An Acoustic Source Modeling Technique to Predict the Near Sound Field of Axisymmetric Turbulent Jets
Abstract
The objective of the investigation reported herein was to develop a technique for determining the free, unreflected sound field produced by a jet engine based on sound measurements obtained in an engine test cell. As a first step in this direction, a procedure has been developed for modeling the sound sources in an axisymmetric jet which allows prediction of the near sound field generated by the jet. The procedure involves modeling the sources for each one- third octave frequency band by a combination of uncorrelated elementary sources derived from the multipole expansion. The strengths of the various source components at a particular frequency are determined by a constrained least squares fit to the far field directivity pattern. When the effects of source motion and axial source distribution with frequency are taken into account, the computed sound field agrees reasonably well with data obtained in the near field. The results of the study indicate however, that it will be very difficult to predict the far field sound from acoustic measurements in an engine test cell.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1979
- Accession Number
- ADA069627
Entities
People
- C. V. Sundaram
- J. R. Maus
- L. B. Bates
- M. G. Scott
Organizations
- University of Tennessee Space Institute