孤立冰块流拖曳系数的优化辨识  

OPTIMIZATION AND IDENTIFICATION ON CURRENT DRAG COEFFICIENT OF ISOLATED ICE FLOE

作　　者：白乙拉[1] 李志军[2] 卢鹏[2] 张丽敏[2] 

机构地区：[1]大连理工大学应用数学系,大连116024 [2]大连理工大学海岸和近海工程国家重点实验室,大连116024

出　　处：《极地研究》2006年第2期108-115,共8页Chinese Journal of Polar Research

基　　金：国家自然科学基金重点项目(40233032);科技部科技基础性工作和社会公益研究专项(2003DEB5J057);国家自然科学基金(40376006)资助。

摘　　要：流拖曳系数是海冰动力学模型中的重要参数,实际海冰运动时受到水流的底面剪切作用和侧面正压力作用,相应的拖曳系数分别为摩拖曳系数和形拖曳系数。利用实验室波流水槽设备,对长方平底、长方粗糙底和圆饼型淡水冰试样进行拖曳运动试验,获得26组冰样运动数据。根据这些试验数据,利用动量法原理和数学优化方法构造了摩拖曳系数和形拖曳系数的辨识模型,将摩拖曳系数和形拖曳系数两项分开。在此基础上,分析了冰样粗糙度指标(支承长度率和冰厚均方根偏差)对这两个系数的影响；发现了摩拖曳系数同冰样水平尺寸和垂直尺寸之比的关系,该关系能将冰山和浮冰的摩拖曳系数归结到同一条曲线上。Current drag coefficient is one of the most important parameters in sea ice dynamics model. In actual motion, both shear stress on the under surface and pressure on profile are exerted on ice, corresponding to skin drag coefficient and form drag coefficient, respectively. By using a wave-current tank in laboratory, drag movement experiments were performed for freshwater ice samples with different shapes, including cuboid with smooth underside, cuboid with rough underside and disk with smooth underside, and 26 data sets were obtained. Based on these data, an optimization model to distinguish skin drag coefficient and form drag coefficient was established. Then the effect of ice under surface roughness on these two drag coefficients was analyzed, the result revealed the relationship between skin drag coefficient and horizontal/vertical size of ice samples, which can make the skin drag coefficients of floe and iceberg in a same curve.

关 键 词：浮冰 拖曳系数 粗糙度 优化辨识 

分 类 号：P731.15[天文地球—海洋科学]