Comparison of post storm non-adiabatic recovery of trapped protons with radial diffusion
Comparison of post magnetic storm nonadiabatic recovery of geomagnetically trapped protons with radial diffusion
Soeraas, F.↗
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Non-adiabatic effects in van der Waals broadening
Nonadiabatic effects in van der Waal line broadening, taking into account mixing between degenerate magnetic sublevels in atomic collisions
Cooper, J.↗
Viscous non-adiabatic laminar flow through a supersonic nozzle - Experimental results and numerical calculations.
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Back, L. H.↗
Mean and fluctuating flow measurements of a fully-developed, non-adiabatic, hypersonic boundary layer
Extensive boundary-layer measurements have been made on a cone-ogive-cylinder model at a free-stream Mach number of 7.0 and momentum-thickness Reynolds number of 8500. Mean flow transformations and calculated turbulence correlations are presented which are in good agreement with previous incompressible results. New quantitative turbulence measurements including measurements of the first higher moment and probability density of fluctuations in mass flow and total temperature in hypersonic flow are also presented. The higher moment and probability density data show that the characters of the fluctuation modes of the mass flow and total temperature are significantly different in the wall region and in the outer part of the boundary layer. These differences together with data on the turbulence scale and lifetime obtained from autocorrelation and space-time correlation measurements are discussed.
Owen, F. K.↗
Wall-wake velocity profile for compressible non-adiabatic flows
A form of the wall-wake profile, which is applicable to flows with heat transfer, and for which a variation in y = O at y = delta, was suggested. The modified profile, which takes into account the effect of turbulent Prandtl number, was found to provide a good representation of experimental data for a wide range numbers and heat transfer. The Cf values which are determined by a least squares fit of the profile to the data agree well with values which were measured by the floating element technique. In addition, the values of delta determined by the fit correspond more closely to the outer edge of the viscous flow region than those obtained with earlier versions of the wall-wake profile.
Sun, C. C.↗
A theoretical study of non-adiabatic surface effects for a model in the NTF cryogenic wind tunnel
A theoretical analysis was made of the severity and effect of nonadiabatic surface conditions for a model in the NTF cryogenic wind tunnel. The nonadiabatic condition arises from heaters that are used to maintain a constant thermal environment for instrumentation internal to the model. The analysis was made for several axi-symmetric representations of a fuselage cavity, using a finite element heat conduction code. Potential flow and boundary layer codes were used to calculate the convection condition for the exterior surface of the model. The results of the steady state analysis show that it is possible to maintain the surface temperature very near the adiabatic value, with the judicious use of insulating material. Even for the most severe nonadiabatic condition studied, the effects on skin friction drag and displacement thickness were only marginally significant. The thermal analysis also provided an estimate of the power required to maintain a specified cavity temperature.
Macha, J. M.↗
Electric and magnetic drift of non-adiabatic ions in the earth's geomagnetic tail current sheet
It has been shown recently that nonadiabatic particles in the earth's magnetotail drift across the tail roughly as predicted for adiabatic particles with 90 deg pitch angles. In this paper it is shown that this result implies the existence of an approximate invariant of the motion. Adding the effect of convection associated electric fields, the approximate bounce averaged motion of nonadiabatic particles in the magnetotail can be obtained. Thus the particle motion and energization due to combined magnetic and electric drifts in the magnetotail are easily predicted.
Beard, D. B.↗
Adjoint-operators and non-adiabatic learning algorithms in neural networks
Adjoint sensitivity equations are presented, which can be solved simultaneously (i.e., forward in time) with the dynamics of a nonlinear neural network. These equations provide the foundations for a new methodology which enables the implementation of temporal learning algorithms in a highly efficient manner.
Toomarian, N.↗
A search for geographic control on the occurrence of magnetospheric ELF emissions
Search coil magnetometer data obtained in the magnetosphere on Ogo 5 and Ogo 6 were studied for evidence of man-induced stimulation of the two dominant electromagnetic emissions, chorus and plasmaspheric hiss. Variability of chorus with geographic longitude and enhancements, onsets, and quantum jumps in chorus emissions at frequencies related to harmonics of the earth's transmission lines are discussed. The enhancement of weak emissions in the 340-360 deg dipole longitude region during quiet geomagnetic conditions is present only when ELF hiss is weak, and will not contribute to the non-adiabatic dynamics of radiation belt electrons. It is concluded that the data analyzed is consistent with a predominantly natural origin for chorus and plasmaspheric hiss, and that triggered waves do not play a major role in the non-adiabatic dynamics of geomagnetically trapped electrons.
Tsurutani, B. T.↗
Thermodynamic and Transport Property Correlation Formulas for Equilibrium Air from 1,000 Degrees Kelvin to 15,000 Degrees Kelvin
The thermodynamic properties, density and temperature, as well as transport property parameters involving viscosity, Prandtl number (including diffusion effects), and gaseous radiation absorption coefficients have been correlated as a function of enthalpy at four pressure levels (10 (sup -1), 10 (sup 0), 10, and 10 (sup 2) atmospheres). The correlation formulas are written in a generalized form for which coefficients for a particular property and pressure level are tabulated. The correlation formulas are useful in digital computer programs for non-adiabatic viscous flow problems.
AIR↗
Very high temperature laminar flow of a gas through the entrance region of a cooled tube - Numerical calculations and experimental results.
The laminar flow equations in differential form are solved numerically on a digital computer for flow of a very high temperature gas through the entrance region of an externally cooled tube. The solution method is described and calculations are carried out in conjunction with experimental measurements. The agreement with experiment is good, with the result indicating relatively large energy and momentum losses in the highly cooled flows considered where the pressure is nearly uniform along the flow and the core flow becomes non-adiabatic a few diameters downstream of the inlet. The effects of a large range of Reynolds number and Mach number (viscous dissipation) are also investigated.
Back, L. H.↗
Retrodictive determinism
With respect to irreversible, non-homeomorphic maps, contravariant and covariant tensor fields have distinctly natural covariance and transformational behavior. For thermodynamic processes which are non-adiabatic, the fact that the process cannot be represented by a homeomorphic map emphasizes the logical arrow of time, an idea which encompasses a principle of retrodictive determinism for covariant tensor fields.
Kiehn, R. M.↗
Direct heating surface combustor
The combustor utilizes a non-adiabatic flame to provide low-emission combustion for gas turbines. A fuel-air mixture is directed through a porous wall, the other side of which serves as a combustion surface. A radiant heat sink disposed adjacent to and spaced from the combustion surface controls the combustor flame temperature in order to prevent the formation of oxides of nitrogen. A secondary air flow cools the heat sink. Additionally, up to 100% of secondary air flow is mixed with the combustion products at the direct heating surface combustor to dilute such products thereby reducing exit temperature. However, if less than 100% secondary air is mixed to the combustor, the remainder may be added to the combustion products further downstream.
Beremand, D. G.↗
Theoretical studies of solar oscillations
Possible sources for the excitation of the solar 5 minute oscillations were investigated and a linear non-adiabatic stability code was applied to a preliminary study of the solar g-modes with periods near 160 minutes. Although no definitive conclusions concerning the excitation of these modes were reached, the excitation of the 5 minute oscillations by turbulent stresses in the convection zone remains a viable possibility. Theoretical calculations do not offer much support for the identification of the 160 minute global solar oscillation (reported by several independent observers) as a solar g-mode. A significant advance was made in attempting to reconcile mixing-length theory with the results of the calculations of linearly unstable normal modes. Calculations show that in a convective envelope prepared according to mixing length theory, the only linearly unstable modes are those which correspond to the turbulent eddies which are the basic element of the heuristic mixing length theory.
Goldreich, P.↗
An artificial energy method for calculating flows with shocks
The artificial-viscosity method, first proposed by von Neumann and Richtmyer, introduces an artificial viscous pressure term in regions of compression such that an increase in entropy occurs in shock transition zones. The paper describes how dissipative flows can be induced by reducing the total energy available for adiabatic processes in shock zones. A class of inviscid fluid flows, called semiflows, is described in which the flows exhibit thermodynamic differences. Induced dissipative flows modify the pressure in regions of compression in a manner analogous to the artificial-viscosity method and for a gas, the effect is equivalent to suitably modifying the gas constant in the equation of state. By employing MacCormack's method and the usual non-adiabatic equations, numerical solutions of a Riemann problem are compared with the modified artificial energy method, showing that the dissipation effect predicted by the analytical formulation is reflected in the numerical method as well.
Rose, M. E.↗
Observational and theoretical studies of the evolving structure of baroclinic waves: Attractor dynamics of global weather systems
Significant progress was made in developing a six-component dry model of mid-latitude baroclinic wave evolution, and a ten-component moist model. These models include representations of airflow over mountians and non-adiabatic processes. As a first step, the properties of a reduced, three component, baroclinic system are studied. The classical baroclinic stability criteria emerge as the properties of one of the three equilibria admitted, with the remaining two equilibria forming the attractor region for the observed weather activity. Passive tracer evolution in a baroclinic wave was studied. A model in which only constituents trapped within low atmospheric levels are considered, has been extended to include the possibility for fluxes into the upper levels of the atmosphere. The reported results for the lower levels achieved previously are shown to be qualitatively similar to those obtained by these new calculations in which the vertical flux constraint is removed. An extensive study of an 8-year record of global outgoing longwave radiation for the Northern Hemisphere reveals that blocking events exhibit only a weak signature of blocking highs, as measured by relatively low values of the ratio of the standard deviation to the mean value of the observed long wave outgoing radiation. Though present in many cases, the signature is not a strongly distinctive feature of the blocking episodes.
Saltzman, B.↗
Experimental verification of the thermodynamic properties for a jet-A fuel
Thermodynamic properties for a Jet-A fuel were determined by Shell Development Company in 1970 under a contract for NASA Lewis Research Center. The polynomial fit necessary to include Jet-A fuel (liquid and gaseous phases) in the library of thermodynamic properties of the NASA Lewis Chemical Equilibrium Program is calculated. To verify the thermodynamic data, the temperatures of mixtures of liquid Jet-A injected into a hot nitrogen stream were experimentally measured and compared to those calculated by the program. Iso-octane, a fuel for which the thermodynamic properties are well known, was used as a standard to calibrate the apparatus. The measured temperatures for the iso-octane/nitrogen mixtures reproduced the calculated temperatures except for a small loss due to the non-adiabatic behavior of the apparatus. The measurements for Jet-A were corrected for this heat loss and showed excellent agreement with the calculated temperatures. These experiments show that this process can be adequately described by the thermodynamic properties fitted for the Chemical Equilibrium Program.
Graciasalcedo, Carmen M.↗
Current carriers in the near-earth cross-tail current sheet during substorm growth phase
Throughout most of the growth phase of a substorm, the cross-tail current at x about -10 Re can be supplied by the curvature drift of a bi-directional field aligned distribution of 1 keV electrons. Just prior to its local disruption after substorm onset, the cross-tail current in the now thin (about 400 km) current sheet is carried by the cross-tail serpentine motion of non-adiabatic ions (Speiser, 1965). The instability of this latter current leads to the local disruption of the near-earth current sheet.
Mitchell, D. G.↗