Prediction of Flyover Jet Noise Spectra from static Tests

Kurzfassung

A scaling law is derived for predicting the flyover noise spectra of a single-stream shock-free circular jet from static experiments. The theory is based on the Lighthill approach to jet noise. Density terms are retained to include the effect of jet heating. The influence of flight on the turbulent flow field is considered by an experimentally supported similarity assumption. The resulting scaling laws for the difference between one-third-octave spectra and the overall sound pressure level compare vey well with flyover experiments with a jet engine and wind tunnel experiments with a heated model jet.