Measurements of Upstream History Effects in Compressible Turbulent Boundary Layers

Measurements of Upstream History Effects in Compressible Turbulent Boundary Layers
Author: David F. Gates
Publisher:
Total Pages: 124
Release: 1973
Genre: Supersonic nozzles
ISBN:

The report describes an experimental study of compressible turbulent boundary layers for which the upstream history was systematically varied. A series of experiments was conducted using both a supersonic half nozzle and a conventional flat plate for which the nozzle throat and flat plate leading edge can be temperature controlled. The supersonic nozzle provided a favorable upstream pressure gradient together with a controlled thermal history at the throat. The flat plate provided upstream temperature control with no pressure history. Velocity and temperature profile and heat-transfer measurements were made in a downstream region of zero-pressure-gradient and constant wall temperature. (Modified author abstract).

Experimental Study of Nozzle Wall Boundary Layers at Mach Numbers 20 to 47

Experimental Study of Nozzle Wall Boundary Layers at Mach Numbers 20 to 47
Author: Joseph H. Kemp
Publisher:
Total Pages: 116
Release: 1972
Genre: Aerodynamics, Hypersonic
ISBN:

The nozzle wall boundary layer of an M-50 helium tunnel was investigated with pitot pressure, total temperature, skin friction, and wall heat transfer measurements at five stations and hot wire measurements at two stations. The results indicated that the boundary layer was turbulent with a thick viscous sublayer. Pressure gradients were observed across the boundary layer; the effect of these gradients on the equations of motion are discussed. The direct skin friction measurements were higher than expected from empirical predictions; the Reynolds analogy factors however were lower than expected. Hot wire measurements indicated mass flow fluctuations as large as 80 percent of the local mean mass flow at the edge of the viscous sublayer with a maximum value relative to the edge mass flow of about 15 percent at gamma about equal to 0.8.