Noise predictions of helicopter rotors in hover and forward flight


ÖZYÖRÜK Y. , Ünal A., Yüksel A. O.

23rd AIAA/CEAS Aeroacoustics Conference, 2017, Colorado, Amerika Birleşik Devletleri, 5 - 09 Haziran 2017 identifier

  • Cilt numarası:
  • Doi Numarası: 10.2514/6.2017-3529
  • Basıldığı Şehir: Colorado
  • Basıldığı Ülke: Amerika Birleşik Devletleri

Özet

© 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.A helicopter rotor noise prediction code has been developed integrating the Ffowcs Williams-Hawkings equation. Time integration is carried out using optionally a retarded time or advance time algorithm, while surface integrals are carried out using high order quadratures both on structured and unstructured meshes. In the latter type of meshes the required surface quadrature points and normals are computed using a special interpolation algorithm commonly used in computer graphics. All integrations are carried out in parallel decomposing either the surface meshes or observer times using the message passing libraries. Following several verification studies for thickness and loading noise predictive capability, including forward flight, both high-speed impulsive noise computations of an experimentally tested hovering rotor from literature, and thickness and loading noise calculations of an experimental whirl tower rotor are also performed and their results are compared with measurements. While the accuracy of the acoustic predictions for the high-speed impulsive noise appears limited due to excluding the sources from supersonic region, good acoustic comparisons are shown possible for the whirl tower rotor, especially when the ground effects are included in the predictions, despite that the aerodynamic calculations omit these effects.