A two‐fluid single‐column model of the dry, shear‐free, convective boundary layer
A two‐fluid single‐column model of the dry, shear‐free, convective boundary layer
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干燥、无剪切、对流边界层的双流体单柱模型
DOI：
10.1002/qj.3510
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发表时间：
2019
影响因子：
8.9
通讯作者：
R. Beare
中科院分区：
文献类型：
--
作者：
J. Thuburn;G. Efstathiou;R. Beare
提出了一个干燥、无剪切、对流边界层的单柱模型，其中相干结构（如热气流）的非局部输送通过将流体分为两个分量（上升气流和环境）来表示，每个分量都有一套完整的预报动力学方程。局部涡扩散输送和夹带和detrainment表示的参数类似于涡扩散质量通量方案中使用的。列入的垂直扩散的垂直速度被证明是重要的抑制固有的不稳定性的控制方程。提出了一种半隐式半拉格朗日数值求解方法，并证明了该方法在大的声学和扩散Courant数下是稳定的，但在大的对流Courant数下变得不稳定。这些解能够捕捉到干对流边界层的关键物理特征。一些尖锐的功能在解决方案中提出的数值挑战进行了讨论，并强调了模型可以改进的领域。
A single‐column model of the dry, shear‐free, convective boundary layer is presented in which non‐local transports by coherent structures such as thermals are represented by the partitioning of the fluid into two components, updraught and environment, each with a full set of prognostic dynamical equations. Local eddy diffusive transport and entrainment and detrainment are represented by parametrizations similar to those used in eddy diffusivity mass flux schemes. The inclusion of vertical diffusion of the vertical velocity is shown to be important for suppressing an instability inherent in the governing equations. A semi‐implicit semi‐Lagrangian numerical solution method is presented and shown to be stable for large acoustic and diffusive Courant numbers, though it becomes unstable for large advective Courant numbers. The solutions are able to capture key physical features of the dry convective boundary layer. Some of the numerical challenges posed by sharp features in the solution are discussed, and areas where the model could be improved are highlighted.
影响因子：
3.1
作者：
R. Plant;G. Craig
通讯作者：
R. Plant;G. Craig