Accession Number : AD0691329

Title :   TWO-WAVELENGTH LASER INTERFEROMETRY OF HYPERSONIC IONIZED FLOWS,

Corporate Author : BALLISTIC RESEARCH LABS ABERDEEN PROVING GROUND MD

Personal Author(s) : Oertel,F. H. ; Spurk,J. H.

Report Date : MAY 1969

Pagination or Media Count : 27

Abstract : An experiment to measure the electron concentration in a hypersonic flow is described. The experimental method, two-wavelength interferometry, is based on the fact that the refractivity of the heavy polarizable particles (atoms and ions) is practically independent of wavelength, while the refractivity for free electrons is proportional to the square of the wavelength and negative. A Mach-Zehnder optical interferometer backlighted by a giant pulse ruby laser is used. The flow is a hypersonic high energy flow of argon over a two-inch diameter spherical body. The free stream velocity is 5180 m/s. At a free stream density of 0.024 kg/cu. meters and a free stream pressure of 3640 N/sq meters, the electron number density at the stagnation point is 4 x 10 to the 17th power/cc. (Author)

Descriptors :   (*HYPERSONIC FLOW, ELECTRON DENSITY), (*FLOW VISUALIZATION, *LASERS), REFRACTIVE INDEX, INTERFEROMETERS, ARGON, GAS IONIZATION

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE