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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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NASA NTRS1976

Empirical effective temperatures and bolometric corrections for early-type stars

An empirical effective temperature for a star can be found by measuring its apparent angular diameter and absolute flux distribution. The angular diameters of 32 bright stars in the spectral range O5f to F8 have recently been measured with the stellar interferometer at Narrabri Observatory, and their absolute flux distributions have been found by combining observations of ultraviolet flux from the Orbiting Astronomical Observatory (OAO-2) with ground-based photometry. In this paper, these data have been combined to derive empirical effective temperatures and bolometric corrections for these 32 stars.

Code, A. D.↗

NASA NTRS1979

User guide for STRMLN: A boundary-layer program for contoured wind-tunnel liner design

A 2-D boundary layer computer code developed to process data for an arbitrary number of streamlines is presented. Provisions are included for the computer code to determine either mass transfer rates necessary for an effective boundary layer displacement of zero thickness or the effective displacement thickness for a specified mass transfer-rate distribution. The computer code was developed to be compatible with other computer codes which are being modified and/or developed at the NASA-Langley Research Center in order to design the three dimensional, contoured, wind tunnel liner used in transonic testing of a laminar flow control system installed on a supercritical airfoil section. A brief discription of the liner design procedure, representative liner calculations, adaptive-wall design for a two dimensional wind tunnel test, and other applications are reported.

Anderson, E. C.↗

NASA NTRS1979

Ultraviolet photometry from the Orbiting Astronomical Observatory. XXVI - Energy distributions of seven early-type galaxies and the central bulge of M31

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Code, A. D.↗

NASA NTRS1979

Ultraviolet photometry from the Orbiting Astronomical Observatory. XXXII - An atlas of ultraviolet stellar spectra

Ultraviolet stellar fluxes are presented in graphs and tables for 164 bright stars in the spectral region from 1200 to 3600 A. The spectra represent a subset of OAO 2 spectrometer data on file at the National Space Science Data Center. The monochromatic flux is given in units of erg per (sq cm-s-A) with a spectral resolution of about 22 A in the region from 3600 to 1850 A and of approximately 12 A in the region from 1850 to 1160 A.

Code, A. D.↗

NASA NTRS1980

Ultraviolet photometry from the Orbiting Astronomical Observatory. XXXVIII - A second atlas of ultraviolet stellar spectra

Ultraviolet stellar spectra are presented for 132 stars in the spectral region from 1200 to 1850 A and 34 stars in the region from 1800 to 3600 A in a graphical and tabular form. The spectra represent a subset of OAO 2 spectrometer data on file at the National Space Science Data Center. The monochromatic flux is given in units of ergs/sq cm s A with a spectral resolution of about 12 A in the region from 1850 to 1160 A and of about 22 A in the region from 3600 to 1800 A.

Meade, M. R.↗

NASA NTRS1981

Picture gallery: A structured presentation of OAO-2 photometric data supported by UBV, ANS, and TD1 observations

Stellar fluxes for 531 stars in the wavelength range lambda 5500-1330A lambda are presented in the form of graphs. The stars are divided into 52 different categories on the basis of their spectral types and objects within one category are shown together. The agreement between the various ultraviolet photometric systems for early type stars is generally better than 0.10 mag. Stars with known and/or observed variability have been grouped separately. A list of stars with observed photometric properties which are indicative of stellar or interstellar anomalies is also provided.

Koornneed, J.↗

NASA NTRS1981

The far-ultraviolet energy distribution of two globular cluster blue horizontal-branch stars in M13

The far-UV energy distribution of two blue horizontal-branch (BHB) stars detected in the nucleus of M13 is presented. Their continua can be characterized by a model atmosphere of an effective temperature of 15,000 to 20,000 K and log g = 4.5, and it follows that V is in the range 15.9-16.7 for these stars. Comparison with integrated photometry by OAO 2 and by ANS indicates that, at wavelengths smaller than 1800 A, the integrated light is from BHB stars only, of which M13 contains about 200. For these far-UV wavelengths, the color of the BHB stars is also very similar to the integrated color of the elliptical galaxy M87.

