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  • General Chemistry  (16,023)
  • Life and Medical Sciences  (10,627)
  • Cell & Developmental Biology  (8,816)
  • AERODYNAMICS  (6,057)
  • EARTH RESOURCES AND REMOTE SENSING  (4,808)
  • THERMODYNAMICS AND COMBUSTION
  • 1985-1989  (15,874)
  • 1980-1984  (13,418)
  • 1965-1969  (9,921)
Collection
Keywords
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Years
Year
  • 1
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    MAMS - A high spatial resolution multispectral scanner (1989)
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    Publication Date: 2011-08-19
    Description: The Multispectral Atmospheric Mapping Sensor (MAMS) is an airborne scanner which collects imagery in eight visible and three IR bands, with ground resolution of 100 m at a nominal aircraft altitude of 20 km. The visible channels provide continuous spectral coverage from 0.42 to 1.05 microns, and the IR channels measure upwelling and reflected radiation at combinations of 3.7, 6.5, 11.1, and 12.5 microns. These include channels nearly identical to the Landsat TM channels 1-4, and similar to those on the VISSR Atmospheric Sounder (VAS) and AVHRR instruments. The high spatial resolution permits investigation of surface thermal and atmospheric water vapor structure at scales not available from current stabilities. Significant modifications have been made since engineering flights in 1985 to improve the radiometric performance. The increased data quality and recent multidisciplinary applications of this data are presented.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
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  • 2
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    Inference of geophysical parameters from multifrequency polarimetric radar observations and model inversion (1989)
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    Publication Date: 2011-08-19
    Description: In summer 1988 an intensive field experiment was conducted in the vicinity of the Pisgah lava flow in the Mojave Desert. Physical properties such as microtopography, composition, soil moisture, and dielectric constant were measured at five sites representing surfaces with rms heights varying from less than one centimeter to tens of centimeters. In addition, polarimetric radar images at P-band, L-band, and C-band were acquired at three different incidence angles with the NASA/JPL airborne imaging radar polarimeter. Using trihedral corner reflectors deployed in the area prior to imaging, the L- and C-band images were calibrated to provide sigma0 values for each resolution element in the scene. The results of inferring geophysical parameters such as rms surface height and correlation length of the measured surfaces by fitting the observed signatures with those predicted by the small-perturbation model are presented: for smoother surfaces, the rms height values inferred are in good agreement with in situ measurements.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
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  • 3
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    Radar modeling of tropical mangal forest stands (1989)
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    Publication Date: 2011-08-19
    Description: Radar modeling of mangal forest stands in the Sundarbans area of southern Bangladesh is discussed. The modeling uses radar system parameters with forest data on tree height, spacing, biomass, species combinations, and water content (including slightly conductive water) in leaves and trunks of the mangal. For Sundri and Gewa tropical mangal forests, six model components are proposed; the models are required to explain the contributions of various combinations of forest species in the attenuation and scattering of mangal-vegetated nonflooded or flooded surfaces. Statistical data of simulated images have been compared with those of SIR-B images both to refine the modeling procedures and to characterize the model output appropriately. The possibility of delineation of flooded or nonflooded boundaries is discussed.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
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  • 4
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    A one- and two-layer model for estimating evapotranspiration with remotely sensed surface temperature and ground-based meteorological data over partial canopy cover (1989)
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    Publication Date: 2011-08-19
    Description: Surface-air temperature differences are commonly used in a bulk resistance equation for estimating sensible heat flux (H), which is inserted in the one-dimensional energy balance equation to solve for the latent heat flux (LE) as a residual. Serious discrepancies between estimated and measured LE have been observed for partial-canopy-cover conditions, which are mainly attributed to inappropriate estimates of H. To improve the estimates of H over sparse canopies, one- and two-layer resistance models that account for some of the factors causing poor agreement are developed. The utility of the two models is tested with remotely sensed and micrometeorological data for a furrowed cotton field with 20 percent cover and a dry soil surface. It is found that the one-layer model performs better than the two-layer model when a theoretical bluff-body correction for heat transfer is used instead of an empirical adjustment; otherwise, the two-layer model is better.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
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  • 5
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    Determining experimentally induced variation in coniferous canopy chemistry with Airborne Imaging Spectrometer data (1989)
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    Publication Date: 2011-08-19
    Description: Experimental treatments in a Douglas-fir forest in NE New Mexico were carried out to determine whether differences in forest canopy chemistry could be detected using data from the Airborne Imaging Spectrometer (AIS-2). Experimental treatments consisted of nitrogen fertilizer additions, sawdust additions, and control plots. After AIS-2 data were collected, the digital number of a given pixel was extracted from each channel, yielding 128 values that were used to form a spectrum. Four spectra were extracted from each treatment plot. Multiple stepwise linear regressions between first and second difference transformations of AIS-2 spectra and the canopy characteristics of biomass, nitrogen concentration, and nitrogen content were performed. The results showed a coefficient of multiple determination of 0.71 between first-difference AIS-2 spectra and measured nitrogen concentration in foliage, indicating that it may be possible to predict nitrogen concentration in Douglas fir using AIS-2 spectra.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
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  • 6
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    Feature utility in polarimetric radar image classification (1989)
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    Publication Date: 2011-08-19
    Description: The information content in polarimetric SAR images is examined, and the polarimetric image variables containing the information that is important to the classification of terrain features in the images are determined. It is concluded that accurate classification can be done when just over half of the image variables are retained. A reduction in image data dimensionality gives storage savings, and can lead to the improvement of classifier performance. In addition, it is shown that a simplified radar system with only phase-calibrated CO-POL or SINGLE TX channels can give classification performance which approaches that of a fully polarimetric radar.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
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  • 7
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    Remote sensing of geobotanical trends in East Africa (1989)
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    Publication Date: 2011-08-19
    Description: The spatial and phenological distribution of vegetation was examined in a remote sensing geobotanical study of the East Africa Rift region. Six normalized difference vegetation index (NDVI) AVHRR (advanced very high resolution radiometer) scenes (February, June, and September of both 1984 and 1987) were used as a measure of vegetation presence. NOAA ETOPO-5 elevation and geographic coordinate data were coregistered with the multitemporal NDVI images. Univariate and multivariate statistics indicate that the NDVI values are significantly associated with elevation, latitude, and longitude. This supports the concept of quantifiable, regional gradients that affect large-scale geobotanical studies. A quadratic regression line was fitted to the NDVI, elevation, latitude, and longitudinal data. In this way a regional trend, as affected by elevation, was determined. The deviation of the actual data from this regional trend was displayed as an image, and shows the local climatic and geological influences.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
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  • 8
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    Segmentation of SAR images (1989)
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    Publication Date: 2011-08-19
    Description: The statistical characteristics of image speckle are reviewed. Existing segmentation techniques that have been used for speckle filtering, edge detection, and texture extraction are sumamrized. The relative effectiveness of each technique is briefly discussed.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
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  • 9
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    Attenuation of soil microwave emissivity by corn and soybeans at 1.4 and 5 GHz (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Theory and experiments have shown that passive microwave radiometers can be used to measure soil moisture. However, the presence of a vegetative cover alters the measurement that might be obtained under bare conditions. Deterministically accounting for the effect of vegetation and developing algorithms for extracting soil moisture from observations of a vegetable-soil complex present significant obstacles to the practical use of this approach. The presence of a vegetation canopy reduces the sensitivity of passive microwave instruments to soil moisture variations. The reduction in sensitivity, as compared to a bare-soil relationship, increases as microwave frequency increases, implying that the longest wavelength sensors should provide the most information. Sensitivity also decreases as the amount of vegetative wet biomass increases for a given type of vegetation.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
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  • 10
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    The need for SAR calibration (1989)
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    Publication Date: 2011-08-19
    Keywords: EARTH RESOURCES AND REMOTE SENSING
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  • 11
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    Bidirectional reflectances of three soil surfaces and their characterization through model inversion (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Spectral bidirectional reflectances were measured over three natural soil sites using a specially designed radiometer called the Parabola. Two of the sites were bare soils, and the third had a sparse cover of desert scrub. The reflectances were strongly non-Lambertian for all three surfaces, but with markedly different patterns. The measured data were fitted with a quasi-physical reflectance model in which the surface backscattering and forwardscattering are separately formulated. A soil reflectance characterization was obtained by assessing the contributions of the forward, backward, and Lambertian components. This three-parameter characterization produced a satisfactory fit to the measured reflectances and appears promising as a basis for soils categorization.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
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  • 12
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    Reflectance and transmittance of snow at high spectral resolution (1989)
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    Publication Date: 2011-08-19
    Description: A radiative-transfer model for the bidirectional reflectance-distribution function (BRDF) shows that snow is moderately anisotropic in the NIR wavelengths. Although the directional-hemispherical albedo of snow decreases as the grains become larger, the forward scattering also increases, with the result that the illumination and viewing geometry must be considered when interpreting physical properties of the surface layer of the snow pack from remote sensing data. Measurements of the BRDF and the transmittance for a variety of snow conditions were made throughout the winter and spring seasons with an SE-590 spectroradiometer, for wavelengths from 0.38 to 1.11 microns. Coincident with these, the surface grain properties were analyzed by stereological methods. A sphere with the same surface-to-volume ratio as the ice grains is used as the equivalent sphere.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
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  • 13
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    Remote sensing of foliar chemistry (1989)
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    Publication Date: 2011-08-19
    Description: Remotely sensed data are being used to estimate foliar chemical content. This paper reviews how stepwise multiple regression and deconvolution have been used to extract chemical information from foliar spectra, and concludes that both methods are useful, but neither is ideal. It is recommended that the focus of research be modeling in the long term and experimentation in the short term. Long-term research should increase our understanding of the interaction between radiation and foliar chemistry so that the focus of research can move from leaf model to canopy model to field experiment. Short-term research should aim to design experiments in which remotely sensed data are used to generate unambiguous and accurate estimates of foliar chemical content.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Remote Sensing of Environment (ISSN 0034-4257); 30; 271-278
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  • 14
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    Mapping surface energy balance components by combining Landsat Thematic Mapper and ground-based meteorological data (1989)
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    Publication Date: 2011-08-19
    Description: Surface energy balance components were evaluated by combining satellite-based spectral data with on-site measurements of solar irradiance, air temperature, wind speed, and vapor pressure. Maps of latent heat flux density and net radiant flux density were produced using Landsat TM data for three dates. The TM-based estimates differed from Bowen-ratio and aircraft-based estimates by less than 12 percent over mature fields of cotton, wheat, and alfalfa.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Remote Sensing of Environment (ISSN 0034-4257); 30; 77-87
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  • 15
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    Multipolarization P-, L-, and C-band radar for coastal zone mapping - The Louisiana example (1989)
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    Publication Date: 2011-08-19
    Description: Multipolarization P-, L-, and C-band airborne SAR data sets were acquired over a coastal zone and a forested wetland of southern Louisiana. The data sets were used with field-collected surface-parameter data in order to determine the value of SAR systems in assessing and mapping coastal-zone surface features. The coastal-zone surface features in this study are sediments, sediment distribution, and the formation of new isles and banks. Results of the data analysis indicate that the P-band radar with 68-cm wavelength is capable of detecting the submerged sediment if the area is very shallow (i.e., a water depth of less than one meter). The penetration capability of P-band radar is also demonstrated in the forested wetland area. The composition and condition of the ground surface can be detected, as well as the standing water beneath dense tree leaves.
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  • 16
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    Spectroscopic measurement of atmospheric water vapor and schemes for determination of evaporation from land and water surfaces using the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) (1989)
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    Publication Date: 2011-08-19
    Keywords: EARTH RESOURCES AND REMOTE SENSING
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  • 17
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    Using passive, thermal remote sensing techniques for detecting subsurface gravel accumulations in vegetated, unconsolidated sedimentary terrains (1989)
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    Publication Date: 2011-08-19
    Description: Multiband radiometric data from an airborne imaging thermal scanner are being studied for use in finding buried gravel deposits. The techniques are based on measuring relative differences in the thermal properties between gravel-laden targets and the surrounding gravelless background. These properties are determined from modeling the spectral radiant emittance recorded over both types of surfaces in conjunction with ground measurements of the most significant heat flows above and below the surface. Thermodynamic properties of sampled materials from control sites are determined, and diurnal and annual subsurface heat waves are recorded. Thermal models that account for heat exchange at the surface, as well as varying levels of soil moisture, humidity, and vegetation, are needed for adaptation and modification to simulate the physical and radiative environments of this region.
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  • 18
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    Forest and grassland ecosystem studies using the advanced solid-state array spectroradiometer (1989)
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    Publication Date: 2011-08-19
    Description: The advanced solid-state array spectroradiometer (ASAS) is an airborne, off-nadir pointing imaging spectroradiometer used to acquire bidirectional radiance data for terrestrial targets. As its platform aircraft flies over a target the sensor can image the target through a sequence of at least seven fore-to-aft view directions ranging up to 45 deg on either side of nadir. ASAS acquires data for 29 spectral bands in the visible and near-infrared portions of the spectrum with a resolution of 15 nm. ASAS data were recently acquired for a prairie ecosystem and a northern forest ecosystem. The data demonstrate the combined effects of reflectance anisotropy and increased atmospheric path length on off-nadir observations. One result of these effects is a variation in vegetation indices as a function of view direction. Normalized-difference-vegetation-indices for prairie grass, coniferous, and deciduous canopies varied up to 14 percent, 23 percent, and 6 percent, respectively, relative to nadir as a function of view zenith angle along the solar principal plane.
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  • 19
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    Image processing software for providing radiometric inputs to land surface climatology models (1989)
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    Publication Date: 2011-08-19
    Description: During the First International Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE), 80 gigabytes of image data were generated from a variety of satellite and airborne sensors in a multidisciplinary attempt to study energy and mass exchange between the land surface and the atmosphere. To make these data readily available to researchers with a range of image data handling experience and capabilities, unique image-processing software was designed to perform a variety of nonstandard image-processing manipulations and to derive a set of standard-format image products. The nonconventional features of the software include: (1) adding new layers of geographic coordinates, and solar and viewing conditions to existing data; (2) providing image polygon extraction and calibration of data to at-sensor radiances; and, (3) generating standard-format derived image products that can be easily incorporated into radiometric or climatology models. The derived image products consist of easily handled ASCII descriptor files, byte image data files, and additional per-pixel integer data files (e.g., geographic coordinates, and sun and viewing conditions). Details of the solutions to the image-processing problems, the conventions adopted for handling a variety of satellite and aircraft image data, and the applicability of the output products to quantitative modeling are presented. They should be of general interest to future experiment and data-handling design considerations.
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  • 20
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    Estimation of thermal flux and emissivity of the land surface from multispectral aircraft data (1989)
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    Publication Date: 2011-08-19
    Description: In order to evaluate the importance of surface thermal flux and emissivity variations on surface and boundary layer processes, a technique that uses thermal data from an airborne multispectral scanner to determine the surface skin temperature and thermal emissivity over a regional area has been developed. These values are used to estimate the total flux density emanating from the surface and at the top of the atmosphere. Data from the multispectral atmospheric mapping sensor (MAMS) collected during the First ISLSCP Field Experiment (FIFE) are used to develop the technique, and to show the time and space variability of the flux values. The ground truth data available during FIFE provide a unique resource to evaluate this technique.
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  • 21
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    Measurement of surface microtopography using helicopter-mounted stereo film cameras and two stereo matching techniques (1989)
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    Publication Date: 2011-08-19
    Description: A common problem in acquiring ground-truth data for use in microwave interaction modeling is the capture of surface roughness data that are both sampled at distances comparable to a fraction of the wavelength and extensive enough to represent the surface statistics in at least one resolution cell of the microwave remote sensor used. A technique has been developed for acquiring the necessary photogrammetric data using twin 70-mm film cameras mounted on a helicopter boom. The apparatus is described, and the accuracy with which ground surface roughness can be characterized using this device is estimated. Both standard and cross-correlation methods were used for data reduction. Stereogrammetry is compared with a completely automated image-matching technique. Dense disparity images were generated from the helicopter stereo pairs. Using interior orientation parameters supplied by the camera manufacturers, and assuming that exterior orientation parameters remain constant between control target and test field photography, an extremely dense DEM (digital elevation model) for a test field has been derived. Results are compared, and accuracy estimates are presented.
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  • 22
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    Atmospheric correction of high resolution land surface images (1989)
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    Publication Date: 2011-08-19
    Description: Algorithms to correct for atmospheric-scattering effects in high-spatial resolution land-surface images require the ability to perform rapid and accurate computations of the top-of-atmosphere diffuse radiance field for arbitrarily general surface reflectance distributions (which may be both heterogeneous and non-Lambertian) and atmospheric models. Using three-dimensional radiative transfer (3DRT) theory algorithms are being developed. The methodology used to perform the 3DRT calculations is described. It is shown how these calculations are used to perform atmospheric corrections, and the sensitivity of the retrieved surface reflectances to atmospheric structural parameters is illustrated.
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  • 23
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    Utility of airborne electromagnetic profiler data for determining water depths and characterizing coastal sediments and marsh soils (1989)
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    Publication Date: 2011-08-19
    Keywords: EARTH RESOURCES AND REMOTE SENSING
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  • 24
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    Comparison of theoretical and measured brightness temperature of a soybean canopy (1989)
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    Publication Date: 2011-08-19
    Description: A model for the brightness temperature of a canopy which is based on the physical characteristics of the vegetation is being developed. This model uses the Peake model to relate the scattering coefficient of the vegetation to its radiometric brightness temperature and a discrete scattering model to computer the scattering coefficient. A distorted Born approximation is used to provide a tractable solution to the scattering problem. To verify the theory a comparison has been made with experiments. Radiometric measurements of brightness temperature were made at L- and C-bands over a crop of mature soybeans, along with ground truth measurements. All model input parameters were measured; there were no free parameters to adjust to obtain agreement with the measurements. Results showed that agreement between theory and measurements was reasonable for horizontal polarization at both L- and C-bands with dry underlying soil.
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  • 25
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    Results of the 1988 NASA/JPL airborne SAR calibration campaign (1989)
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    Publication Date: 2011-08-19
    Description: During the spring of 1988, the NASA/JPL multifrequency, multipolarization SAR (synthetic aperture radar) flew in series of calibration experiments over the Goldstone dry lake bed. An array of calibration devices was deployed, including dihedral and trihedral corner reflectors, polarimetric active radar calibrators, passive receivers, and CW (continuous wave) tone generators. The aim of the campaign was to calibrate both amplitude and phase of the resulting SAR images, over long and short time scales. The results of the analysis of the calibration data collected in the spring of 1988 are presented. Trihedral corner reflector signatures and certain image background measures are used to externally calibrate relative amplitude and phase between polarizations at a given frequency, and to calibrate across frequencies. Assessments are made of the calibration accuracy as a function of image frame position for each frequency, and the stability of the radar calibration over long and short time-scales.
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  • 26
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    Segmentation of multifrequency polarimetric radar images to facilitate the inference of geophysical parameters (1989)
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    Publication Date: 2011-08-19
    Description: An unsupervised clustering algorithm is used to segment multifrequency polarimetric radar data from the NASA/JPL airborne SAR (synthetic aperture radar). Twenty-two parameters are evaluated for their discriminatory capability for each pixel of an image. A clustering analysis is then performed using different subsets of these parameters. This analysis relies on data taken as part of an intensive field experiment during the summer of 1988 in the vicinity of the Pisgah lava flow in the Mojave Desert in southern California. As part of the experiment, extensive ground truth was acquired, including dielectric constant and topography measurements. Segmentation results show good agreement with these measurements.
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  • 27
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    Nonequilibrium hypersonic aerothermodynamics (1989)
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    Publication Date: 2011-08-19
    Description: Nonequilibrium phenomena in hypersonic flows are examined on the basis of theoretical models and selected experimental data, in an introduction intended for second-year graduate students of aerospace engineering. Chapters are devoted to the physical nature of gas atoms and molecules, transitions of internal states, the formulation of the master equation of aerothermodynamics, the conservation equations, chemical reactions in CFD, the behavior of air flows in nonequilibrium, experimental aspects of nonequilibrium flow, a review of experimental results, and gas-solid interaction. Diagrams, graphs, and tables of numerical data are provided.
    Keywords: AERODYNAMICS
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  • 28
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    Georeferencing airborne imagery over new deltas in Louisiana (1989)
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    Publication Date: 2011-08-19
    Description: An experiment to study the hypothesis that winter cold fronts are more important that violent summer storms in moving sediment in midlatitude coastal river deltas. The experiment is based on Calibrated Airborne Multispectral Scanner (CAMS) data. A new approach for the georeferencing of aircraft imagery has been developed for use in this experiment. The software for the approach uses the aircraft inertial navigation data and is able to automatically map a three-channel 1600 line file through a 90 deg rotation in less than 14 minutes. Results from tests of the technique show rms errors of less than 2/3 of a pixel.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Photogrammetric Engineering and Remote Sensing (ISSN 0099-1112); 4; 1161-116
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  • 29
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    Transonic region of high dynamic response encountered on an elastic supercritical wing (1989)
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 26; 870-875
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  • 30
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    Transonic aeroelasticity of fighter wings with active control surfaces (1989)
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 26; 682-684
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  • 31
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    Hypersonic parabolized Navier-Stokes code validation on a sharp nose cone (1989)
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 26; 650-656
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  • 32
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    Validation of aerodynamic parameters for high-incidence research models (1989)
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 26; 621-628
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    Observation of airplane flowfields by natural condensation effects (1989)
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 26; 593-604
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    The decrease of Lake Chad as documented during twenty years of manned space flight (1989)
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    Publication Date: 2011-08-19
    Description: Space photography has been successfully used to extend the space remote sensing data base for environmental monitoring by a decade. In this study of Lake Chad, space photographs were digitized and registered to a topographic base map before water classifications were performed. From 1966 to 1985 over a 21,000-square-kilometer decrease in lake surface area was observed.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Geocarto International (ISSN 1010-6049); 4; 75-79
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    Geologic applications of Space Shuttle photography (1989)
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    Publication Date: 2011-08-19
    Description: Space Shuttle astronauts have used handheld cameras to take about 30,000 photographs of the earth as seen from orbit. These pictures provide valuable, true-color depictions of many geologically significant areas. While the photographs have areal coverages and resolutions similar to the more familiar Landsat MSS and TM images, they differ from the latter in having a wide variety of solar illumination angles and look angles. Astronaut photographs can be used as very small scale aerial photographs for geologic mapping and planning logistical support for field work. Astronaut photography offers unique opportunities, because of the intelligence and training of the on-orbit observer, for documenting dynamic geologic activity such as volcanic eruptions, dust storms, etc. Astronauts have photographed more than 3 dozen volcanic eruption plumes, some of which were not reported otherwise. The stereographic capability of astronaut photography also permits three-dimensional interpretation of geologic landforms which is commonly useful in analysis of structural geology. Astronauts have also photographed about 20 known impact craters as part of project to discover presently unknown examples in Africa, South America, and Australia.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Geocarto International (ISSN 1010-6049); 4; 49-54
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  • 36
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    Separation control on an airfoil by periodic forcing (1989)
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    Publication Date: 2011-08-19
    Description: The introduction of transverse velocity fluctuations into a separated shear layer on an airfoil at high angles of attack is presently demonstrated to be an effective separation-control technique. Airfoil aerodynamic characteristics, including poststall lift and drag as well as maximum lift coefficient and stall angle, all exhibited improvements controlled forcing at 20 deg angle of attack led to an increased spreading of the mean velocity profile, together with increased turbulence activity; separation moved from the leading edge to about 80 percent of chord.
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 27; 820
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    Boundary-layer transition on a cone and flat plate at Mach 3.5 (1989)
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 27; 687-693
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  • 38
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    Full-potential analysis of a supersonic delta wing/body (1989)
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 26; 235-240
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  • 39
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    A new lagoon on the Namibian coast of South Africa - Sand spit growth documented from STS-29 Shuttle photography (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Geocarto International (ISSN 1010-6049); 4; 63-66
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  • 40
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    Earth observations during Space Shuttle flight STS-29 - Discovery's voyage to the earth (1989)
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    Publication Date: 2011-08-19
    Description: The environmental, geologic, meteorologic, and oceanographic phenomena documented by earth photography during the Space Shuttle STS-29 mission are reviewed. A map of the nadir point positions of earth-viewing photographs from the mission is given and color photographs of various regions are presented. The mission photographs include atmospheric dust and smoke over parts of Africa and Asia, Sahelian water sites, center pivot irrigation fields in the Middle East, urban smog over Mexico City, isolated burning in the Bolivian Amazon, and various ocean features and cloud formations.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Geocarto International (ISSN 1010-6049); 4; 67-80
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  • 41
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    Remote sensing of global change (1989)
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    Publication Date: 2011-08-19
    Description: Remote sensing instruments for monitoring global changes are examined. The use of the earth observing system, a set of instrument platforms in polar, sun-synchoronous orbit that provide coverage of the entire globe, is discussed. The radar and imaging spectrometers utilized to obtain surface measurements are described. Atmospheric data is collected by the atmospheric IR sounder, the tropospheric emission spectrometer, and the stratospheric wind IR limb sounder. Consideration is given to the operation of the microwave limb sounder, the active cavity radiometer, and the TDRSS.
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    Type: Signal (ISSN 0049-0474)
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  • 42
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    Radiometric sensitivity comparisons of multispectral imaging systems (1989)
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    Publication Date: 2011-08-19
    Description: Multispectral imaging systems provide much of the basic data used by the land and ocean civilian remote-sensing community. There are numerous multispectral imaging systems which have been and are being developed. A common way to compare the radiometric performance of these systems is to examine their noise-equivalent change in reflectance, NE Delta-rho. The NE Delta-rho of a system is the reflectance difference that is equal to the noise in the recorded signal. A comparison is made of the noise equivalent change in reflectance of seven different multispectral imaging systems (AVHRR, AVIRIS, ETM, HIRIS, MODIS-N, SPOT-1, HRV, and TM) for a set of three atmospheric conditions (continental aerosol with 23-km visibility, continental aerosol with 5-km visibility, and a Rayleigh atmosphere), five values of ground reflectance (0.01, 0.10, 0.25, 0.50, and 1.00), a nadir viewing angle, and a solar zenith angle of 45 deg.
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  • 43
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    Studies of ice sheet hydrology using SAR (1989)
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    Publication Date: 2011-08-19
    Description: Analysis of SAR data of the Greenland ice sheet in summer and winter suggest the use of SAR to monitor the temporal hydrology of ice sheets. Comparisons of each SAR data set with summer Landsat TM imagery show an areal-positive correlation with summer SAR data and a negative correlation with winter SAR data. It is proposed that the summer SAR data are most sensitive to the variable concentrations of free water in the surface snow and that the winter SAR data indicate variations in snow grain size.
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    Modelling Rift Valley fever (RVF) disease vector habitats using active and passive remote sensing systems (1989)
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    Publication Date: 2011-08-19
    Description: The NASA Ames Ecosystem Science and Technology Branch and the U.S. Army Medical Research Institute of Infectious Diseases are conducting research to detect Rift Valley fever (RVF) vector habitats in eastern Africa using active and passive remote-sensing. The normalized difference vegetation index (NDVI) calculated from Landsat TM and SPOT data is used to characterize the vegetation common to the Aedes mosquito. Relationships have been found between the highest NDVI and the 'dambo' habitat areas near Riuru, Kenya on both wet and dry data. High NDVI values, when combined with the vegetation classifications, are clearly related to the areas of vector habitats. SAR data have been proposed for use during the rainy season when optical systems are of minimal use and the short frequency and duration of the optimum RVF mosquito habitat conditions necessitate rapid evaluation of the vegetation/moisture conditions; only then can disease potential be stemmed and eradication efforts initiated.
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  • 45
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    Remotely sensed soil moisture input to a hydrologic model (1989)
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    Publication Date: 2011-08-19
    Description: The possibility of using detailed spatial soil moisture maps as input to a runoff model was investigated. The water balance of a small drainage basin was simulated using a simple storage model. Aircraft microwave measurements of soil moisture were used to construct two-dimensional maps of the spatial distribution of the soil moisture. Data from overflights on different dates provided the temporal changes resulting from soil drainage and evapotranspiration. The study site and data collection are described, and the soil measurement data are given. The model selection is discussed, and the simulation results are summarized. It is concluded that a time series of soil moisture is a valuable new type of data for verifying model performance and for updating and correcting simulated streamflow.
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  • 46
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    Color composite processing of multi-wavelength, multi-polarization airborne radar imagery (1989)
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    Publication Date: 2011-08-19
    Description: Multiwavelength, multipolarization radar image data can be processed to allow the clear depiction of most information in color composite displays. The first principal component, depicted as variations in image intensity, captures the dominant variation in the data and reduces noise without degradation of spatial detail. Other principal components, depicted primarily as variations in image chromaticity, are derived from spatially filtered data so that image colors can be attributed to significant wavelength and polarization contrasts, and not to speckle. Processing paths can be designed to emphasize wavelength contrasts, polarization contrasts, or overall discrimination of surface features.
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    Covariance of greenness and terrain variables over the Konza Prairie (1989)
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    Publication Date: 2011-08-19
    Description: An analysis is made of time-dependent covariance of the greenness vegetation index with mapped terrain variables over the Konza Prarie (Kansas) during the 1987 growing season. The analysis was part of an ongoing project to establish appopriate ground-sampling and data-integration strategies for satellite-based monitoring of land surface climate conditions. Greenness images for six dates between May and October were derived from atmospherically corrected thematic mapper (TM) data and coregistered with maps of woody vegetation, fire, and soils. Local variance in greenness peaked in mid-June, falling rapidly until mid-August, and declining gradually thereafter. Greenness images exhibited positive autocorrelation up to distances of 180-210 m, but the dominant scale of pattern occurred at a block size of 60 m by 60 m throughout the growing season. 40-44 percent of total scene variance in July and August was accounted for by the effects of woody vegetation (8.9 percent of the area), prairie burning, and soil type. The effect of these terrain variables was fairly consistent between June and late August and was manifested as additional high-frequency spatial variation in imagery from that period.
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    The Alaska SAR processor - Operations and control (1989)
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    Publication Date: 2011-08-19
    Description: The Alaska SAR (synthetic-aperture radar) Facility (ASF) will be capable of receiving, processing, archiving, and producing a variety of SAR image products from three satellite-borne SARs: E-ERS-1 (ESA), J-ERS-1 (NASDA) and Radarsat (Canada). Crucial to the success of the ASF is the Alaska SAR processor (ASP), which will be capable of processing over 200 100-km x 100-km (Seasat-like) frames per day from the raw SAR data, at a ground resolution of about 30 m x 30 m. The processed imagery is of high geometric and radiometric accuracy, and is geolocated to within 500 m. Special-purpose hardware has been designed to execute a SAR processing algorithm to achieve this performance. This hardware is currently undergoing acceptance testing for delivery to the University of Alaska. Particular attention has been devoted to making the operations semi-automated and to providing a friendly operator interface via a computer workstation. The operations and control of the Alaska SAR processor are described.
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    Decorrelation distance of snow in the Colorado River Basin (1989)
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    Publication Date: 2011-08-19
    Description: The problem of estimating areal averages from point measurement has been extensively studied by mining engineers and hydrologists. Its application to satellite measurements has recently been introduced. The semivariaogram has been used in many geostatistical applications to estimate spatial structures of observed properties, such as mineral distributions. An examination is made of snow variations in Colorado from daily snow data collected in 11 SNOTEL stations. The associated semivariogram is estimated. The objective is to estimate the spatial structure of the snow field so that the point data can be used for comparison with, and validation for, satellite measurements.
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    Correlations of scanning multichannel microwave radiometer (SMMR) observations with snowpack properties of the Upper Colorado River Basin for water year 1986 (1989)
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    Publication Date: 2011-08-19
    Keywords: EARTH RESOURCES AND REMOTE SENSING
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    Spaceborne technology contributions to hydrological studies in the context of global change (1989)
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    Publication Date: 2011-08-19
    Description: Spaceborne observations have become increasingly accepted for studies of the hydrological cycle and as a source of information that can be used for management and assessment of water resources over large areas. As data records are extended over long periods of time, using sensors that improve their reliability and quality, the utility of spaceborne observations will become increasingly evident. The Earth Observing System (EOS) concept being studied by NASA holds potential for providing improved means and procedures for hydrological studies, particularly on a global basis, using spaceborne sensors and a comprehensive information system. Continuing emphasis needs to be placed on research exploring the interpretation of remotely sensed observations through the assimilation and use of these data in models of hydrological processes.
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    Using remotely sensed data to monitor land surface climatology variations in a semi-arid grassland (1989)
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    Publication Date: 2011-08-19
    Keywords: EARTH RESOURCES AND REMOTE SENSING
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  • 53
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    Approach to derivation of SIR-C science requirements for calibration (1989)
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    Publication Date: 2011-08-19
    Description: A study undertaken to determine SIR-C (Shuttle Imaging Radar-C) science requirements for polarimetric calibration is described. A model describing the effect of miscalibration is presented, followed by a description of specific experiments and the resulting requirements levied on the system. The effects of miscalibration on some commonly used measures which can be extracted from SAR (synthetic aperture radar) data are also discussed. It is concluded that polarimetric calibration requirements are strongly application-dependent, and that a compromise must be made to maximize the domain of application of the data without prohibitive cost. Data summarizing SIR-C polarimetric calibration goals are also presented.
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  • 54
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    Regression and ratio estimators to integrate AVHRR and MSS data (1989)
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    Publication Date: 2011-08-19
    Description: Regression and ratio estimators are used to integrate AVHRR-Global Area Coverage (GAC) and Landsat MSS digital data to estimate forest area in the continental United States. Forestlands are enumerated for the 48 contiguous states using five different AVHRR-GAC data sets. Results indicated that the GAC and MSS forest estimates were not highly correlated. Although the ratio of means and linear regression corrections were, on the average, closer to national U.S. Forest Service forest area estimates, these correction procedures did not consistently improve GAC estimates of forest area. GAC forest area estimates tended to be high in densely forested regions such as the northeast and low in sparsely forested areas.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Remote Sensing of Environment (ISSN 0034-4257); 30; 201-216
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    Thematic Mapper detection of changes in the leaf area of closed canopy pine plantations in central Massachusetts (1989)
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    Publication Date: 2011-08-19
    Description: Consideration is given to the possibility of using Landsat TM data to detect differences and changes in the leaf area index (LAI) of closed canopy pine plantations in central Massachusetts. Field measurements of the LAI were obtained using locally-derived allometric relationships between leaf area and trunk diameter. The relationship between the Landsat TM Band 3/Band 4 ratio and regional differences in LAI is examined. A thinning treatment was conducted to demonstrate the ability of TM to detect a known reduction in LAI. It is concluded that, for the detection of moderate changes and differences in the LAI of closed canopy pine plantations at local scales, the TM sensor is better than field measurements involving allometric equations.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Remote Sensing of Environment (ISSN 0034-4257); 30; 129-140
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    Use of vegetation indices to estimate intercepted solar radiation and net carbon dioxide exchange of a grass canopy (1989)
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    Publication Date: 2011-08-19
    Description: Results are presented from field experiments relating spectral reflectance to intercepted photosynthetically active radiation (PAR) and net CO2 exchange in a natural canopy composed of the marsh cordgrass (Spartina alterniflora). Reflectance measurements made by a hand-held radiometer with Landsat TM spectral wavebands are used to compute remote sensing indices such as the normalized difference vegetation index. Consideration is given to the impact of standing dead canopy material on the relationship between intercepted PAR and spectral vegetation indices and the impact of changes in photosynthetic efficiency on the relationship between vegetation indices and CO2 exchange rates. The results suggest that quantitative remote assessment of photosynthesis and net gas exchange in natural vegetation is feasible, especially if the analysis incorporates information on biological responses to environmental variables.
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    Type: Remote Sensing of Environment (ISSN 0034-4257); 30; 115-128
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    Detection of changes in leaf water content using near- and middle-infrared reflectances (1989)
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    Publication Date: 2011-08-19
    Description: A method to detect plant water stress by remote sensing is proposed using indices of near-IR and mid-IR wavelengths. The ability of the Leaf Water Content Index (LWCI) to determine leaf relative water content (RWC) is tested on species with different leaf morphologies. The way in which the Misture Stress Index (MSI) varies with RWC is studied. On test with several species, it is found that LWCI is equal to RWC, although the reflectances at 1.6 microns for two different RWC must be known to accurately predict unknown RWC. A linear correlation is found between MSI and RWC with each species having a different regression equation. Also, MSI is correlated with log sub 10 Equivalent Water Thickness (EWT) with data for all species falling on the same regression line. It is found that the minimum significant change of RWC that could be detected by appying the linear regression equation of MSI to EWT is 52 percent. Because the natural RWC variation from water stress is about 20 percent for most species, it is concluded that the near-IR and mid-IR reflectances cannot be used to remotely sense water stress.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Remote Sensing of Environment (ISSN 0034-4257); 30; 43-54
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    Direct simulation of three-dimensional hypersonic flow about intersecting blunt wedges (1989)
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 27; 1536-154
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    Turbulent separated flow over and downstream of a two-element airfoil (1989)
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    Publication Date: 2011-08-19
    Description: Flow characteristics in the vicinity of the flap of a single-slotted airfoil are presented and analyzed. The flow remained attached over the model surfaces, except in the vicinity of the flap trailing edge where a small region of boundary-layer separation extended over the aft 7 percent of flap chord. The airfoil configuration was tested at a Mach number of 0.09 and a chord Reynolds number of 1.8 x 10 to the 6th in the NASA Ames Research Center 7- by 10-Foot Wind Tunnel. The flow was complicated by the presence of a strong, initially inviscid, jet, emanating from the slot between airfoil and flap, and a gradual merging of the main airfoil wake and flap suction-side boundary layer.
    Keywords: AERODYNAMICS
    Type: Experiments in Fluids (ISSN 0723-4864); 7; 8, Se
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    Aerothermodynamic study of slender conical vehicles (1989)
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Thermophysics and Heat Transfer (ISSN 0887-8722); 3; 361-367
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    Regional analysis of tertiary volcanic Calderas (western U.S.) using Landsat Thematic Mapper imagery (1989)
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    Publication Date: 2011-08-19
    Description: The Landsat Thematic Mapper (TM) imagery of the Basin and Range province of southern Nevada was analyzed to identify and map volcanic rock assemblages at three Tertiary calderas. It was found that the longer-wavelength visible and the NIR TM Bands 3, 5, and 7 provide more effective lithologic discrimination than the shorter-wavelength bands, due partly to deeper penetration of the longer-wavelength bands, resulting in more lithologically driven radiances. Shorter-wavelength TM Bands 1 and 2 are affected more by surficial weathering products including desert varnish which may or may not provide an indirect link to lithologic identity. Guidelines for lithologic analysis of volcanic terrains using Landsat TM imagery are outlined.
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    Type: Remote Sensing of Environment (ISSN 0034-4257); 28; 257-272
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    Tropical forest biomass and successional age class relationships to a vegetation index derived from Landsat TM data (1989)
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    Publication Date: 2011-08-19
    Description: Forest stand structure and biomass data were collected using conventional forest inventory techniques in tropical, subtropical, and warm temperate forest biomes. The feasibility of detecting tropical forest successional age class and total biomass differences using Landsat-Thematic mapper (TM) data, was evaluated. The Normalized Difference Vegetation Index (NDVI) calculated from Landsat-TM data were not significantly correlated with forest regeneration age classes in the mountain terrain of the Luquillo Experimental Forest, Puerto Rico. The low sun angle and shadows cast on steep north and west facing slopes reduced spectral reflectance values recorded by TM orbital altitude. The NDVI, calculated from low altitude aircraft scanner data, was significatly correlated with forest age classes. However, analysis of variance suggested that NDVI differences were not detectable for successional forests older than approximately 15-20 years. Also, biomass differences in young successional tropical forest were not detectable using the NDVI. The vegetation index does not appear to be a good predictor of stand structure variables (e.g., height, diameter of main stem) or total biomass in uneven age, mixed broadleaf forest. Good correlation between the vegetation index and low biomass in even age pine plantations were achieved for a warm temperate study site. The implications of the study for the use of NDVI for forest structure and biomass estimation are discussed.
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    Type: Remote Sensing of Environment (ISSN 0034-4257); 28; 143-156
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    Analysis of Thematic Mapper data for studying the suspended matter distribution in the coastal area of the German Bight (North Sea) (1989)
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    Publication Date: 2011-08-19
    Description: Thematic Mapper data were analyzed with respect to its capability for mapping the complex structure and dynamics of suspended matter distribution in the coastal area of the German Bight (North Sea). Three independent pieces of information were found by factor analysis of all seven TM channels: suspended matter concentration, atmospheric scattering, and sea surface temperature. For the required atmospheric correction, the signal-to-noise ratios of Channels 5 and 7 have to be improved by averaging over 25 x 25 pixels, which also makes it possible to monitor the aerosol optical depth and aerosol type over cloud-free water surfaces. Near-surface suspended matter concentrations may be detected with an accuracy of factor less than 2 by using an algorithm derived from radiative transfer model calculation. The patchiness of suspended matter and its relation to underwater topography was analyzed with autocorrelation and cross-correlation.
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    Type: Remote Sensing of Environment (ISSN 0034-4257); 28; 61-73
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    Modeling future trends in wetland loss and brown shrimp production in Louisiana using Thematic Mapper imagery (1989)
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    Publication Date: 2011-08-19
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Remote Sensing of Environment (ISSN 0034-4257); 28; 45-59
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    Comparison of in situ and Landsat derived reflectance of Alaskan glaciers (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Reflectances calculated from TM data and corrected for atmospheric effects correspond with in situ measured reflectances in the nadir-viewing mode, and are shown to be related to a glacier's mass balance if measured over a period of years. A reflectance of 0.895 for a test site in the Wrangell Mountains, Alaska, was calculated from TM Band 4 (0.76 - 0.90 micron) data and corrected for atmospheric effects. This value was comparable to the in situ reflectance of 0.90 measured in the same 0.76 - 0.90 micron wavelength region. For the same site, a reflectance value of 0.79 derived from integrating over most (0.40 - 3.0 micron) of the reflective portion of the electromagnetic spectrum was quite different from the integrated reflectance of 0.95 calculated for the spectral range 0.40 - 1.0 micron. This demonstrates the importance of using the full reflective energy spectrum for calculating the albedo of snow, and for obtaining a meaningful computation of a glacier's energy and mass balance change.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Remote Sensing of Environment (ISSN 0034-4257); 28; 23-31
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    Thematic Mapper research in the earth sciences (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: This paper's studies were initiated under the NASA program for the purpose of conducting the earth sciences research using the Landsat Thematic Mapper. The goals of the program include studies of the factors influencing the growth, health, condition, and distribution of vegetation on the earth; the processes controlling the evolution of the earth's crust; the earth's water budget and the hydrologic processes that operate at local, regional, and global scales; the physical and chemical interaction between different types of surficial materials; and the interaction between the earth's surface and its atmosphere. Twenty-seven domestic and five foreign investigations were initiated in 1985, with the results from most of them already published (one study was terminated due to the delay in the TDRSS). Twelve of the studies addressed hydrology, snow and ice, coastal processes, and near-shore oceanographic phenomena; seven addressed vegetation, soils, or animal habitat; and twelve addressed geologic subjects.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Remote Sensing of Environment (ISSN 0034-4257); 28; 5-7
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  • 67
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    Navier-Stokes computations of a prolate spheroid at angle of attack (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 26; 986-993
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  • 68
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    Application of transonic flow analysis to helicopter rotor problems (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The transonic aspect of helicopter flow analysis is addressed. The equations of motion and their implementations are examined, and the computation of real rotor flows is considered. Nonlifting rotor flows, high-speed hover, high advance ratio lifting rotor flows, and strong blade/vortex interaction computations are discussed.
    Keywords: AERODYNAMICS
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  • 69
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    Basic numerical methods (1989)
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    Publication Date: 2011-08-19
    Description: Some of the basic finite-difference schemes that can be used to solve the nonlinear equations that describe unsteady inviscid and viscous transonic flow are reviewed. Numerical schemes for solving the unsteady Euler and Navier-Stokes, boundary-layer, and nonlinear potential equations are described. Emphasis is given to the elementary ideas used in constructing various numerical procedures, not specific details of any one procedure.
    Keywords: AERODYNAMICS
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  • 70
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    Comparison of data from the Scanning Multifrequency Microwave Radiometer (SMMR) with data from the Advanced Very High Resolution Radiometer (AVHRR) for terrestrial environmental monitoring - An overview (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Comparison between the microwave polarized difference temperature (MPDT) derived from 37 GHz band data and the normalized difference vegetation index (NDVI) derived from near-infrared and red bands, from several empirical investigations are summarized. These indicate the complementary character of the two measures in environmental monitoring. Overall the NDVI is more sensitive to green leaf activity, whereas the MPDT appears also to be related to other elements of the above-ground biomass. Monitoring of hydrological phenomena is carried out much more effectively by the MPDT. Further work is needed to explain spectral and temporal variation in MPDT both through modelling and field experiments.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: International Journal of Remote Sensing (ISSN 0143-1161); 10; 1687-169
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  • 71
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    Comparing SMMR and AVHRR data for drought monitoring (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Coincident Scanning Microwave Multi-channel Radiometer 37 GHz and Advanced Very High Resolution Radiometer normalized difference vegetation index satellite data have been compared from drought-affected regions of sub-Saharan Africa and northeastern Brazil for the time period of 1980-1985. Although the two satellite data types can be highly correlated, differences between them were found for the Sahel zone in 1985 and for northeastern Brazil from 1984-1985. These findings suggest that scattering or surface roughness contributions may be greater than previously assumed for the 37 GHz microwave data.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: International Journal of Remote Sensing (ISSN 0143-1161); 10; 1663-167
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  • 72
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    Observation of hydrological features with Nimbus-7 37 GHz data, applied to South America (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The microwave polarization difference temperature (MPDT) prepared from 37 GHz Scanning Multifrequnecy Microwave Radiometer (SMMR) data from the Nimbus-7 satellite allows a unique vision of hydrological features, especially of humid areas. From the series of monthly images from 1979 to 1985 the major hydrological features of four major river basins of South America are briefly examined. These include rivers of the Amazon, La Plata, Orinoco and Sao Francisco, wetlands in the La Plata and Amazon basins and floods in the La Plata basin. Many hydrological features appear much as they do on conventional maps. An interesting prespective can be derived from the ways in which they differ from conventional maps.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: International Journal of Remote Sensing (ISSN 0143-1161); 10; 1673-168
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  • 73
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    Interpretation of Nimbus-7 37 GHz microwave brightness temperature data in semi-arid southern Africa (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Monthly 37 GHz microwave polarization difference temperatures (MPDT) derived from the Nimbus-7 scanning multichannel microwave radiometer (SMMR) for southern Africa from 1979 to 1985 are compared with rainfall and Advanced Very High Resolution Radiometer (AVHRR) normalized difference vegetation index (NDVI) data. MPDT rose sharply during a drought episode which occurred within the period included in the data. The rise was seen not only in the growing season, but also in the dry season MPDT when no actively photosynthetic, water-containing leaves are present. The results suggest that scattering of the emitted microwave radiation by dead and living vegetation is a more important factor than has previously been recognized.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: International Journal of Remote Sensing (ISSN 0143-1161); 10; 1643-166
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  • 74
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    Monitoring global land surface using Nimbus-7 37 GHz data - Theory and examples (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Simplified radiative transfer models for 37 GHz brightness temperatures are developed and applied to observations taken with the Nimbus-7 scanning multichannel microwave radiometer. It is found that, as the vegetation density increases, polarization difference decreases. The polarization difference also decreases with increasing surface roughness. Empirical relations are established between the satellite observations and annual rainfall over Africa and Australia, primary productivity, and actual evaporation. Color-coded maps of primary productivity and evaporation are presented.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: International Journal of Remote Sensing (ISSN 0143-1161); 10; 1579-160
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  • 75
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    Numerical study of chemically reacting flows using a lower-upper symmetric successive overrelaxation scheme (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 27; 1752-176
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  • 76
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    Navier-Stokes computations of lee-side flows over delta wings (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 27; 1673-167
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  • 77
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    Laminar-flow flight experiments (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The flight testing conducted over the past 10 years in the NASA laminar-flow control (LFC) will be reviewed. The LFC program was directed towards the most challenging technology application, the high supersonic speed transport. To place these recent experiences in perspective, earlier important flight tests will first be reviewed to recall the lessons learned at that time.
    Keywords: AERODYNAMICS
    Type: Transonic Symposium: Theory, Application and Experiment, Volume 2; p 59-104
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  • 78
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    Laminar-flow wind tunnel experiments (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Although most of the laminar flow airfoils recently developed at the NASA Langley Research Center were intended for general aviation applications, low-drag airfoils were designed for transonic speeds and wind tunnel performance tested. The objective was to extend the technology of laminar flow to higher Mach and Reynolds numbers and to swept leading edge wings representative of transport aircraft to achieve lower drag and significantly improved operation costs. This research involves stabilizing the laminar boundary layer through geometric shaping (Natural Laminar Flow, NLF) and active control involving the removal of a portion of the laminar boundary layer (Laminar-Flow Control, LFC), either through discrete slots or perforated surface. Results show that extensive regions of laminar flow with large reductions in skin friction drag can be maintained through the application of passive NLF boundary-layer control technologies to unswept transonic wings. At even greater extent of laminar flow and reduction in the total drag level can be obtained on a swept supercritical airfoil with active boundary layer-control.
    Keywords: AERODYNAMICS
    Type: Transonic Symposium: Theory, Application and Experiment, Volume 2; p 105-145
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  • 79
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    Reynolds number effects on the transonic aerodynamics of a slender wing-body configuration (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Aerodynamic forces and moments for a slender wing-body configuration are summarized from an investigation in the Langley National Transonic Facility (NTF). The results include both longitudinal and lateral-directional aerodynamic properties as well as slideslip derivatives. Results were selected to emphasize Reynolds number effects at a transonic speed although some lower speed results are also presented for context. The data indicate nominal Reynolds number effects on the longitudinal aerodynamic coefficients and more pronounced effects for the lateral-directional aerodynamic coefficients. The Reynolds number sensitivities for the lateral-directional coefficients were limited to high angles of attack.
    Keywords: AERODYNAMICS
    Type: Transonic Symposium: Theory, Application and Experiment, Volume 2; p 41-58
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  • 80
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    A review of high-speed, convective, heat-transfer computation methods (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The objective is to provide useful engineering formulations and to instill a modest degree of physical understanding of the phenomena governing convective aerodynamic heating at high flight speeds. Some physical insight is not only essential to the application of the information presented here, but also to the effective use of computer codes which may be available to the reader. Given first is a discussion of cold-wall, laminar boundary layer heating. A brief presentation of the complex boundary layer transition phenomenon follows. Next, cold-wall turbulent boundary layer heating is discussed. This topic is followed by a brief coverage of separated flow-region and shock-interaction heating. A review of heat protection methods follows, including the influence of mass addition on laminar and turbulent boundary layers. Next is a discussion of finite-difference computer codes and a comparison of some results from these codes. An extensive list of references is also provided from sources such as the various AIAA journals and NASA reports which are available in the open literature.
    Keywords: AERODYNAMICS
    Type: Nielsen Engineering and Research, Inc., Missile Aerodynamics: NEAR Conference on Missile Aerodynamics; 64 p
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  • 81
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    Experience with some repeat tests on the 9 inch chord CAST-10-2/DOA 2 airfoil model in the Langley 0.3-m TCT adaptive wall test section (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: A co-operative testing program is in progress between the Langley Research Center (NASA) and the National Aeronautical Establishment (NAE, Canada) to validate two different techniques of airfoil testing at transonic speeds. The procedure employed is to test the same airfoil model in the NAE two-dimensional tunnel and the Langley 0.3-m Transonic Cryogenic Tunnel (0.3-m TCT). The airfoil model used in testing was CAST-10-2/DOA-2 super-critical airfoil. The Langley 0.3-m TCT has a relatively small cross section of 13 in x 13 in, giving a (h/c) ratio of 1.44 for the same 9 in chord model. The approach employed in the 0.3-m TCT aims towards eliminating the wall effects by using active walls. The top and bottom walls are flexible. By changing the wall shapes during a test in an iterative manner, the wall interference effects are reduced. The method employed to change the wall shapes is the adaptive wall technique. The current test program provided an opportunity to validate the adaptive wall technique in the 0.3-m TCT. The relatively long chord airfoil represents a severe test case to test the efficacy of the adaptive wall technique under cryogenic conditions. The program also involved removal of side wall boundary-layer thus increasing the complexity of the wall adaptation technique. This paper deals with some salient results obtained regarding repeatability of test data and possible residual interference effects.
    Keywords: AERODYNAMICS
    Type: CAST-10-2(DOA 2 Airfoil Studies Workshop Results; p 213-231
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  • 82
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    Coherent radar measurement of ocean currents from geostationary orbit (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: A coherent HF radar system developed by Barrick has successfully measured ocean surface currents near shore. This innovative system, called CODAR, can map the current vector for coastal areas as large as 10,000 sq km. CODAR's range is limited owing to the strong attenuation suffered by HF ground waves. An alternate technique was proposed by Schuler, in which the cross-product power spectrum of two (different frequency) microwave signals is processed. The frequency of the resonant peak corresponds close by to the Doppler shift of an ocean gravity wave traveling toward the radar at the phase velocity, v(sub p). The slight difference between the frequency of the measured resonant delta K peak and the Doppler frequency shift caused by the motion of the gravity wave is attributed to be the current velocity in the pointing direction of the radar. The Microwave Remote Sensing Laboratory (MIRSL) has considered the feasibility of using this technique to measure ocean surface currents from geostationary satellite platforms. Problems are discussed that must be overcome if a satellite current measurement system is to be realized. MIRSL research activities that address some of these problem areas are discussed. Current measurements are presented that were made using a specially-designed C-Band, step-frequency delta K radar. These measurements suggest that progress is being achieved in detecting ocean surface current motion for a wide variety of ocean surface conditions.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA, Langley Research Center, Earth Science Geostatonary Platform Technology; p 155-165
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  • 83
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    Comparison of two- and three-dimensional Navier-Stokes solutions with NASA experimental data for CAST-10 airfoil (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The two-dimensional (2-D) and three-dimensional Navier-Stokes equations are solved for flow over a NAE CAST-10 airfoil model. Recently developed finite-volume codes that apply a multistage time stepping scheme in conjunction with steady state acceleration techniques are used to solve the equations. Two-dimensional results are shown for flow conditions uncorrected and corrected for wind tunnel wall interference effects. Predicted surface pressures from 3-D simulations are compared with those from 2-D calculations. The focus of the 3-D computations is the influence of the sidewall boundary layers. Topological features of the 3-D flow fields are indicated. Lift and drag results are compared with experimental measurements.
    Keywords: AERODYNAMICS
    Type: CAST-10-2(DOA 2 Airfoil Studies Workshop Results; p 233-258
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  • 84
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    An experimental AWTS process and comparisons of ONERA T2 and 0.3-m TCT AWTS data for the ONERA CAST-10 aerofoil (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: An experimental Adaptive Wall Test Section (AWTS) process is described. Comparisons of the ONERA T2 and the 0.3-m TCT (transonic cryogenic tunnel) AWTS data for the ONERA CAST-10 airfoil are presented. Most of the 0.3-m TCT data is new and preliminary and no sidewall boundary layer control is involved. No conclusions are given.
    Keywords: AERODYNAMICS
    Type: CAST-10-2(DOA 2 Airfoil Studies Workshop Results; p 137-153
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  • 85
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    High Reynolds number tests of the CAST-10-2/DOA 2 transonic airfoil at ambient and cryogenic temper ature conditions (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The transonic airfoil CAST 10-2/DOA 2 was investigated in several major transonic wind tunnels at Reynolds numbers ranging from Re=1.3 x 10(exp 6) to 45 x 10(exp 6) at ambient and cryogenic temperature conditions. The main objective was to study the degree and extent of the effects of Reynolds number on both the airfoil aerodynamic characteristics and the interference effects of various model-wind-tunnel systems. The initial analysis of the CAST 10-2 airfoil results revealed appreciable real Reynolds number effects on this airfoil and showed that wall interference can be significantly affected by changes in Reynolds number thus appearing as true Reynolds number effects.
    Keywords: AERODYNAMICS
    Type: CAST-10-2(DOA 2 Airfoil Studies Workshop Results; p 47-60
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  • 86
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    Finite element flow-thermal-structural analysis of aerodynamically heated leading edges (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Hypersonic vehicles operate in a hostile aerothermal environment which has a significant impact on their aerothermostructural performance. Significant coupling occurs between the aerodynamic flow field, structural heat transfer, and structural response creating a multidisciplinary interaction. A long term goal of the Aerothermal Loads Branch at the NASA Langley Research Center is to develop a computational capability for integrated fluid, thermal and structural analysis of aerodynamically heated structures. The integrated analysis capability includes the coupling between the fluid and the structure which occurs primarily through the thermal response of the structure, because: (1) the surface temperature affects the external flow by changing the amount of energy absorbed by the structure, and (2) the temperature gradients in the structure result in structural deformations which alter the flow field and attendant surface pressures and heating rates. In the integrated analysis, a finite element method is used to solve: (1) the Navier-Stokes equations for the flow solution, (2) the energy equation of the structure for the temperature response, and (3) the equilibrium equations of the structure for the structural deformation and stresses.
    Keywords: AERODYNAMICS
    Type: Recent Advances in Multidisciplinary Analysis and Optimization, Part 2; p 971-990
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  • 87
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    Wall interference assessment and corrections (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Wind tunnel wall interference assessment and correction (WIAC) concepts, applications, and typical results are discussed in terms of several nonlinear transonic codes and one panel method code developed for and being implemented at NASA-Langley. Contrasts between 2-D and 3-D transonic testing factors which affect WIAC procedures are illustrated using airfoil data from the 0.3 m Transonic Cryogenic Tunnel and Pathfinder 1 data from the National Transonic Facility. Initial results from the 3-D WIAC codes are encouraging; research on and implementation of WIAC concepts continue.
    Keywords: AERODYNAMICS
    Type: Transonic Symposium: Theory, Application, and Experiment, Volume 1, Part 2; p 817-851
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  • 88
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    Stability of compressible boundary layers (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The stability of compressible 2-D and 3-D boundary layers is reviewed. The stability of 2-D compressible flows differs from that of incompressible flows in two important features: There is more than one mode of instability contributing to the growth of disturbances in supersonic laminar boundary layers and the most unstable first mode wave is 3-D. Whereas viscosity has a destabilizing effect on incompressible flows, it is stabilizing for high supersonic Mach numbers. Whereas cooling stabilizes first mode waves, it destabilizes second mode waves. However, second order waves can be stabilized by suction and favorable pressure gradients. The influence of the nonparallelism on the spatial growth rate of disturbances is evaluated. The growth rate depends on the flow variable as well as the distance from the body. Floquet theory is used to investigate the subharmonic secondary instability.
    Keywords: AERODYNAMICS
    Type: NASA, Langley Research Center, Transonic Symposium: Theory, Application, and Experiment, Volume 1, Part 2; p 629-689
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  • 89
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    Turbulent eddy viscosity modeling in transonic shock/boundary-layer interactions (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The treatment of turbulence effects on transonic shock/turbulent boundary layer interaction is addressed within the context of a triple deck approach valid for arbitrary practical Reynolds numbers between 1000 and 10 billion. The modeling of the eddy viscosity and basic turbulent boundary profile effects in each deck is examined in detail using Law-of-the-Wall/Law-of-the-Wake concepts as the foundation. Results of parametric studies showing how each of these turbulence model aspects influences typical interaction zone property distributions (wall pressure, displacement thickness and local skin friction) are presented and discussed.
    Keywords: AERODYNAMICS
    Type: NASA, Langley Research Center, Transonic Symposium: Theory, Application, and Experiment, Volume 1, Part 2; p 611-627
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  • 90
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    Airframe/propulsion integration characteristics at transonic speeds (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The aerodynamic characteristics for both single and twin-engine high-performance aircraft are significantly affected by shock induced flow interactions as well as other local flow interference effects which usually occur at transonic speeds. These adverse interactions can not only cause high drag, but also cause unusual aerodynamic loadings and/or severe stability and control problems. Many programs are under way to not only develop method for reducing the adverse effects, but also to develop an understanding of the basic flow conditions which are the primary contributors. It is anticipated that these programs will result in technologies which can reduce the aircraft cruise drag through improved integration as well as increase aircraft maneuverability through the application of thrust vectoring. Some of the primary integration problems for twin-engine aircraft at transonic speeds are identified, and several methods are demonstrated for reducing or eliminating the undersirable characteristics, while enhancing configuration effectiveness.
    Keywords: AERODYNAMICS
    Type: Transonic Symposium: Theory, Application, and Experiment, Volume 1, Part 1; p 1-31
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  • 91
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    Generation of unstructured grids and Euler solutions for complex geometries (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Algorithms are described for the generation and adaptation of unstructured grids in two and three dimensions, as well as Euler solvers for unstructured grids. The main purpose is to demonstrate how unstructured grids may be employed advantageously for the economic simulation of both geometrically as well as physically complex flow fields.
    Keywords: AERODYNAMICS
    Type: Transonic Symposium: Theory, Application, and Experiment, Volume 1, Part 1; p 377-408
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  • 92
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    Asymptotic methods for internal transonic flows (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: For many internal transonic flows of practical interest, some of the relevant nondimensional parameters typically are small enough that a perturbation scheme can be expected to give a useful level of numerical accuracy. A variety of steady and unsteady transonic channel and cascade flows is studied with the help of systematic perturbation methods which take advantage of this fact. Asymptotic representations are constructed for small changes in channel cross-section area, small flow deflection angles, small differences between the flow velocity and the sound speed, small amplitudes of imposed oscillations, and small reduced frequencies. Inside a channel the flow is nearly one-dimensional except in thin regions immediately downstream of a shock wave, at the channel entrance and exit, and near the channel throat. A study of two-dimensional cascade flow is extended to include a description of three-dimensional compressor-rotor flow which leads to analytical results except in thin edge regions which require numerical solution. For unsteady flow the qualitative nature of the shock-wave motion in a channel depends strongly on the orders of magnitude of the frequency and amplitude of impressed wall oscillations or fluctuations in back pressure. One example of supersonic flow is considered, for a channel with length large compared to its width, including the effect of separation bubbles and the possibility of self-sustained oscillations. The effect of viscosity on a weak shock wave in a channel is discussed.
    Keywords: AERODYNAMICS
    Type: NASA, Langley Research Center, Transonic Symposium: Theory, Application, and Experiment, Volume 1, Part 1; p 261-291
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  • 93
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    Euler solvers for transonic applications (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The 1980s may well be called the Euler era of applied aerodynamics. Computer codes based on discrete approximations of the Euler equations are now routinely used to obtain solutions of transonic flow problems in which the effects of entropy and vorticity production are significant. Such codes can even predict separation from a sharp edge, owing to the inclusion of artificial dissipation, intended to lend numerical stability to the calculation but at the same time enforcing the Kutta condition. One effect not correctly predictable by Euler codes is the separation from a smooth surface, and neither is viscous drag; for these some form of the Navier-Stokes equation is needed. It, therefore, comes as no surprise to observe that the Navier-Stokes has already begun before Euler solutions were fully exploited. Moreover, most numerical developments for the Euler equations are now constrained by the requirement that the techniques introduced, notably artificial dissipation, must not interfere with the new physics added when going from an Euler to a full Navier-Stokes approximation. In order to appreciate the contributions of Euler solvers to the understanding of transonic aerodynamics, it is useful to review the components of these computational tools. Space discretization, time- or pseudo-time marching and boundary procedures, the essential constituents are discussed. The subject of grid generation and grid adaptation to the solution are touched upon only where relevant. A list of unanswered questions and an outlook for the future are covered.
    Keywords: AERODYNAMICS
    Type: NASA, Langley Research Center, Transonic Symposium: Theory, Application, and Experiment, Volume 1, Part 1; p 217-230
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  • 94
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    Transonics and fighter aircraft: Challenges and opportunities for CFD (1989)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The application of computational fluid dynamics (CFD) to fighter aircraft design and development is discussed. Methodology requirements for the aerodynamic design of fighter aircraft are briefly reviewed. The state-of-the-art of computational methods for transonic flows in the light of these requirements is assessed and the techniques found most adequate for the subject application are identified. Highlights from some proof-of-feasibility Euler and Navier-Stokes computations about a complete fighter aircraft configuration are presented. Finally, critical issues and opportunities for design application of CFD are discussed.
    Keywords: AERODYNAMICS
    Type: NASA, Langley Research Center, Transonic Symposium: Theory, Application, and Experiment, Volume 1, Part 1; p 153-173
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  • 95
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    Shock-boundary-layer interaction in flight (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: A brief survey is given on the study of transonic shock/boundary layer effects in flight. Then the possibility of alleviating the adverse shock effects through passive shock control is discussed. A Swedish flight experiment on a swept wing attack aircraft is used to demonstrate how it is possible to reduce the extent of separated flow and increase the drag-rise Mach number significantly using a moderate amount of perforation of the surface.
    Keywords: AERODYNAMICS
    Type: NASA, Langley Research Center, Transonic Symposium: Theory, Application, and Experiment, Volume 1, Part 1; p 61-77
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  • 96
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    Two-measured variable method for wall interference assessment/correction (1989)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: An iterative method for wall interference assessment and/or correction is presented for transonic flow conditions in wind tunnels equipped with two component velocity measurements on a single interface. The iterative method does not require modeling of the test article and tunnel wall boundary conditions. Analytical proof for the convergence and stability of the iterative method is shown in the subsonic flow regime. The numerical solutions are given for both 2-D and axisymmetrical cases at transonic speeds with the application of global Mach number correction.
    Keywords: AERODYNAMICS
    Type: NASA, Langley Research Center, Transonic Symposium: Theory, Application, and Experiment, Volume 1, Part 2; p 853-866
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  • 97
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    Developments and trends in three-dimensional mesh generation (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: An intense research effort over the last few years has produced several competing and apparently diverse methods for generating meshes. Recent progress is reviewed and the central themes are emphasized which form a solid foundation for future developments in mesh generation.
    Keywords: AERODYNAMICS
    Type: NASA, Langley Research Center, Transonic Symposium: Theory, Application, and Experiment, Volume 1, Part 1; p 341-376
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  • 98
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    An embedded mesh procedure for leading-edge vortex flows (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: A cell-vertex scheme is outlined for solving the flow about a delta wing with M (sub infinity) is greater than 1. Embedded regions of mesh refinement allow solutions to be obtained which have much higher resolution than those achieved to date. Effects of mesh refinement and artificial viscosity on the solutions are studied, to determine at what point leading-edge vortex solutions are grid-converged. A macroscale and a microscale for the size of the vortex are defined, and it is shown that the macroscale (which includes the wing surface properties) is converged on a moderately refined grid, while the microscale is very sensitive to grid spacing. The level of numerical diffusion in the core of the vortex is found to be substantial. Comparisons with the experiment are made for two cases which have transonic cross-flow velocities.
    Keywords: AERODYNAMICS
    Type: NASA, Langley Research Center, Transonic Symposium: Theory, Application, and Experiment, Volume 1, Part 1; p 231-259
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  • 99
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    Computation of aircraft component flow fields at transonic Mach numbers using a three-dimensional Navier-Stokes algorithm (1989)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: A computer analysis was developed for calculating steady (or unsteady) three-dimensional aircraft component flow fields. This algorithm, called ENS3D, can compute the flow field for the following configurations: diffuser duct/thrust nozzle, isolated wing, isolated fuselage, wing/fuselage with or without integrated inlet and exhaust, nacelle/inlet, nacelle (fuselage) afterbody/exhaust jet, complete transport engine installation, and multicomponent configurations using zonal grid generation technique. Solutions can be obtained for subsonic, transonic, or hypersonic freestream speeds. The algorithm can solve either the Euler equations for inviscid flow, the thin shear layer Navier-Stokes equations for viscous flow, or the full Navier-Stokes equations for viscous flow. The flow field solution is determined on a body-fitted computational grid. A fully-implicit alternating direction implicit method is employed for the solution of the finite difference equations. For viscous computations, either a two layer eddy-viscosity turbulence model or the k-epsilon two equation transport model can be used to achieve mathematical closure.
    Keywords: AERODYNAMICS
    Type: NASA, Langley Research Center, Transonic Symposium: Theory, Application, and Experiment, Volume 1, Part 1; p 175-194
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  • 100
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    Transonic CFD applications at Boeing (1989)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The use of computational methods for three dimensional transonic flow design and analysis at the Boeing Company is presented. A range of computational tools consisting of production tools for every day use by project engineers, expert user tools for special applications by computational researchers, and an emerging tool which may see considerable use in the near future are described. These methods include full potential and Euler solvers, some coupled to three dimensional boundary layer analysis methods, for transonic flow analysis about nacelle, wing-body, wing-body-strut-nacelle, and complete aircraft configurations. As the examples presented show, such a toolbox of codes is necessary for the variety of applications typical of an industrial environment. Such a toolbox of codes makes possible aerodynamic advances not previously achievable in a timely manner, if at all.
    Keywords: AERODYNAMICS
    Type: NASA, Langley Research Center, Transonic Symposium: Theory, Application, and Experiment, Volume 1, Part 1; p 79-107
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