Accession Number:

ADA036295

Title:

Spatial Sampling Criteria for Nearfield Measurements Made on Cylindrical Surfaces,

Descriptive Note:

Corporate Author:

ADMIRALTY UNDERWATER WEAPONS ESTABLISHMENT PORTLAND (ENGLAND)

Personal Author(s):

Report Date:

1976-09-01

Pagination or Media Count:

31.0

Abstract:

This report establishes the spatial sampling criteria for nearfield measurements, made on a cylindrical surface enclosing the sources, that enable the farfield of those sources to be calculated faithfully from the nearfield data. Examples are given of the criterial applied to both omnidirectional and directional sources their nearfield and calculated farfield. The sampling criteria for nearfield measurements made on a cylindrical surface have been established in this report for both axial and circumferential samples. In general the common practice of using half wave length samples circumferentially is shown to be adequate for omnidirectional field narrow spatial bandwidths but not adequate for the broad circumferential spatial bandwidth fields encountered with directional sources.

Subject Categories:

  • Acoustics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE