solver and PSU-WOPWOP for aeroacoustic predictions, this paper analyzes the rotor wake interactions and tonal noise mechanisms under two different collective pitch angles. Given the distinctive low Reynolds numbers and high Mach regimes associated with Mars’ thin atmosphere, this work focuses on characterizing noise sources, including laminar vortex shedding, laminar flow separation, and rotor blade crossover events in a coaxial rotor system. It is found that blade crossover events serve as a primary source of tonal noise, while laminar flow separation contributes to increased noise levels at high collective pitch angles. Understanding and measuring the acoustic signature and spectrum would aid in analyzing rotor performance and diagnosing the health of rotor systems under Martian conditions, where direct monitoring is challenging. This paper represents an initial step in that direction.