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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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Diffraction of hf radio waves by ionospheric irregularities - radiation from artificial satellites
Longitudinal oscillations of propellant tanks and wave propagations in feed lines with streaming fluid
Fluid wave propagation in liquid propellant feed system
A monolithic 120 GHz free-space, continuous-wave source capable of providing 10 dBm of EIRP at 11.1 percent DC-to-EIRP conversion efficiency is presented.
Theory and equations for propagating pressure waves in liquid filled cylindrical shells
Dispersion relation involving space-time harmonics obtained for electromagnetic wave propagation in dielectric medium
Very low frequency electric and magnetic wave measurements for Mariner Venus Mercury 1973 mission
Numerical results for perturbed downstream flow field resulting from entropy wave interaction with normal shock and oblique shock generated by wedge flow
Ultrasonic wave propagation guided by fluid layer between two elastic solids, plotting normalized velocities and layer thicknesses
Electron-acoustic, ion-acoustic and electromagnetic plane waves coupling at shock front in two fluid ionized viscous plasma
Heat transfer from turbulent boundary layer interacting with shock and expansion waves in supersonic flow
Upstream discrete wave packets propagation interplanetary medium from Ogo 5 observation
Charge particle motion and radiation in strong plane and spherical electromagnetic waves with nonthermal astrophysical applications
Homogeneous positive plasma column perturbation analysis in axial magnetic field, deriving model for ionization waves dispersion characteristics
Wavefront singularities for the displacement functions, associated with the radiation of linear elastic waves from a point source embedded in a finitely strained two-dimensional elastic solid, are examined in detail. It is found that generally the singularities are of order d to the -1/2 power, where d measures distance away from the front. However, in certain exceptional cases singularities of order d to the -n power, where n = 1/4, 2/3, 3/4, may be encountered.
The method of variation of parameters is used to analyze wave propagation in variable area, plane ducts with no mean flow. The method has an explicit representation of the fast axial variation of the acoustic modes, and numerical integration is required only for the slower axial variations of the mode amplitudes and phases. Results are presented which demonstrate the numerical advantages of the method. Comparison of the results with those of a small perturbation theory are given. The relationship between this method and the method of weighted residuals is discussed.
Wave field continuation theory, which allows transformation of the seismic record section data directly into velocity-depth space, is tested for upper mantle analysis using a large array-recorded data set obtained at the 200-station Caltech-USGS Southern California Seismic Network that is representative of the structure beneath the gulf of California. The method's resolution capability is illustrated by the comparison of the slant stacks and downward continuation of both synthetic and data record sections. It is stressed that when high-quality, densely sampled digital data are available, the technique is easy to implement, provides an inversion which contains all the data in the global format, and produces an objective estimate of depth resolution as a function of ray parameter.
Orthogonal probes on a free-flying plasma diagnostics payload are used to study ELF electric disturbances in the auroral ionosphere that are due to the injection of powerful electron beams. Frequency spectrograms are presented for various pitch angles, pulsing characteristics, and other properties of the injected beams; the large scale DC ionospheric convection electric field is measured, together with auroral particle precipitation, visual auroral forms, and ionospheric parameters. In view of the experimental results obtained, it is postulated that the observed ELF waves are in the Alfven and drift modes, and are generated by the positive vehicle potential during beam injection.