Search NASA⌕ Search

SEARCH · Search NASA

Results for “Ames”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

Investigation of flexible nozzle wall-flutter incidents in the NASA-Ames Research Center 11- by 11-foot transonic wind tunnel

Twice during the spring of 1978, the two steel-plate 'flex-walls' that form the variable-geometry nozzle of the 11- by 11-foot tunnel at Ames Research Center experienced a severe dynamic instability. Both walls fluttered in the fundamental beam-bending mode and experienced stresses approaching the yield strength of the material. Both flutter incidents occurred at Mach numbers of about 1.15. The tunnel, operational for 24 years, had no history of such an instability. The cause of these flutter incidents, the steps taken to prevent a recurrence, and the requalification of the facility are described.

Erickson, L. L.↗
NASA NTRS1979

Operational procedures for ground station operation: ATS-3 Hawaii-Ames satellite link experiment

Hardware description and operational procedures for the ATS-3 Hawaii-Ames satellite computer link are presented in basic step-by-step instructions. Transmit and receive channels and frequencies are given. Details such as switch settings for activating the station to the sequence of turning switches on are provided. Methods and procedures for troubleshooting common problems encountered with communication stations are also provided.

Nishioka, K.↗
NASA NTRS1980

Ames Research Center publications: A continuing bibliography, 1978

This bibliography lists formal NASA publications, journal articles, books, chapters of books, patents and contractor reports issued by Ames Research Center which were indexed by Scientific and Technical Aerospace Abstracts, Limited Scientific and Technical Aerospace Abstracts, and International Aerospace Abstracts in 1978. Citations are arranged by directorate, type of publication and NASA accession numbers. Subject, personal author, corporate source, contract number, and report/accession number indexes are provided.

Source record↗
NASA NTRS1980

Comparison of the Nimbus-4 BUV ozone data with the Ames two-dimensional model

A comparison is made of the first two years of Nimbus 4 backscattered ultraviolet (BUV) ozone measurements with the predictions of the Ames two dimensional model. The ozone observations used consist of the mixing ratio on the 1, 2, 5, and 10 mb pressure surfaces. The data are zone and time averaged to obtain seasonal means for 1970 and 1971 and are found to show strong and repeatable meridional and seasonal dependencies. The model used for comparison with the observations extends from 80 N to 80 S latitude and from altitudes of 0 to 60 km with 5 deg horizontal grid spacing and 2.5 km vertical grid spacing. Chemical reaction and photolysis rates are diurnally averaged and the photodissociation rates are corrected for the effects of scattering. The large altitude, latitude, and seasonal changes in the ozone data agree with the model predictions. Model predictions of the sensitivity of the comparisons to changes in the assumed mixing ratios of water vapor, odd nitrogen, and odd chlorine, as well as to changes in the ambient temperature and transport parameters are also shown.

Borucki, W. J.↗
NASA NTRS1980

Upper surface blowing noise of the NASA-Ames quiet short-haul research aircraft

An experimental study of the propulsive-lift noise of the NASA-Ames quiet short-haul research aircraft (QSRA) is described. Comparisons are made of measured QSRA flyover noise and model propulsive-lift noise data available in references. Developmental tests of trailing-edge treatments were conducted using sawtooth-shaped and porous USB flap trailing-edge extensions. Small scale parametric tests were conducted to determine noise reduction/design relationships. Full-scale static tests were conducted with the QSRA preparatory to the selection of edge treatment designs for flight testing. QSRA flight and published model propulsive-lift noise data have similar characteristics. Noise reductions of 2 to 3 dB were achieved over a wide range of frequency and directivity angles in static tests of the QSRA. These noise reductions are expected to be achieved or surpassed in flight tests planned by NASA in 1980.

Bohn, A. J.↗
NASA NTRS1980

A measurement of forward-flight effects on the noise from a JT15D-1 turbofan engine in the NASA-Ames 40- by 80-Foot Wind Tunnel

A Pratt and Whitney JT15D-1 turbofan engine was tested in two facilities at Ames Research Center: the outdoor Static Test Facility and the 40- by 80-Foot Wind Tunnel. The primary purposes of the test were to determine the effects of forward velocity on the turbofan spectra in the forward quadrant for the cruise inlet and to compare these wind-tunnel spectra with outdoor spectra to determine the possibility of simulating forward-velocity effects from purely outdoor measurements. The wind-tunnel data show a reduction in the blade-passage frequency tones of the order of 10 dB with increasing forward velocity at subsonic fan-tip speeds. No forward-velocity variation was observed at supersonic tip speeds. Comparison of in-duct spectra for the cruise inlet at forward velocity, with spectra from outdoor tests with a distortion-control inlet shows excellent agreement for the in-duct data when allowance is made for different in-duct volumes. This is also reflected in good agreement for the far-field spectra at small forward angles. The comparisons of wind-tunnel and outdoor data also indicate that at least for the JT15D-1, it may be possible to approximate the shape of the far-field spectra at large directivity angles from an outdoor measurement with the cruise inlet, providing an effective inflow control device is used.

