黄河小型清沟封冻过程现场模拟实验与实测数据分析

利用黄河封冻阶段的冰层,开16m2敞流水面模拟清沟,通过雷达测冰厚的方法,观测敞流水面因冰花封冻过程,并测量敞流水面封冻后冰盖厚度分布,并用费氏台观察冰晶体结构.通过将实测冰厚数据绘成等高线图以及冰厚剖面图,证实封河过程中,由周边向中间封冻的清沟除了与冰冻度日有关外,还与清沟下水流速度和方向以及冰花含量有关.水流携带冰花流至清沟时,冰花会漂浮在清沟中.由于水的粘性作用,水流使清沟中的水起动,然后冲击下游冰壁引起涡旋.涡旋场在清沟上游形成较平静区域,可以积累大量冰花;而在下游冰壁处水体运动活跃,冰花无法堆积.经过长时间冻结,上游处冰花被冻结成为较厚的冰花冰,而下游逐渐冻结成较薄的冰花冰.之后,柱状冰在冰花冰下开始生长.最后经过1个月的冻结,形成了敞流水面下游处冰较薄,上游处冰较厚的非对称冻结厚度分布,并在与水流垂直的方向表现为对称冻结厚度分布.

Site Simulation Test and Data Analysis of Freezing Process of Open Water Surface in the Yellow River

Use of the Yellow River ice freezing stage to open 16 m2 empty,simulated open water surface of the Yellow River.Open water surface observation simulation for ice freezing and measurement simulation crumbing after freezing ice thickness distribution.Confirmed during freeze-up,through the analysis of the measured data from the surrounding to intermediate frozen open water surface in addition to related to the temperature,and freezing open water surface under the ice water flow speed and direction.Water ice flow to carry to open water surface,ice flowers will float in the ditch cleaning,due to the effect of viscosity of the water,the water makes the water in the open water surface starting,impact on downstream flow vortex.Changes the vortex formed in the upstream again is calm water,can accumulate a large number of ice crystals;Active and downstream on water movement,ice flowers can't pile up.After a long time to freeze,upstream ice frozen become thicker frost flowers ice,but downstream gradually freeze into thinner frost flowers ice.After the columnar under ice in the frost flowers,ice begins to grow.Finally after 1 month of frozen,forming simulation crumbing downstream ice is thinner,the upstream ice freezing thicker asymmetric thickness distribution,and in a direction perpendicular to the flow of water freezing thickness distribution of symmetry.