A Nearfield Asymptotic Analysis for Underwater Acoustics
Abstract
The method of stationary phase is used to show that the homogeneous half-space field projects properly onto the normal modes near a point source. The half-space field is useful for initializing the parabolic equation (PE) in both the time domain and the frequency domain and in both two and three spatial dimensions. It is shown to be more accurate for wide-angle propagation than the Gaussian PE starter. A Gaussian time-domain PE starter is derived and compared with the half-space starter. Application of the approach to scattering problems is discussed. The half-space field is the inner solution of a matched asymptotics solution. A simple approach for speeding up PE calculations and an efficient ray-tracing model for source localization are motivated by the matching. Keywords: Matched asymptotics; Nearfield; Ray tracing. Reprints.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1989
- Accession Number
- ADA206770
Entities
People
- Michael D. Collins
Organizations
- United States Naval Research Laboratory