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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Finite amplitude standing transverse resonant acoustic field effects upon flow behavior of viscous fluid in cylindrical enclosure to acoustically model combustion instability
Mass entrainment of round turbulent jet exhausting into cross flow
Film cooling following air injection through inclined flat plate holes into turbulent boundary layer
Start-up process in gaseous squeeze film thrust bearings
Film cooling effectiveness measured following air injection through discrete holes into turbulent boundary layer of air on flat plate
The targeting techniques are developed which are required to determine the guidance reference release time of the space shuttle navigation system, the orbital insertion targeting values, and a time line of orbital maneuvers. An extension is made for rendezvous with a target satellite in an elliptical orbit.
Equations are developed for a vehicle consisting of a system of particles which move in a generally prescribed fashion. These equations are then specialized to apply to a rigid vehicle with a constant amount of fluid contained in tanks and flowing through interconnecting lines. Various simplifications and specialized forms of the equations are derived, and relationships between mass and inertia that result from the fluid transfer logic and the physical constraints of the configuration are formulated. A tank arrangement and fluid transfer logic are devised which permit each vehicle product of inertia to be varied without varying the remaining elements of the inertia matrix or shifting the center of mass. Vehicle control is achieved by sensing angular rate and the local vertical and by transferring fluid as a function of these variables.
Heat transfer and pressure measurements obtained in the separation, reattachment, and redevelopment regions along a tube and nozzle located downstream of an abrupt channel expansion are presented for a very high enthalpy flow of argon. The ionization energy fraction extended up to 0.6 at the tube inlet just downstream of the arc heater. Reattachment resulted from the growth of an instability in the vortex sheet-like shear layer between the central jet that discharged into the tube and the reverse flow along the wall at the lower Reynolds numbers, as indicated by water flow visualization studies which were found to dynamically model the high-temperature gas flow. A reasonably good prediction of the heat transfer in the reattachment region where the highest heat transfer occurred and in the redevelopment region downstream can be made by using existing laminar boundary layer theory for a partially ionized gas. In the experiments as much as 90 per cent of the inlet energy was lost by heat transfer to the tube and the nozzle wall.
The polarizer is briefly described. The polarization of the whole pulse is not significantly different from zero (-0.15 plus or minus 0.70 per cent). Polarization measurements of the leading edge and trailing edge of the main pulse are also given.
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The infinitely long cylindrical shell under axial compression with axisymmetric sinusoidal imperfections is considered. The bifurcation problem is formulated exactly, and a complete family of buckling modes is identified. Koiter's (1963) upper bound pertains to the critical stress associated with one restricted set of modes, and the critical stress for a set of long wavelength modes reproduces some numerical results obtained by Almroth (1966). The initial postbuckling analysis is also formulated exactly. An exact analytical solution is obtained for the limiting case of modes with infinitely long wavelengths, and numerical analysis is used to solve the equations for the other cases. An appendix gives the details of the analysis.
This paper summarizes and evaluates the work done on the elastic analysis of the surface flaw problem by the application of the alternating method. An attempt is made to describe the alternating method and to present the history of its application to the surface flaw problem and to related problems in fracture mechanics. Stress intensity factors obtained by this method are summarized and compared. Results are also compared to those obtained by investigators using other methods of analysis. An evaluation of the use of the alternating method is presented with the purpose of pointing out the advantages and disadvantages in the application of this technique to the surface flaw problem.
Potentially automated pultrusion technique has been provided for production of curved, glass-reinforced polyimide, epoxy, and graphite reinforced structures. Specially designed apparatus has been manufactured for production of curved structures.
Utilize coaxial horn feed to illuminate reflector; feed has inner horn for X-band, and outer horn for S-band. Tracking error signals for servo correction are derived from measurements of relative phase and relative amplitude between two modes.
The fabrication of full-size structural rings from composite materials is described. Results of glass/epoxy and graphite/epoxy hat stringer sections prepared by pultrusion are discussed.
An experimental study was made of the local and average heat-transfer characteristics of a single turbulent air jet impinging on the concave surface of a hemisphere. Correlations were developed for expressing the effects of a number of dimensionless variables on the local and average Nusselt numbers. Results of the present study are compared with those from a similar study concerning a concave surface of a semicylindrical shell.