The double-diffusive modon
The double-diffusive modon
复制标题
双扩散模态
DOI：
10.1017/s0022112008002127
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发表时间：
2008
影响因子：
3.7
通讯作者：
T. Radko
中科院分区：
文献类型：
--
作者：
T. Radko
充分发展的二维盐指对流的特征是出现相干的偶极涡旋，其向上携带相对新鲜和冷的流体，向下携带含盐和温暖的流体。这样的结构-双扩散modons -是普遍的制度，其中密度分层接近中性和盐指不稳定性是非常有力的。根据背景密度比趋于1的渐近展开式讨论了模子的结构和平移速度。有人认为，盐通量的垂直驱动主要是由双扩散modons，这使得人们有可能推导出明确的表达式作为其背景梯度的函数的温度和盐度的混合率。建议的混合模型的预测成功地测试直接数值模拟。
Fully developed two-dimensional salt-finger convection is characterized by the appearance of coherent dipolar eddies which carry relatively fresh and cold fluid upward and salty and warm fluid downward. Such structures – the double-diffusive modons – are prevalent in the regime in which density stratification is close to neutral and the salt-finger instability is extremely vigorous. The structure and translation velocities of modons are discussed in terms of the asymptotic expansion in which the background density ratio approaches unity. It is argued that the vertical salt flux is driven primarily by double-diffusive modons, which makes it possible to derive explicit expressions for the mixing rates of temperature and salinity as a function of their background gradients. Predictions of the proposed mixing model are successfully tested by direct numerical simulations.