Accession Number : AD0782038

Title :   Theoretical Studies on Fan Noise Generation by a Transonic Compressor Blade Row.

Descriptive Note : Final rept. 1 Jul 69-3 Dec 73,


Personal Author(s) : Lordi,J. A. ; Homicz,G. F.

Report Date : JUN 1974

Pagination or Media Count : 51

Abstract : A program of theoretical research on discrete-tone noise generation in transonic flows through fan and compressor blade rows is summarized. The sound field produced by an isolated rotor in an infinitely long annular duct with a uniform throughflow was considered. Linearized, three-dimensional analyses for the flow through lifting and nonlifting blade rows were used to relate the sound field to the blade thickness and loading distributions. Expressions were derived for the acoustic intensity within the duct and the sound pressure field outside the duct. Computational methods were then developed to evaluate the required reflection coefficients and directivity factors. (Modified author abstract)

Descriptors :   *Compressor noise, *Transonic characteristics, *Acoustic fields, *Compressor blades, Theory, Mathematical models, Lifting surfaces, Three dimensional flow, Thickness, Aerodynamic loading, Ducts, Geometry

Subject Categories : Hydraulic and Pneumatic Equipment
      Jet and Gas Turbine Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE