Accession Number : AD0715750

Title :   A Sequence of Transient Acoustical Sources in an Idealized Jet,

Corporate Author : BOEING SCIENTIFIC RESEARCH LABS SEATTLE WASH

Personal Author(s) : Graham,E. W.

Report Date : SEP 1970

Pagination or Media Count : 22

Abstract : A sequence of transient acoustical point sources is considered as a noise generator in an idealized two-dimensional jet. Each transient source starts at the same position relative to the stationary nozzle (or external air), drifts downstream with the local fluid for a given time, then disappears. As each source disappears a new one appears at the initial position. The far field mean-square pressures are obtained from a previous analysis of the effects of permanent sources, and are converted from a coordinate system fixed in the source to 'retarded' coordinates fixed in the external air (or stationary nozzle). In the examples, two jet velocity profiles are studied, first a jet composed of linear velocity profile shear layers meeting at the center, and second a uniform jet bounded by velocity discontinuities. (Author)

Descriptors :   (*AERODYNAMIC NOISE, *JETS), SOURCES, TWO DIMENSIONAL FLOW, MATHEMATICAL ANALYSIS

Subject Categories : Aerodynamics
      Acoustics
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE