Resonator measurements of acoustic characteristics of some marine crustaceans : a laboratory experiment.
Authors
Mallgrave, Fred Joseph
Subjects
sound absorption
marine crustaceans
absorption cross section
marine crustaceans
absorption cross section
Advisors
Medwin, H.
Haderlie, E.
Novarini, J.
Date of Issue
1977-03
Date
Publisher
Monterey, CA; Naval Postgraduate School
Language
en_US
Abstract
Sound absorption due to single marine crustaceans was measured employing reverberation chamber techniques 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 1150 Hz to 3200 Hz by varying the height of the water column. Absorption cross sections ( a ) 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 a due to viscous effects ranged from 0.152 -5 -5 2 x 10 to 1.042 x 10 m whereas a due to thermal losses varied from 0.311 x 10" 5 to 1.670 x 10~ 5 m 2 . These values of a 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. These values resulted from a laboratory concentration of one specimen in 0.002 to 0.007 ra 3 of water.
Type
Thesis
Description
Series/Report No
Department
Oceanography (OC)
Physics (PH)
Physics and Chemistry