Accession Number : ADA255445


Title :   Acoustic Propagation Loss Predictions for a Site on the Bermuda Rise at Low and Very Low Frequencies


Descriptive Note : Technical memo.


Corporate Author : DEFENCE RESEARCH ESTABLISHMENT ATLANTIC DARTMOUTH (NOVA SCOTIA)


Personal Author(s) : Cotaras, Frederick D ; Theriault, James A


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a255445.pdf


Report Date : Jun 1992


Pagination or Media Count : 46


Abstract : Low (10 - 100 Hz) and very low (1 - 10 Hz) frequency acoustic propagation loss is predicted for a site on the Bermuda Rise near 30 deg N 69 deg W. An extensive survey of the open literature is reported, and a geo- acoustic model of the acoustic environment at the site is developed. The results of a brief numerical investigation of the effect of shear waves and detailed sub-bottom layering on the acoustic propagation-loss predictions are discussed. The acoustic propagation-loss model used is SAFARI, which accounts for shear waves in the sediment but assumes a range-invariant environment. The propagation-loss predictions for 5, 10, 20, and 50 Hz are then presented. Also presented are predictions of the reflection loss in the form of grey-scale plots as a function of frequency and grazing angle. No comparison with experimental data is attempted.


Descriptors :   *ACOUSTIC WAVES , *WAVE PROPAGATION , *UNDERWATER ACOUSTICS , *TRANSMISSION LOSS , FREQUENCY , FUNCTIONS , ANGLES , PROPAGATION , COMPARISON , SURVEYS , ACOUSTICS , BERMUDA , LOW FREQUENCIES , GRAZING , UNDERWATER , SEDIMENTS , BOTTOM , SCALE , REFLECTION , SITES , EXPERIMENTAL DATA , ENVIRONMENTS , PREDICTIONS , MODELS


Subject Categories : Physical and Dynamic Oceanography
      Acoustics


Distribution Statement : APPROVED FOR PUBLIC RELEASE