Characterization of Acoustic Liners Absorption using a Lattice-Boltzmann Method

The impedance of acoustic liners is predicted using lattice-Boltzmann fluid dynamics simulations. The complete three-dimensional geometry of liners, which corresponds to the combination of micro-perforated sheets, honeycomb cavities and porous materials are directly characterized through a numerical setup that reproduces a Kundt's tube and realistic liner samples. In a first step, a mesh resolution study is performed for a One Degree of Freedom (1-DOF) liner in order to show the convergence of the deducted value of the acoustic impedance with the grid size. In a second step, the influence of all the geometric parameters of the liner is predicted for 1-DOF, Two Degree of Freedom (2-DOF) and Bulk Absorber (BA) liners. The predicted impedance is compared with two analytical impedance models available in the literature.