Freezeup Dynamics of a Frazil Ice Screen
Abstract
Fence booms made of wire mesh screen have been proposed as economical, temporary frazil ice control structures. These screens incorporate frazil ice as it freezes to the screen material, eventually forming a frazil ice dam and raising the water level at a specified location. The purpose of raising the water level is to allow the formation of a stable ice cover that will incorporate still more frazil ice through hydraulic thickening of the cover and deposition beneath the cover. A series of experiments examining the freezeup and blocking dynamics of an expanded metal frazil ice screen were conducted using both an impermeable barrier and frazil ice. A qualitative analysis of the complex frazil ice accumulation process indicated three phases of blocking - an orifice flow stage, a transition stage, and a permeable flow stage. Downstream velocities decreased during the permeable flow stage, although piping resulted in velocity jets. The test results indicate that a rapidly and completely blocked screen is desirable to minimize the time during which high downstream velocities, which lead to bed scour, occur. Fence booms; Frazil ice; Frazil ice control structures; Ice control; Winter navigation; Flooding; Cold region.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1990
- Accession Number
- ADA219588
Entities
People
- Kathleen D. Axelson
Organizations
- Cold Regions Research and Engineering Laboratory