CONVOL: A Computer Program for Parametric Source Nearfield and Farfield Beam Patterns.
Abstract
Because it is often impractical to make measurements in the farfield of parametric acoustic sources, it is desirable to be able to predict the farfield from the nearfield measurements. A nearfield beam pattern theory, previously outlined (J. Acoust. Soc. Am. 63, 1622-1624 (L) (1978)), has been programmed for digital computation. The results compare favorably with experimental data from an absorption-limited source involving substantial difference-frequency generation in the primary farfield and from a saturation-limited source with most of the generation taking place in the primary nearfield. In the first example, the nearfield beam pattern is broader and the apparent source level is lower than in the farfield. In the second example, the nearfield pattern is narrower and the apparent source level higher than in the farfield. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 17, 1979
- Accession Number
- ADA080038
Entities
People
- Mark B. Moffett
- Robert H. Mellen
Organizations
- Naval Underwater Systems Center