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  • Books  (6)
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  • 1
    Call number: ZSP-201-76/31
    In: CRREL Report, 76-31
    Description / Table of Contents: Sections in the Connecticut River where ice jam potential is high were identified through the use of low-altitude black and white photographs taken during low-flow, ice-free conditions. The hydraulics and mechanics of ice jam initiation were investigated in the river reach where these sections were identified. Certain areas were found in the river that had a high susceptibility to ice clogging, but this high potential decreased with increasing discharge because of the improved surface conveyance of the ice through the reach. The stability of ice floes was established along the channel, but the floes generally became unstable as the flow increased. This was calculated by using a Froude number criterion. Grounding locations for ice became evident when the critical Froude number was zero for a given thickness and water depth. No single factor was determined to be responsible for initiating the ice jams in the Connecticut River at Windsor. Apparently there existed a multitude of interacting conditions: surface constrictions, possible high backwater conditions from the Brattleboro Dam, a solid ice cover in the backwater of the Brattleboro Dam that prevented ice transport from the Windsor area, deep pools followed by shallow depth sections upstream of bridge piers, a greater ice thickness accumulation of fragmented floes than would result if a uniform cover could be established in the same reach, and the diurnal fluctuation of river stage casued by the release of water at Wilder Dam.
    Type of Medium: Series available for loan
    Pages: vi, 39 Seiten , Illustrationen
    Series Statement: CRREL Report 76-31
    Language: English
    Note: CONTENTS Abstract Preface Summary Conversion factors: U.S. customary to metric units of measurement Introduction Testsite Aerial photography Channel morphology — Interpretation of aerial photographs Ground surveys Hydraulic analysis Analysis of ice jam locations Winter field observations Conclusions Literature cited Appendix: Locations and plots of cross sections from Sumner Falls to Chase Island, Connecticut River
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  • 2
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-79/14
    In: CRREL Report, 79-14
    Description / Table of Contents: Solid ice growth rates due to the presence of frazil slush beneath the ice cover have been shown to be greater than the so-called static growth. The frazil slush reduces the effective heat of ice solidification and the frazil particles freeze into the interstitial water. Numerical schemes are presented which clearly show the effect of frazil ice porosity on ice cover growth rates and the numerical model using air temperature as the major input is compared with field data on ice thickness in a small river laden with frazil ice beneath its cover.
    Type of Medium: Series available for loan
    Pages: ii, 4 Seiten , Illustrationen
    Series Statement: CRREL Report 79-14
    Language: English
    Location: AWI Archive
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  • 3
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    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-82/9
    In: CRREL Report, 82-9
    Description / Table of Contents: This study deals with the distribution of forces along the converging boundaries of the Port Huron, Michigan, region where unconsolidated ice in Lake Huron is held against wind and water stresses. An experimental basin was built to induce uniform shear stress on the model ice cover by flowing water beneath the ice. The boundary segments, which held the ice cover in the region, were instrumented to measure force in the normal and tangential directions. The distribution of normal forces along the boundary was compared with as distribution derived by using a theoretical model. An ice control structure (ICS) was installed in the basin and experiments were conducted to measure the forces on the ICS and the ice release through the opening in the ICS during simulated ship passages. The experimental results are presented in a nondimensional form. In addition, the force per unit length on the ICS and the area of ice released through its opening were estimated for the expected wind conditions at the Port Huron site.
    Type of Medium: Series available for loan
    Pages: v, 27 Seiten , Illustrationen
    Series Statement: CRREL Report 82-9
    Language: English
    Note: CONTENTS Abstract Preface List of symbols Introduction Theoretical models Case 1 Case 2 Case 3 Experimental program Experimental facility Scaling factors Experimental results Analysis of wind data for lower Lake Huron Summary and conclusions Release of ice through the opening of an ICS Ice forces on the ice control structure Ice forces on ice control structure from a large unconsolidated ice cover Literature cited Appendix A. Equation for the stress resultants and velocities of the ice cover Appendix B. Monthly summary of wind data at Port Huron
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  • 4
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-82/34
    In: CRREL Report, 82-34
    Description / Table of Contents: The ice discharge through an opening in an ice control structure was documented to be a function of the floe size, ice type, ice floe conditions and vessel direction. The model data for the average ice discharge per vessel transit scaled to prototype values compared favorably with data taken at the St. Marys River ice control structure (ICS). The model results of the force measurements were also consistent with data taken at the St. Marys ICS. The dynamic loading conditions were independent of vessel direction. The dynamic loading to the structure using 3 types of ice (plastic, natural and urea-doped) showed a considerable difference in their means and standard deviations. The urea-doped ice was evaluated for dynamic loading conditions, and reasonable peak values of 3 to 5 times the mean load at each measuring position were recorded, independent of vessel direction. It appears that synthetic random ice floes may be used in model studies where ice discharge through an opening in a structure needs to be documented. This study shows the synthetic random ice floe discharge to fall reasonably within the values obtained for natural ice discharge for both rafted and non-rafted ice fields above the ICS. However, the question of whether synthetic ice can be used for analyzing force distributions and dynamic force loading criteria cannot be fully answered at this time because the load distributions of the synthetic and natural floes appear to differ.
    Type of Medium: Series available for loan
    Pages: 68 Seiten , Illustrationen
    Series Statement: CRREL Report 82-34
    Language: English
    Note: CONTENTS Abstract Preface Introduction Scope of work Ice discharge from Lake Huron into St. Clair River Water velocity profiles at Port Huron Ice conditions Physical model Basis for selection Description Instrumentation Model ice control structure Open water calibration Open water tests Experimental procedures and techniques Ice cover calibration Ice control structure orientation Analysis of ice discharge due to ship transits Natural ice Synthetic ice Forces on the ice control structure Static measurements Dynamic force measurements Potential additional shear stresses Anticipated ice conditions with ICS Conclusions Literature cited Appendix A. Application of model results Appendix B. Suggested additional studies Appendix C. Derivation of ice discharge
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  • 5
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-76/42
    In: CRREL Report, 76-42
    Description / Table of Contents: A study of arching of mixed, square fragmented ice floes at an opening in an ice boom is documented, using results from a model study in which two sizes of plastic blocks represented real ice. A power function, relating the upstream ice concentration to the ratio of a characteristic block dimension to the gap opening, is found adequate to distinguish between arching and nonarching events for block mixtures of two component sizes. It is demonstrated that when the respective total areas of the two block components are nearly equal, a minimum ice concentration initiates an arch across the opening. As the mixture of two sizes of blocks approaches a uniform (one-sized) mixture, a higher concentration of ice is needed to initiate the arch. When the ratio of the block dimension to the gap opening is equal to or less than 0.10, arching of the fragmented ice is not possible, even when the upstream ice discharge exceeds the maximum discharge of ice through a gap opening. The distribution of fragmented ice areas is an important parameter in establishing the minimum size of opening at which an ice boom will retain its arching capability.
    Type of Medium: Series available for loan
    Pages: iv, 17 Seiten , Illustrationen
    Series Statement: CRREL Report 76-42
    Language: English
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  • 6
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-80/24
    In: CRREL Report, 80-24
    Description / Table of Contents: The fluid shear stress applied to the underside of a simulated floating ice cover was measured in a laboratory flume. The measured values were compared with values of the shear stress computed from the von Karman-Prandtl velocity distribution fitted to the velocity profiles measured beneath the cover. For the lower velocity runs (approx 0.079 m/s) the measured and computed values of the shear stress were in close agreement. At the high velocity flows (approx 0.137 m/s) the measured values were roughly one-half those calculated from the velocity distribution. As the underside of the cover became increasingly rougher, the position of maximum velocity moved closer to the bottom of the channel. It was shown that the Darcy friction coefficient is exponentially related to a normalized ice cover thickness, which suggests that it is measure of the roughness of a fragmented ice cover.
    Type of Medium: Series available for loan
    Pages: iv, 11 Seiten , Illustrationen
    Series Statement: CRREL Report 80-24
    Language: English
    Note: CONTENTS Abstract Preface List of symbols Introduction Experimental apparatus Experimental procedures Analysis of forces Experimental results Analysis of data Conclusions Literature cited
    Location: AWI Archive
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