Improving Understanding of Non-Equilibrium Surface-Layer Stress-Strain-Rate Relationships Using a Novel Stationarity-Analysis Technique and Large-Eddy Simulation

使用新颖的平稳性分析技术和大涡模拟提高对非平衡表面层应力-应变-速率关系的理解

• 批准号: 2113854
• 负责人: Ying Pan
• 金额: $ 66万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2113854&HistoricalAwards=false
• 关键词: Improving; Understanding; Non; Equilibrium; Surface

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).Numerical weather modeling of the atmospheric boundary layer, which is the lowest layer of the atmosphere, is extremely complex due to the different scales of motion of the air and the interaction of flow with the Earth’s surface. Scientists attempt to simulate flows in the boundary layer using several techniques, some of which can take up enormous amounts of computing power. In this project, the researcher will investigate a simplified technique for modeling the boundary layer that requires fewer computational resources and better fits existing observational data. The project has the potential to impact numerical modeling of the boundary layer, which is especially relevant to convective scale processes and near-surface wind predictions. The project also contains a strong educational component which will provide training activities for the next generation of scientists.This award is for a research project with the goal of reducing errors in numerical simulations of turbulent atmospheric flows. These errors are induced by unrealistic assumptions of equilibrium relationships between unresolved turbulent fluxes and resolved fields. Currently, the most straightforward approach to addressing this problem is by computing the time-evolution of the unresolved fluxes, which is known as the second-order closure. However, this method has multiple issues, including significant computational expense. The researcher plans to work with a simplified version of this approach, known as the pseudo-second-order closure model. The major research objectives in the proposal are to: 1) Reduce uncertainties in field-data estimates of turbulence statistics by applying a multi-sensor stationarity-analysis technique (MSATv2) to existing field campaign data, 2) Investigate external driving forces that enable Large Eddy Simulation (LES) to reproduce field data by conducting LES runs of field campaign data, and 3) Evaluate and refine pseudo-second-order closure models using the field and LES data.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该奖项是根据2021年《美国救援计划法》（公法117-2）全部或部分资助的。大气边界层的数量建模是大气的最低层，由于空气运动的不同规模以及流动与地球表面的相互作用，因此非常复杂。科学家试图使用几种技术模拟边界层中的流，其中一些技术可能会占据大量的计算能力。在这个项目中，研究人员将研究一种简化的技术，用于建模边界层，该技术需要更少的计算资源并更好地适合现有的观察数据。该项目有可能影响边界层的数值建模，这与对流尺度过程和近乎表面的风预测特别相关。该项目还包含一个强大的教育组成部分，该项目将为下一代科学家提供培训活动。该奖项是为一个研究项目提供的奖项，目的是减少动荡大气流的数值模拟中的错误。这些误差是由对未解决的湍流和解决场之间的等效关系的不切实际的假设引起的。当前，解决此问题的最直接方法是计算未解决的通量的时间进化，这被称为二阶闭合。但是，该方法有多个问题，包括大量计算费用。研究人员计划使用这种方法的简化版本，称为伪二阶闭合模型。 The major research objectives in the proposal are to: 1) Reduce uncertainties in field-data estimates of turbulence statistics by applying a multi-sensor stationarity-analysis technique (MSATv2) to existing field campaign data, 2) Investigate external driving forces that enable Large Eddy Simulation (LES) to reproduce field data by conducting LES runs of field campaign data, and 3) Evaluate and refine pseudo-second-order closure models该奖项反映了NSF的法定任务，并通过评估使用基金会的知识分子优点和更广泛的影响审查标准来表示支持。