A finite element scheme for attenuation in ducts lined with porous material: Comparison with experiment

A general finite element formulation for analysis of the sound field in a uniform flow duct with a bulk-reacting porous liner is given. Numerical results on rectangular ducts lined on all four sides are shown, and some of the lower order acoustic modes are described. Comparison is made between numerically predicted and measured values of modal axial attenuation rate, phase speed and transverse pressure profile both with and without mean airflow. Generally good agreement between prediction and measurement is observed.