Accession Number : ADA290312

Title :   Revisions and Notes on a Model for Bubble Attenuation in Near-Surface Propagation.

Descriptive Note : Technical rept.,

Corporate Author : WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB

Personal Author(s) : Dahl, Peter H.

PDF Url : ADA290312

Report Date : NOV 1994

Pagination or Media Count : 26

Abstract : A revised model for predicting surface bubble loss (SBL) as a function of wind speed, surface grazing angle, and frequency is discussed. SBL is defined as the residual loss (i.e., the loss in excess of that due to spreading and chemical absorption) in acoustic energy propagating near the sea surface that is attributable to attenuation by near-surface bubbles. This loss is a key input parameter for predicting bubble attenuation in simulations of weapon-system performance in near-surface environments. The original SBL model was introduced by the Applied Physics Laboratory, University of Washington, in 1993. The revision consists of a new wind-speed threshold for breaking waves and the subsequent onset of bubble production, and an alternative formulation capable of handling more general ray geometries such as a ray vertexing near the surface. Model/data comparisons and examples of the model applied to a linear sound-speed profile are presented. (MM)

Descriptors :   *BUBBLES, OCEAN WAVES, OCEAN SURFACE, ATTENUATION, WIND VELOCITY, REFRACTION, AIR WATER INTERACTIONS, ACOUSTIC VELOCITY, GRAZING.

Subject Categories : Fluid Mechanics
      Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE