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  • Other Sources  (4,512)
  • SPACE RADIATION  (2,601)
  • FLUID MECHANICS AND HEAT TRANSFER  (1,904)
  • Cell & Developmental Biology
  • Physics
  • 1995-1999  (312)
  • 1980-1984  (2,057)
  • 1970-1974  (2,137)
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  • 1
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    In situ ground deformation measurements from the summit of Axial Volcano during the 1998 volcanic episode (1999)
    In:  Geophys. Res. Lett., Kobe, 1, vol. 26, no. 23, pp. 3437-3440, pp. 8010, (ISBN: 0534351875, 2nd edition)
    Details
    Publication Date: 1999
    Description: The formation of ocean crust along the midocean ridge system is volumetrically one of the most important geological processes on the surface of the earth. Volcanic eruptions along the ridge can be catastrophic events during which magma rises to the surface of the sea floor to release heat and gases into turbulent megaplumes that disrupt the overlying water column, initiate and rejuvenate hydrothermal circulation, and trigger an outpouring of microbial debris. Though these events may persist only a few weeks or months at one site, taken together, they may play a major role in the oceanic biogeochemical cycle. Axial Volcano on the Juan de Fuca Ridge has become a laboratory for the study of ephemeral aspects of sea floor volcanism, including results from expeditionary, rapid response, and permanent instrument installations. The geological context and description of the most significant magmatic event on the Juan de Fuca Ridge in the past decade is provided by Embley et al. [3425]. Dziak and Fox [3429], describe a rapid increase in the seismicity remotely monitored by the U.S. Navy hydrophone array. The increase in seismic swarms is the earliest indicator that an eruption has begun. Within hours, volcanic deflation is observed in concert with increases in the bottom water temperature due to venting. Instruments in place for the first time during such a midocean ridge volcanic event measured ground deformation and caldera subsidence resulting from the extraction of magma as described by Fox [3437] and Chadwick et al. [3441], while a coincident outpouring of hot water recorded on moored temperature sensors is described in Baker et al. [3445]. A rapid response cruise in February brought researchers to the site only 14 days after the eruption began and in the midst of winter storms. Sohn et al. [3433] describe local seismicity derived from a network of sea floor hydrophones deployed during the February cruise. Repeated measurements of helium anomalies in the water column before and after the eruption are used by Lupton et al. [3449] to fingerprint the hydrothermal plume associated with the eruption, extending a considerable distance off-axis. Water samples collected during the February 1998 cruise were analyzed for hydrothermal methane and hydrogen by McLaughlin-West et al. [3453]. They find both species to be significantly elevated near the vents and invoke microbial processes to explain the observations.
    Keywords: Crustal deformation (cf. Earthquake precursor: deformation or strain) ; Volcanology ; 3035 ; Marine ; geology ; and ; geophysics ; Midocean ; ridge ; processes ; 8145 ; Tectonophysics ; Physics ; of ; magma ; and ; magma ; bodies ; 8419 ; Volcanology ; Eruption ; monitoring ; (7280) ; 8434 ; Magma ; migration ; GRL
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    BIBLIOGRAPHY SEISMOLOGY
  • 2
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    Starch columns: Analog model for basalt columns (1998)
    In:  J. Geophys. Res., Warszawa, American Geophysical Union, vol. 103, no. B7, pp. 15,239-15,253, pp. L08304, (ISSN: 1340-4202)
    Details
    Publication Date: 1998
    Keywords: Stress ; Rock mechanics ; Fracture ; Physical properties of rocks ; Laboratory measurements ; 5104 ; Fracture ; and ; flow ; 8010 ; Structural ; geology ; Fractures ; and ; faults ; 8168 ; Tectonophysics ; Stresses--general ; 8439 ; Volcanology ; Physics ; and ; chemistry ; of ; magma ; bodies ; Muller ; JGR
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    BIBLIOGRAPHY SEISMOLOGY
  • 3
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    Dike propagation through an elastic plate (1998)
    In:  J. Geophys. Res., Kalamazoo, Michigan 49001, The Upjohn Company, vol. 103, no. B8, pp. 18,295-18,324, pp. L09603, (ISSN: 1340-4202)
    Details
    Publication Date: 1998
    Keywords: Elasticity ; Volcanology ; 8434 ; Volcanology ; Magma ; migration ; 8145 ; Tectonophysics ; JGR ; Physics ; of ; magma ; and ; magma ; bodies ; 8414 ; Eruption ; mechanisms
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    BIBLIOGRAPHY SEISMOLOGY
  • 4
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    Volcanic gas concentration and aquifer permeability estimated from tidal fluctuations in groundwater level: Case of Koshimizu Well in Izu-Oshima, Japan (1998)
    In:  Geophys. Res. Lett., New York, Conseil de l'Europe, vol. 25, no. 12, pp. 2237-2240, pp. B06307, (ISSN: 1340-4202)
    Details
    Publication Date: 1998
    Keywords: Volcanology ; Earthquake precursor: chemical (Rn, water(-level,...) ; TIDES ; Earth tides ; Physical properties of rocks ; 8135 ; Tectonophysics ; GRL ; Hydrothermal ; systems ; (8424) ; 8439 ; Volcanology ; Physics ; and ; chemistry ; of ; magma ; bodies ; 7223 ; Seismology ; Seismic ; hazard ; assessment ; and ; prediction ; 1832 ; Hydrology ; Groundwater ; transport
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    BIBLIOGRAPHY SEISMOLOGY
  • 5
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    The effects of topography on magma chamber deformation models: Application to Mt. Etna and radar interferometry (1998)
    In:  Geophys. Res. Lett., Hannover, Dt. Geophys. Ges. e. V., vol. 25, no. 10, pp. 1549-1552, pp. 1058, (ISSN: 1340-4202)
    Details
    Publication Date: 1998
    Keywords: Volcanology ; Modelling ; InSAR ; Crustal deformation (cf. Earthquake precursor: deformation or strain) ; 1243 ; Geodesy ; and ; gravity ; Space ; geodetic ; surveys ; 3210 ; Mathematical ; geophysics ; (new ; field) ; Modeling ; 8145 ; Tectonophysics ; Physics ; of ; magma ; and ; magma ; bodies ; 8499 ; Volcanology ; General ; or ; miscellaneous ; GRL
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    BIBLIOGRAPHY SEISMOLOGY
  • 6
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    Stress fields generating ring faults in volcanoes (1997)
    In:  Geophys. Res. Lett., London, Pergamon, vol. 24, no. 13, pp. 1559-1562, pp. B05401, (ISBN: 0534351875, 2nd edition)
    Details
    Publication Date: 1997
    Keywords: Volcanology ; Stress ; Iceland ; 8145 ; Tectonophysics ; Physics ; of ; magma ; and ; magma ; bodies ; 8414 ; Volcanology ; Eruption ; mechanisms ; GRL
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    BIBLIOGRAPHY SEISMOLOGY
  • 7
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    Readjustment of the Krafla spreading segment to crustal rifting measured by satellite radar interferometry (1997)
    In:  Geophys. Res. Lett., Dordrecht, National Academy of Sciences of the USA, vol. 24, no. 15, pp. 1843-1846, pp. TC5003, (ISSN: 1340-4202)
    Details
    Publication Date: 1997
    Keywords: Iceland ; SAR ; InSAR ; Plate tectonics ; Crustal deformation (cf. Earthquake precursor: deformation or strain) ; 1209 ; Geodesy ; Gravimetry, Gravitation ; 8145 ; Tectonophysics ; Physics ; of ; magma ; and ; magma ; bodies ; 8150 ; Plate ; boundary ; general ; Massonet ; (3040) ; 3035 ; Marine ; geology ; and ; geophysics ; Midocean ; ridge ; processes ; Volcanology ; GRL
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    BIBLIOGRAPHY SEISMOLOGY
  • 8
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    Shielding against galactic cosmic rays (1996)
    In:  Other Sources
    Details
    Publication Date: 2019-04-02
    Description: Ions of galactic origin are modified but not attenuated by the presence of shielding materials. Indeed, the number of particles and the absorbed energy behind most shield materials increases as a function of shield thickness. The modification of the galactic cosmic ray composition upon interaction with shielding is the only effective means of providing astronaut protection. This modification is intimately conntected with the shield transport porperties and is a strong function of shield composition. The systematic behavior of the shield properites in terms of microscopic energy absorption events will be discussed. The shield effectiveness is examined with respect to convectional protection practice and in terms of a biological endpoint: the efficiency for reduction of the probability of transformation of shielded C3H1OT1/2 mouse cells. The relative advantage of developing new shielding technologies is discussed in terms of a shield performance as related to biological effect and the resulting uncertainty in estimating astronaut risk.
    Keywords: SPACE RADIATION
    Type: Advances in Space Research (ISSN 0273-1177); 17; 2; p. (2)31-(2)36
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  • 9
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    Decay rate of the second radiation belt (1996)
    In:  Other Sources
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    Publication Date: 2019-04-02
    Description: Variations in the Earth's trapped (Van Allen) belts produced by solar flare particle events are not well understood. Few observations of increases in particle populations have been reported. This is particularly true for effects in low Earth orbit, where manned spaceflights are conducted. This paper reports the existence of a second proton belt and it's subsequent decay as measured by a tissue-equivalent proportional counter and a particle spectrometer on five Space Shuttle flights covering an eighteen-month period. The creation of this second belt is attributed to the injection of particles from a solar particle event which occurred at 2246 UT, March 22, 1991. Comparisons with observations onboard the Russian Mir space station and other unmanned satellites are made. Shuttle measurements and data from other spacecraft are used to determine that the e-folding time of the peak of the second proton belt. It was ten months. Proton populations in the second belt returned to values of quiescent times within eighteen months. The increase in absorbed dose attributed to protons in the second belt was approximately 20%. Passive dosimeter measurements were in good agreement with this value.
    Keywords: SPACE RADIATION
    Type: Advances in Space Research (ISSN 0273-1177); 17; 2; p. (2)151-158
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  • 10
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    Overview of nuclear fragementation models and needs (1996)
    In:  Other Sources
    Details
    Publication Date: 2019-04-02
    Description: It has been known for some time that adequate assessment of spacecraft requirements and concomitant estimates of astronaut radiation exposures from galactic cosmic radiation requires accurate, quantitative methods for characterizing these radiation fields as they pass through thick absorbers. The main nuclear interaction processes involved are nuclear elastic an inelastic collisions, and nuclear breakup (fragmentation) and electromagnetic dissociation (EMD). Nuclear fragmenation and EMD are important because they alter the elemental and isotopic composition of the transported radiation fields. At present, there is no suitable accurate theory for predicting nuclear fragmentation cross sections for all collision pairs and energies of interest in space radiation protection. Typical cross-section differences between theory and experiment range from about 25 percent to a factor of two. The resulting errors in transported flux, for high linear energy transfer (LET) particles, are compared to these cross-sections errors. In this overview, theoretical models of heavy ion fragmentation currently used to generate input data bases for cosmic-ray transport and shielding codes are reviewed. Their shortcomings are discussed. Further actions needed to improve their accuracy and generality are presented.
    Keywords: SPACE RADIATION
    Type: Advances in Space Research (ISSN 0273-1177); 17; 2; p. (2)59-(2)68
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  • 11
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    Near-Earth Radiation Environment Including Time Variations and Secondary Radiation; Meetings F2.6 and F2.7, COSPAR Scientific Assembly, 30th, Hamburg, Germany, July 11-21, 1994 (1996)
    In:  Other Sources
    Details
    Publication Date: 2019-03-30
    Description: Both man and technological equipment must survive the near-earth space radiation environment, which can, under specific conditions, be extremely severe. This conference produced 17 papers on the dynamic space radiation environment covering: galactic, solar and trapped particles; nuclear fragmentation; nuclear interactions and transport theory; solar proton events; radiation shielding; and heavy ion fluences. Several papers present results from the recent SAMPEX mission.
    Keywords: SPACE RADIATION
    Type: Advances in Space Research (ISSN 0273-1177); 17; 2
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  • 12
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    Theoretical model of HZE particle fragmentation by hydrogen targets (1996)
    In:  Other Sources
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    Publication Date: 2019-04-02
    Description: The fragmenting of high energy, heavy ions (HZE particles) by hydrogen targets is an important, physical process in several areas of space radiation research. In this work quantum mechanical optical model methods for estimating cross sections for HZE particle fragmentation by hydrogen targets are presented. The cross sections are calculated using a modified abrasion-ablation collision formalism adapted from a nucleus-nucleus collision model. Elemental and isotopic production cross sections are estimated and compared with reported measurements for the breakup of neon, sulphur, and iron, nuclei at incident energies between 400 and 910 Mev/nucleon. Good agreement between theory and experiment is obtained.
    Keywords: SPACE RADIATION
    Type: Advances in Space Research (ISSN 0273-1177); 17; 2; p. (2)109-(2)112
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  • 13
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    Light ion components of the galactic cosmic rays: Nuclear interactions and transport theory (1996)
    In:  Other Sources
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    Publication Date: 2019-04-02
    Description: Light nuclei are present in the primary galactic cosmic rays (GCR) and are produced in thick targets due to projectile or target fragmentation from both nucleon and heavy induced reactions. In the primary GCR, He-4 is the most abundant nucleus after H-1. However, there are also a substantial fluxes of H-2 and He-3. In this paper we describe theoretical models based on quantum multiple scattering theory for the description of light ion nuclear interactions. The energy dependence of the light ion fragmentation cross section is considered with comparisons of inclusive yields and secondary momentum distributions to experiments described. We also analyze the importance of a fast component of lights ions from proton and neutron induced target fragementation. These theoretical models have been incorporated into the cosmic ray transport code HZETRN and will be used to analyze the role of shielding materials in modulating the production and the energy spectrum of light ions.
    Keywords: SPACE RADIATION
    Type: Advances in Space Research (ISSN 0273-1177); 17; 2; p. (2)77-(2)86
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  • 14
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    Galactic cosmic radiation model and its applications (1996)
    In:  Other Sources
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    Publication Date: 2019-04-02
    Description: A model for the differential energy spectra of galactic cosmic radiation as a function of solar activity is described. It is based on the standard diffusion-convection theory of solar modulation. Estimates of the modulation potential based on fitting this theory to observed spectral measurements from 1954 to 1989 are correlated to the Climax neutron counting rates and to the sunspot numbers at earlier times taking into account the polarity of the interplanetary magnetic field at the time of observations. These regression lines then provide a method for predicting the modulation at later times. The results of this model are quantitatively compared to a similar Moscow State University (MSU) model. These model cosmic ray spectra are used to predict the linear energy transfer spectra, differential energy spectra of light (charge less than or = 2) ions, and single event upsets rates in memeory devices. These calculations are compared to observations made aboard the Space Shuttle.
    Keywords: SPACE RADIATION
    Type: Advances in Space Research (ISSN 0273-1177); 17; 2; p. (2)7-(2)17
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  • 15
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    Results and current status of the NPARC alliance validation effort (1996)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The NPARC Alliance is a partnership between the NASA Lewis Research Center (LeRC) and the USAF Arnold Engineering Development Center (AEDC) dedicated to the establishment of a national CFD capability, centered on the NPARC Navier-Stokes computer program. The three main tasks of the Alliance are user support, code development, and validation. The present paper is a status report on the validation effort. It describes the validation approach being taken by the Alliance. Representative results are presented for laminar and turbulent flat plate boundary layers, a supersonic axisymmetric jet, and a glancing shock/turbulent boundary layer interaction. Cases scheduled to be run in the future are also listed. The archive of validation cases is described, including information on how to access it via the Internet.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA-TM-107134 , NAS 1.15:107134 , E-10064 , AIAA PAPER 96-0387 , NIPS-96-08124 , Aerospace Sciences Meeting and Exhibit; Jan 15, 1996 - Jan 18, 1996; Reno, NV; United States
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  • 16
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    Geomagnetic transmission disturbances and heavy-ion fluences observed in low Earth orbit during the solar energetic particle events of October 1989 (1996)
    In:  Other Sources
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    Publication Date: 2019-08-27
    Description: The large solar energetic particle (SEP) events and simultaneous large geomagnetic disturbances observed during October 1989 posed a significant, rapidly evolving space radiation hazard. Using data from the GOES-7, NOAA-10, IMP-8 and LDEF satellites, we determined the geomagnetic transmission, heavy ion fluences, mean Fe ionic charge state, and effective radiation hazard observed in low Earth orbit (LEO) for these SEPs. We modeled the geomagneitc transmission by tracing particles through the combination to the internal International Geomagnetic Reference Field (IGRF) and the Tsyganenko (1989) magnetospheric field models, extending the modeling to large geomagnetic disturbances. We used our results to assess the radiation hazard such very large SEP events would pose in the anticipated 52 deg inclination space station orbit.
    Keywords: SPACE RADIATION
    Type: Advances in Space Research (ISSN 0273-1177); 17; 2; p. (2)121-(2)125
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  • 17
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    LET spectra of trapped anomalous cosmic rays in low-Earth orbit (1996)
    In:  Other Sources
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    Publication Date: 2019-08-28
    Description: Observations aboard Cosmos satelites discovered trapped anomalous cosmic rays (ACRs), tracked the variation in their intensity in 1986-1988, and measured their fluence, spectrum, and composition at solar minimum in the previous solar cycle. The MAST instrument aboard the SAMPEX satellite has observed trapped anomalous cosmic rays in the present solar cycle, confirmed the general features of the Cosmos data, and provided the first detailed observations of trapped ACRs. In this paper we apply theoretical modeling of trapped ACRs, which is shown to provide a reasonably good description of both the Cosmos and SAMPEX data, to calculate the integral linear-energy-transfer (LET) spectra due to trapped ACRs in typical low-Earth orbits. We compare these calculations with the LET spectra produced by galactic cosmic rays (GCRs) and non-trapped ACRs in order to assess the relative radiation hazard posed by trapped ACRs.
    Keywords: SPACE RADIATION
    Type: Advances in Space Research (ISSN 0273-1177); 17; 2; p. (2)47-(2)51
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  • 18
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    Marangoni instability in a liquid sheet (1995)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: We study the onset of a pure Marangoni convection in a liquid layer with two deformable interfaces in the no-gravity environment. Both oscillatory and stationary instabilities are considered for a wide range of parameters. It is shown that only stationary instability is possible when surface tension at the colder interface is lower than that at the hotter one. Oscillatory instability tends to disappear and to be replaced by the stationary instability with increase of the Prandtl number and decrease of surface tension at the colder interface.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Advances in Space Research (ISSN 0273-1177); 16; 7; p. (7)83-(7)86
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  • 19
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    Radiative transfer in a semiinfinite medium with a specularly reflecting boundary (1995)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: A consistent solution of the radiative transfer equation characterizing photon transport in a semi-infinite medium of refractive index greater than or equal to one is obtained following the method of Sobolev. Fresnel specular reflection, Snell's law and isotropic scattering are assumed. An algorithm is developed and its accuracy is demonstrated. A numerical Laplace transform inversion leads to an efficient evaluation for the interior flux and source function distributions.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Quantitative Spectroscopy & Radiative Transfer (ISSN 0022-4073); 53; 3; p. 257-267
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  • 20
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    Some velocity field results from the thermocapillary flow experiment aboard USML-1 spacelab (1995)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: Results are reported of the Surface Tension Driven Convection Experiment (STDCE) aboard USML-1 Spacelab. Steady and transient thermocapillary flows were investigated in a 10 cm dia. circular container filled with 10 Cs silicone oil. The velocity and temperature fields were studied in detail under various conditions. It is shown in this paper how the Marangoni number affects the velocity field. A numerical analysis of the flows was also conducted and its results were compared to the experimental data. Good agreement is shown.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Advances in Space Research (ISSN 0273-1177); 16; 7; p. (7)79-(7)82
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  • 21
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    Interstellar propagation and electron capture processes of galactic cosmic ray heavy ions in space (1995)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: The new information on galactic cosmic rays (GCR) derived from the Spacelab-3 cosmic ray experiment 'Anuradha' shows that at 25-125 MeV/N GCR sub-iron and iron (Z = 21-28) particles consists of a mixture of partially ionized and fully ionized ions. Computation of electron capture and loss cross sections in hydrogen in 1-50 MeV/N energy range are made for Fe, Cr, Ti and Ni. From these it is concluded that: (1) these GCR particles must have captured orbital electrons at energies of about 1-5 MeV/N and (2) these particles are then reaccelerated to 300-500 MeV/N most probably in interstellar medium by collision with SNR shock fronts. Some reacceleration may take place also in heliospheric boundary region. It is suggested that these observations of partially ionized GCR ions of about 100 MeV/N in Spacelab-3 provide a direct evidence of reacceleration of GCR.
    Keywords: SPACE RADIATION
    Type: Advances in Space Research (ISSN 0273-1177); 15; 1; p. (1)51
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  • 22
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    Nonequilibrium Flow Expansion Experiment Around a Blunted Cone (1995)
    In:  CASI
    Details
    Publication Date: 2011-07-22
    Description: Eleven tests were carried out in DLR's high enthalpy tunnel in Goettingen (HEG), Germany, for reservoir conditions ranging from 10 to 23 MJ/kg and a free stream Mach number of approximately 10. A blunted cone model with a cylindrical afterbody (sting) was investigated. To obtain information on the influence of defined parameters on the body back flow, especially of the reacting gas, the heat transfer rate along the body contour was measured with fast response surface thermocouples on the forebody and sensitive thin film heat transfer gauges on the base and sting of the model. Flow visualization with a holographic interferometry system was provided. Tests are described, and a preliminary interpretation of the observed flow effects are given.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: ESA, Proceedings of the 2nd European Symposium on Aerothermodynamics for Space Vehicles; p 383-38
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  • 23
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    The VOrtex Ring Transit EXperiment (VORTEX) GAS project (1995)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Get Away Special (GAS) payload G-093, also called VORTEX (VOrtex Ring Transit EXperiment), is an investigation of the propagation of a vortex ring through a liquid-gas interface in microgravity. This process results in the formation of one or more liquid droplets similar to earth based liquid atomization systems. In the absence of gravity, surface tension effects dominate the drop formation process. The Shuttle's microgravity environment allows the study of the same fluid atomization processes as using a larger drop size than is possible on Earth. This enables detailed experimental studies of the complex flow processes encountered in liquid atomization systems. With VORTEX, deformations in both the vortex ring and the fluid surface will be measured closely for the first time in a parameters range that accurately resembles liquid atomization. The experimental apparatus will record images of the interactions for analysis after the payload has been returned to earth. The current design of the VORTEX payload consists of a fluid test cell with a vortex ring generator, digital imaging system, laser illumination system, computer based controller, batteries for payload power, and an array of housekeeping and payload monitoring sensors. It is a self-contained experiment and will be flown on board the Space Shuttle in a 5 cubic feet GAS canister. The VORTEX Project is entirely run by students at the University of Michigan but is overseen by a faculty advisor acting as the payload customer and the contact person with NASA. This paper summarizes both the technical and programmatic aspects of the VORTEX Project.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Goddard Space Flight Center, The 1995 Shuttle Small Payloads Symposium; p 221-229
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  • 24
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    Construction of the GAMCIT gamma-ray burst detector (G-056) (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The GAMCIT (Gamma-ray Astrophysics Mission, California Institute of Technology) payload is a Get-Away-Special payload designed to search for high-energy gamma-ray bursts and any associated optical transients. This paper presents details on the development and construction of the GAMCIT payload. In addition, this paper will reflect upon the unique challenges involved in bringing the payload close to completion, as the project has been designed, constructed, and managed entirely by undergraduate members of the Caltech SEDS (Students for the Exploration and Development of Space). Our experience will definitely be valuable to other student groups interested in undertaking a challenge such as a Get-Away-Special payload.
    Keywords: SPACE RADIATION
    Type: NASA. Goddard Space Flight Center, The 1995 Shuttle Small Payloads Symposium; p 203-212
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  • 25
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    Cryogenic Two-Phase Flight Experiment: Results overview (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: This paper focuses on the flight results of the Cryogenic Two-Phase Flight Experiment (CRYOTP), which was a Hitchhiker based experiment that flew on the space shuttle Columbia in March of 1994 (STS-62). CRYOTP tested two new technologies for advanced cryogenic thermal control; the Space Heat Pipe (SHP), which was a constant conductance cryogenic heat pipe, and the Brilliant Eyes Thermal Storage Unit (BETSU), which was a cryogenic phase-change thermal storage device. These two devices were tested independently during the mission. Analysis of the flight data indicated that the SHP was unable to start in either of two attempts, for reasons related to the fluid charge, parasitic heat leaks, and cryocooler capacity. The BETSU test article was successfully operated with more than 250 hours of on-orbit testing including several cooldown cycles and 56 freeze/thaw cycles. Some degradation was observed with the five tactical cryocoolers used as thermal sinks, and one of the cryocoolers failed completely after 331 hours of operation. Post-flight analysis indicated that this problem was most likely due to failure of an electrical controller internal to the unit.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: The 1995 Shuttle Small Payloads Symposium; p 111-123
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  • 26
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    Flight testing of the Capillary Pumped Loop Flight Experiment (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The Capillary Pumped Loop Flight Experiment (CAPL) employs a passive two-phase thermal control system that uses the latent heat of vaporization of ammonia to transfer heat over long distances. CAPL was designed as a prototype of the Earth Observing System (EOS) instrument thermal control systems. The purpose of the mission was to provide validation of the system performance in micro-gravity, prior to implementation on EOS. CAPL was flown on STS-60 in February, 1994, with some unexpected results related to gravitational effects on two-phase systems. Flight test results and post flight investigations will be addressed, along with a brief description of the experiment design.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: The 1995 Shuttle Small Payloads Symposium; p 1-19
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    The Cryogenic Test Bed experiments: Cryogenic heat pipe flight experiment CRYOHP (STS-53). Cryogenic two phase flight experiment CRYOTP (STS-62). Cryogenic flexible diode flight experiment CRYOFD (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: This paper presents an overview of the Cryogenic Test Bed (CTB) experiments including experiment results, integration techniques used, and lessons learned during integration, test and flight phases of the Cryogenic Heat Pipe Flight Experiment (STS-53) and the Cryogenic Two Phase Flight Experiment (OAST-2, STS-62). We will also discuss the Cryogenic Flexible Diode Heat Pipe (CRYOFD) experiment which will fly in the 1996/97 time frame and the fourth flight of the CTB which will fly in the 1997/98 time frame. The two missions tested two oxygen axially grooved heat pipes, a nitrogen fibrous wick heat pipe and a 2-methylpentane phase change material thermal storage unit. Techniques were found for solving problems with vibration from the cryo-collers transmitted through the compressors and the cold heads, and mounting the heat pipe without introducing parasitic heat leaks. A thermally conductive interface material was selected that would meet the requirements and perform over the temperature range of 55 to 300 K. Problems are discussed with the bi-metallic thermostats used for heater circuit protection and the S-Glass suspension straps originally used to secure the BETSU PCM in the CRYOTP mission. Flight results will be compared to 1-g test results and differences will be discussed.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Goddard Space Flight Center, The 1995 Shuttle Small Payloads Symposium; p 21-30
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  • 28
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    Emerging CFD technologies and aerospace vehicle design (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: With the recent focus on the needs of design and applications CFD, research groups have begun to address the traditional bottlenecks of grid generation and surface modeling. Now, a host of emerging technologies promise to shortcut or dramatically simplify the simulation process. This paper discusses the current status of these emerging technologies. It will argue that some tools are already available which can have positive impact on portions of the design cycle. However, in most cases, these tools need to be integrated into specific engineering systems and process cycles to be used effectively. The rapidly maturing status of unstructured and Cartesian approaches for inviscid simulations makes suggests the possibility of highly automated Euler-boundary layer simulations with application to loads estimation and even preliminary design. Similarly, technology is available to link block structured mesh generation algorithms with topology libraries to avoid tedious re-meshing of topologically similar configurations. Work in algorithmic based auto-blocking suggests that domain decomposition and point placement operations in multi-block mesh generation may be properly posed as problems in Computational Geometry, and following this approach may lead to robust algorithmic processes for automatic mesh generation.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Surface Modeling, Grid Generation, and Related Issues in Computational Fluid Dynamic (CFD) Solutions; p 359-384
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  • 29
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    Prospects and expectations for unstructured methods (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The last decade has witnessed a vigorous and sustained research effort on unstructured methods for computational fluid dynamics. Unstructured mesh generators and flow solvers have evolved to the point where they are now in use for design purposes throughout the aerospace industry. In this paper we survey the various mesh types, structured as well as unstructured, and examine their relative strengths and weaknesses. We argue that unstructured methodology does offer the best prospect for the next generation of computational fluid dynamics algorithms.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Surface Modeling, Grid Generation, and Related Issues in Computational Fluid Dynamic (CFD) Solutions; p 273-287
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  • 30
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    A Cartesian, cell-based approach for adaptively-refined solutions of the Euler and Navier-Stokes equations (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: A Cartesian, cell-based approach for adaptively-refined solutions of the Euler and Navier-Stokes equations in two dimensions is developed and tested. Grids about geometrically complicated bodies are generated automatically, by recursive subdivision of a single Cartesian cell encompassing the entire flow domain. Where the resulting cells intersect bodies, N-sided 'cut' cells are created using polygon-clipping algorithms. The grid is stored in a binary-tree data structure which provides a natural means of obtaining cell-to-cell connectivity and of carrying out solution-adaptive mesh refinement. The Euler and Navier-Stokes equations are solved on the resulting grids using a finite-volume formulation. The convective terms are upwinded: A gradient-limited, linear reconstruction of the primitive variables is performed, providing input states to an approximate Riemann solver for computing the fluxes between neighboring cells. The more robust of a series of viscous flux functions is used to provide the viscous fluxes at the cell interfaces. Adaptively-refined solutions of the Navier-Stokes equations using the Cartesian, cell-based approach are obtained and compared to theory, experiment and other accepted computational results for a series of low and moderate Reynolds number flows.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Surface Modeling, Grid Generation, and Related Issues in Computational Fluid Dynamic (CFD) Solutions; p 207-224
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  • 31
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    Grid related issues for static and dynamic geometry problems using systems of overset structured grids (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Grid related issues of the Chimera overset grid method are discussed in the context of a method of solution and analysis of unsteady three-dimensional viscous flows. The state of maturity of the various pieces of support software required to use the approach is considered. Current limitations of the approach are identified.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Surface Modeling, Grid Generation, and Related Issues in Computational Fluid Dynamic (CFD) Solutions; p 181-192
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  • 32
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    Grid generation: A view from the trenches (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: This paper presents 'A view from the trenches' on CFD grid generation from a Pratt & Whitney perspective. We anticipate that other organizations have similar views. We focus on customer expectations and the consequent requirements. We enunciate a vision for grid generation, discuss issues that developers must recognize.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Surface Modeling, Grid Generation, and Related Issues in Computational Fluid Dynamic (CFD) Solutions; p 45-54
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  • 33
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    Requirements for effective use of CFD in aerospace design (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: This paper presents a perspective on the requirements that Computational Fluid Dynamics (CFD) technology must meet for its effective use in aerospace design. General observations are made on current aerospace design practices and deficiencies are noted that must be rectified for the U.S. aerospace industry to maintain its leadership position in the global marketplace. In order to rectify deficiencies, industry is transitioning to an integrated product and process development (IPPD) environment and design processes are undergoing radical changes. The role of CFD in producing data that design teams need to support flight vehicle development is briefly discussed. An overview of the current state of the art in CFD is given to provide an assessment of strengths and weaknesses of the variety of methods currently available, or under development, to produce aerodynamic data. Effectiveness requirements are examined from a customer/supplier view point with design team as customer and CFD practitioner as supplier. Partnership between the design team and CFD team is identified as an essential requirement for effective use of CFD. Rapid turnaround, reliable accuracy, and affordability are offered as three key requirements that CFD community must address if CFD is to play its rightful role in supporting the IPPD design environment needed to produce high quality yet affordable designs.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Surface Modeling, Grid Generation, and Related Issues in Computational Fluid Dynamic (CFD) Solutions; p 15-28
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  • 34
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    Surface modeling and grid generation for aeropropulsion CFD (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The efforts in geometry modeling and grid generation at the NASA Lewis Research Center, as applied to the computational fluid dynamic (CFD) analysis of aeropropulsion systems, are presented. The efforts are mainly characterized by a focus on the analysis of components of an aeropropulsion system, which involve turbulent viscous flow with heat transfer and chemistry. Thus, this discussion will follow that characterization and will sequence through the components of typical propulsion systems consisting of inlets, compressors, combustors, turbines, and nozzles. For each component, some applications of CFD analysis will be presented to show how CFD is used to compute the desired performance information, how geometry modeling and grid generation are performed, and what issues have developed related to geometry modeling and grid generation. The discussion will illustrate the following needs related to geometry modeling and grid generation as observed in aeropropulsion analysis: (1) accurate and efficient resolution of turbulent viscous and chemically-reacting flowfields; (2) easy-to-use interfaces with CAD data for automated grid generation about complex geometries; and (3) automated batch grid generation software for use with design and optimization software.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Surface Modeling, Grid Generation, and Related Issues in Computational Fluid Dynamic (CFD) Solutions; p 89-103
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  • 35
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    Combustion system CFD modeling at GE Aircraft Engines (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: This viewgraph presentation discusses key features of current combustion system CFD modeling capabilities at GE Aircraft Engines provided by the CONCERT code; CONCERT development history; modeling applied for designing engine combustion systems; modeling applied to improve fundamental understanding; CONCERT3D results for current production combustors; CONCERT3D model of NASA/GE E3 combustor; HYBRID CONCERT CFD/Monte-Carlo modeling approach; and future modeling directions.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Industry-Wide Workshop on Computational Turbulence Modeling; p 87-97
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  • 36
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    Early results from the ultra heavy cosmic ray experiment (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Data extraction and analysis of the LDEF Ultra Heavy Cosmic Ray Experiment is continuing. Almost twice the pre LDEF world sample has been investigated and some details of the charge spectrum in the region from Z approximately 70 up to and including the actinides are presented. The early results indicate r process enhancement over solar system source abundances.
