Shallow-water Frictional Effects in Island Wakes
Shallow-water Frictional Effects in Island Wakes
复制标题
DOI：
10.1006/ecss.1997.0301
复制
发表时间：
1998-04
影响因子：
2.8
通讯作者：
K. Furukawa;E. Wolanski
中科院分区：
文献类型：
--
作者：
K. Furukawa;E. Wolanski
在拉特雷岛的背风处，只有一个涡流出现在岛屿尾迹中，拉特雷岛是一个1600米宽的岛屿，位于澳大利亚近海的浅海水域。这一观察结果与许多二维和三维固定网格数值模型的预测相反，这些模型都预测存在两个涡流，从岛屿的两个尖端各流出一个涡流。离散涡旋模式表明，这一观测结果是由于靠近岛屿尖端的地形的亚网格尺度细节中的摩擦效应造成的。该模式还成功地再现了加拿大鲁珀特湾岛屿背风处的卡曼涡旋街的观测结果。相比之下，固定网格模型预测不会出现这样的涡流脱落。因此，岛屿尾迹对分离点附近的水深测量细节很敏感，必须在固定网格模型中进行参数化，无论是规则网格模型还是边界拟合模型，或者在离散涡旋模型等非固定网格模型中进行显式计算。
Only one eddy is present in the island wake in the lee of Rattray Island, a 1600 m wide island in shallow coastal waters off Australia. This observation is contrary to the predictions of a number of two- and three-dimensional, fixed grid, numerical models which all predict that two eddies are present, one eddy being shed from each of the two tips of the island. The discrete vortex model suggests this observation results from the frictional effects in sub-grid scale details of the topography close to the tips of the island. This model also successfully reproduces the observations of a Karman vortex street in the lee of islands in Rupert Bay, Canada. By contrast, fixed-grid models predict no such eddy shedding. Island wakes are thus sensitive to details of the bathymetry near the separation points and these must be either parameterized in fixed grid models, whether regular or boundary fitted, or explicitly calculated in non-fixed grid models such as the discrete vortex model.