Criteria for Submergence of Ice Blocks in Front of Ice Cover

• 作者: Jueyi Sui Jun Wang Natalie Linklater Tiejie Cheng Wanlong Yang Zhiqi Li
• 来源期刊: 世界工程和技术(英文)
• 学科: 工学
• 关键词: Critical Velocity Ice Block Maximum Anti-Overturn Moment Kinetic Energy
• 年，卷（期）: sjgchjsyw_2020,（3）
• 页码范围: 523-536
• 页数: 14页
• 分类号: TP3

摘要

During winter, ice jams develop when floating ice blocks accumulate in rivers. Ice jams can dramatically decrease in the capacity of flow in a river and can cause ice flooding due to increase in water level. Submergence of floating ice blocks in front of ice cover is critical for the development of an ice jam. In this study, the effect of the rotation angle of ice blocks on the submergence of ice block was assessed. The impacts of both the drag force caused by the flow and the hydraulic pressure force on the rotation of ice block were studied. Considering both the maximum moment for anti-overturn of an ice block, and the associated rotation angle </span><i><span style="font-family:Verdana;">θ</span></i>_{<span style="font-family:Verdana;font-size:12px;">1</span>}<span style="font-family:Verdana;">, equations for describing the criteria for ice block entrainment in front of ice cover have been derived. On the basis of the theorem for moment equilibrium, relating the moment acting on a horizontal ice block with the maximum anti-overturn moment of an ice block, the criteria for assessing the overturn-and-submergence of an ice block have been proposed. To verify results using the derived equations for calculating the critical flow velocity for ice block submergence in front of ice cover, data was collected from flume experiments in the laboratory. Experiments have been conducted using different sizes of ice block under different flow conditions in a flume which is 26.68 m long, 0.40 m wide, and 0.6 m deep. Model ice blocks were </span><span style="font-family:Verdana;">made of polypropylene </span><span style="font-family:Verdana;">and have</span><span style="font-family:Verdana;"> nearly the same as the mass density of the nat</span><span style="font-family:Verdana;">ural ice. Using proposed method for assessing ice block submergence in front of ice cover, calculated critical flow velocities agree well with those of experi</span><span style="font-family:Verdana;">ments.