    Keywords: SPACE RADIATION
    Type: NASA. Langley Research Center, LDEF: 69 Months in Space. Third Post-Retrieval Symposium, Part 1; p 129-133
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  • 37
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    A procedure for automating CFD simulations of an inlet-bleed problem (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: A procedure was developed to improve the turn-around time for computational fluid dynamics (CFD) simulations of an inlet-bleed problem involving oblique shock-wave/boundary-layer interactions on a flat plate with bleed into a plenum through one or more circular holes. This procedure is embodied in a preprocessor called AUTOMAT. With AUTOMAT, once data for the geometry and flow conditions have been specified (either interactively or via a namelist), it will automatically generate all input files needed to perform a three-dimensional Navier-Stokes simulation of the prescribed inlet-bleed problem by using the PEGASUS and OVERFLOW codes. The input files automatically generated by AUTOMAT include those for the grid system and those for the initial and boundary conditions. The grid systems automatically generated by AUTOMAT are multi-block structured grids of the overlapping type. Results obtained by using AUTOMAT are presented to illustrate its capability.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Surface Modeling, Grid Generation, and Related Issues in Computational Fluid Dynamic (CFD) Solutions; p 731-749
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  • 38
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    Application of CFD in aeronautics at NASA Ames Research Center (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The role of Computational Fluid Dynamics (CFD) at Ames Research Center has expanded to address a broad range of aeronautical problems, including wind tunnel support, flight test support, design, and analysis. Balancing the requirements of each new problem against the available resources - software, hardware, time, and expertise - is critical to the effective use of CFD. Several case studies of recent applications highlight the depth of CFD capability at Ames, the tradeoffs involved in various approaches, and lessons learned in the use of CFD as an engineering tool.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Surface Modeling, Grid Generation, and Related Issues in Computational Fluid Dynamic (CFD) Solutions; p 57-67
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  • 39
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    Grid generation and surface modeling for CFD (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: When computing the flow around complex three dimensional configurations, the generation of the mesh is the most time consuming part of any calculation. With some meshing technologies this can take of the order of a man month or more. The requirement for a number of design iterations coupled with ever decreasing time allocated for design leads to the need for a significant acceleration of this process. Of the two competing approaches, block-structured and unstructured, only the unstructured approach will allow fully automatic mesh generation directly from a CAD model. Using this approach coupled with the techniques described in this paper, it is possible to reduce the mesh generation time from man months to a few hours on a workstation. The desire to closely couple a CFD code with a design or optimization algorithm requires that the changes to the geometry be performed quickly and in a smooth manner. This need for smoothness necessitates the use of Bezier polynomials in place of the more usual NURBS or cubic splines. A two dimensional Bezier polynomial based design system is described.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Surface Modeling, Grid Generation, and Related Issues in Computational Fluid Dynamic (CFD) Solutions; p 29-43
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  • 40
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    Neutrons, gamma rays, and beta particles interactions with IIaO films flown on Astro I and Astro II and comparison with IIaO flown on the get-away-special STS-7 (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The current requirements for the Laboratory for Astronomy and Solar Physics, sends rocket satellites and in the near future will involve flights in the shuttle to the upper reaches of the Earth's atmosphere where they will be subjected to the atomic particles and electromagnetic radiation produced by the Sun and other cosmic radiation. It is therefore appropriate to examine the effect of neutrons, gamma rays, beta particles, and X-rays on the film currently being used by the Laboratory for current and future research requirements. It is also hoped by examining these particles in their effect that we will have simulated the space environment of the rockets, satellites, and shuttles. Several samples of the IIaO film were exposed to a neutron howitzer with a source energy of approximately 106 neutrons/steradians. We exposed several samples of the film to a 10 second blast of neutrons in both metal and plastic containers which exhibited higher density readings which indicated the possibility of some secondary nuclear interactions between neutrons and the aluminum container. The plastic container showed some variations at the higher densities. Exposure of the samples of IIaO film to a neutron beam of approximately 10 neutrons per steradians for eight minutes produces approximately a 13% difference in the density readings of the dark density grids. It is not noticeable that at the lighter density grid the neutrons have minimal effects, but on a whole the trend of the eight minute exposed IIaO film density grids at the darker end had a 7.1% difference than the control. Further analysis is anticipated by increasing the exposure time. Two sets of film were exposed to a beta source in a plastic container. The beta source was placed at the bottom so that the cone of rays striking the film would be conical for a period of seven days. It was observed in the films, designated 4a and 4b, a dramatic increase in the grid densities had occurred. The attenuation of beta particles due to the presence of air were observed. The darker density grids, whose positions were the furthest from the beta source, displayed minimal fluctuations as compared with the control. It is suspected that the orientation of the film in the cansister with the beta source is the key factor responsible for the dramatic increases of the lighter density grids. Emulsions 3a and 3b exposed for a period of six days with the grid orientation reserved produced substantial differences in the darker grids as shown in the graphs. There is a great deal of fluctuations in this sample between the beta exposed density grids and the control density grids. The lighter density grids whose orientations were reversed displays minimal fluctuations due to the presence of this beta source and the attenuation that is taking place.
    Keywords: SPACE RADIATION
    Type: NASA. Goddard Space Flight Center, The 1995 Shuttle Small Payloads Symposium; p 247-253
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  • 41
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    Boundary layer blockage in expansion tube nozzles (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The results of a first order perfect gas correction for the effects of the boundary layer formation within expansion tubes with nozzles are presented. The analytical model developed to describe the boundary layer formation within the expansion tube and an expansion nozzle located at the end of the acceleration tube is based on the Karman integral equations. The results of this analytical model are compared with experimental data from an expansion diffuser. The model provides a useful tool for the preliminary design of nozzles for such facilities.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Shock Tunnel Studies of Scramjet Phenomena 1994; 6 p
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  • 42
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    Demonstration of an automated CFD system for three-dimensional flow simulations (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: In this paper the capabilities of an automated CFD system which is currently available at NLR are demonstrated. Transonic flow around the AS28G wing/body configuration and hypersonic flow through a generic three-dimensional mixed-compression airbreathing inlet are simulated. An assessment of the level of automation of the current CFD-system is made. The problem-turnaround time lies within the order of a week for both applications.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Surface Modeling, Grid Generation, and Related Issues in Computational Fluid Dynamic (CFD) Solutions; p 713-730
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  • 43
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    Advanced Methodology for Simulation of Complex Flows Using Structured Grid Systems (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Detailed simulations of viscous flows in complicated geometries pose a significant challenge to current capabilities of Computational Fluid Dynamics (CFD). To enable routine application of CFD to this class of problems, advanced methodologies are required that employ (a) automated grid generation, (b) adaptivity, (c) accurate discretizations and efficient solvers, and (d) advanced software techniques. Each of these ingredients contributes to increased accuracy, efficiency (in terms of human effort and computer time), and/or reliability of CFD software. In the long run, methodologies employing structured grid systems will remain a viable choice for routine simulation of flows in complex geometries only if genuinely automatic grid generation techniques for structured grids can be developed and if adaptivity is employed more routinely. More research in both these areas is urgently needed.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Surface Modeling, Grid Generation, and Related Issues in Computational Fluid Dynamic (CFD) Solutions; p 697-710
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  • 44
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    The role of overset grids in the development of the general purpose CFD code (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: A discussion of the strengths and weaknesses of overset composite grid and solution technology is given, along with a sampling of current work in the area. Major trends are identified, and the observation is made that generalized and hybridized overset methods provide a natural framework for combining disparate mesh types and physics models. Because of this, the author concludes that overset methods will be the foundation for the general purpose computational fluid dynamics programs of the future.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Surface Modeling, Grid Generation, and Related Issues in Computational Fluid Dynamic (CFD) Solutions; p 193-204
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  • 45
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    Block-structured grids for complex aerodynamic configurations: Current status (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The status of CFD methods based on the use of block-structured grids for analyzing viscous flows over complex configurations is examined. The objective of the present study is to make a realistic assessment of the usability of such grids for routine computations typically encountered in the aerospace industry. It is recognized at the very outset that the total turnaround time, from the moment the configuration is identified until the computational results have been obtained and postprocessed, is more important than just the computational time. Pertinent examples will be cited to demonstrate the feasibility of solving flow over practical configurations of current interest on block-structured grids.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Surface Modeling, Grid Generation, and Related Issues in Computational Fluid Dynamic (CFD) Solutions; p 163-177
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  • 46
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    Overview of turbulence model development and applications at Rocketdyne (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: This viewgraph presentation discusses turbulence modeling requirements, development philosophy, and approach; two major areas of concentration (high speed and low speed turbulence modeling); high speed turbulence modeling; compressibility effects; turbulence models adapted to USA code; M = 9.2 flat plate flow; Mach 7.05 flow over axisymmetric flare; Mach 8.6 flow over cold wall edge; low speed turbulence modeling; turbulence models being assessed; turbulence model deck structure and integration with Navier-Stokes solver; nonlinear algebraic-stress model; rotation modified k-epsilon model; and Reynolds stress model.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Industry-Wide Workshop on Computational Turbulence Modeling; p 107-117
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  • 47
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    Turbulence models for gas turbine combustors (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: This viewgraph presentation covers gas turbine combustor flow physics, turbulence model investigations, turbulent combustion modeling, and present status and future needs.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Industry-Wide Workshop on Computational Turbulence Modeling; p 79-85
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  • 48
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    Experience with k-epsilon turbulence models for heat transfer computations in rotating (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: This viewgraph presentation discusses geometry and flow configuration, effect of y+ on heat transfer computations, standard and extended k-epsilon turbulence model results with wall function, low-Re model results (the Lam-Bremhorst model without wall function), a criterion for flow reversal in a radially rotating square duct, and a summary.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Industry-Wide Workshop on Computational Turbulence Modeling; p 65-77
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  • 49
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    Turbulence model development and application at Lockheed Fort Worth Company (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: This viewgraph presentation demonstrates that computationally efficient k-l and k-kl turbulence models have been developed and implemented at Lockheed Fort Worth Company. Many years of experience have been gained applying two equation turbulence models to complex three-dimensional flows for design and analysis.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Industry-Wide Workshop on Computational Turbulence Modeling; p 29-37
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  • 50
