Mesoscale to Microscale Coupling Using Continuous Eddy Simulation

大气数值模拟模拟基于与所模拟的尺度最为相关的技术。用于研究城市建筑中风的模型与用于模拟大陆尺度天气的模型使用的方法不同。如何跨越这些尺度一直是该领域的一个长期挑战。该项目采用了工程学科的研究成果，并将其应用于大气建模，目的是更好地模拟最接近地球表面的运动。这项工作与风能生产特别相关，但也与一般的天气预报有关。博士后研究科学家将在该项目中发挥重要作用，从而为下一代科学家提供培训。本项目是将一种新开发的数学方法应用于中尺度和微尺度大气模式耦合的“未知地”问题。针对雷诺平均纳维-斯托克斯（RANS）和大涡模拟（LES）模式的工程问题，提出了连续涡模拟（CES）方法。在气象学中，这涉及到在中等网格间距的模拟中运行模型的困难，其中方程与特征时间和长度尺度的缩放之间存在不一致。CES能够稳定地响应网格和雷诺数变化所暗示的变化条件。工作计划的重点是两个任务和子项目：1。在天气研究与预报（WRF）模式环境中将CES作为一个微观模型来实现。集成将需要展示正确覆盖几乎所有ran和几乎所有可解析LES制度的能力，并根据网格变化一致地重新分配已解析和建模的模式。CES-WRF将使用现有的LES模拟进行验证。CES-WRF还将用于验证汤森德涡流理论（TET），这是最近发展起来的壁面湍流结构的概念模型。验证CES为中尺度WRF。CES- microscale /Mesoscale （MIME）将在大范围的域大小和粗网格中进行评估，以验证CES模式再分配机制的功能。将研究各种耦合情况。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Atmospheric numerical modeling simulations are based on techniques that are most relevant to the scales that are being simulated. Models that are built to study wind flow through urban buildings use a different methodology as ones that simulate weather at continental scales. It has been a standing challenge in the field on how to bridge these scales. This project takes research that has been conducted in the engineering discipline and applies it to atmospheric modeling, with a goal of better simulating the motions closest to the Earth’s surface. The work has particular relevance to wind energy production, but also to weather forecasting in general. A postdoctoral research scientist will play a large role in the project, thereby providing training for the next generation of scientists.This project is for the application of a newly-developed mathematical method to the “Terra-Incognita” problem of coupling mesoscale and microscale atmospheric models. The Continuous Eddy Simulation (CES) method was developed for engineering problems that span the Reynolds-averaged Navier Stokes (RANS) and Large Eddy Simulation (LES) modes. In meteorology, this relates to the difficulty in running models on simulations at intermediate grid spacing, where there are inconsistencies between equations and the scaling of characteristic time and length scales. CES is able to stably respond to changing conditions as implied by grid and Reynolds number variations. The work plan is focused on two tasks with subprojects:1. Implement CES as a microscale model in the Weather Research and Forecasting (WRF) model environment. The integration will need to demonstrate the ability to correctly cover almost RANS and almost resolving LES regimes, and consistently redistribute resolved and modeled modes in response to grid variations. CES-WRF will be validated using an existing LES simulation. CES-WRF will also be used to validate the Townsend Eddy Theory (TET), which is a recently developed conceptual model for the structure of wall-bounded turbulent flows.2. Validate CES as mesoscale WRF. CES-Microscale/Mesoscale (MIME) will be evaluated for a wide range of domain sizes and coarse grids to verify the functioning of the CES mode redistribution mechanism. A variety of coupling cases will be studied.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.