Prediction of the Absorption Characteristics of Non-Uniform Acoustic Absorbers with Grazing Flow

In this paper, planar and the cylindrical broadband non-uniform acoustic absorbers were constructed, both of which use absorption units (BAUs) as their building blocks. The impedance boundary Navier–Stokes equation (IBNSE) method was developed to predict characteristics lined duct with absorbers, in each small piece perforated plate is acoustically equivalent a semi-empirical model through condition. A total four models compared under different control parameters. full (FNSE) used verify accuracy these models. It found that IBNSE Goodrich had highest prediction accuracy. Finally, constructed spatial extensions BAU. transmission losses coefficients rectangular duct–planar absorber (RDPAA) annular duct–cylindrical (ADCAA) systems grazing flow predicted, respectively. results demonstrated designed achieved. accurate computationally efficient, can be an treated presence flow.