A semiempirical method for calculating the far acoustic field of the lift rotor of a helicopter operating in the regime of oblique flow over it is described. The basic parametric relations for the acoustic radiation power of rotor noise components have been obtained on the basis of the Lamb idea that vortex-free motion arises under the action of a periodic force on an infinitely small volume of the medium. All sources of lift rotor noise are subdivided into two groups pertaining, respectively, to the inductive and profile parts of the total power supplied to the rotor. A comparison has been made between the results of calculation of the harmonic components of lift rotor noise made on the basis of the power method and the experimental data for the Mi-28 helicopter.
Power method for calculating the far acoustic field of the helicopter lift rotor
Leistungsmethode zur Berechnung des akustischen Fernfeldes des Hubschrauberhauptrotors
Journal of Engineering Physics and Thermophysics ; 84 , 3 ; 599-610
2011
12 Seiten, 4 Bilder, 15 Quellen
Article (Journal)
English