Efficient Domain Decomposition Method for Acoustic Scattering in Multi-Layered Media

The time-harmonic acoustic scattering in multi-layered media is modeled with an inhomogeneous Helmholtz equation for the pressure field. For example, such problems result from acoustic geological surveys. The exterior problem is truncated into a rectangle and an absorbing boundary condition is posed on its boundaries. A low-order finite...

Experimental investigation on the influence of liner non-uniformities on prevailing modes

From the in-flight measured circumferential modal spectra of the Rolls-Royce Tay 650 engine mounted on the Fokker 100, it was found that the sound field propagating upstream in the inlet is strongly modulated by intercostal hard-walled strips in the lined area, the non-cylindrical geometry of the duct, and the non-axisjnmnetric flow velocity...