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    The applicability of turbulence models to aerodynamic and propulsion flowfields at McDonnell-Douglas Aerospace (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The objective of this viewgraph presentation is to evaluate turbulence models for integrated aircraft components such as the forebody, wing, inlet, diffuser, nozzle, and afterbody. The one-equation models have replaced the algebraic models as the baseline turbulence models. The Spalart-Allmaras one-equation model consistently performs better than the Baldwin-Barth model, particularly in the log-layer and free shear layers. Also, the Sparlart-Allmaras model is not grid dependent like the Baldwin-Barth model. No general turbulence model exists for all engineering applications. The Spalart-Allmaras one-equation model and the Chien k-epsilon models are the preferred turbulence models. Although the two-equation models often better predict the flow field, they may take from two to five times the CPU time. Future directions are in further benchmarking the Menter blended k-w/k-epsilon and algorithmic improvements to reduce CPU time of the two-equation model.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Industry-Wide Workshop on Computational Turbulence Modeling; p 47-63
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    A summary of computational experience at GE Aircraft Engines for complex turbulent flows in gas turbines (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: This viewgraph presentation summarizes some CFD experience at GE Aircraft Engines for flows in the primary gaspath of a gas turbine engine and in turbine blade cooling passages. It is concluded that application of the standard k-epsilon turbulence model with wall functions is not adequate for accurate CFD simulation of aerodynamic performance and heat transfer in the primary gas path of a gas turbine engine. New models are required in the near-wall region which include more physics than wall functions. The two-layer modeling approach appears attractive because of its computational complexity. In addition, improved CFD simulation of film cooling and turbine blade internal cooling passages will require anisotropic turbulence models. New turbulence models must be practical in order to have a significant impact on the engine design process. A coordinated turbulence modeling effort between NASA centers would be beneficial to the gas turbine industry.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Industry-Wide Workshop on Computational Turbulence Modeling; p 39-46
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  • 52
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    Turbulence program for propulsion systems (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Program goals at the Center for Modeling of Turbulence and Transition (CMOTT), NASA Lewis Research Center, are (1) to develop reliable turbulence (including bypass transition) and combustion models for complex flows in propulsion systems and (2) to integrate developed models into deliverable CFD tools for propulsion systems in collaboration with industry. This viewgraph presentation covers the following topics: development of turbulence and combustion models; collaboration with industry and technology transfer; isotropic eddy viscosity models; algebraic Reynolds stress models; scalar turbulence models; second order closure models; multiple scale k-epsilon models; and PDF modeling of turbulent reacting flows.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Industry-Wide Workshop on Computational Turbulence Modeling; p 1-27
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    Dosimetric results on EURECA (1995)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Detector packages were exposed on the European Retrievable Carrier (EURECA) as part of the Biostack experiment inside the Exobiology and Radiation Assembly (ERA) and at several locations around EURECA. The packages consist of different plastic nuclear track detectors, nuclear emulsions and thermoluminescence dosimeters (TLD's). Evaluation of these detectors yields data on absorbed dose and particle and LET spectra. Preliminary results of absorbed dose measurements in the EURECA dosimeter packages are reported and compared to results of the LDEF experiments. The highest dose rate measured on EURECA is 63.3 plus or minus 0.4 mGy d(exp -1) behind a shielding thickness of 0.09 g cm(exp -2) in front of the detector package.
    Keywords: SPACE RADIATION
    Type: NASA. Langley Research Center, LDEF: 69 Months in Space. Third Post-Retrieval Symposium, Part 1; p 37-42
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    An assessment of unstructured grid technology for timely CFD analysis (1995)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: An assessment of two unstructured methods is presented in this paper. A tetrahedral unstructured method USM3D, developed at NASA Langley Research Center is compared to a Cartesian unstructured method, SPLITFLOW, developed at Lockheed Fort Worth Company. USM3D is an upwind finite volume solver that accepts grids generated primarily from the Vgrid grid generator. SPLITFLOW combines an unstructured grid generator with an implicit flow solver in one package. Both methods are exercised on three test cases, a wing, and a wing body, and a fully expanded nozzle. The results for the first two runs are included here and compared to the structured grid method TEAM and to available test data. On each test case, the set up procedure are described, including any difficulties that were encountered. Detailed descriptions of the solvers are not included in this paper.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Surface Modeling, Grid Generation, and Related Issues in Computational Fluid Dynamic (CFD) Solutions; p 385-400
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    Future requirements in surface modeling and grid generation (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The past ten years have seen steady progress in surface modeling procedures, and wholesale changes in grid generation technology. Today, it seems fair to state that a satisfactory grid can be developed to model nearly any configuration of interest. The issues at present focus on operational concerns such as cost and quality. Continuing evolution of the engineering process is placing new demands on the technologies of surface modeling and grid generation. In the evolution toward a multidisciplinary analysis-bascd design environment, methods developed for Computational Fluid Dynamics are finding acceptance in many additional applications. These two trends, the normal evolution of the process and a watershed shift toward concurrent and multidisciplinary analysis, will be considered in assessing current capabilities and needed technological improvements.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Surface Modeling, Grid Generation, and Related Issues in Computational Fluid Dynamic (CFD) Solutions; p 3-13
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    Improvements and new features in the PDF module (1995)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: This viewgraph presentation discusses what models are used in this package and what their advantages and disadvantages are, how the probability density function (PDF) model is implemented and the features of the program, and what can be expected in the future from the NASA Lewis PDF code.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Industry-Wide Workshop on Computational Turbulence Modeling; p 269-275
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    A composition joint PDF method for the modeling of spray flames (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: This viewgraph presentation discusses an extension of the probability density function (PDF) method to the modeling of spray flames to evaluate the limitations and capabilities of this method in the modeling of gas-turbine combustor flows. The comparisons show that the general features of the flowfield are correctly predicted by the present solution procedure. The present solution appears to provide a better representation of the temperature field, particularly, in the reverse-velocity zone. The overpredictions in the centerline velocity could be attributed to the following reasons: (1) the use of k-epsilon turbulence model is known to be less precise in highly swirling flows and (2) the swirl number used here is reported to be estimated rather than measured.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Industry-Wide Workshop on Computational Turbulence Modeling; p 259-268
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    PDF methods for turbulent reactive flows (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Viewgraphs are presented on computation of turbulent combustion, governing equations, closure problem, PDF modeling of turbulent reactive flows, validation cases, current projects, and collaboration with industry and technology transfer.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Industry-Wide Workshop on Computational Turbulence Modeling; p 247-257
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    Modeling of turbulent chemical reaction (1995)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Viewgraphs are presented on modeling turbulent reacting flows, regimes of turbulent combustion, regimes of premixed and regimes of non-premixed turbulent combustion, chemical closure models, flamelet model, conditional moment closure (CMC), NO(x) emissions from turbulent H2 jet flames, probability density function (PDF), departures from chemical equilibrium, mixing models for PDF methods, comparison of predicted and measured H2O mass fractions in turbulent nonpremixed jet flames, experimental evidence of preferential diffusion in turbulent jet flames, and computation of turbulent reacting flows.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Industry-Wide Workshop on Computational Turbulence Modeling; p 219-230
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    Second-order closures for compressible turbulence (1995)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: This viewgraph presentation discusses project description, turbulence models, and computational engine and results for second-order closures for compressible turbulence.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Industry-Wide Workshop on Computational Turbulence Modeling; p 203-217
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    Turbulence requirements of a commerical CFD code (1995)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: This viewgraph presentation gives a profile of Advanced Scientific Computing (ASC) Ltd., applications, clients and clients' needs, ASC's directions, and how the Center for Modeling of Turbulence and Transition (CMOTT) can help.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Industry-Wide Workshop on Computational Turbulence Modeling; p 193-202
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    Turbulence modeling needs of commercial CFD codes: Complex flows in the aerospace and automotive industries (1995)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: This viewgraph presentation discusses the following: STAR-CD computational features; STAR-CD turbulence models; common features of industrial complex flows; industry-specific CFD development requirements; applications and experiences of industrial complex flows, including flow in rotating disc cavities, diffusion hole film cooling, internal blade cooling, and external car aerodynamics; and conclusions on turbulence modeling needs.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Industry-Wide Workshop on Computational Turbulence Modeling; p 171-192
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    Progress in simulating industrial flows using two-equation models: Can more be achieved with further research? (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: This viewgraph presentation provides a brief review of two-equation eddy-viscosity models (TEM's) from the perspective of applied CFD. It provides objective assessment of both well-known and newer models, compares model predictions from various TEM's with experiments, identifies sources of modeling error and gives historical perspective of their effects on model performance and assessment, and recommends directions for future research on TEM's.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Industry-Wide Workshop on Computational Turbulence Modeling; p 155-169
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    Experiences with two-equation turbulence models (1995)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: This viewgraph presentation discusses the following: introduction to CFD Research Corporation; experiences with two-equation models - models used, numerical difficulties, validation and applications, and strengths and weaknesses; and answers to three questions posed by the workshop organizing committee - what are your customers telling you, what are you doing in-house, and how can NASA-CMOTT (Center for Modeling of Turbulence and Transition) help.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Industry-Wide Workshop on Computational Turbulence Modeling; p 143-153
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    Recent advances in PDF modeling of turbulent reacting flows (1995)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: This viewgraph presentation concludes that a Monte Carlo probability density function (PDF) solution successfully couples with an existing finite volume code; PDF solution method applied to turbulent reacting flows shows good agreement with data; and PDF methods must be run on parallel machines for practical use.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Industry-Wide Workshop on Computational Turbulence Modeling; p 119-129
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    Experience with turbulence interaction and turbulence-chemistry models at Fluent Inc. (1995)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: This viewgraph presentation discusses (1) turbulence modeling: challenges in turbulence modeling, desirable attributes of turbulence models, turbulence models in FLUENT, and examples using FLUENT; and (2) combustion modeling: turbulence-chemistry interaction and FLUENT equilibrium model. As of now, three turbulence models are provided: the conventional k-epsilon model, the renormalization group model, and the Reynolds-stress model. The renormalization group k-epsilon model has broadened the range of applicability of two-equation turbulence models. The Reynolds-stress model has proved useful for strongly anisotropic flows such as those encountered in cyclones, swirlers, and combustors. Issues remain, such as near-wall closure, with all classes of models.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Industry-Wide Workshop on Computational Turbulence Modeling; p 131-142
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    Recent progress in the joint velocity-scalar PDF method (1995)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: This viewgraph presentation discusses joint velocity-scalar PDF method; turbulent combustion modeling issues for gas turbine combustors; PDF calculations for a recirculating flow; stochastic dissipation model; joint PDF calculations for swirling flows; spray calculations; reduced kinetics/manifold methods; parallel processing; and joint PDF focus areas.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Industry-Wide Workshop on Computational Turbulence Modeling; p 99-10
