Nonlinear aeroacoustic characterization of resonators

The nonlinear damping of acoustic resonators is investigated by means of fluid dynamic simulations and reduced-order models for this behavior are developed. The strong impact of the shape of the resonator opening on the acoustic resistance as well as on the scattering to higher harmonics is demonstrated and confirmed by quasi-steady analysis. Based on simulation data, reduced-order models are generated using system identification techniques. For the nonlinear identification, a novel model structure and bias-free identification procedure are proposed. Since this model is robust and can be evaluated efficiently, it can serve as an acoustic boundary condition in fluid dynamic or aeroacoustic simulation and can support the resonator design in an early stage of development.