Abstract:

A computerized method for estimating exhaust noise spectra from a database is provided. The variables considered in the interpolation/extrapolation routine make the procedure particularly applicable to estimating noise from coaxial jets. The database need not be restricted to data for an isolated coaxial jet but could include installation and flight effects as well as other components of coaxial jet noise (e.g. combustion noise, shock noise, etc.). The computation involves a least-squares fitting procedure where four independent variables are used. Appropriate weighting of the data is included. The program uses quadratic interpolation within the least-squares fitting procedure. To provide a basic prediction procedure for the estimation of far-field, jet mixing noise from stationary jet engines with conical nozzles, a comprehensive database is provided. The computer program may be run using either the provided database or another database. The database can be altered as new data become available. A computer program to generate a database from the user's own data is included.