Accession Number:

AD0436671

Title:

TURBULENCE IN THE NOISE-PRODUCING REGION OF A CIRCULAR JET,

Descriptive Note:

Corporate Author:

ADVISORY GROUP FOR AERONAUTICAL RESEARCH AND DEVELOPMENT PARIS (FRANCE)

Report Date:

1963-04-01

Pagination or Media Count:

81.0

Abstract:

Measurements in a 2 in. cold air jet at M0.3 have shown that about a quarter of the Reynolds shear stress is produced by large eddies with a rather narrow range of wavelengths. It is deduced from the nine orthogonal spatial correlations that these eddies take the form of mixing jets, inclined to the radial direction in any cross-sectional plane. The same eddies appear to dominate the near-field pressure fluctuations. The large-eddy intensity and shear stress contribution decrease at distances from the exit of more than two or three diameters. The artificial modification of these well-defined eddies seems to offer the best hope of increasing the jet mixing rate and permitting noise reduction by the use of acceptably short ejector shrouds. Measurements leading to a turbulent energy balance are also described. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE