R. W. Harrison
Feb 1, 1990
Le Journal De Physique Colloques
A dedicated, time dependent finite element program was used to study the absorption of sound in a viscoelastic cylinder containing a cavity. The effect on the sound absorption and the cylinder surface impedance of varying the cavity's size and shape was examined. Representative models were made and tested in a novel impedance tube and the experimental data is in good agreement with the finite element studies. We have studied such a cavity using a finite eleolent analysis supported by data obtained from a guided wave tube for experimental verification. Here we observe the changes in resonant frequency and impedance as the hole height varies from .0015 meters to .003 meters. As the hole height controls the side wall resonance, the frequency shift is most noticeable in the 20-30 kHz area where the side wall system has its resonance.