Sound pressure attenuation in an acoustically lined parallel-plate duct containing an off-centre cylindrical radiator

We employ the classical method of images along with a simple local surface reaction model involving a complex amplitude (plane) wave reflection coefficient to investigate the radiated field due to an infinite cylinder undergoing harmonic modal surface vibrations at an arbitrary location between the locally reacting walls of a two- dimensional planar waveguide. The numerical results reveal the important effects of source location, size, impedance, excitation frequency, mode of surface vibrations, orientation, and local lining reaction on the acoustic pressure attenuation along the duct. The presented solution can lead to a better understanding of acoustics of a two-dimensional waveguide source that is of practical interest in building acoustics, environmental acoustics and noise control engineering.