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  • 1
    Schriftenreihen ausleihbar
    Schriftenreihen ausleihbar
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Dazugehörige Bände
    Signatur: ZSP-201-78/16
    In: CRREL Report, 78-16
    Beschreibung / Inhaltsverzeichnis: A model investigation of drifting snow conditions was conducted in a hydraulic flume using a sand-water analog. Model results were evaluated to define modeling parameters that would allow quantitative correlation between measured prototype drift conditions and the model. The modeled structure was the standard plan snow fence designed by the Wyoming Highway Department and installed along Interstate Highway 80 in 1971. The performance of this system was documented by the Rocky Mountain Forest and Range Experiment Station of the U.S. Forest Service. Models of the fence were constructed for three heights and two geometric scales. Geometric scaling was based on terrain roughness and boundary layer thickness considerations, while velocity scaling was based on particle fall velocity and threshold of motion characteristics. Simulation of the atmospheric boundary layer was found to be of primary importance. Velocity scaling analysis suggested the use of a 'significant wind' concept based on a combination of velocity magnitude and frequency. Similarity of precipitation rate was not essential, and could be altered within limits to adjust the time scale. The response of the model to the shape of model elements was significant. Although the model is distorted and inexact similarity is achieved, it appears useful on a practical basis.
    Materialart: Schriftenreihen ausleihbar
    Seiten: vi, 26 Seiten , Illustrationen
    Serie: CRREL Report 78-16
    Sprache: Englisch
    Anmerkung: CONTENTS Abstract Preface Nomenclature Introduction Background Experimental design Similitude considerations The model Model operation Results Velocity Fence height Porosity Model correlation Summary and conclusions Recommeqdations for future work Literature cited Appendix A
    Standort: AWI Archiv
    Zweigbibliothek: AWI Bibliothek
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    Signatur: ZSP-201-86/11
    In: CRREL Report, 86-11
    Beschreibung / Inhaltsverzeichnis: This initial study of the ice-covered Tanana River, near Fairbanks, Alaska, attempted to 1) establish field methods for systematic and repetitive quantitative analyses of an ice-covered river's regime, 2) evaluate the instruments and equipment for sampling, and 3) obtain the initial data of a long-term study of ice cover effects on the morphology, hydraulics and sediment transport of a braided river. A methodology was established, and detailed measurements and samplings, including profiling by geophysical techniques, were conducted along cross sections of the river. A small, portable rotary drill rig equipped with a 356-mm (14-in.) ice auger was used to cut large diameter holes in the ice cover for through-the-ice measurements. Portable heat sources and a heated shelter were required to continuously thaw and dry equipment for the repetitive measurements. Measurements included ice cover thickness, water level, water depth, temperature, flow velocity, suspended load and bed load, frazil ice distribution and bed material composition. Remotely gathered data included apparent resistivity and subsurface radar profiling. The various techniques, sampling gear and problems encountered during use in the subfreezing cold are described in detail in this report.
    Materialart: Schriftenreihen ausleihbar
    Seiten: v, 49 Seiten , Illustrationen
    Serie: CRREL Report 86-11
    Sprache: Englisch
    Anmerkung: CONTENTS Abstract Preface Introduction Study objectives and field locale Study site Equipment Vehicles Drilling equipment Sampling equipment Geophysical equipment Shelter and icing control Surveying equipment Miscellaneous equipment Field techniques and methodology Logistics Drilling procedures Data collection Geophysical analyses Experiences summary Morphology, transport and hydraulic data Mid-winter physical characteristics Hydraulic characteristics Sediment transport Late winter physical characteristics Seasonal morphology Geophysical data interpretation Spatial morphology Frazil ice characteristics Discussion and conclusions Recommendations Equipment Research Literature cited
    Standort: AWI Archiv
    Zweigbibliothek: AWI Bibliothek
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
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