Effects of Near-Bottom Return Flows on Wind-Induced Currents
Effects of Near-Bottom Return Flows on Wind-Induced Currents
复制标题
近底部回流对风生流的影响
DOI：
10.1175/1520-0485(1987)017
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
Jin Wu
中科院分区：
文献类型：
--
作者：
Joe Wang;Jin Wu
摘要在一个循环风浪箱中测量了风、流和表面波。分别模拟了海岸和海洋有无底回流的情况。发现海流谱在主波引起的运动频率范围之外呈现-5/3斜率。对于海岸条件，雷诺应力随深度线性减小，湍流能量以z−1趋势衰减，其中z为深度。这在很大程度上是由于顺风海岸的水堆积造成的，动量的垂直分布受到回流和反向压力梯度的显著影响。在海洋条件下，风致漂移流向下延伸得更远，存在一个动量通量恒定的区域，湍流能量在垂直方向上分布均匀，在该区域之下，湍流能量以z−2的趋势衰减，这可能意味着耗散机制。
Abstract Wind, currents, and surface waves have been measured in a circulating wind-wave tank. Conditions corresponding to both coast and ocean, with and without bottom return flows respectively, have been simulated. Spectra of currents were found to exhibit a −5/3 slope outside the frequency range of motions induced by dominant waves. For the coastal condition, the Reynolds stress decreases linearly with depth, and the turbulence energy decays with a z−1 trend, where z is the depth. Much of this results from the piling up of water at the downwind coast, with the vertical distribution of momentum significantly affected by return flows and the reverse pressure gradient. For the oceanic condition, the wind-induced drift currents are extended much further downward; a region of constant momentum flux prevails, and a uniform vertical distribution of turbulence energy was found. Below this surface region, the turbulence energy decays with a z−2 trend, possibly implying a dissipative mechanism.