Helicopter Rotor Rotational Noise Prediction and Correlation. Volume 2. Documentation of Noise Prediction Computer Program
Final rept. 27 Jun 1966-31 May 1968
UNITED TECHNOLOGIES CORP STRATFORD CT SIKORSKY AIRCRAFT DIV
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A computer program for rotational noise prediction is documented. The program was developed as a part of a study to develop more accurate methods for predicting rotational noise levels under conditions of nonuniform inflow over the rotor disc. The computer program will calculate the root-mean-square sound pressure level for up to the 10th harmonic of rotor noise at any field point in the near or far field outside of the rotor disc. Noise levels can be calculated either from a rectangular chordwise distribution of pressure or from the measured chordwise distribution. Although the report concentrated on a helicopter rotor, the analytical results are applicable to propellers in general.