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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 361 records · Page 20
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

The multiple nesting of mesoscale, submesoscale, and nonhydrostatic microscale numerical models for a case of mesocyclogenesis and severe storm development

A fundamental approach involving the integration of two different numerical models over several different spatial mesh lengths is considered. Model I is a hydrostatic, incompressible, and adiabatic primitive (Newtonian) equation set with no boundary layer forcing, i.e., surface heat or moisture flux or external frictional stresses. Typically this model is initialized from conventional radiosonde data and run for a 12-15 hour forecast period over a 40 km horizontal mesh. If phase I of the tornado developmental processes develops, the data is 'frozen' in space and time, interpolated to a 20 km mesh, and integrated for a shorter time period (3 hours) with a shorter time step. Model II is a nonhydrostatic compressible 18-level complement of model I. If model II indicates the development of the intensification of phase V dynamical processes, the data is frozen and interpolated to finer mesh lengths until the tornadic circulation system is approximated

Kaplan, M. L.↗
NASA NTRS1978

Severe storm environments: A Skylab EREP report

The results from the severe storm experiment over Texas and Oklahoma are presented. Correlation of data, soil moisture, water temperature, and cloud characteristics were considered. The sensors used in this study were multispectral band cameras, multispectral band scanners, infrared spectrometers, radiometers, and scatterometers.

Pitts, D. E.↗
NASA NTRS1978

Severe storms

An overview of severe storms given by a representative of the U.S. Department of Commerce/NOAA and how they affect aviation is presented. What is being done and the organizations responsible for the work in this area are briefly discussed. A partial list of the things that the representative feels need to be done is also presented.

Connolly, J. W.↗
NASA NTRS1977

Severe storms and their interaction with the environment

A brief description is given of significant research accomplishments and of planned research on atmospheric variability and the interaction of severe storms with their environment using atmospheric variability experiments data. Use of the results for the assessment of satellite capabilities are described briefly.

Scoggins, J. R.↗
NASA NTRS1979

Analytic studies on satellite detection of severe, two-cell tornadoes

It is argued that a two-cell structure is likely to be the unique property, and potentially satellite-accessible observable, of the exceptionally severe tornado. Analysis elucidating the dynamic, thermodynamic, and geometric properties of this two-cell structure is described. The analysis ultimately will furnish instrumentation requirements.

Carrier, G. F.↗
NASA NTRS1979

Effect of number of probes and their orientation on the calculation of several compressor face distortion descriptors

A study was performed to determine the effects of the number and position of total pressure probes on the calculation of five compressor face distortion descriptors. This study used three sets of 320 steady state total pressure measurements that were obtained with a special rotating rake apparatus in wind tunnel tests of a mixed-compression inlet. The inlet was a one third scale model of the inlet on a YF-12 airplane, and it was tested in the wind tunnel at representative flight conditions at Mach numbers above 2.0. The study shows that large errors resulted in the calculation of the distortion descriptors even with a number of probes that were considered adequate in the past. There were errors as large as 30 and -50 percent in several distortion descriptors for a configuration consisting of eight rakes with five equal-area-weighted probes on each rake.

Stoll, F.↗
NASA NTRS1979

Effect of several geometric parameters on the static internal performance of three nonaxisymmetric nozzle concepts

Effects of several geometric parameters on the internal performance of nonaxisymmetric convergent-divergent, single-ramp expansion, and wedge nozzles were investigated at nozzle pressure ratios up to approximately 10. In addition, two different thrust-vectoring schemes were investigated with the wedge nozzle. The results indicated that as with conventional round nozzles, peak nonaxisymmetric nozzle, internal performance occurred near the nozzle pressure ratio required for fully expanded exhaust flow. Nozzle sidewall length or area generally had little effect on the internal performance of the nozzles investigated.

Berrier, B. L.↗
NASA NTRS1979

Relationship of red and photographic infrared spectral radiances to alfalfa biomass, forage water content, percentage canopy cover, and severity of drought stress

Red and photographic infrared spectral data were collected using a handheld radiometer for two cuttings of alfalfa. Significant linear and non-linear correlation coefficients were found between the spectral variables and plant height, biomass, forage water content, and estimated canopy cover for the earlier alfalfa cutting. The alfalfa of later cutting experienced a period of severe drought stress which limited growth. The spectral variables were found to be highly correlated with the estimated drought scores for this alfalfa cutting.

Tucker, C. J.↗
NASA NTRS1979

Lightning as an indication of storm severity

There is a substantial case for the theory that cloud electrification is related primarily to strong convection and the sizeable relative air motion that it implies; therefore, the electrification and subsequent discharge rates can be related to the air motion environment of thunderstorms. The isoceraunic contour map used by the WMO for observing and measuring thunderstorm occurrence contains no information on flash rates, flash density, flash relationship to storm severity, or flash variation with meteorological environment. A constant-view geosynchronous lightning mapper would permit simultaneous studies of the lightning discharge patterns and the meteorological environment of storms, thus establishing whether or not there is a reliable enough relationship to use the observed flash rates and characteristics as supplemental guidance for storm forecast refinement.

