Large-Eddy Simulation of Canopy and Surface Layer Flow

冠层和表层流的大涡模拟

• 批准号: 9521586
• 负责人: Roger Shaw
• 金额: $ 26.8万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-03-01 至 2000-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9521586&HistoricalAwards=false
• 关键词: Large; Eddy; Simulation; Canopy; Surface

Shaw/Abstract The objective of this research is large-eddy simulation (LES) of the atmospheric surface layer in which the lowest portion of the three-dimensional computational domain represents a plant copy such as a forest. The vegetation is represented by a foliage element are density, a drag coefficient, and a sensible heat and water vapor source or sink at each grid point within the canopy. In the LES, scales of motion resolved by the grid network are computed directly in time-dependent form, while sub-grid-scale processes are parameterized. Our plan is to use the simulations to study the nature of turbulence in the vicinity of plant canopies, and to apply the technique to more realistic (such as inhomogeneous) situations. We will perform in-depth studies of coherent structures created within the computed flow fields and follow them from inception to dissipation (an impossible task in the field). Structures will initially be detected using wavelet and other related techniques, complemented by computer animation. It is our aim to obtain as complete a picture as possible of coherent structures developing at the interface between the lower atmosphere and a plant canopy. The method of proper orthogonal decomposition will also be applied to computed LES fields. A complete thermal energy balance of the vegetation and of the underlying soil will be incorporated into the model to more correctly introduce soil evaporation, transpiration, and heat storage in both soil and biomass. The influence of aeroelastic properties of the vegetation will also be introduced and a study made of the phenomenon of honami. As a demonstration of our interests in this regard, we have begun an examination of the windbreak problem. All computation will be performed on the Cray Y-MP at the National Center for Atmospheric Research (NCAR).

肖/摘要 本研究的目的是大气表层的大涡模拟（LES），其中三维计算域的最低部分代表一个植物的副本，如森林。 植被是由一个树叶元素是密度，阻力系数，和感热和水汽源或汇在每个网格点内的冠层。 在LES中，网格网络所解决的运动尺度直接以时间依赖的形式计算，而亚网格尺度的过程被参数化。 我们的计划是使用模拟来研究植物冠层附近湍流的性质，并将该技术应用于更现实的（如不均匀）情况。 我们将对计算流场中产生的相干结构进行深入研究，并从开始到消散（现场不可能完成的任务）。首先将使用小波和其他相关技术检测结构，并辅以计算机动画。 我们的目标是获得尽可能完整的图像，在低层大气和植物冠层之间的界面上发展的相干结构。 适当的正交分解的方法也将适用于计算LES字段。 植被和底层土壤的完整热能平衡将被纳入模型中，以更正确地引入土壤蒸发，蒸腾和土壤和生物量中的热储存。 此外，还将介绍植被气动弹性特性的影响，并对honami现象进行研究。 为了表明我们在这方面的兴趣，我们已开始审查防风林问题。 所有计算将在国家大气研究中心（NCAR）的Cray Y-MP上进行。