Direct Numerical Simulation of Differential Scalar Diffusion in Three-Dimensional Stratified Turbulence
Direct Numerical Simulation of Differential Scalar Diffusion in Three-Dimensional Stratified Turbulence
复制标题
三维分层湍流中微分标量扩散的直接数值模拟
DOI：
10.1175/2403.1
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发表时间：
2003
影响因子：
3.5
通讯作者：
G. Holloway
中科院分区：
文献类型：
--
作者：
A. Gargett;W. Merryfield;G. Holloway
摘要利用衰减层结湍流的三维直接数值模拟，探讨了海洋温度（T）和盐度（S）的差分湍流输运的可能性。模拟采用了一个现实的分子扩散系数T，和一个“盐”标量S是小10倍。最初，均匀分层的介质被扰动的湍流爆发，其初始能量被分配的值的范围。在每种情况下，在爆发的随后衰变中积分的T的输运都超过S的输运。更多的精力充沛的情况下占据的参数范围相似，并表现出光谱特性，基本上是无法区分的，在分层的海洋内部的湍流的直接观测。在这些情况下，T的湍流扩散系数超过S的湍流扩散系数6%-22%。这些模拟低估了T和盐度S（分子扩散率比T小100倍）之间的差异扩散程度;因此，在…
Abstract The potential for differential turbulent transport of oceanic temperature (T) and salinity (S) is explored using three-dimensional direct numerical simulations of decaying stratified turbulence. The simulations employ a realistic molecular diffusion coefficient for T, and one for a “salt” scalar S that is 10 times smaller. Initially, a uniformly stratified medium is disturbed by a turbulent burst whose initial energy is assigned a range of values. In each instance, transports of T integrated over the subsequent decay of the burst exceed those of S. The more energetic cases occupy parameter ranges similar to, and exhibit spectral characteristics that are essentially indistinguishable from, those of direct observations of turbulence in the stratified ocean interior. In these cases, the turbulent diffusivity of T exceeds that of S by 6%–22%. These simulations underestimate the degree of differential diffusion between T and salinity S (which has a molecular diffusivity 100 times less than T); thus at...