A theoretical and experimental investigation of the nonlinear acoustic response of acoustic insertion elements

In a previous paper, a model was developed for the nonlinear acoustic resistance for compact insertion elements. Within the model, two loss coefficients are used to tune the model for each type of element, and data were used to empirically determine these coefficients for an area contraction. This paper extends the nonlinear model, developing expressions based on physical principles for the forward and reverse loss coefficients for both an area contraction and orifice. In addition, experimental data for the acoustic resistance of both elements was taken using an impedance tube. Utilizing the expressions developed, the model compares favorably with the experimental data.