Minwoo Kim, Jonghoon Bin and Soogab Lee*
The Journal of Mechanical Science and Technology, vol. 26, no. 2, pp.463-471, 2012

Abstract : Based on impedance prediction methods for a perforated plate acoustic liner, time-domain impedance boundary conditions are enhanced with consideration of incident intensity. The impedance coefficient of the time-domain boundary condition is re-derived using parameters of the liner structure, and is classified by physical characteristics. To show the capability of the reconstructed impedance boundary condition, two numerical calculations are performed with comparison to analytical results. The first considers the onedimensional wave propagation problem to account for the reflection wave due to an incident intensity variation on the acoustic liner. The second considers the excess attenuation of impedance surface. The numerical simulation is performed using the linearized Euler equations (LEEs). Dispersion-relation-preserving finite difference scheme and optimized Adams-Bashforth time-integration method are used spatial discretization / time integration, respectively. The numerical results show excellent agreement with analytical results. Moreover, a reconstruction method of impedance boundary condition can easily obtain the impedance coefficients under environments of variant magnitudes of incident waves.

Keyword : Acoustic liner; Computational aeroacoustics; Impedance boundary condition