Resonator Measurements of Acoustic Characteristics of Some Marine Crustaceans: A Laboratory Experiment.

摘要

Sound absorption due to single marine crustaceans was measured employing reverberation chamber technique in the laboratory. Viscous and thermal losses were measured separately by varying the position of the absorbing body in the sound field. Only primary axial modes were employed and discreet frequencies were utilized in the range 1150Hz to 3200 Hz by varying the height of the water column. Absorption cross sections (sigma) were determined for both the thermal and viscous effects for two species of crustaceans (Sergestes similis and Pasiphea pacifica) which are prominent members of the scattering layer present in Monterey Bay, California. Values of sigma due to viscous effects and due to thermal losses are given. These values of sigma resulted from measured viscous absorption coefficients of 3.19 to 8.65 dB/km and thermal absorption coefficients of 5.93 to 11.88 dB/km and resulted from a laboratory concentration of one specimen in 0.002 to 0.007 cum of water.