A proof-of-concept for surface airflow sensing using an array of bio-inspired flexible magnetic cilia

The precise perception of unsteady flow environments is critical for realizing 'fly-by-feel' flight control in next-generation aircraft. However, existing artificial hair sensors typically operate in a rigid, low-Cauchy-number regime and rely on scalar transduction, limiting their ability to resolve the flow direction without complex, dense arrays. In this study, we present a bio-inspired sensing system based on flexible magnetic cilia fabricated from a soft elastomer matrix. These sensors achieve a low elastic modulus that places them in a high-Cauchy-number regime, mechanically mimicking the compliance of seal whiskers and bat hairs. By synergizing this mechanical compliance with vector-sensitive magnetic transduction, we demonstrate that a single cilium can simultaneously resolve both the magnitude and direction of the airflow. Experimental validation on a non-slender delta wing confirms the array's ability to capture critical aerodynamic features, including leading-edge vortex migration, flow separation, and reattachment. Unlike traditional isotropic designs, this approach provides directional sensitivity at the single-sensor level, offering a scalable pathway for distributed aerodynamic monitoring.