Reactive stream separation photography
Reactive stream separation high speed color photography for impinging streams of nitrogen tetroxide and hydrazine
Campbell, D. T.↗
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A coaxial, three-coil probe for measuring local values of electrical conductivity and velocity in plasma streams
Coaxial three coil probe measuring local electrical conductivity and velocity in plasma streams, discussing operations in electrolytes and axisymmetric plasma stream
Cook, G. R.↗
Reactive stream separation photography Final report
High speed photographic techniques to study impinging streams of propellants in experimental investigation of reactive stream separation
Cordill, J. D.↗
A computerized stream search among 2401 photographic meteor orbits
Computerized search for meteor streams in 2401 photographic meteor orbits, and association with other streams or comets
Source record↗
Interaction between an upstream facing wall jet and a supersonic stream
The flow field resulting from the interaction of an upstream facing wall jet with a supersonic counterflowing stream has been investigated. A flow field model and the main parameters governing the phenomena were determined from quantitative and qualitative experimental observations. Experimental results for different ranges of the main parameters are presented. A theoretical analysis was performed to describe the flow field in the mixing region between the two counterflowing streams. The results obtained by applying a locally similar solution compare favorably with the experimentally measured values. Large values of jet penetration were obtained with a high subsonic or low supersonic jet; large interaction forces are characteristics of higher supersonic injections. For the case of large penetration the cooling effectiveness presented as a function of the main parameters indicates the possibility of interacting cooling applications.
Piva, R.↗
An observation of the Gulf Stream surface front structure by ship, aircraft, and satellite.
Evaluation of observations of surface temperature and salinity along the western edge of the Gulf Stream made from a ship and of concurrent temperature observations obtained by instrumented aircraft at six altitudes. The major feature along a five-kilometer line normal to the Stream's edge is a temperature gradient of about 0.75 C/kilometer within which are embedded two abrupt temperature increases of about 1.5 C. Temperature variations were compensated by salinity variations, yielding nearly constant density through the frontal zone; a sharp lateral current shear was associated with the thermohaline mixing region between the steps. The attenuation of surface temperature measured by the airborne radiometer was compared with a theoretical model. The analysis supports the view that a two-part correction technique is required: one part for bulk-skin temperature differences, and another for atmospheric attenuation of sea surface emission due to the mass and temperature of interfering gases.
Maul, G. A.↗
Anomalous type III bursts explained in terms of intermittent solar wind streams observed by Pioneer spacecraft.
Occasional solar radio bursts drift downward in frequency (like type III bursts), but the drift slows or ceases or it may even reverse. These anomalous forms are called L-bursts, U-bursts, etc., and are observed as low as 1 MHz by spacecraft. The conventional explanation involves guidance of relativistic exciting particles by solar magnetic fields that do not have the spiral shape expected in undisturbed conditions. A reasonable alternative explanation is possible and, indeed, it follows directly from the inferences which have been drawn from the Stanford dual-frequency experiment flown on four Pioneer spacecraft. Analysis of temporal variations in these data leads to the conclusion that narrow streams of enhanced concentration have lifetimes which are typically about one day and the streams seem to be intermittently ejected by long-enduring sources at the sun. Each enhancement is thought to lie along a spiral and to have a beginning and an end. It may happen that relativistic exciters encounter the tail of such a discrete streamer; the concentration encountered by such exciters would initially decline but, at the streamer tail, it would level off and perhaps increase. The plasma frequency versus time (the burst frequency) would then cease to drop in the typical type III profile and would level off or increase (as in a U-burst).
Croft, T. A.↗
An impedance analysis of double-stream interaction in semiconductors
The electromagnetic waves propagating through a drifting semiconductor plasma are studied from a macroscopic point of view in terms of double-stream interaction. The possible existing waves (helicon waves, longitudinal waves, ordinary waves, and pseudolongitudinal waves) which depend upon the orientation of the dc external magnetic field are derived. A powerful impedance concept is introduced to investigate the wave behavior of longitudinal (space charge) waves or pseudolongitudinal waves in a semiconductor plasma. The impedances due to one- and two-carrier stream interactions were calculated theoretically.
Chen, P. W.↗
Discrete Levels of Beginning Height of Meteors in Streams
Consideration is given for 26 streams of meteors classified according to Ceplecha's discrete levels of beginning height, 13 of which are associated with known comets. Comet Biela produced in the Andromedids a double-peaked distribution (Classes A and C). Apparently no known comets produce a stream of Class B. Consideration of Whipple and Stefanik's model of an icy conglomerate nucleus with radioactive heating and redistribution of ice leads to association of Ceplecha's Class C with the residue of the ice-impregnated surface of a cometary nucleus after sublimation of the ices, and of Ceplecha's Class A with the core of a cometary nucleus. Class B meteoroids are then associated with less dense cores of smaller cometary nuclei that have lost their surfaces and are too small to have been observed. It is concluded that the density of Class A meteoroids (1.2 g/cu cm) is so close to that of Type 1 carbonaceous chondrites (2 g/cu cm) as to suggest that the latter come from old cores of very large nuclei of comets, an idea originally proposed by McCrosky and Ceplecha.
Cook, A. F., II↗
Implications of a quadratic stream definition in radiative transfer theory.
An explicit definition of the radiation-stream concept is stated and applied to approximate the integro-differential equation of radiative transfer with a set of twelve coupled differential equations. Computational efficiency is enhanced by distributing the corresponding streams in three-dimensional space in a totally symmetric way. Polarization is then incorporated in this model. A computer program based on the model is briefly compared with a Monte Carlo program for simulation of horizon scans of the earth's atmosphere. It is found to be considerably faster.
Whitney, C.↗
Turbulent heating of colliding streams in the solar wind.
Turbulent heating of colliding plasma streams has previously been observed in the solar wind. The original data were interpreted in terms of a fluid model. It is contended that a plasma-kinetic description is the more appropriate theoretical approach and is necessary in order to better understand the microscopic physical phenomena that underlie all fluid models. Microscopic solar-wind parameters characteristic of conditions during the observations were used, together with the quasi-linear plasma-kinetic theory, to compute the expected magnetic field and temperature enhancements in the interaction region between two counterstreaming plasma beams. The physical mechanism of excitation is the electromagnetic two-stream instability in which Alfven waves are unstable. A total field in the interaction region of about 8 gamma and a change in temperature of about 100,000 K are obtained.
Goldstein, M. L.↗
Gulf Stream eddies - Recent observations in the western Sargasso Sea.
A cyclonic Gulf Stream eddy was observed in the western Sargasso Sea by satellite infrared measurements and later confirmed by ship measurements. Fourteen months of observations indicate that the eddy moved southwestward at an average rate of 1 mile per day. The evidence suggests that the eddy was absorbed by the Gulf Stream off Florida.
Richardson, P. L.↗
Unsteady aerodynamic loads on slender cones at free-stream Mach numbers from 0 to 22.
Results of an experimental study to determine the flow-induced unsteady aerodynamic loads on slender cones at very high Mach numbers. Experiments on 8-deg half-angle-cone/flat-base configurations were conducted at free-stream Mach numbers of 6 and 15 and Reynolds numbers corresponding to shuttle reentry conditions. The flow facilities used were the H-3 Hypersonic Facility (Mach 6) and the Longshot Free Piston Tunnel (Mach 15) of the Von Karman Institute for Fluid Dynamics in Rhode-St.-Genese, Belgium. With these test results and pertinent results from other research efforts, data were available at free-stream Mach numbers of 0.67, 2.5, 3, 4, 6, 15, and 22, so that empirical expressions could be developed for the Mach number dependence (1) of the overall fluctuating pressure under an attached turbulence boundary layer and (2) of the overall fluctuating base pressure.
Heller, H. H.↗
A working list of meteor streams
The list is restricted to meteor streams that do exist; included are six streams with activity near the threshold of detection by photography not related to any known comet and not shown to be active for as long as a decade.
Cook, A. F.↗
Effect of ratio of wall boundary layer thickness to jet diameter on mixing of a normal hydrogen jet in a supersonic stream
A preliminary experimental program was conducted to determine the effect of the ratio of the free-stream boundary-layer thickness to jet diameter on the secondary jet penetration and mixing rate. Tests were conducted on a flat plate in a Mach number 4.05 airflow with sonic injection of hydrogen normal to the free-stream direction from circular underexpanded injectors. The ratio of boundary-layer thickness to jet diameter ranged from 1.25 to 6.5. Previous correlations of mixing performance were modified to account for the effect of the ratio of boundary-layer thickness to jet diameter.
Mcclinton, C. R.↗
On the effects of accretion and fragmentation in interplanetary matter streams
The time evolution of interplanetary matter streams is studied using simple mathematical models, taking into account the effects of accretion and fragmentation. While the characteristic behavior is determined essential by the initial ratio of the accretion time scale to the internal collision time scale, a focusing following an initial expansion is generally observed. The relevance of the results to cosmogenic 'jetstreams', as well as present day meteor streams, is discussed.
Ip, W.-H.↗
Decomposition of nitric oxide in a hot nitrogen stream to synthesize air for hypersonic wind tunnel combustion testing
A clean source of high enthalpy air was obtained from the exothermic decomposition of nitric oxide in the presence of strongly heated nitrogen. A nitric oxide jet was introduced into a confined coaxial nitrogen stream. Measurements were made of the extent of mixing and reaction. Experimental results are compared with one- and two-dimensional chemical kinetics computations. Both analyses predict much lower reactivity than was observed experimentally. Inlet nitrogen temperatures above 2400 K were sufficient to produce experimentally a completely reacted gas stream of synthetic air.
Zumdieck, J. F.↗
Interplanetary stream magnetism: Kinematic effects
The particle density, and the magnetic field intensity and direction are calculated in corotating streams of the solar wind, assuming that the solar wind velocity is constant and radial and that its azimuthal variations are not two rapid. The effects of the radial velocity profile in corotating streams on the magnetic fields were examined using kinematic approximation and a variety of field configurations on the inner boundary. Kinematic and dynamic effects are discussed.
Burlaga, L. F.↗