Analysis of the performance of the drive system and diffuser of the Langley unitary plan wind tunnel

A broad program was initiated at the Langley Research Center in 1973 to reduce the energy consumption of the laboratory. As a part of this program, the performance characteristics of the Unitary Plan Wind Tunnel were reexamined to determine if potential methods for incresing the operating efficiencies of the tunnel could be formulated. The results of that study are summarized. The performance characteristics of the drive system components and the variable-geometry diffuser system of the tunnel are documented and analyzed. Several potential methods for reducing the energy requirements of the facility are discussed

Wind-tunnel measurements and comparison with flight of the boundary layer and heat transfer on a hollow cylinder at Mach 3

The wind tunnel tests were conducted both with and without boundary layer trips at Mach 3 and nominal free stream Reynolds numbers per meter ranging from 3.3 x 10 the 6th power. Instrumentation consisted of pressure orifices, thermocouples, a boundary layer pitot pressure rake, and a floating element skin friction balance. Measurements from both wind tunnel and flight were compared with existing engineering prediction methods

A simplified method for calculating temperature time histories in cryogenic wind tunnels

Average temperature time history calculations of the test media and tunnel walls for cryogenic wind tunnels have been developed. Results are in general agreement with limited preliminary experimental measurements obtained in a 13.5-inch pilot cryogenic wind tunnel

Sweep effect on the drag of rows of perpendicular circular cylinders in a laminar boundary layer at supersonic free-stream velocities

Drag measurements were obtained for circular cylinders attached perpendicularly to a flat-plate surface. Measurements were obtained for a single cylinder and for rows of cylinders. The cylinders were alined at various sweep angles relative to the free-stream velocity vector and at spacings appropriate for roughness elements used as boundary layer trips. The drag measurements were obtained for Mach numbers of 3.95 and 4.60, ratios of cylinder height to an undisturbed laminar boundary layer displacement thickness of approximately 1.0 to 3.0, a cylinder height-to-diameter ratio of approximately 2, and sweep angles up to 60. A complete presentation of the experimental results is given. A discussion of the more significant findings, including the most appropriate parameters for correlating the experimental results, is presented

Experimental pressure distributions for a family of blunt bodies at Mach numbers from 2.49 to 4.63 and angles of attack from 0 deg to 15 deg

Pressure distributions for blunt body wind tunnel models at supersonic speeds and angles of attack from 0 to 15 degree

Supersonic axial-force characteristics of a rectangular-box cavity with various length-to-depth ratios in a flat plate

A wind-tunnel investigation has been conducted at Mach numbers of 1.50, 2.16, and 2.86 to obtain axial-force data on a metric rectangular-box cavity with various length-to-depth ratios. The model was tested at angles of attack from -4 deg to -2 deg. The results are summarized to show variations in cavity axial-force coefficient for deep- and shallow-cavity configurations with detached and attached cavity flow fields, respectively. The results of the investigation indicate that for a wide range of cavity lengths and depths, good correlations of the cavity axial-force coefficients (based on cavity rear-face area) are obtained when these coefficients are plotted as a function of cavity length-to-depth ratio. Abrupt increases in the cavity axial-force coefficients at an angle of attack of 0 deg. reflect the transition from an open (detached) cavity flow field to a closed (attached) cavity flow field. Cavity length-to-depth ratio is the dominant factor affecting the switching of the cavity flow field from one type to the other. The type of cavity flow field (open or closed) is not dependent on the test angles of attack except near the critical value of length-to-depth ratio

Effect of Reynolds number on stability characteristics of a cruciform wing-body

An experimental investigation was conducted to determine the effect of Reynolds number on the stability characteristics of a body with cruciform wings at large angles of attack. Pressure distributions and force and moment data (axial force not measured) are presented for Mach 1.60 and 2.70, Reynolds numbers based on body diameter from approximately 130,000 to 2,800,000, and angles of attack from 0 deg to 50 deg. In general, the data show only small effects of Reynolds number throughout the range of test condition. Also discussed are force balance and pressure data that suggest a direct relationship between wind choking and the onset of a nonlinear stability variaton with angle of attack

Aerodynamic characteristics of a Sparrow 3 missile model in the flow field of a generalized parent body at Mach 2.86

Longitudinal aerodynamic characteristics of a Sparrow 3 wing control missile model were measured through a range of separation distances relative to a flat plate surface that represented the parent-body configuration. Measurements were obtained with and without two dimensional circular arc protuberances attached to the flat plate surface. The tests were conducted at a Mach number of 2.86 and a Reynolds number per meter of 6.56 million. The behavior of these longitudinal characteristics with varying separation distance in the flow field created by the flat plate and protuberance was generally as would be expected on the basis of flow field boundaries determined from the second order approximation of Friedrich. In general, varying roll angle from 0 deg to 45 deg caused no significant effect on the store separation characteristics

Cognitive Information Processing

Contains reports on two research projects.National Institutes of Health (Grant 5 PO1 GM14940 -05