| Popis: |
Acoustic measurements of insertion loss and echo reduction at normal incidence were made for several materials for evaluation of their use as underwater sound transducer windows in the frequency range of 50–500 kHz. Materials tested included the commercial polyurethane products such as PR‐1527, CPC‐19, Scotchcast 221, Scotchcast 8, and some of these materials with talc added during curing to vary the density. Values of sound velocity are derived from the echo reduction data and allow determination of ρc values for each material. A computer model of the echo variation with frequency accurately matches the measured echo reduction plots. |
