Accession Number : AD0647954

Title :   WIND TUNNEL MEASUREMENTS OF TURBULENT WAKE COOLING WITH BASE INJECTION.

Descriptive Note : Final scientific rept., 1 Feb 65-31 Jul 66,

Corporate Author : MITHRAS INC CAMBRIDGE MASS

Personal Author(s) : Hill,Jacques A. F. ; Luce,Richard W.

Report Date : AUG 1966

Pagination or Media Count : 60

Abstract : Wind-tunnel measurements of the turbulent wake flow behind a slender body at M=8 were made with and without fluid injection from the base. Helium and nitrogen were injected at temperatures about one-half of the tunnel stagnation temperature. The maximum injection rates were 0.8 percent and 4 percent respectively of the freestream flow swept out by the model base area. Two injector configurations were used, to obtain either subsonic or supersonic injection velocities. The wake measurements consisted of pilot pressure, cone surface pressure, total temperature and helium mass fraction. They were reduced to velocity and static temperature profiles along and across the wake. The results show a strong dependence of static temperature on injection velocity. With nitrogen injection at a given rate, substantial cooling can be accomplished with supersonic injection while subsonic injection in general actually raises the wake temperature. The nitrogen flow rates required to achieve a given reduction in static temperature are 4-5 times larger than for helium. A theory for fully turbulent base flows is described which predicts quite well the variation with injection rate of the total temperature in the wake neck. (Author)

Descriptors :   (*SLENDER BODIES, WAKE), (*WAKE, *TURBULENCE), (*INJECTION, *COOLING), BASE FLOW, WIND TUNNELS, MEASUREMENT, HELIUM, NITROGEN, TEMPERATURE

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE