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B Report on Frazil

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B Report on Frazil □ International Association for Hydraulic Research Working Group on Thermal Regimes Report on Frazil Ice Steven F. Daly, Editor August 1994 Abstract This report, prepared by members of the Working Group on Thermal Regimes of the Section on Ice Research and Engineering of the International Association for Hydraulic Research, is a comprehensive overview of frazil ice. Starting from the initial nucléation of single frazil ice crystals to the formation of ice covers that may be many kilometers long, the physics and evolution of frazil ice in natural water bodies are described. Laboratory experiments conducted over the last 30 years on frazil ice dynamics and other aspects of frazil are described and classified. A physically based, quantitative model that describes the dynamic evolution of the crystal size distribution function is presented. In addition, the development of numerical models of frazil ice in oceans and rivers is discussed and their results described. This report serves as a review of the state of the art of the present understanding of frazil, and the extensive references are a comprehensive resource. DATEIDUE GAYLORD P R IN T E R N UJS.A. For conversion of SI metric units to U.S./British customary unite of measurement consult ASTM Standard E380-89a, Standard Practice for Use o f the International System o f Units; published by the American Society for Testing and Materials, 1916 Race St„ Philadelphia, Pa. 19103. This report is printed on paper that contains a minimum of 50% recycled m aterial. BUREAU OF RECLAMATION DENVER LIBRARY 92049782 J t> t> Special Report 94-23 A é h / Z ? - US Army Corps of Engineers ¿b 'c>n' ¿b 'c>n' /ofiZ PO Cold Regions Research & Engineering Laboratory International Association for Hydraulic Research Working Group on Thermal Regimes Report on Frazil Ice Steven F. Daly, Editor August 1994 Prepared by INTERNATIONAL ASSOCIATION FOR HYDRAULIC RESEARCH WORKING GROUP ON THERMAL REGIMES Approved for public release; distribution is unlimited. PREFACE This report was prepared by the Working Group on Thermal Regimes of the Section on Ice Research and Engineering of the International Association for Hydraulic Research. It was edited by Steven F. Daly, Research Hydraulic Engineer, Ice Engineering Research Branch, Experimental Engineering Division, U.S. Army Cold Regions Research and Engineering Laboratory; he also contributed several of the chapters herein. Other contributors are Dr. Thomas Forest, Professor of Mechanical Engineering, University of Alberta, Edmonton, Alberta; Dr. Anders Omstedt, Associate Professor, Swedish Meteorological and Hydrologi­ cal Institute, Norrkoping, Sweden; and Kathleen D. White, Research Hydraulic Engineer, Ice Engineering Research Branch, CRREL. The contents of this report are not to be used for advertising or promotional purposes. Citation of brand names does not constitute an official endorsement or approval of the use of such commercial products. 11 CONTENTS Page Preface................................................................................................................................. ii Chapter 1: Physics of Frazil Ice Nomenclature............................................................................................................. 1 Introduction ...................................................................................................... 1 Nucléation of frazil crystals...................................................................................... 1 Frazil ice morphology............................................................................. 2 Stability of frazil crystals........................................................................................... 3 Chapter 2: Experimental Investigation of Frazil Ice Nomenclature............................................................................................................. 5 Introduction................................................................................................................ 5 Frazil ice formation.................................................................................................... 5 Other aspects of frazil ice.......................................................................................... 8 Summary...................................................................................................... 10 Chapter 3: Evolution of Frazil Ice in Natural Water Bodies Introduction................................................................................................................ 11 Seeding................................................................................................ 12 Frazil ice dynamics—disk crystals.......................................................................... 13 Flocculation and deposition..................................................................................... 13 Frazil floes.......................................................................................................... 13 Anchor ice.......................................................................................................... 14 Transport and mixing................................................................................................ 14 Frazil slush.................. 14 Suspension................. 14 Determination of vertical transport.............................................................. 14 Floe formation............................................................................................................ 15 Ice cover formation and under-ice transport......................................................... 16 Summary................................................................................................................. 17 Chapter 4: Frazil Ice Dynamics Nomenclature............................................................................................................. 19 Introduction................................................................................................................ 19 Basic equations........................................................................................................... 20 Crystal number continuity equation............................................................. 20 Heat balance...................................................................................................... 20 Parameters in the basic equations.................................................................. 21 Ice crystal growth rates.................. 21 Intrinsic kinetic growth rate............................................................................ 21 Heat transfer from ice crystals suspended in turbulent water.................. 22 Secondary nucléation....................................................................................... 23 Summary..................................................................................................................... 24 Chapter 5: Numerical Simulation of Frazil Ice Nomenclature............................................................................................................. 25 Introduction................................................................................................................ 25 Scope of the chapter......................................................................................... 25 Physical processes to be considered.............................................................. 25 Guidance and simplifying assumptions................................................................. 26 Turbulence......................................................................................................... 26 Mass exchange and morphology................................................................... 26 iii Page Gravity............................................................................................................... 27 Salt rejection..................................................................................................... 27 Flocculation....................................................................................................... 27 Review of the literature............................................................................................. 27 Mathematical formulation.................................................................................... 28 Properties of water and ice.............................................................................. 28 Heat equation....................................... ................................. ...... ,................. 28 Salt equation............................................................................. ............ ........... 29 Frazil ice equation........................................................................ ................... 29 Frazil-floc equation.......................................................................................... 29 Mixture density equation...................................................................... ........ 30 Boundary layer equations............................................................................ 30 Turbulence model....................................................................... .............. 31 Details of calculations............................................................................................... 31 Results.......................................................................................................................... 32 Laboratory simulations...................................................................................
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