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    Single-drop reactive extraction/extractive reaction with forced convective diffusion and interphase mass transfer (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: An algorithm has been developed for time-dependent forced convective diffusion-reaction having convection by a recirculating flow field within the drop that is hydrodynamically coupled at the interface with a convective external flow field that at infinity becomes a uniform free-streaming flow. The concentration field inside the droplet is likewise coupled with that outside by boundary conditions at the interface. A chemical reaction can take place either inside or outside the droplet, or reactions can take place in both phases. The algorithm has been implemented, and for comparison results are shown here for the case of no reaction in either phase and for the case of an external first order reaction, both for unsteady behavior. For pure interphase mass transfer, concentration isocontours, local and average Sherwood numbers, and average droplet concentrations have been obtained as a function of the physical properties and external flow field. For mass transfer enhanced by an external reaction, in addition to the above forms of results, we present the enhancement factor, with the results now also depending upon the (dimensionless) rate of reaction.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, The Sixth Annual Thermal and Fluids Analysis Workshop; p 291-315
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    The Benard problem: A comparison of finite difference and spectral collocation eigen value solutions (1995)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The application of spectral methods, using a Chebyshev collocation scheme, to solve hydrodynamic stability problems is demonstrated on the Benard problem. Implementation of the Chebyshev collocation formulation is described. The performance of the spectral scheme is compared with that of a 2nd order finite difference scheme. An exact solution to the Marangoni-Benard problem is used to evaluate the performance of both schemes. The error of the spectral scheme is at least seven orders of magnitude smaller than finite difference error for a grid resolution of N = 15 (number of points used). The performance of the spectral formulation far exceeded the performance of the finite difference formulation for this problem. The spectral scheme required only slightly more effort to set up than the 2nd order finite difference scheme. This suggests that the spectral scheme may actually be faster to implement than higher order finite difference schemes.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: The Sixth Annual Thermal and Fluids Analysis Workshop; p 275-290
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    Turbulance boundary conditions for shear flow analysis, using the DTNS flow solver (1995)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The effects of different turbulence boundary conditions were examined for two classical flows: a turbulent plane free shear layer and a flat plate turbulent boundary layer with zero pressure gradient. The flow solver used was DTNS, an incompressible Reynolds averaged Navier-Stokes solver with k-epsilon turbulence modeling, developed at the U.S. Navy David Taylor Research Center. Six different combinations of turbulence boundary conditions at the inflow boundary were investigated: In case 1, 'exact' k and epsilon profiles were used; in case 2, the 'exact' k profile was used, and epsilon was extrapolated upstream; in case 3, both k and epsilon were extrapolated; in case 4, the turbulence intensity (I) was 1 percent, and the turbulent viscosity (mu(sub t)) was equal to the laminar viscosity; in case 5, the 'exact' k profile was used and mu(sub t) was equal to the laminar viscosity; in case 6, the I was 1 percent, and epsilon was extrapolated. Comparisons were made with experimental data, direct numerical simulation results, or theoretical predictions as applicable. Results obtained with DTNS showed that turbulence boundary conditions can have significant impacts on the solutions, especially for the free shear layer.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: The Sixth Annual Thermal and Fluids Analysis Workshop; p 247-262
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    Thermal neutral format based on the step technology (1995)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The exchange of models is one of the most serious problems currently encountered in the practice of spacecraft thermal analysis. Essentially, the problem originates in the diversity of computing environments that are used across different sites, and the consequent proliferation of native tool formats. Furthermore, increasing pressure to reduce the development's life cycle time has originated a growing interest in the so-called spacecraft concurrent engineering. In this context, the realization of the interdependencies between different disciplines and the proper communication between them become critical issues. The use of a neutral format represents a step forward in addressing these problems. Such a means of communication is adopted by consensus. A neutral format is not directly tied to any specific tool and it is kept under stringent change control. Currently, most of the groups promoting exchange formats are contributing with their experience to STEP, the Standard for Exchange of Product Model Data, which is being developed under the auspices of the International Standards Organization (ISO 10303). This paper presents the different efforts made in Europe to provide the spacecraft thermal analysis community with a Thermal Neutral Format (TNF) based on STEP. Following an introduction with some background information, the paper presents the characteristics of the STEP standard. Later, the first efforts to produce a STEP Spacecraft Thermal Application Protocol are described. Finally, the paper presents the currently harmonized European activities that follow up and extend earlier work on the area.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, The Sixth Annual Thermal and Fluids Analysis Workshop; p 263-273
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    A Navier-Stokes boundary element solver (1995)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Using global interpolation functions (GIF's) boundary element solutions are obtained for two-dimensional laminar flows. Two schemes are proposed for handling the convective terms. The first treats convection as a forcing function, and converts the flow equations to pseudo-Poisson equations. In the second scheme, some convective effect is incorporated into the fundamental solution used in constructing the pertinent integral equations. The lid-driven cavity flow is selected as the benchmark problem.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: The Sixth Annual Thermal and Fluids Analysis Workshop; p 233-246
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    Transitional flow in thin tubes for space station freedom radiator (1995)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: A two dimensional finite volume method is used to predict the film coefficients in the transitional flow region (laminar or turbulent) for the radiator panel tubes. The code used to perform this analysis is CAST (Computer Aided Simulation of Turbulent Flows). The information gathered from this code is then used to augment a Sinda85 model that predicts overall performance of the radiator. A final comparison is drawn between the results generated with a Sinda85 model using the Sinda85 provided transition region heat transfer correlations and the Sinda85 model using the CAST generated data.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, The Sixth Annual Thermal and Fluids Analysis Workshop; p 227-232
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    A probabilistic model of a porous heat exchanger (1995)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: This paper presents a probabilistic one-dimensional finite element model for heat transfer processes in porous heat exchangers. The Galerkin approach is used to develop the finite element matrices. Some of the submatrices are asymmetric due to the presence of the flow term. The Neumann expansion is used to write the temperature distribution as a series of random variables, and the expectation operator is applied to obtain the mean and deviation statistics. To demonstrate the feasibility of the formulation, a one-dimensional model of heat transfer phenomenon in superfluid flow through a porous media is considered. Results of this formulation agree well with the Monte-Carlo simulations and the analytical solutions. Although the numerical experiments are confined to parametric random variables, a formulation is presented to account for the random spatial variations.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, The Sixth Annual Thermal and Fluids Analysis Workshop; p 215-226
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    Numerical solution of fluid flow and heat tranfer problems with surface radiation (1995)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: This paper presents a numerical scheme, based on the finite element method, to solve strongly coupled fluid flow and heat transfer problems. The surface radiation effect for gray, diffuse and isothermal surfaces is considered. A procedure for obtaining the view factors between the radiating surfaces is discussed. The overall solution strategy is verified by comparing the available results with those obtained using this approach. An analysis of a thermosyphon is undertaken and the effect of considering the surface radiation is clearly explained.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, The Sixth Annual Thermal and Fluids Analysis Workshop; p 175-188
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    Single-drop reactive extraction/extractive reaction with forced convective diffusion and interphase mass transfer (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: An algorithm has been developed for the forced convective diffusion-reaction problem for convection inside and outside a droplet by a recirculating flow field hydrodynamically coupled at the droplet interface with an external flow field that at infinity becomes a uniform streaming flow. The concentration field inside the droplet is likewise coupled with that outside by boundary conditions at the interface. A chemical reaction can take place either inside or outside the droplet or reactions can take place in both phases. The algorithm has been implemented and results are shown here for the case of no reaction and for the case of an external first order reaction, both for unsteady behavior. For pure interphase mass transfer, concentration isocontours, local and average Sherwood numbers, and average droplet concentrations have been obtained as a function of the physical properties and external flow field. For mass transfer enhanced by an external reaction, in addition to the above forms of results, we present the enhancement factor, with the results now also depending upon the (dimensionless) rate of reaction.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, The Sixth Annual Thermal and Fluids Analysis Workshop; p 189-213
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    Effect of turbulence models on criticality conditions in swirling flows (1995)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The critical state of vortex cores downstream of vortex breakdown has been studied. Base vortical flows were computed using the Reynolds-averaged, axisymmetric Navier-Stokes equations. Standard K - epsilon, RNG and second-order Reynolds stress models were employed. Results indicate that the return to supercriticality is highly dependent on the turbulence model. The K - epsilon model predicted a rapid return of the vortex to supercritical conditions, the location of which showed little sensitivity to changes in the swirl ratio. The Reynolds stress model predicted that the vortex remains subcritical to the end of the domain for each of the swirl ratios employed, and provided results in qualitative agreement with experimental work. The RNG model produced intermediate results, with a downstream movement in the critical location with increasing swirl. Calculations for which area reductions were introduced at the exit in a subcritical flow were also performed using the Reynolds stress model. The structure of the resulting recirculation zone was altered significantly. However, when area reductions were employed within supercritical flows as predicted using the two-equation models, no significant influence on the recirculation zone was noted.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, The Sixth Annual Thermal and Fluids Analysis Workshop; p 163-173
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    A case study of view-factor rectification procedures for diffuse-gray radiation enclosure computations (1995)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The view factors which are used in diffuse-gray radiation enclosure calculations are often computed by approximate numerical integrations. These approximately calculated view factors will usually not satisfy the important physical constraints of reciprocity and closure. In this paper several view-factor rectification algorithms are reviewed and a rectification algorithm based on a least-squares numerical filtering scheme is proposed with both weighted and unweighted classes. A Monte-Carlo investigation is undertaken to study the propagation of view-factor and surface-area uncertainties into the heat transfer results of the diffuse-gray enclosure calculations. It is found that the weighted least-squares algorithm is vastly superior to the other rectification schemes for the reduction of the heat-flux sensitivities to view-factor uncertainties. In a sample problem, which has proven to be very sensitive to uncertainties in view factor, the heat transfer calculations with weighted least-squares rectified view factors are very good with an original view-factor matrix computed to only one-digit accuracy. All of the algorithms had roughly equivalent effects on the reduction in sensitivity to area uncertainty in this case study.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, The Sixth Annual Thermal and Fluids Analysis Workshop; p 115-131
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    Transient studies of G-induced capillary dryout and rewet (1995)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: A transient, one-dimensional numerical code is developed to model the liquid motion in an axial groove with square cross section. Axial variation in liquid level, shear stress and heat transfer between the groove wall and the liquid, evaporation and transient body forces are accounted for in the model. Dryout and rewet of the groove are allowed; the front location is determined numerically using conservation of mass and linear extrapolation. Several numerical test results are presented and discussed.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, The Sixth Annual Thermal and Fluids Analysis Workshop; p 85-105
