{"title":"Setting Up a Large-Eddy Simulation to Focus on the Atmospheric Surface Layer","authors":"","doi":"10.1007/s10546-023-00841-x","DOIUrl":null,"url":null,"abstract":"<h3>Abstract</h3> <p>Large-eddy simulations (LES) above forests and cities typically constrain the simulation domain to the first 10–20% of the Atmospheric Boundary Layer (ABL), aiming to represent the finer details of the roughness elements and sublayer. These simulations are also commonly driven by a constant pressure gradient term in the streamwise direction and zero stress at the top, resulting in an unrealistic fast decay of the total stress profile. In this study, we investigate five LES setups, including pressure and/or top-shear driven flows with and without the Coriolis force, with the aim of identifying which option best represents turbulence profiles in the atmospheric surface layer (ASL). We show that flows driven solely by pressure not only result in a fast-decaying stress profile, but also in lower velocity variances and higher velocity skewnesses. Top-shear driven flows, on the other hand, better replicate ASL statistics. Overall, we recommend, and provide setup guidance for, simulation designs that include both a large scale pressure forcing and a non-zero stress and scalar flux at the top of the domain, and that also represent the Coriolis force. Such setups retain all the forces used in typical full ABL cases and result in the best match of the profiles of various statistical moments. </p>","PeriodicalId":9153,"journal":{"name":"Boundary-Layer Meteorology","volume":"63 1","pages":""},"PeriodicalIF":2.3000,"publicationDate":"2024-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Boundary-Layer Meteorology","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1007/s10546-023-00841-x","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"METEOROLOGY & ATMOSPHERIC SCIENCES","Score":null,"Total":0}
引用次数: 0
Abstract
Large-eddy simulations (LES) above forests and cities typically constrain the simulation domain to the first 10–20% of the Atmospheric Boundary Layer (ABL), aiming to represent the finer details of the roughness elements and sublayer. These simulations are also commonly driven by a constant pressure gradient term in the streamwise direction and zero stress at the top, resulting in an unrealistic fast decay of the total stress profile. In this study, we investigate five LES setups, including pressure and/or top-shear driven flows with and without the Coriolis force, with the aim of identifying which option best represents turbulence profiles in the atmospheric surface layer (ASL). We show that flows driven solely by pressure not only result in a fast-decaying stress profile, but also in lower velocity variances and higher velocity skewnesses. Top-shear driven flows, on the other hand, better replicate ASL statistics. Overall, we recommend, and provide setup guidance for, simulation designs that include both a large scale pressure forcing and a non-zero stress and scalar flux at the top of the domain, and that also represent the Coriolis force. Such setups retain all the forces used in typical full ABL cases and result in the best match of the profiles of various statistical moments.
摘要 森林和城市上空的大涡度模拟（LES）通常将模拟域限制在大气边界层（ABL）的前 10-20%，目的是表现粗糙度要素和子层的更精细细节。这些模拟还通常由流向方向的恒定压力梯度项和顶部的零应力驱动，导致总应力剖面不切实际地快速衰减。在本研究中，我们研究了五种 LES 设置，包括有科里奥利力和无科里奥利力的压力和/或顶部剪切力驱动流动，目的是确定哪种方案最能代表大气表层（ASL）的湍流剖面。我们的研究表明，仅由压力驱动的流动不仅会产生快速衰减的应力剖面，还会产生较低的速度方差和较高的速度偏度。另一方面，顶部剪切驱动的流动能更好地复制 ASL 统计数据。总之，我们建议在模拟设计中同时包含大尺度压力强迫和域顶非零应力和标量通量，并体现科里奥利力，并为其提供设置指导。这种设置保留了典型的全 ABL 案例中使用的所有力，并使各种统计力矩的剖面达到最佳匹配。
期刊介绍：
Boundary-Layer Meteorology offers several publishing options: Research Letters, Research Articles, and Notes and Comments. The Research Letters section is designed to allow quick dissemination of new scientific findings, with an initial review period of no longer than one month. The Research Articles section offers traditional scientific papers that present results and interpretations based on substantial research studies or critical reviews of ongoing research. The Notes and Comments section comprises occasional notes and comments on specific topics with no requirement for rapid publication. Research Letters are limited in size to five journal pages, including no more than three figures, and cannot contain supplementary online material; Research Articles are generally fifteen to twenty pages in length with no more than fifteen figures; Notes and Comments are limited to ten journal pages and five figures. Authors submitting Research Letters should include within their cover letter an explanation of the need for rapid publication. More information regarding all publication formats can be found in the recent Editorial ‘Introducing Research Letters to Boundary-Layer Meteorology’.
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