De Boer, K. S.↗

NASA NTRS1980

Ultraviolet photometry from the Orbiting Astronomical Observatory. XXXIV - Filter photometry of 531 stars of diverse types

Ultraviolet magnitudes for 531 stars observed with the Wisconsin Experiment Package on OAO 2 are tabulated. It is noted that these data constitute a subset of the OAO 2 data on file at the National Space Science Data Center. The tabulation contains previously published data all reduced to a uniform magnitude system. It is pointed out that the observations were obtained with the medium band interference filter photometers. Eleven magnitudes are given designated by their centroid wavelengths.

Code, A. D.↗

NASA NTRS1981

Ultraviolet interstellar extinction in the large Magellanic Cloud using observations with the International Ultraviolet Explorer

Ten early-type supergiants in the Large Magellanic Cloud (LMC) have been observed with the International Ultraviolet Explorer (IUE). The spectra (1150-3200 A) are shown, and their photometric properties are discussed. It is confirmed that the LMC interstellar extinction law for these stars deviates significantly from the average galactic law in the sense that the 2200 A feature is deficient in strength and that, in the far-ultraviolet (wavelength less than 2000 A), the observed LMC extinction law is significantly above the galactic curve.

Koornneef, J.↗

NASA NTRS1982

The wide field/planetary camera

A wide site of potential astronomical and solar system scientific studies using the wide field planetary camera on space telescope are described. The expected performance of the camera as it approaches final assembly and testing is also detailed.

Westphal, J. A.↗

NASA NTRS1982

Picture gallery - A structured presentation of OAO-2 photometric data supported by OAO-2 spectrophotometric data and UBV, ANS and TD1 observations

Graphs are presented for the stellar fluxes of 531 stars in the 5500-1330 A wavelength range, which have been divided into 52 categories on the basis of spectral types. The merging of medium band interference filter photometry, UBV photometry, ANS photometry and TD1 fluxes, as well as the ordering of the objects, should prove helpful in studies of interstellar reddening, luminosity effects, bandwidth effects, and comparisons with model stellar atmospheres. The agreement between the various UV photometric systems for early-type stars is generally better than 0.10 mag. A list of stars whose photometric properties indicate stellar or interstellar anomalies is also provided.

Koornneef, J.↗

NASA NTRS1982

Ultraviolet photometry from the Orbiting Astronomical Observatory. XL - The energy distributions of spiral and irregular galaxies

Measurements of the total light of 40 spiral and irregular galaxies are presented. The photometry covers the wavelength range 1550-4250 A and is calibrated on an absolute basis. On the average later-type galaxies are not only bluer at short wavelengths than ellipticals but significantly bluer than visual colors would imply. This reflects a recent history of more vigorous formation of massive stars. The shape of the upper part of the initial mass function apparently varies more among early-type galaxies, producing a wide scatter in their energy distributions. In at least some galaxies interstellar dust appears to have little influence upon the emerging radiation. The local volume luminosity spectrum due to galaxies turns up steeply at short wavelengths, and is shaped largely by contributions from late-type galaxies. The observed ultraviolet background cannot be produced by normal galaxies, although the large corrections implied by theoretical evolutionary models may account for the measurements.

Code, A. D.↗

NASA NTRS1982

Results from the Orbiting Astronomical Observatory. XLI - Photometry of M31 and M33

Filter photometry observations from the Orbiting Astronomical Observatory, in six wavelength bands between 1550 and 4250 A, are reported for several positions along the major and minor axes in M31 and at some positions in M33. The spatial resolution is 10 arcmin. The colors along the major axis of M31 within about 20 arcmin of the nucleus are similar to the nucleus; at 45 arcmin the colors are much bluer, indicating a spiral arm population. This behavior is expected from other observations of H I, CO, and early-type stars, which are all concentrated in a ring of material whose inner edge is about 7 kpc (= 35 arcmin) from the nucleus. The center of M33 is bluer than the ring of M31, and the arms of M33 even bluer. There are no colors too blue to be explained (within observational error) by unreddened B stars.

