Publication Date:
2019-07-13
Description:
This paper presents a new method for computing acoustic signals from helicopter rotors in forward flight. The aerodynamic and acoustic solutions in the near field are computed with a finite-difference solver for the Euler equations. A nonrotating cylindrical Kirchhoff surface is then placed around the entire rotor system. This Kirchhoff surface moves subsonically with the rotor in forward flight. The finite-difference solution is interpolated onto this cylindrical surface at each time step and a Kirchhoff integration is used to carry the acoustic signal to the far field. Computed values for high-speed impulsive noise show excellent agreement with model-rotor and flight-test experimental data. Results from the new method offer high accuracy with reasonable computer resource requirements.
Keywords:
ACOUSTICS
Type:
NASA-CR-196132
,
NAS 1.26:196132
,
RIACS-TR-94-06
,
Army Science Conference; Jun 20, 1994 - Jun 24, 1994; Orlando, FL; United States
Format:
application/pdf
Permalink