Mechanisms of hydrodynamic noise suppression via electromagnetic active flow control: A multi-physics study on rod-airfoil configurations

A novel electromagnetic active flow control method is proposed to suppress hydrodynamic noise through multi-physics field interactions. A multi-domain numerical framework coupling electromagnetic, hydrodynamic, and acoustic physics is developed to analyze the rod-airfoil configuration. Results demonstrate that the electromagnetic volume force in boundary layer flow achieves effective flow field regulation. The method has been shown to suppress flow separation, reduce vortex scale, and improve flow stability, with a significant reduction in vibration amplitudes of rod and airfoil surface forces. The directivity of the hydrodynamic noise after equipping electromagnetic active flow control presents dipole noise characteristics, while reducing sound pressure levels across all directions. At an upstream monitoring point 1850 mm from the source, a significant decrease in sound pressure level of 5.06 dB is observed, accompanied by a shift in the dominant frequency from 1280 to 1365 Hz. The hydrodynamic noise suppression effect under different control parameters is analyzed. At the maximum applied voltage (10 V), the sound pressure level at points 0° and 90° decreases to 76.64 and 83.15 dB, corresponding to total reductions of 8.58 and 6.92 dB, respectively. This multi-physics study underscores the efficacy of the electromagnetic active flow control method in mitigating hydrodynamic noise for rod-airfoil configurations.