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High-Subsonic Performance Characteristics and Boundary-Layer Investigations of a 12 10-Inch-Inlet-Diameter Conical Diffuser

Description: Performance and boundary-layer data were taken in a 12 degree 10-inch inlet-diameter conical diffuser of 2:1 exit- to inlet-area ratio. These data were taken for two inlet-boundary-layer conditions. The first condition was that of a thinner inlet boundary later (boundary-layer displacement thickness, delta* approximately equal to 0.034) produced by an inlet section approximately 1 inlet diameter in length between the entrance bell and the diffuser. The second condition was a thicker inlet boundary layer (delta* approximately equal to 0.120) produced by an additional inlet section length of approximately 6 diameters. Longitudinal static-pressure distributions were measured fro wall static orifices. Transverse total- and static-pressure surveys were made at the inlet and exit stations. Boundary-layer velocity distributions were measured at seven stations between the inlet and exit. These data were obtained for a Reynolds number (based on inlet diameter) range of 1 x 10(exp 6) to 3.9 x 10(exp 6). The corresponding Mach number range was from M = 0.2 to choking. At the maximum-power-available condition supersonic flow was obtained as far as 4.5 inches downstream from the diffuser inlet with a maximum Mach number of M approximately equal to 1.5. The total-pressure loss through the diffuser in percentage of inlet dynamic pressure was approximately 2.5 percent for the thinner inlet boundary later and 5.5 percent for the thicker inlet boundary later over the lower subsonic range. These valued increased with increasing flow rate- the values for the thicker inlet boundary later more than those for the thinner inlet boundary layer. The diffuser effectiveness, expressed as the ratio of the actual static-pressure rise to the ideal static-pressure rise, was about 85 percent for the thinner inlet boundary layer and about 67 percent for the thicker inlet boundary later in the lower subsonic range. These values decrease with increasing flow rate. Separated flow ...
Date: May 11, 1950
Creator: Little, B. H., Jr. & Wilbur, Stafford W.
Partner: UNT Libraries Government Documents Department

Turbulence-intensity measurements in a jet of air issuing from a long tube

Description: Report presenting data for turbulent-velocity-fluctuation components and mean-velocity distributions measured in the subsonic jet issuing from a pipe in which a fully developed turbulent flow was established. Axial and radial components of the fluctuation velocities were examined as functions of Reynolds number and position in the jet.
Date: May 1951
Creator: Little, Barney H., Jr. & Wilbur, Stafford W.
Partner: UNT Libraries Government Documents Department

Performance and boundary-layer data from 12 degree and 23 degree conical diffusers of area ratio 2.0 at Mach numbers up to choking and Reynolds numbers up to 7.5 x 10(6)

Description: For each of two inlet-boundary-layer thicknesses, performance and boundary-layer characteristics have been determined for a 12 degree, 10-inch-inlet-diameter diffuser, a 12 degree, 21-inch-inlet-diameter diffuser, and a 23 degree, 21-inch-inlet-diameter diffuser. The investigation covered an inlet Mach number range from about 0.10 to coking. The corresponding inlet Reynolds number, based on inlet diameter, varied from about 0.5 x 10(6) to 7.5 x 10(6).
Date: November 15, 1954
Creator: Little, B. H., Jr. & Wilbur, Stafford W.
Partner: UNT Libraries Government Documents Department

Preliminary investigation of the flow in an annular-diffuser-tailpipe combination with an abrupt area expansion and suction, injection, and vortex-generator flow controls

Description: Report presenting an investigation of the performance of an annular-diffuser-tailpipe combination with an abrupt area expansion with and without flow controls in the form of suction, injection, and vortex generators. Results regarding the inlet measurements, longitudinal static-pressure distribution, radial distributions, and mean performance coefficients are provided.
Date: February 10, 1954
Creator: Henry, John R. & Wilbur, Stafford W.
Partner: UNT Libraries Government Documents Department

Summary of subsonic-diffuser data

Description: Report presenting a review of subsonic-diffuser data, which was reduced to certain appropriate performance coefficients and presented as functions of the significant geometric and flow variables. The report is divided into the following sections: performance at low speeds, the effect of increasing the inlet speed up to choking Mach numbers, illustrations of the effectiveness of boundary-layer controls, and illustrations of the effects of distorted inlet velocity distributions at subsonic speeds.
Date: October 12, 1956
Creator: Henry, John R.; Wood, Charles C. & Wilbur, Stafford W.
Partner: UNT Libraries Government Documents Department