摘要
长期以来,人们一直用临界流速或临界佛汝德数的准则来确定冰塞的演变。然而原型观测发现,在不同的河段,临界流速的值不同,而且即使在同一河段的不同时间临界流速的值也不尽相同。这清楚地表明,临界流速的概念有其不足之处,本文认为冰屑粒在冰盖下的运动与推移质泥沙在冲积河流中的运动是相似的,其区别仅在于冰所受的浮力大于重力,而泥沙所受的浮力小于重力,冰粒常常是在冰盖下以盖移质的形式运动。本文以黄河河曲段的资料印证了这一概念,并在对实测资料分析后发现,可以用现有的轻质推移质输沙公式来描述输冰能力。
The critical velocity, or critical Froude number criterion has long been accepted as a means of determining frazil jam profiles. Field observations, however, indicated that the value of the critical velocity not only varies from river reach to river reach but also from time to time in a given teach. This clearly shows the deficiency of the critical velocity concept. The transport of frazil particles on the underside of an ice cover is similar to the transport of bed sediments in an alluvial river; the difference being only that in one the buoyant force exceeds the gravity force while in the other the reverse is true. Frazil particles are generally transported along the cover in the form of the cover load. In this paper, ice transport capacity for the Hequ reach of the Yellow River is analyzed. The analysis of field data shows that the ice transport capacity can be described by existing bed load transport formulas for low density sediments.
出处
《泥沙研究》
CSCD
北大核心
1993年第4期1-10,共10页
Journal of Sediment Research
基金
山西省水利厅赞助
山西省防洪抗旱办公室赞助
国家自然科学基金
