THIS study analyzes the acoustic planform method as an alternative to using the equation of Ffowes Williams and Hawkings for predicting transonic and supersonic rotor noise. The studied method avoids the singularity encountered when the noise source travels towards the observer at sonic velocity. It introduces the necessity for computing acoustic planforms and integrating over them. Results are presented for a rotating, rectangular, monopole surface with supersonic tip velocity. These computations show a decrease in peak acoustic pressure as the tip speed increases beyond a critical supersonic Mach number. The results provide an explanation for some experimental data and some guidelines for proceeding on to the prediction of actual rotor noise.
ASJC Scopus subject areas
- Aerospace Engineering