分层流体中冰脊拖曳力的数值模拟研究

冰脊在分层流体表面的漂移运动会在内界面激发出内波,内波又会对冰脊的运动、堆积产生重要影响。利用湍流模型对冰脊在分层流体中的运行过程进行了数值模拟研究,并与已有物理模型实验结果做了比较,冰脊拖曳力和内波界面的数值模拟结果与物理实验结果吻合良好。当流场属于跨临界区时,内波的产生使冰脊拖曳力随弗劳德数Fr先增大后减小,冰脊拖曳系数随Fr的变化规律类似。当流场属于超临界区时,拖曳力随Fr增大而增大,拖曳系数不再随弗劳德数变化。当内波波峰达到最高点的时候,冰脊拖曳力达到一个峰值。

Numerical simulation of drag force on an ice ridge keel in stratified flow

The drift of the ice ridge in the stratified fluid will induce the generation of internal waves at the inner interface, which in turn will have an important influence on the movement of the ice ridge. Through the numerical simulation of the motion process of the ice ridge in the stratified fluid,variations in the flow field and drag forces are obtained, and agree well with the results of previous physical modeling experiments. The flow field can be divided into three types:subcritical, transcritical and supercritical flow. In transcritical flow,the drag force on ice ridge first increases and then decreases with the Froude Number Fr. The drag coefficient has the same trend with that of the drag force. In supercritical flow, the drag force increases with increasing Fr, and the drag coefficient does not change any more with increasing Fr. When the peak of internal waves reaches the maximum value, the drag force on ice ridge reaches an ex-treme point. This study explains the influence of internal wave on ice ridge, and provides a basis for pa-rameterization of ice ridge drag coefficient in stratified fluid.