van Hooft J Antoon, Popinet Stéphane, van Heerwaarden Chiel C, van der Linden Steven J A, de Roode Stephan R, van de Wiel Bas J H
1Department of Geoscience and Remote Sensing, Delft University of Technology, Delft, The Netherlands.
2Sorbonne Université, Centre National de la Recherche Scientifique, UMR 7190, Institut Jean Le Rond d'Alembert, F-75005 Paris, France.
Boundary Layer Meteorol. 2018;167(3):421-443. doi: 10.1007/s10546-018-0335-9. Epub 2018 Feb 14.
We present a proof-of-concept for the adaptive mesh refinement method applied to atmospheric boundary-layer simulations. Such a method may form an attractive alternative to static grids for studies on atmospheric flows that have a high degree of scale separation in space and/or time. Examples include the diurnal cycle and a convective boundary layer capped by a strong inversion. For such cases, large-eddy simulations using regular grids often have to rely on a subgrid-scale closure for the most challenging regions in the spatial and/or temporal domain. Here we analyze a flow configuration that describes the growth and subsequent decay of a convective boundary layer using direct numerical simulation (DNS). We validate the obtained results and benchmark the performance of the adaptive solver against two runs using fixed regular grids. It appears that the adaptive-mesh algorithm is able to coarsen and refine the grid dynamically whilst maintaining an accurate solution. In particular, during the initial growth of the convective boundary layer a high resolution is required compared to the subsequent stage of decaying turbulence. More specifically, the number of grid cells varies by two orders of magnitude over the course of the simulation. For this specific DNS case, the adaptive solver was not yet more efficient than the more traditional solver that is dedicated to these types of flows. However, the overall analysis shows that the method has a clear potential for numerical investigations of the most challenging atmospheric cases.
我们展示了应用于大气边界层模拟的自适应网格细化方法的概念验证。对于在空间和/或时间上具有高度尺度分离的大气流动研究，这种方法可能成为静态网格的一种有吸引力的替代方案。示例包括昼夜循环以及由强逆温层覆盖的对流边界层。对于此类情况，使用常规网格的大涡模拟通常必须在空间和/或时间域中最具挑战性的区域依赖亚网格尺度闭合。在此，我们使用直接数值模拟（DNS）分析一种描述对流边界层生长及随后衰减的流动配置。我们验证所得结果，并将自适应求解器的性能与使用固定常规网格的两次运行进行基准测试。结果表明，自适应网格算法能够在保持精确解的同时动态地粗化和细化网格。特别是，与湍流衰减的后续阶段相比，在对流边界层的初始生长阶段需要更高的分辨率。更具体地说，在模拟过程中网格单元数量变化了两个数量级。对于这个特定的DNS案例，自适应求解器尚未比专门用于此类流动的更传统求解器更高效。然而，总体分析表明，该方法在对最具挑战性的大气案例进行数值研究方面具有明显潜力。
