Flow-induced noise control in wing-plate junction flow using electromagnetic force

This study proposes an active control strategy based on electromagnetic force (EMF) to mitigate the hydrodynamic noise generated by the horseshoe vortex (HSV) at a wing-plate junction. Large eddy simulations are combined with gravity-driven water tunnel experiments on a NACA 0018 (National Advisory Committee for Aeronautics) hydrofoil at a chord-based Reynolds number of Rec=1.26×106 and an angle of attack of 6°. The analysis successively addresses the HSV dynamics, the wall pressure fluctuations, and the resulting far-field radiated sound, thereby clarifying how the control mechanisms evolve with EMF strength. The results reveal that the acoustic response varies non-monotonically with the forcing intensity. Under weak EMF (N=1), the Lorentz force mainly displaces and compresses the vortex topology without altering the quasi-periodic shedding mechanism, leading to only limited suppression of the numerically predicted low-frequency noise. At intermediate intensity (N=5), the disruption of the multimodal switching of the primary vortex generates spatially coherent pressure loading and produces a narrow-band radiation peak near 30 Hz, although the numerically integrated sound power within 20–500 Hz is reduced by 1.69 dB. Under strong EMF (N=10), the near-wall dynamics are reorganized into a stable shear interface upstream of the leading edge, reducing the radiation efficiency of the low-frequency pressure loading and yielding a numerically predicted reduction of 4.34 dB over 20–500 Hz. The water tunnel measurements verify the acoustic response within the experimentally reliable 500–2000 Hz range, where weak forcing produces measurable attenuation, whereas stronger forcing leads to a high-frequency noise penalty. These results indicate that EMF control can suppress low frequency flow-induced noise through vortex topology reconstruction, but its practical application requires consideration of possible high-frequency acoustic penalties under stronger forcing.