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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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Estimate of chemical kinetics behind normal shock waves in carbon dioxide and nitrogen mixtures for Martian atmospheric entry
Shock wave radio emission near earth and in interplanetary gas
An analysis is presented of the equations of motion for steady MHD shock waves proopagating in interstellar clouds, for boundary conditions that preclude C shocks. In addition to J shocks, in which the neutral fluid component becomes subsonic at an adiabatic jump front, the equations admit a new class of solutions, called C-asterisk shocks, in which the transition to subsonic flow occurs continuously at a sonic point. Numerical methods are developed for computing the structure of J and C-asterisk shocks propagating in diffuse interstellar clouds. The effects of chemical, ionization, and recombination processes are included in this treatment. An alternative numerical method, which uses artificial viscosity to facilitate integration through sonic points, is analyzed and shown to be invalid. A set of exemplary solutions, computed for realistic shock parameters, shows that C-asterisk shocks occur for a broad range of conditions relevant to diffuse interstellar clouds.
Iterative solution to Krook-Boltzmann kinetic equation noting Navier-Stokes numerical solution, computation and analysis of distribution function within shock wave
A study has been made of 16 interplanetary shock waves observed in 1968 by Pioneer 8 at large distances from earth. A comparison with the shapes of interplanetary shock fronts obtained by De Young and Hundhausen (1971) suggests that in general the ejection of flare gas occurs within a cone of half-angle between 30 and 60 deg. For near-earth events a deflection of the shock front has been observed, possibly owing to an interaction with the bow shock. The average duration of the postshock perturbation is about 20 hours. Strong magnetic fields and rapid fluctuations occur during the first 6 to 12 hours. Electric field perturbations in the VLF band are also noted during these periods. There is limited evidence for one corotating shock in these data.
Martian entry condition analyzed as nonequilibrium flow field phenomenon, noting chemical kinetics and radiation behind shock wave in gas mixtures
Modification of mathematical approach to general body problem for investigating direct shock wave problem for bodies with spherical nose
Time histories of noise pressures near ground level were measured during flight tests of fighter-type airplanes over fairly flat, partly wooded terrain in the e Mach number range between 1.13 and 1.4 and at altitudes from 25,000 to 45,000 feet. Atmospheric soundings and radar tracking studies were made for correlation with the measured noise data. The measured and calculated values of the pressure rise across the shock wave were generally in good agreement. There is a tendency for the theory to overestimate the pressure at locations remote from the track and to underestimate the pressures for conditions of high tailwind at altitude. The measured values of ground-reflection factor averaged about 1.8 f or the surface tested as compared to a theoretical value of 2.0. P o booms were measured in all cases. The observers also generally reported two booms; although, in some cases, only one boom was reported. The shock-wave noise associated with some of the flight tests was judged to be objectionable by ground observers, and in one case the cracking of a plate-glass store window was correlated in time with the passage of the airplane at an altitude of 25,000 feet.
Pressure sensor responds only to high pressure crest of a shock wave, and will not respond to conditions of overpressure. The sensor uses plates of a battery to produce voltage output used to actuate an alarm signal or crew escape system.
Shock wave pressure decay in polycarbonate targets impacted by hypervelocity cylindrical projectile
Experimental methods and apparatus for studying panel instabilities caused by shock waves
Critical study of Tidman model for turbulent electrostatic shock wave structure in plasmas, noting velocity distribution function role
Method of characteristics for calculating oblique shock wave interaction with turbulent boundary layer
Interplanetary energetic particle diffusion coefficient determination using random walk from shock waves
Hugoniot equation of state measurements from shock wave loading study of Coconino sandstone
Atmospheric turbulence effects on sonic boom shock wave scattering
Approximation analysis for laminar two dimensional boundary layer behind plane shock wave moving over infinite flat plate
Nonlinear analysis of arterial flow pulses and shock waves, simulating aortic insufficiency under pathological conditions by mathematical model