A research team in the Department of Mechanical Engineering at Toyohashi University of Technology developed a method for reducing aerodynamic noise via plasma. Cavity flow, such as the flow around car gaps of high-speed trains, often radiates aerodynamic noise. A plasma actuator inducing flow was applied to suppress this noise. By periodically switching off the power of the plasma actuator, a higher reduction in sound pressure level was observed when compared with continuous operation under the same power consumption.
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Source: Phys.org