Davis, J.↗

NASA NTRS1982

Dilution zone mixing studies

The objectives and status of a project to investigate various aspects of the jet in a confined cross flow problem are outlined. The experiments performed thus far dealt primarily with a single row of jets mixing into an isothermal flow in a constant cross section duct. Variations in the mixing were observed as a function of jet to mainstream momentum ratio, orifice size, and spacing. The current experiments examine perturbations of this problem characteristic to gas turbine combustion chambers, namely: flow area convergence, nonisothermal mainstream flow, and opposed in line and staggered injection. An empirical model was developed to describe the observed temperature distributions. The current interactive code provides a 3-D pictorial representation of the temperature, as given by these correlations, for any user specified downstream location, flow, and orifice parameters.

Holdeman, J. D.↗

NASA NTRS1984

Analytical fuel property effects--small combustors

The consequences of using broad-property fuels in both conventional and advanced state-of-the-art small gas turbine combustors are assessed. Eight combustor concepts were selected for initial screening, of these, four final combustor concepts were chosen for further detailed analysis. These included the dual orifice injector baseline combustor (a current production 250-C30 engine combustor) two baseline airblast injected modifications, short and piloted prechamber combustors, and an advanced airblast injected, variable geometry air staged combustor. Final predictions employed the use of the STAC-I computer code. This quasi 2-D model includes real fuel properties, effects of injector type on atomization, detailed droplet dynamics, and multistep chemical kinetics. In general, fuel property effects on various combustor concepts can be classified as chemical or physical in nature. Predictions indicate that fuel chemistry has a significant effect on flame radiation, liner wall temperature, and smoke emission. Fuel physical properties that govern atomization quality and evaporation rates are predicted to affect ignition and lean-blowout limits, combustion efficiency, unburned hydrocarbon, and carbon monoxide emissions.

Sutton, R. D.↗

NASA NTRS1986

Perspectives on dilution jet mixing

A microcomputer code which displays 3-D oblique and 2-D plots of the temperature distribution downstream of jets mixing with a confined crossflow has been used to investigate the effects of varying the several independent flow and geometric parameters on the mixing. Temperature profiles calculated with this empirical model are presented to show the effects of orifice size and spacing, momentum flux ratio, density ratio, variable temperature mainstream, flow area convergence, orifice aspect ratio, and opposed and axially staged rows of jets.

Holdeman, J. D.↗

NASA NTRS1986

Perspectives on dilution jet mixing

Holdeman, J. D.↗

NASA NTRS1988

Numerical analysis of three-dimensional viscous internal flows

A 3-D Navier-Stokes code has been developed for analysis of turbomachinery blade rows and other internal flows. The Navier-Stokes equations are written in a Cartesian coordinate system rotating about the x-axis, and then mapped to a general body-fitted coordinate system. Streamwise viscous terms are neglected using the thin-layer assumption, and turbulence effects are modeled using the Baldwin-Lomax turbulence model. The equations are discretized using finite differences on stacked C-type grids and are solved using a multistage Runge-Kutta algorithm with a spatially-varying time step and implicit residual smoothing. Calculations have been made of a horseshoe vortex formed in front of a flat plate with a round leading edge standing in a turbulent endwall boundary layer. Comparisons are made with experimental data taken by Eckerle and Langston for a circular cylinder under similar conditions. Computer and measured results are compared in terms of endwall flow visualization pictures and total pressure loss contours and vector plots on the symmetry plane. Calculated details of the primary vortex show excellent agreement with the experimental data. The calculations also show a small secondary vortex not seen experimentally.

Chima, Rodrick V.↗