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

1603131/1603589/1604142 Givi/Mavriplis/GiriMaji几乎所有的能量转换装置都会遇到湍流燃烧，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实现低排放、高效率的燃烧装置的设计和优化至关重要。这项研究将开发准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的燃烧设备，从而有利于环境。将进行广泛的代码开发和计算机模拟。此外，这个项目还将包括许多教育和推广活动，包括开发一个跨学科的计算科学辅修课程以提供关于高性能计算的额外课程，计算建模和模拟多学科领域的学生培训，通过现在投资和Camp-Soar计划推广K-12，以及通过EXCEL程序从少数群体和代表不足的群体招募学生。为了努力提高湍流燃烧模拟的准确性，该奖项提供资金，以开发新的朗之万亚网格尺度(SGS)封闭，并通过用于湍流大涡模拟(LES)的新的不连续Galerkin数值格式来实施。前者为各种湍流，包括可压缩的和化学反应的，提供了SGS传输的精确模型。合并后的方法将放在一个包中，其中以动态、自适应的方式利用现有的计算核心。这是高性能计算中的一个重要概念，对于高达千万亿级和(未来)亿级级的大规模并行模拟是必要的。新的大涡模拟工具将用于几种湍流的预报。以其最复杂的形式和利用最高预期分辨率的拟议大涡模拟的计算需求将比直接数值模拟所需的少几个数量级。这项研究一旦顺利完成，将对湍流燃烧研究产生重大影响。这对行业和政府机构都将是极其有价值的。这项工作的结果也可以对其他学科产生积极影响，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.