An analysis has previously established that local shock surfaces attached to helicopter rotor blades moving at high subsonic speeds are potent noise generators; in pursuit of this insight, a novel formulation is presented for the prediction of the noise of a deformable shock, whose area changes as a function of the azimuthal position of the blade. The derivation of this formulation has its basis in a mapping of the moving shock to a time-independent region. In virtue of this mapping, the implementation of the main result on a computer becomes straightforward enough for incorporation into the available rotor-noise prediction code. A problem illustrating the importance of rotor shocks in the generation of high-intensity noise is presented.
Can shock waves on helicopter rotors generate noise? - A study of the quadrupole source
AHS, Annual Forum ; 1990 ; Washington, DC, United States
1990-01-01
Conference paper
No indication
English
Supersonic quadrupole noise theory for high-speed helicopter rotors
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