NUMERICAL EVALUATION OF THE SERIES EXPANSION METHOD FOR THE PREDICTION OF THE FAR FIELD INTENSITY FROM NEAR FIELD CROSS-POWER MEASUREMENTS

Abstract

An evaluation of a series expansion method for predicting the far- field from near-field cross-power measurements of partially coherent sound fields is given. This series method is based on an expansion in spherical wave functions truncated to include only the number of terms equal to the number of near field measuring points (which need not be restricted to the usual separable surfaces). The evaluation is through a set of numerical examples where the predicted far field is compared with the exact far field from a theoretical source of partially coherent sound. It is shown that good results can be obtained for incoherent, partially coherent, and coherent sound fields.

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Document Details

Document Type
Technical Report
Publication Date
Aug 01, 1968
Accession Number
AD0672774

Entities

People

  • Dorothy A. Moran
  • John L. Butler

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Acoustics
  • Agreements
  • Classification
  • Coefficients
  • Contracts
  • Coordinate Systems
  • Far Field
  • Frequency
  • Intensity
  • Measurement
  • Military Research
  • Navy
  • Near Field
  • Power Measurement
  • Security
  • Wave Functions
  • Waves

Fields of Study

  • Physics

Readers

  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.
  • Calculus or Mathematical Analysis
  • Structural Dynamics.