Numerical calculation of sound absorbing structures (SAS) for modern aircraft engines

In this article the calculation results of impedance and absorption factor for different types of sound-absorbing structures (SAS) are presented. The one-, two- and three-layered constructions with rectangle profile and one-layered constructions with non-rectangle profile (extending or convergent to bottom) were considered. In case of two-layered SAS the results are coincided with calculations and experimental data of other authors. It is shown for such type of structures additional optimization on parameters (unused of other authors) allows to achieve more efficiency.