Ahtye, W. F.↗
NASA NTRS1979

The 1979 Ames Research Center Publications: A continuing bibliography

This bibliography lists formal NASA publications, journal articles, books, chapters of books, patents, and contractor reports issued by Ames Research Center which were indexed by Scientific and Technical Aerospace Reports, Limited Scientific and Technical Aerospace Reports, and International Aerospace Abstracts in 1979. Citations are arranged by directorate, type of publication, and NASA accession numbers. Subject, Personal Author, Corporate Source, Contract Number, and Report/Accession Number Indexes are provided.

Source record↗
NASA NTRS1981

Ames Research Center publications: A continuing bibliography, 1980

This bibliography lists formal NASA publications, journal articles, books, chapters of books, patents, contractor reports, and computer programs that were issued by Ames Research Center and indexed by Scientific and Technical Aerospace Reports, Limited Scientific and Technical Aerospace Reports, International Aerospace Abstracts, and Computer Program Abstracts in 1980. Citations are arranged by directorate, type of publication, and NASA accession numbers. Subject, personal author, corporate source, contract number, and report/accession number indexes are provided.

Source record↗
NASA NTRS1981

Measurements of flow quality in the Ames 2 x 2ft transonic wind tunnel

For decades, wind tunnel testing has been conducted in test section environments which have not been adequately documented. However, with the advent of the energy shortage, the need for improved fuel-efficient transports employing supercritical or LFC airfoils has increased the awareness of the possible influence of freestream turbulence on advanced experimental testing. This has already lead to detailed flow quality measurements in NASA transonic wind tunnels. The purpose of this paper is to present results of a study in the Ames 2 x 2 ft transonic wind tunnel.

Owen, F. K.↗
NASA NTRS1980

Forward velocity effects on fan noise and the suppression characteristics of advanced inlets as measured in the NASA-Ames 40 by 80 foot wind tunnel

Forward velocity effects on the forward radiated fan noise and on the suppression characteristics of three advanced inlets relative to a baseline cylindrical inlet were measured in the NASA Ames Research Center 40 x 80 foot Wind Tunnel. A modified JT15D turbofan engine in a quiet nacelle was the source of fan noise; the advanced inlets were a Conventional Takeoff/Landing (CTOL) hybrid inlet, a Short Takeoff/Landing (STOL) hybrid inlet, and a treated deflector inlet. Also measured were the static to flight effects on the fan noise of canting the baseline inlet 4 deg downward to simulate typical wing mounted turbofan engines. The CTOL hybrid inlet suppressed the high tip speed fan noise as much as 18 PNdB on a 61 m (200 ft) sideline scaled to a CF6 size engine while the STOL hybrid inlet suppressed the low tip speed fan noise as much as 13 PNdB on a 61 m (200 ft) sideline scaled to a OCSEE size engine. The deflector inlet suppressed the high tip speed fan noise as much as 13 PNdB at 61 m (200 ft) overhead scaled to a CF6 size engine. No significant changes in fan noise suppression for the CTOL and STOL hybrid inlets occurred for forward velocity changes above 21 m/s (68 ft/s) or for angle of attack changes up to 15 deg. However, changes in both forward velocity and angle of attack changed the deflector inlet noise unpredictably due to the asymmetry of the inlet flow field into the fan.

Moore, M. T.↗
NASA NTRS1982

Holographic interferometry and tomography at Ames Research Center

A YAG laser holographic interferometer system and reconstruction laboratory for the Ames 2- by 2-Foot Transonic Wind Tunnel are discussed. This system provides dual plate and double pulse holography for quantitative and qualitative measurements, respectively. Interferometric measurements of two-dimensional airfoils and three-dimensional bodies of revolution for a tomography feasibility study were made. The two-dimensional work included supercritical airfoils, an oscillating airfoil undergoing dynamic stall, and a circulation control airfoil. The tomography experiments centered around hemispherical nose and tangent ogive models. In addition, the tomography work covered the development of a Fourier transform code for the retrieval of the three dimensional density distributions from the interferograms.

Lee, G.↗
NASA NTRS1981

Comparison of the Nimbus-4 BUV ozone data with the Ames two-dimensional model

Predictions by the Ames two-dimensional model of altitude, latitude and seasonal variations in ozone distribution are compared with the first two years of Nimbus 4 backscattered ultraviolet (BUV) measurements in a preliminary attempt at model verification. The ozone observations consist of mixing ratios on the 1-, 2-, 5-, and 10-mbar pressure surfaces zonally and time averaged to obtain seasonal means for 1970 and 1971. The model is based on chemical reaction and photolysis rate constants recommended by the NASA Panel for Data Evaluation (1979), diurnally averaged for latitudes from 80 deg N to 80 deg S and altitudes from 0 to 60 km with 5 deg horizontal and 2.5 km vertical grid spacings. The large altitude, latitude and seasonal variations observed in the data are found to agree well with model predictions. Examination of the sensitivity of the model predictions to various assumed parameters indicates that improvements in agreement may be obtained by variations of the odd chlorine mixing ratio, odd-nitrogen level and transport parameters.

