Sound-vortex conversion on droplets: Kinematic model of sound activated vortices

The rapid pace of urbanization across the globe has led to the proliferation of various urban infrastructure. They generate aerodynamic noise, posing significant challenges to urban planning and residents' comfort. Despite Lighthill's mathematical analogy, current noise control applications rely heavily on wind tunnel tests and computer simulations. Physical mechanisms behind aeroacoustic noise have yet to be validated and elucidated experimentally. This work observed the geometry of sound-activated vortices and determined their streamline and velocity distribution. The theoretical results are consistent with experimental observations, offering a kinematic model for sound activated vortices. The work experimentally improves the understanding of aeroacoustic noise and provides a kinematic model for the development of noise control strategies.