Dodge, J. C.↗
NASA NTRS1978

Microflora analysis of a child with severe combined immune deficiency

The paper presents a microflora analysis of a 5-year-old male child with severe combined immune deficiency who was delivered by Caesarean section and continuously maintained in an isolator. Despite precautions, it was found that the child had come in contact with at least 54 different microbial contaminants. While his skin autoflora was similar to that of a reference group of healthy male adults in numbers of different species and the number of viable cells present per square centimeter of surface area, the subject's autoflora differed from the reference group in that significantly fewer anaerobic species were recovered from the patient's mouth and feces. It is suggested that the child's remaining disease free shows that the reported bacteria are noninvasive or that the unaffected components of the child's immune defense mechanisms are important.

Taylor, G. R.↗
NASA NTRS1978

The chaotic solar nebula - Evidence for episodic condensation in several distinct zones

Abundances of rare earth elements in Allende inclusions are considered along with the rim sequence on coarse-grained chondrules. It is found that in at least several zones the nebula went through episodes of condensation and gas/grain separation. Four separate zones are required to make the two types of fine-grained aggregates and the two types of coarse-grained chondrules. Other types of inclusions in Allende, such as the olivine aggregates, may well require additional condensation zones. All of these conclusions are based on data from one meteorite. Although the details of the gas/grain separation mechanism in these zones is not well understood, it is clear that a single monotonic-cooling condensation sequence followed by isolation of grains from gas cannot account for the observations.

Boynton, W. V.↗
NASA NTRS1979

Several preliminary designs for heavy-lift earth-to-orbit transport

Several design concepts are identified for earth-to-orbit delivery of payloads in the 200 Mg range. The concept include winged vehicles which take-off vertically and land horizontally and ballistic shapes similar to the Gemini or Mercury vehicles which take-off and land vertically. Major technology issues include stability problems for the winged vehicle with large base mounted engines and heat shield design problems for the ballistic vehicle, the latter requiring doors in the heat shield for the main engines.

Brien, E. P.↗
NASA NTRS1979

Several recent findings concerning the dynamics of the earth's magnetotail

Several recent results concerning the nature of earth's magnetotail are briefly reviewed. These observational findings include: (1) the three-dimensional character of the plasma sheet via a comprehensive survey of proton bulk flows, (2) a region of earthward-flowing plasmas at the interfaces of the plasma sheet and magnetotail lobes during magnetic substorm recovery, and (3) the signature of electrostatic acceleration for protons within the jetting plasmas from magnetotail fireballs.

Frank, L. A.↗
NASA NTRS1981

Data-acquisition and control system for severe environments

Report evaluates control system by measuring accuracy and performance of system subcomponents, including interface wiring unit, power controller, and tape recorder. Test parameters establish variety of severe operation environments. Text features test program descriptions, sample readouts, and results. Summary of custom solar system simulator is included.

Source record↗
NASA NTRS1980

Severe storms forecast systems

Two research tasks are described: (1) the improvement and enhancement of an existing mesoscale numerical simulation system, and (2) numerical diagnostic studies associated with an individual case of severe storm development (April 10, 1979 in the Red River Valley of Texas and Oklahoma).

Kaplan, M.↗
NASA NTRS1980

Evaluation of the stress corrosion cracking resistance of several high strength low alloy steels

The stress corrosion cracking resistance was studied for high strength alloy steels 4130, 4340, for H-11 at selected strength levels, and for D6AC and HY140 at a single strength. Round tensile and C-ring type specimens were stressed up to 100 percent of their yield strengths and exposed to alternate immersion in salt water, salt spray, the atmosphere at Marshall Space Flight Center, and the seacoast at Kennedy Space Center. Under the test conditions, 4130 and 4340 steels heat treated to a tensile strength of 1240 MPa (180 ksi), H-11 and D6AC heat treated to a tensile strength of 1450 MPa (210 ksi), and HY140 (1020 MPa, 148 ksi) are resistant to stress corrosion cracking because failures were not encountered at stress levels up to 75 percent of their yield strengths. A maximum exposure period of one month for alternate immersion in salt water or salt spray and three months for seacoast is indicated for alloy steel to avoid false indications of stress corrosion cracking because of failure resulting from severe pitting.

Humphries, T. S.↗
NASA NTRS1980

Aerodynamic and inlet flow characteristics of several hypersonic airbreathing missile concepts

Four conceptual hypersonic missile configurations were examined experimentally and theoretically. Two of the concepts employed twin module bottom-mounted engines and two were designed for upper surface inlets or engines with the intent of reducing the vehicle observables. The tests were conducted at Mach 6 and Reynolds numbers of 6 to 7.5 x 10 to the 6th per foot. Flow field surveys in the vicinity of the engine inlet were made on all configurations and force and moment tests were conducted on three of the vehicles. Stability and control characteristics of the bottom-mounted engine configurations which incorporated slender, low wings were dominated by strong vortices that promoted severe pitchup tendencies. The shock layer and flow quality in the vicinity of the bottom-mounted engine inlets were dependent on nose shape. The spatula-like upper surface engine concept demonstrated good performance and had uniform flow entering the engine inlet, while the upper surface inlet concept with a highly swept forebody incurred large gradients due to interactions with leading edge shocks.

Dillon, J. L.↗