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    Analysis of developing laminar flows in circular pipes using a higher-order finite-difference technique (1995)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: A higher-order finite-difference technique is developed to calculate the developing-flow field of steady incompressible laminar flows in the entrance regions of circular pipes. Navier-Stokes equations governing the motion of such a flow field are solved by using this new finite-difference scheme. This new technique can increase the accuracy of the finite-difference approximation, while also providing the option of using unevenly spaced clustered nodes for computation such that relatively fine grids can be adopted for regions with large velocity gradients. The velocity profile at the entrance of the pipe is assumed to be uniform for the computation. The velocity distribution and the surface pressure drop of the developing flow then are calculated and compared to existing experimental measurements reported in the literature. Computational results obtained are found to be in good agreement with existing experimental correlations and therefore, the reliability of the new technique has been successfully tested.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: The Sixth Annual Thermal and Fluids Analysis Workshop; p 107-114
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    Validation of the SINDA/FLUINT code using several analytical solutions (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The Systems Improved Numerical Differencing Analyzer and Fluid Integrator (SINDA/FLUINT) code has often been used to determine the transient and steady-state response of various thermal and fluid flow networks. While this code is an often used design and analysis tool, the validation of this program has been limited to a few simple studies. For the current study, the SINDA/FLUINT code was compared to four different analytical solutions. The thermal analyzer portion of the code (conduction and radiative heat transfer, SINDA portion) was first compared to two separate solutions. The first comparison examined a semi-infinite slab with a periodic surface temperature boundary condition. Next, a small, uniform temperature object (lumped capacitance) was allowed to radiate to a fixed temperature sink. The fluid portion of the code (FLUINT) was also compared to two different analytical solutions. The first study examined a tank filling process by an ideal gas in which there is both control volume work and heat transfer. The final comparison considered the flow in a pipe joining two infinite reservoirs of pressure. The results of all these studies showed that for the situations examined here, the SINDA/FLUINT code was able to match the results of the analytical solutions.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, The Sixth Annual Thermal and Fluids Analysis Workshop; p 69-84
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    Features and applications of the Groove Analysis Program (GAP) (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: An IBM Personal Computer (PC) version of the Groove Analysis program (GAP) was developed to predict the steady state heat transport capability of an axially grooved heat pipe for a specified groove geometry and working fluid. In the model, the capillary limit is determined by the numerical solution of the differential equation for momentum conservation with the appropriate boundary conditions. This governing equation accounts for the hydrodynamic losses due to friction in liquid and vapor flows and due to liquid/vapor shear interaction. Back-pumping in both 0-g and 1-g is accounted for in the boundary condition at the condenser end. Slug formation in 0-g and puddle flow in 1-g are also considered in the model. At the user's discretion, the code will perform the analysis for various fluid inventories (undercharge, nominal charge, overcharge, or a fixed fluid charge) and heat pipe elevations. GAP will also calculate the minimum required heat pipe wall thickness for pressure containment at design temperatures that are greater than or lower than the critical temperature of the working fluid. This paper discusses the theory behind the development of the GAP model. It also presents the many useful and powerful capabilities of the model. Furthermore, a correlation of flight test performance data and the predictions using GAP are presented and discussed.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, The Sixth Annual Thermal and Fluids Analysis Workshop; p 53-68
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  • 83
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    Computation of three-dimensional mixed convective boundary layer flow (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The paper presents the numerical solution of heat and mass transfer during cross-flow (orthogonal) mixed convection. In this class of flow, a buoyancy-driven transport in the vertical direction and a forced convective flow in the horizontal direction results in a three-dimensional boundary layer structure adjacent to the plate. The rates of heat and mass transfer are determined by a combined influence of the two transport processes. The equations for the conservation of mass, momentum, energy, and species concentration were solved along with appropriate boundary conditions to determine the distributions of velocity components, temperature, and concentration across the thickness of the boundary layer at different locations on the plate. Results were expressed in dimensionless form using Reynolds number, Richardson number for heat transfer, Richardson number for mass transfer, Prandtl number, and Schmidt number as parameters. It was found that the transport is dominated by buoyancy at smaller vertical locations and at larger distances away from the forced convection leading edge. Effects of forced convection appeared to be very strong at smaller horizontal distances from the leading edge. The cross stream forced convection enhanced the rate of heat and mass transfer by a very significant amount.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, The Sixth Annual Thermal and Fluids Analysis Workshop; p 25-36
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  • 84
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    Analysis of gas absorption to a thin liquid film in the presence of a zero-order chemical reaction (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The paper presents a detailed theoretical analysis of the process of gas absorption to a thin liquid film adjacent to a horizontal rotating disk. The film is formed by the impingement of a controlled liquid jet at the center of the disk and subsequent radial spreading of liquid along the disk. The chemical reaction between the gas and the liquid film can be expressed as a zero-order homogeneous reaction. The process was modeled by establishing equations for the conservation of mass, momentum, and species concentration and solving them analytically. A scaling analysis was used to determine dominant transport processes. Appropriate boundary conditions were used to solve these equations to develop expressions for the local concentration of gas across the thickness of the film and distributions of film height, bulk concentration, and Sherwood number along the radius of the disk. The partial differential equation for species concentration was solved using the separation of variables technique along with the Duhamel's theorem and the final analytical solution was expressed using confluent hypergeometric functions. Tables for eigenvalues and eigenfunctions are presented for a number of reaction rate constants. A parametric study was performed using Reynolds number, Ekman number, and dimensionless reaction rate as parameters. At all radial locations, Sherwood number increased with Reynolds number (flow rate) as well as Ekman number (rate of rotation). The enhancement of mass transfer due to chemical reaction was found to be small when compared to the case of no reaction (pure absorption), but the enhancement factor was very significant when compared to pure absorption in a stagnant liquid film. The zero-order reaction processes considered in the present investigation included the absorption of oxygen in aqueous alkaline solutions of sodiumdithionite and rhodium complex catalyzed carbonylation of methanol. Present analytical results were compared to previous theoretical results for limiting conditions, and were found to have very good agreement.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, The Sixth Annual Thermal and Fluids Analysis Workshop; p 37-52
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  • 85
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    Extensional flow convecting a reactant undergoing a first order homogeneous reaction and diffusional mass transfer from a sphere at low to intermediate Peclet and Damkohler numbers (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Forced convective diffusion-reaction is considered for viscous axisymmetric extensional convecting velocity in the neighborhood of a sphere. For Peclet numbers in the range 0.1 less than or equal to Pe less than or equal to 500 and for Damkohler numbers increasing with increasing Pe but in the overall range 0.02 less than or equal to Da less than or equal to 10, average and local Sherwood numbers have been computed. By introducing the eigenfunction expansion c(r, Theta) = Sum of c(n)(r)P(n)(cos Theta) into the forced convective diffusion equation for the concentration of a chemical species undergoing a first order homogeneous reaction and by using properties of the Legendre functions Pn(cos Theta), the variable coefficient PDE can be reduced to a system of N + 1 second order ODEs for the radial functions c(sub n)(r), n = 0, 1, 2,..., N. The adaptive grid algorithm of Pereyra and Lentini can be used to solve the corresponding 2(N + 1) first order differential equations as a two-point boundary value problem on 1 less than or equal to r less than or equal to r(sub infinity). Convergence of the expansion for a specific value of N can thus be established and provides 'spectral' behavior as well as the full concentration field c(r, Theta).
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, The Sixth Annual Thermal and Fluids Analysis Workshop; p 1-23
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  • 86
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    An annotation system for 3D fluid flow visualization (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Annotation is a key activity of data analysis. However, current systems for data analysis focus almost exclusively on visualization. We propose a system which integrates annotations into a visualization system. Annotations are embedded in 3D data space, using the Post-it metaphor. This embedding allows contextual-based information storage and retrieval, and facilitates information sharing in collaborative environments. We provide a traditional database filter and a Magic Lens filter to create specialized views of the data. The system has been customized for fluid flow applications, with features which allow users to store parameters of visualization tools and sketch 3D volumes.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Digital Equipment Corp., Three-Dimensional User Interfaces for Scientific Visualization; 8 p
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  • 87
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    Reduction of fluctuating pressure loads in shock wave turbulent boundary layer interactions (1995)
    In:  Other Sources
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    Publication Date: 2013-08-29
    Description: Fluctuating surface pressure measurements have been made to investigate the effectiveness of boundary layer separators (BLS's) in reducing the fluctuating pressure loads produced by separated shock wave turbulent boundary layer interactions. Measurements have been made under unswept and swept compression corner interactions in a Mach 5 flow. BLS's fix the separation location and eliminate the large-amplitude, low-frequency fluctuating pressure loads upstream of the compression corners. The loads on the unswept compression corner face are reduced by as much as 59%. The BLS's also shift the mean pressure distribution on the unswept corner face in the streamwise direction. Results show that the loads on the corner face vary with the BLS height and the distance between the BLS and the compression corner. Suggestions for the optimum placement and the use of the BLS's are also made.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Control and Reduction of Unsteady Pressure Loads in Separated Shock Wave Turbulent Boundary Layer Interaction; 19 p
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  • 88
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    Experimental study of the use of vortex generators to reduce fluctuating pressure loads in shock wave turbulent boundary layer interactions (1995)
    In:  Other Sources
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    Publication Date: 2013-08-29
    Description: Fluctuating wall pressure measurements have been made in a separated shock wave/turbulent boundary layer interaction produced by an unswept compression corner in a Mach 5 flow. Wheeler doublet vortex generators were placed 15.8 boundary layer thicknesses upstream of the corner to study their effect on the fluctuating pressure loads produced by the translating separation shock. The vortex generators produced significant three-dimensionality in an otherwise two-dimensional interaction. They reduced the upstream influence and the length of the region of shock motion by 60% and 64%, respectively, decreased the maximum wall pressure rms by 23%, and shifted the fluctuations to a higher frequency band. The maximum fraction of energy in the 100-500 Hz frequency band is decreased by 11%. These changes are due to a fuller boundary layer profile, a weaker separation shock, and increased boundary layer turbulence causing increased separation shock jitter.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Control and Reduction of Unsteady Pressure Loads in Separated Shock Wave Turbulent Boundary Layer Interaction; 20 p
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  • 89
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    Stellar ionization of the thermal radio emission regions of the Galactic Center (1995)
    In:  Other Sources
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    Publication Date: 2013-08-29
    Description: We have used the Anglo-Australian Telescope imaging spectrometer IRIS to search for hot young stars which may ionize the thermal radio emission regions within the inner 40 pc of the Galaxy. Several hot stars were discovered based on their Br gamma (2.165 micron) and He I (2.058 micron) emission, including a cluster of possible WN 8-9 stars. Comparison of the spectra of the new stars with optically classified stars suggests a spectral classification of B(e) and WN7-9. Based on the calculated luminosity of the new stars and comparisons with radio data, the emission stars could be largely responsible for the ionization of the thermal radio emission regions.
