Observation of the Biot slow wave in a plastic foam of high flow resistance at acoustical frequencies

摘要

The surface impedance of a plastic foam with high flow resistance has been measured with a new method at acoustical frequencies. The Biot theory provides a description of the behavior of this surface impedance from the contributions of the fast and the slow compressional waves to pressure and acoustical velocity at the surface of the foam. The contribution of the slow wave can be observed in spite of its strong damping.