The project aims to further enhance the understanding of the source mechanisms of solid and porous materials inside turbulent flows by the use of scale-resolving simulations. On the basis of Large Eddy Simulations (LES), the source mechanism and sound reduction of porous materials (simple as well as spatially graded) are investigated. The porous material will be modeled with a volume-averaged approach, where a linear model version is supplied by project A1. This volume-averaged model, extended with nonlinear terms, serves to clarify the sound generation while fully accounting for the nonlinear interaction between fluid and acoustics. The simulation method will be validated with DNS data and (aeroacoustic) experimental data.