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.

Report Date : DEC 1963

Pagination or Media Count : 35

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, non-isotropy of the turbulence structure, and finite width of the wake on the scattering cross section in its frequency and aspect-angle dependence are of primary concern. Phenomena of turbulence relevant to the scattering problem are briefly discussed. In particular, it is shown that electron-density 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 electron-density distribution, and Townsend's intermittency function. Phenomenological consideration of the physical process by which the turbulent electron-density 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 electron-density 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. (Author)

Descriptors :   (*REENTRY VEHICLES, WAKE), (*WAKE, ELECTROMAGNETIC RADIATION), SCATTERING, HYPERSONIC FLOW, THERMODYNAMICS, TURBULENCE, IONIZATION, ELECTRON DENSITY, DIELECTRIC PROPERTIES, REFRACTION, RADAR CROSS SECTIONS, MATHEMATICAL ANALYSIS, CORRELATION TECHNIQUES

Distribution Statement : APPROVED FOR PUBLIC RELEASE