Suppression of vortex-induced vibration of a flexible splitter plate attached to a cylinder by the Lorentz force active flow control

This numerical investigation explores the use of active flow control through Lorentz force actuation to suppress vortex-induced vibrations in a flexible splitter plate positioned behind a cylinder. Building on the fluid–structure interaction benchmark, now extended to three dimensions, the approach employs a Halbach array of permanent magnets to strengthen the magnetic field and improve Lorentz force generation. Simulations that combine magnetohydrodynamics with fluid–structure interaction demonstrate that the applied Lorentz force significantly alters near-wall flow dynamics, delays boundary layer separation, and reshapes the wake into a hybrid structure—one that merges a stationary vortex pair with periodic shedding. As a direct consequence, structural vibrations are strongly suppressed: amplitude decreases reach 42.7% in the stream-wise direction and 38.5% in the transverse direction. Meanwhile, the mean drag force falls by 7.2%, and lift fluctuations are reduced by 21.5%. Spectral analysis further supports the observed attenuation of dominant vibration frequencies and a breakdown of frequency lock-in. Importantly, the effectiveness of this control strategy exhibits a clear monotonic relationship with the applied electromagnetic volume force, underscoring its potential for real-world flow control applications.