Accession Number : AD0785579

Title :   Development of an Improved Design Tool for Predicting and Simulating Helicopter Rotor Noise

Descriptive Note : Final rept.

Corporate Author : ROCHESTER APPLIED SCIENCE ASSOCIATES NY

Personal Author(s) : Johnson, H K

PDF Url : AD0785579

Report Date : Jun 1974

Pagination or Media Count : 48

Abstract : The rotor noise prediction program has been improved by the following items: (1) inclusion of the helicopter rotor noise ground reflection phenomenon, (2) inclusion of the variability of oscillatory forces as related to the vortex shedding phenomenon, (3) expansion of the data base for the broadband noise data bank, and (4) description of a calculation procedure which demonstrates how the program input deck can be modified to account for impulse signals of single-rotor blade vortex interactions. The rotor noise prediction program has been developed so that the acoustic characteristics of new, untested rotor designs could be evaluated as well as the effects of basic design changes on the acoustic signature of existing rotors.

Descriptors :   *GEAR NOISE, *HELICOPTER ROTORS, ACOUSTIC SIGNATURES, AIRCRAFT NOISE, HOVERING, LEVEL FLIGHT, POWER SPECTRA, ROTOR BLADES(ROTARY WINGS), SIMULATION, VORTEX SHEDDING

Subject Categories : Helicopters
      Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE