
Accession Number : AD0429172
Title : SOME ASPECTS OF TURBULENT SCATTERING OF ELECTROMAGNETIC WAVES BY HYPERSONIC WAKE FLOWS
Corporate Author : GENERAL ELECTRIC CO PHILADELPHIA PA MISSILE AND SPACE DIV
Personal Author(s) : Yen, K T
PDF Url : AD0429172
Report Date : Dec 1963
Pagination or Media Count : 43
Abstract : This analytical study of the turbulent scattering of electromagnetic waves is directed to certain features of the phenomenon considered as peculiar to hypersonic wakes. Effects of flow intermittency, nonisotropy of the turbulence structure, and finite width of the wake on the scattering cross section in its frequency and aspectangle dependence are of primary concern. Phenomena of turbulence relevant to the scattering problem are briefly discussed. In particular, it is shown that electrondensity fluctuations of a turbulent nature, in addition to those caused by ''turbulence'', will be produced by the intermittency behavior of turbulent wake flows. This fluctuation is found to depend on the mean electrondensity distribution, and Townsend's intermittency function. Phenomenological consideration of the physical process by which the turbulent electrondensity fluctuations are likely to be produced in hypersonic wakes yields an expression for the intensity of the fluctuations in terms of the gradient of the mean electrondensity distribution, the intensity of the turbulent velocity fluctuation, and a turbulence scale of the turbulent velocity field. Application of the above considerations to turbulent scattering by underdense wakes has been made.
Descriptors : *REENTRY VEHICLES, *WAKE, CORRELATION TECHNIQUES, DIELECTRIC PROPERTIES, ELECTROMAGNETIC RADIATION, ELECTRON DENSITY, HYPERSONIC FLOW, IONIZATION, MATHEMATICAL ANALYSIS, RADAR CROSS SECTIONS, REFRACTION, SCATTERING, THERMODYNAMICS, TURBULENCE
Subject Categories : Unmanned Spacecraft
Distribution Statement : APPROVED FOR PUBLIC RELEASE