Design and experiment of metaliner for sound insulation in a duct with flow

Abstract

We propose a metaliner that insulates duct noise while allowing fluid passage with little flow resistance. A unit cell of a metaliner consists of two different subwavelength Helmholtz resonators, and the unit cells are alternately arranged along the direction of sound propagation underneath the duct. To predict sound insulation of the metaliner in a duct with grazing flow, we establish an effective impedance model of the metaliner, considering the effect of flow. We design metaliners with target frequencies of 500Hz or 1000Hz that achieve high transmission loss for various flow speeds. The experimental results show that designed metaliners exhibit transmission loss above 45 dB/m within ±5% of target frequencies for different flow speeds of 0, 17, and 34 m/s.