Local Similarity in the Stable Boundary Layer and Mixing-Length Approaches: Consistency of Concepts
Local Similarity in the Stable Boundary Layer and Mixing-Length Approaches: Consistency of Concepts
复制标题
稳定边界层和混合长度方法中的局部相似性：概念的一致性
DOI：
10.1007/s10546-008-9277-y
复制
发表时间：
2008
影响因子：
4.3
通讯作者：
H. Jonker
中科院分区：
文献类型：
--
作者：
B. V. D. Wiel;A. Moene;W. H. Ronde;H. Jonker
在稳定分层流动中，涡流的垂直运动受到动能转化为势能的限制，导致浮力位移尺度为zB。我们在稳定边界层中紊流输运的新混合长度概念遵循刚性壁面的类比，从某种意义上说，我们假设浮力长度尺度类似于中性长度尺度。这意味着浮力长度尺度为：κB = κ bzb，其中κB≈κ为冯卡门常数。利用这一概念，局部尺度参数z/Λ的物理相关性自然出现，对数线性相似函数$${\phi_{m,h}=1+\alpha z/\Lambda}$$的α系数等于c/κ2，其中c为接近于1的常数。预测值α≈1/κ2 = 6.25在观察性研究的范围内。最后表明，传统的中性混合长度与浮力极限之间的逆线性插值与经典的对数线性稳定性函数不一致。作为一种替代方法，提出了对数线性一致插值方法。
In stably stratified flows vertical movement of eddies is limited by the fact that kinetic energy is converted into potential energy, leading to a buoyancy displacement scale zB. Our new mixing-length concept for turbulent transport in the stable boundary layer follows a rigid-wall analogy, in the sense that we assume that the buoyancy length scale is similar to neutral length scaling. This implies that the buoyancy length scale is: ℓB = κBzB, with κB ≈ κ, the von Karman constant. With this concept it is shown that the physical relevance of the local scaling parameter z/Λ naturally appears, and that the α coefficient of the log-linear similarity functions $${\phi_{m,h}=1+\alpha z/\Lambda}$$ is equal to c/κ2, where c is a constant close to unity. The predicted value α ≈ 1/κ2 = 6.25 lies within the range found in observational studies. Finally, it is shown that the traditionally used inverse linear interpolation between the mixing length in the neutral and buoyancy limits is inconsistent with the classical log-linear stability functions. As an alternative, a log-linear consistent interpolation method is proposed.