On the Excitation of a Zero Mass Flow Liner for Acoustic Damping

The Zero Mass Flow Liner is able to convert a perforated liner with minimal damping qualities into a very effective sound absorber. The damping improvement results from an additional acoustic excitation within the Zero Mass Flow Liner. This paper studies the damping performance of the Zero Mass Flow Liner while changing the parameters of this excitation. A strong dependency on the sound pressure level and frequency is revealed from the experiments. Though, a mode structure with a distinct pressure pattern seems to be of minor importance. However, it is of great benefit to operate the actuator at its natural resonances. This leads to a very good damping performance from a minimum of input power.

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