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本文讨论由地形引起的二维潮流速度变化的有效混掺,这种混掺作用用潮平均扩散系数表征,它取决于相对平均水深的水深变化值、速度的变化和基本的扩散系数.分析方法主要是对二维对流扩散方程和时间、空间都具有调和特征的二维速度场采用泰勒近似(大尺度水团,小浓度变化)。略去瞬变现象及应用时间和空间平均的方法,可以得到有效扩散系数。在某些情况下,我们可以找到速度变化和水深变化之间的相关关系.因此,有效扩散系数最终可以用水深的能谱来确定。本文有些章节研究了在对流扩散方程的数值积分中模拟次网格的混掺情况.结果表明、考虑次网格混掺的扩散系数不仅与网格内的流速变化有关,而且还和大尺度的速度变化有关.
This paper discusses the effective mixing of two-dimensional tidal velocity caused by topography, which is characterized by tidal average diffusion coefficient, which depends on the change of water depth, velocity and basic diffusion coefficient of relative average depth. Mainly for the two-dimensional convection diffusion equation and time and space are two-dimensional characteristics of the harmonic velocity using Taylor approximation (large-scale water masses, small concentrations of changes). Ignoring the phenomenon of transient and applying the method of time and space averaging, the effective diffusion coefficient can be obtained. In some cases, we can find the correlation between velocity change and water depth change, so the effective diffusion coefficient can finally be determined by the energy spectrum of water depth. Some chapters of this paper study the mixing of sub-grids in the numerical integration of convection-diffusion equations. The results show that the diffusion coefficient considering sub-grid mixing is not only related to the change of the flow velocity in the grid, but also to the large-scale Speed changes related.