Sonic Booms in Shallow Water: The Influence of the Seabed

PDF

Authors
  1. Chapman, D.M.F.
  2. Godin, O.A.
Corporate Authors
Defence R&D Canada - Atlantic, Dartmouth NS (CAN);Colorado Univ, Boulder CO (US)
Abstract
Sonic booms generated by aircraft contain a broad band of infrasonic frequencies. For example, a measured Mach 2 Concorde sonic boom spectrum shows most energy below 6 Hz, peaking at 2.5 Hz. However, this aircraft speed is subsonic relative to the speed of sound in water, and simple theory indicates that the penetration of the sonic boom from air into water is evanescent in nature. Typically, the transmitted energy is confined to depths less than several tens of metres. If the sea is shallow, then reflection at the seabed may enhance underwater sound levels, a significant effect if the seabed supports seismic interface waves with speeds coincident with the aircraft speed in the relevant frequency range. A model of sonic boom propagation is presented for the case of a shallow ocean with a layered elastic seabed, and results are compared with available experimental data.

Il y a un résumé en français ici.

Keywords
Concorde;Evanescent wave;Elastic seabed;Seismic interface wave;Shear waves;Resonance
Report Number
DRDC-ATLANTIC-SL-2004-038 — Scientific Literature
Date of publication
01 Jul 2004
Number of Pages
6
DSTKIM No
CA024391
CANDIS No
521961
Format(s):
CD ROM

Permanent link

Document 1 of 1

Date modified: