Collaborative Research: A Langevin Subgrid Scale Closure and Discontinuous Galerkin Exascale Large Eddy Simulation of Complex Turbulent Flows

湍流燃烧在几乎所有的能量转换装置中都会遇到，例如内燃机、燃气轮机、锅炉和燃气燃烧器。湍流燃烧涉及许多复杂的物理和化学现象。准确预测湍流燃烧过程的能力对于设计和优化燃烧装置以实现低排放和高效率至关重要。这项研究将开发精确的计算机模型和数值算法，可以揭示基本的湍流燃烧过程，并允许工业设计清洁燃烧装置，从而有益于环境。广泛的代码开发和计算机模拟将进行。此外，该项目还将包括许多教育和推广活动，包括开发跨学科计算科学辅修课程，提供额外的高性能计算课程，计算建模和仿真多学科领域的学生培训，通过INVESTING NOW和CAMP-SOAR项目进行K-12推广，以及通过EXCEL项目招募少数民族和代表性不足的群体的学生。为了提高湍流燃烧模拟的准确性，该奖项为开发一种新的Langevin亚网格尺度（SGS）闭合提供了资金，并将其与用于湍流大涡模拟（LES）的新的不连续Galerkin数值格式一起实现。前者为包括可压缩流和化学反应流在内的大范围湍流提供了精确的SGS输运建模。组合的方法将放在一个包中，其中可用的计算核心以动态的、自适应的方式加以利用。在高性能计算中，这是一个重要的概念，对于大规模并行模拟来说，这是必不可少的，可以达到千兆级，甚至是（未来的）百亿亿级。新的LES工具将用于几种湍流的预测。拟议的LES的计算需求，在其最复杂的形式和利用最高的预期分辨率，将比直接数值模拟所需的少几个数量级。本研究的成功完成将对紊流燃烧研究产生重大影响。这对工业和政府机构来说都是非常有价值的。这项工作的结果也可以积极影响其他学科，如气候和大气建模或生物工程。

1603131/1603589/1604142 Givi/Mavriplis/Girimaji Turbulent combustion is encountered in nearly all energy conversion devices, such as internal combustion engines, gas turbines, boilers, and gas burners. Turbulent combustion involves many complex physical and chemical phenomena. The ability to predict accurately the turbulent combustion process is critical to the design and optimization of combustion devices for achieving low emissions and high efficiency. This research will develop accurate computer models and numerical algorithms that can reveal the fundamental turbulent combustion processes and allow industry to design clean combustion devices, thus benefiting the environment. Extensive code development and computer simulations will be conducted. Additionally, this project will also include numerous education and outreach activities, including the development of an Interdisciplinary Computational Science Minor to provide additional courses on high-performance computing, student training in the multidisciplinary field of Computational Modeling and Simulation, K-12 outreach through the INVESTING NOW and CAMP-SOAR programs, and recruitment of students from minority and under-represented groups through the EXCEL program.In an effort to increase the accuracy of turbulent combustion simulation, this award provides funding to develop a new Langevin subgrid scale (SGS) closure and to implement it with a new discontinuous Galerkin numerical scheme for large eddy simulation (LES) of turbulent flows. The former provides accurate modeling of the SGS transport for a wide range of turbulent flows, including compressible and chemically reactive. The combined methodology will be put together in a package in which the available computational cores are utilized in a dynamic, adaptive manner. This is an important concept in high performance computing necessary for massively parallel simulations up to petascale, and towards (future) exascale. The new LES tool will be employed for predictions of several turbulent flows. The computational requirements for the proposed LES, in its most sophisticated form and utilizing the highest intended resolution, will be several orders of magnitude less than that required for direct numerical simulations. When successfully completed, this research will have a significant impact on turbulent combustion research. It will be extremely valuable for both industry and government agencies. The outcome of this work can also positively impact other disciplines, such as climate and atmospheric modeling or bioengineering.