Scattering of Underwater Sound From a Porous Solid Sphere
Abstract
An experiment was performed to measure the scattering of underwater sound from a porous solid for the first time. Two porous solid spheres composed of heat-epoxied glass beads of 100 and 500 micron mean bead diameter were used. The permeability, porosity, and shear modulus of each sample were estimated from measurements made on cylindrical samples which had been manufactured at the same time and of the same glass beads as the spheres. These material properties were used as input to a theoretical model for the sound scattered from a poro-elastic sphere imbedded in a poroelastic host developed by Kargl and Lim. The experimental data were compared to the theoretical calculations. Theoretical calculations with 0%, 3%, and 10% skeletal frame damping were compared to experimental data. Very good agreement between measured and predicted scattering was obtained for each sample over certain frequency ranges, taking 10% frame damping in the calculations. For other frequency ranges the agreement was less than good. No systematic trend in the agreement could be discerned with regard to porous grain size or sound frequency.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1993
- Accession Number
- ADA274837
Entities
People
- Theodore W. Huskey
Organizations
- Naval Postgraduate School