Empirical relations between acoustical properties and flow resistivity of porous plastic open-cell foam

Abstract Based on an analysis of a large amount of experimental data, the empirical relations between the characteristic impedance and propagation constant of porous plastic open-cell foams and the unit-depth flow resistivity are established. It is found that the correlation coefficients of acoustical properties of foams with the unit-depth flow resistivity have values up to 0·99. A comparison of the results with Delany and Dunn's studies of fibrous and foam materials is made.