    Keywords: SPACE RADIATION
    Type: Astronomical Society of the Pacific, Airborne Astronomy Symposium on the Galactic Ecosystem: From Gas to Stars to Dust, Volume 73; p 511-514
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  • 90
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    Observations of localized NiII emission in M82: Evidence for supernovae activity in the molecular cloud east of the nucleus (1995)
    In:  Other Sources
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    Publication Date: 2013-08-29
    Description: Narrow band images of M82 at wavelengths of 6.63 microns (NiII) and 6.8 microns (continuum) are discussed in terms of new evidence for supernova activity in the nuclear region of the M82 starburst galaxy. Data were recorded using a 128x128 Si:Ga array in an infrared camera on the KAO Southern Expedition in April '94.
    Keywords: SPACE RADIATION
    Type: Astronomical Society of the Pacific, Airborne Astronomy Symposium on the Galactic Ecosystem: From Gas to Stars to Dust, Volume 73; p 437-440
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  • 91
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    Silicate and related dust emission in stars on the asymptotic giant branch (1995)
    In:  Other Sources
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    Publication Date: 2013-08-29
    Description: The Low-Resolution Spectrometer (LRS) on the Infrared Astronomical Satellite (IRAS) produced a rich set of spectra from oxygen-rich circumstellar dust shells. Little-Marenin and Little found that in addition to the classic 10 micron emission feature due to silicate dust, many oxygen-rich shells also produce components at 11 and 13 microns. Some shells exhibit only a broad, low-contrast feature which peaks longward of 11 microns and has been attributed to alumina dust. We have modified the classification method of Little-Marenin and Little, applied it to a large sample of bright oxygen-rich variables on the asymptotic giant branch, and undertaken a study of the 13 micron emission feature and the sources which produce it. We present some of the results of these studies.
    Keywords: SPACE RADIATION
    Type: Astronomical Society of the Pacific, Airborne Astronomy Symposium on the Galactic Ecosystem: From Gas to Stars to Dust, Volume 73; p 425-428
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  • 92
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    A 7 micron dust emission feature in oxygen-rich circumstellar shells (1995)
    In:  Other Sources
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    Publication Date: 2013-08-29
    Description: New 4 to 8 micron infrared spectroscopic observations of two oxygen-rich stars are presented and combined with IRAS low resolution spectrometer (LRS) data to span the 4 to 24 micron wavelength range. In the 4 to 8 micron range, we observe a 7.15 micron (1400 cm(exp -1)) emission feature. This new feature is not uniquely correlated with any of the sharply defined 10, 11, 13.1, and 19.7 micron emission features that are known to be present in this class of circumstellar shells, but it does appear to be correlated with the spectrally broad dust emission in the 10 to 20 micron spectral region. The feature has not been reported previously in any other astronomical environment. A reinterpretation of prior 4 to 8 micron spectroscopy of alpha Ori and R Cas reveals the presence of the 7.15 micron emission in alpha Ori and possibly in R Cas. The spectrally narrow 19.7 micron emission, that is distinctly different than the relatively broad silicate 18 micron emission feature in oxygen-rich dust shells, is also observed to be present in the LRS spectrum of SAO 197549. The implication of these observations is that a universal astronomical silicate does not exist in oxygen-rich circumstellar shells.
    Keywords: SPACE RADIATION
    Type: Astronomical Society of the Pacific, Airborne Astronomy Symposium on the Galactic Ecosystem: From Gas to Stars to Dust, Volume 73; p 419-424
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  • 93
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    Mid- and far-infrared emission bands in C-rich proto-planetary nebulae (1995)
    In:  Other Sources
    Details
    Publication Date: 2013-08-29
    Description: The 16-48 micron spectra of five carbon-rich post-asymptotic giant branch (post-AGB) objects known to have an unidentified 21 micron feature in their IRAS low resolution spectrometer (LRS) spectra have been obtained using the Kuiper Airborne Observatory. A broad emission band extending from 24 to approximately 45 microns is present in the spectra of these objects. The strength of this band is variable from source to source and is not correlated with the strength of the 21 micron band. The possible identifications for the emitting material of both the 21 and 30 micron emission bands is discussed.
    Keywords: SPACE RADIATION
    Type: Astronomical Society of the Pacific, Airborne Astronomy Symposium on the Galactic Ecosystem: From Gas to Stars to Dust, Volume 73; p 413-418
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  • 94
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    Fine structure line emission from supergiants (1995)
    In:  Other Sources
    Details
    Publication Date: 2013-08-29
    Description: We have detected (O I) 63 micron and (Si II) 35 micron emission from the oxygen-rich, M supergiants alpha Orionis (Betelgeuse), alpha Scorpii (Antares), and alpha Herculis (Rasalgethi). The measured fluxes indicate that the emission originates in dense, warm gas in the inner envelope or transition region where molecules and dust are expected to form and the acceleration of the wind occurs. Mass-loss rates are derived, evidence for time variability is presented, and results for other evolved stars are included.
    Keywords: SPACE RADIATION
    Type: Astronomical Society of the Pacific, Airborne Astronomy Symposium on the Galactic Ecosystem: From Gas to Stars to Dust, Volume 73; p 397-404
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  • 95
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    A search for hydrogen lasers in MWC 349 from the KAO (1995)
    In:  Other Sources
    Details
    Publication Date: 2013-08-29
    Description: We report the first observations of H15 alpha (169.4114 microns) and H10 alpha (52.5349 microns) in MWC 349 from the KAO. We obtain a 3 sigma upper limit of 2 x 10(exp -19) W/sq cm for H15 alpha and a flux of 3.6 +/- 1.3 x 10(exp -19) W/sq for H10 alpha. These fluxes are consistent with an appreciable excess due to laser amplification down to quantum numbers n approx. equals 10.
    Keywords: SPACE RADIATION
    Type: Astronomical Society of the Pacific, Airborne Astronomy Symposium on the Galactic Ecosystem: From Gas to Stars to Dust, Volume 73; p 271-274
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  • 96
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    The pressure field of a gust interacting with a flat plate (1995)
    In:  Other Sources
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    Publication Date: 2013-08-29
    Description: A semianalytical solution is presented for the unsteady pressure field of a vortical gust interacting with a flat-plate airfoil in subsonic flow. The solution will serve as a benchmark for evaluating the accuracy and efficiency of time dependent numerical schemes. The specific case considered corresponds to the ICASE benchmark problem number 6. The results are compared with those of asymptotic theories for high frequency and show excellent agreement.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Langley Research Center, ICASE(LaRC Workshop on Benchmark Problems in Computational Aeroacoustics (CAA) p 291-296 (SEE N95-30133 10-71); NASA. Langley Resear
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  • 97
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    Extragalactic diffuse (C II) emission (1995)
    In:  Other Sources
    Details
    Publication Date: 2013-08-29
    Description: The 158 micro m (CII) line has been mapped in the galaxies Centaurus A, M83, NGC 6946, and NGC 891. The emission exists over very large scales, peaking in the nuclei and extending beyond the spiral arms and molecular disks. While most of the (CII) emission from the nuclei and spiral arms originates in photodissociated gas, the diffuse atomic gas can account for much of the (CII) emission in the extended regions.
    Keywords: SPACE RADIATION
    Type: Astronomical Society of the Pacific, Airborne Astronomy Symposium on the Galactic Ecosystem: From Gas to Stars to Dust, Volume 73; p 181-184
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  • 98
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    Computation of wave propagation in a complex flow (1995)
    In:  Other Sources
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    Publication Date: 2013-08-29
    Description: A numerical method has been developed in order to address aeroacoustic problems modeled by the linearized Euler equations. A weak formulation of the equations leads to a time-dependent equation for the test functions. The basic solver being one dimensional, two dimensional problems are handled by directional splitting. This method shows low dissipation and dispersion errors.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Langley Research Center, ICASE(LaRC Workshop on Benchmark Problems in Computational Aeroacoustics (CAA) p 125-132 (SEE N95-30133 10-71); NASA. Langley Resear
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  • 99
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    Radio emission from spinning grains (1995)
    In:  Other Sources
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    Publication Date: 2013-08-29
    Description: We present a study of the radio emission from rotating, charged dust grains immersed in the ionized gas constituting the thick, H alpha-emitting disk of many spiral galaxies.
    Keywords: SPACE RADIATION
    Type: Astronomical Society of the Pacific, Airborne Astronomy Symposium on the Galactic Ecosystem: From Gas to Stars to Dust, Volume 73; p 93-96
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  • 100
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    Auto-adaptive finite element meshes (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Accurate capturing of discontinuities within compressible flow computations is achieved by coupling a suitable solver with an automatic adaptive mesh algorithm for unstructured triangular meshes. The mesh adaptation procedures developed rely on non-hierarchical dynamical local refinement/derefinement techniques, which hence enable structural optimization as well as geometrical optimization. The methods described are applied for a number of the ICASE test cases are particularly interesting for unsteady flow simulations.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Langley Research Center, ICASE(LaRC Workshop on Adaptive Grid Methods; p 219-232
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