Corona discharge actuator as an active sound absorber under normal and oblique incidence

Abstract

In the majority of active sound absorbing systems, a conventional electrodynamic loudspeaker is used as a controlled source. However, particular situations may require an actuator that is more resistant to harsh environments, adjustable in shape, and lighter. In this work, a plasma-based electroacoustic actuator operating on the atmospheric corona discharge principle is used to achieve sound absorption in real-time. Two control strategies are introduced and tested for both normal in the impedance tube and grazing incidence in the flow duct. The performance of plasma-based active absorber is competitive with conventional passive technologies in terms of effective absorption bandwidth and low-frequency operation, however, it presents some inherent limitations that are discussed. The study reveals that the corona discharge technology is suitable for active noise control in ducts while offering flexibility in design, compactness, and versatility of the absorption frequency range.

Ultrabroadband sound control with deep-subwavelength plasmacoustic metalayers

“…Derivation of equations (( 1 )–( 2 )) and their contributions to the total generated pressure in free field are discussed in the previous work 23 . In 24 , an attempt was made to control the corona discharge transducer, where it was used as a generic transducer to absorb sound, without benefiting from the physics of the corona discharge. However, equations (( 1 )–( 2 )) are frequency-independent, which suggests that they can form the basis for an active actuator that can be controlled over a potentially broad frequency range, as we now demonstrate.…”

Plasma-based acoustic liner for broadband noise reduction

“…The actuator can also be used to control sound, for example, create an impedance-matched condition for sound absorption or cancel out acoustic pressure or a specific location [6]. For noise reduction under grazing sound incidence, an array of four identical plasma actuators used as an active acoustic liner was tested in CAIMAN flow duct facility at Ecole Centrale de Lyon.…”

Corona-discharge acoustic transducer as a perfect matched acoustic source

“…Accordingly, the AC component can be tuned for desired local pressure field perturbation and sound generation at a favorable frequency. CD transducers can be employed for sound generation [8,[10][11], as well as sound absorption [12]. The theoretical concept of such a perfectly matched sound source has already been introduced and widely utilized in many analytical studies, however, it still remains a physically unattainable ideal.…”