Borucki, W. J.↗
NASA NTRS1983

Ames Research Center overview

The aeronautical research programs of the Ames Research Center are reviewed with particular emphasis on V/STOL aircraft development. Test facilities and simulation capabilities are briefly described. The Tilt Rotor Research Aircraft, X-Wing vehicle, Rotor Systems Research Aircraft, and the Quiet Short Haul Aircraft are discussed.

Snyder, C. T.↗
NASA NTRS1983

Supporting flight data analysis for Space Shuttle Orbiter experiments at NASA Ames Research Center

The space shuttle orbiter experiments program is responsible for collecting flight data to extend the research and technology base for future aerospace vehicle design. The infrared imagery of shuttle (IRIS), catalytic surface effects, and tile gap heating experiments sponsored by Ames Research Center are part of this program. The software required to process the flight data which support these experiments is described. In addition, data analysis techniques, developed in support of the IRIS experiment, are discussed. Using the flight data base, the techniques provide information useful in analyzing and correcting problems with the experiment, and in interpreting the IRIS image obtained during the entry of the third shuttle mission.

Green, M. J.↗
NASA NTRS1983

The influence of inlet design on the aeroacoustic performance of a JT15D turbofan engine as measured in the NASA-Ames 40 x 80 foot wind tunnel

The influence of inlet design on the aeroacoustic performance of a JT15D turbofan engine was investigated in the NASA-Ames 40 x 80 ft wind tunnel. Four inlet designs representative of those found in commercial service were evaluated at a forward velocity of 80 kn. The inlet designs considered were selected to evaluate the importance of circumferential static pressure distortion (SPD) for a diffusing sound suppressing inlet and throat Mach number (Mth) for a hardwall inlet on the acoustic characteristics of the JT15D engine. Several speed points were studied simulating the operating conditions spanning approach to take-off. Results demonstrated that the dependency of the forward radiated noise on inlet aerodynamic design parameters was significant (about 5 dB) for the range of SPD (0.1-3.0%) and Mth (0.3-0.6) tested. The performance of the bulk absorber acoustic treatment used in the diffusing sound suppressing inlet is also discussed.

Holm, R. G.↗
NASA NTRS1982

The display of molecular models with the Ames Interactive Modeling System (AIMS)

A visualization of molecular models can lead to a clearer understanding of the models. Sophisticated graphics devices supported by minicomputers make it possible for the chemist to interact with the display of a very large model, altering its structure. In addition to user interaction, the need arises also for other ways of displaying information. These include the production of viewgraphs, film presentation, as well as publication quality prints of various models. To satisfy these needs, the display capability of the Ames Interactive Modeling System (AIMS) has been enhanced to provide a wide range of graphics and plotting capabilities. Attention is given to an overview of the AIMS system, graphics hardware used by the AIMS display subsystem, a comparison of graphics hardware, the representation of molecular models, graphics software used by the AIMS display subsystem, the display of a model obtained from data stored in molecule data base, a graphics feature for obtaining single frame permanent copy displays, and a feature for producing multiple frame displays.

Egan, J. T.↗
NASA NTRS1983

Supporting flight data analysis for Space Shuttle Orbiter Experiments at NASA Ames Research Center

The Space Shuttle Orbiter Experiments program in responsible for collecting flight data to extend the research and technology base for future aerospace vehicle design. The Infrared Imagery of Shuttle (IRIS), Catalytic Surface Effects, and Tile Gap Heating experiments sponsored by Ames Research Center are part of this program. The paper describes the software required to process the flight data which support these experiments. In addition, data analysis techniques, developed in support of the IRIS experiment, are discussed. Using the flight data base, the techniques have provided information useful in analyzing and correcting problems with the experiment, and in interpreting the IRIS image obtained during the entry of the third Shuttle mission.

Green, M. J.↗
NASA NTRS1983

Global biology - An interdisciplinary scientific research program at NASA, Ames Research Center

NASA has initiated new effort in Global Biology, the primary focus of which is to understand biogeochemical cycles. As part of this effort, an interdisciplinary team of scientists has formed at Ames Research Center to investigate the cycling of sulfur in the marine coastal zone and to study the cycling of nitrogen in terrestrial ecosystems. Both studies will use remotely sensed data, coupled with ground-based research, to identify and measure the transfer of major and minor biologically produced gases between these ecosystems and global reservoirs.

Lawless, J. G.↗