Multi-scale Approach for the Comprehensive Modeling and Simulation of Non-Equilibrium Atmospheric-Pressure Turbulent Plasma Flows

非平衡大气压湍流等离子体流动综合建模和模拟的多尺度方法本项目将探索变分多尺度大涡模拟（VMS-LES）作为一种一致、完整、计算可行的湍流等离子体流动建模和模拟方法的新用途。将进行三项主要任务：(i)基于流体守恒和电磁场演化方程的整体处理，以及对小尺度（计算上无法解决的流动特征）的新颖描述，制定等离子体流动的VMS-LES模型；（ii）在软件基础设施中实现模型，用于模拟工业相关的非平衡大气压等离子体流动；（iii）使用模型问题的直接数值模拟（DNS）和来自捷克共和国科学院合作者的实验数据验证该方法。VMS-LES方法的全面性将允许对层流、过渡和湍流非平衡等离子体流动状态进行无缝探索。整体公式预计将提供增加的鲁棒性和计算效率相对于流行的解决方法。该项目将测试小尺度的普遍性假设，这是LES方法的核心，这将导致对等离子体湍流物理学的更广泛理解，并提高湍流模型的预测能力。该项目将影响多种基于非平衡大气压等离子体流动的现代技术，如燃料重整、辅助燃烧、气化、有毒物质修复和材料处理，目前还没有全面的湍流建模和模拟方法。该项目通过提供适用于不同类型等离子体模型的湍流建模和模拟方法，有可能影响等离子体科学与工程的广泛子领域，从而使各种自然（例如，天体物理喷流，太阳耀斑，地球磁层，闪电）和技术(例如，受限聚变，行星进入，在当前和可预见的计算资源条件下，DNS是不可行的。该项目促进了国际合作研究，并通过培养博士生，通过期刊出版物传播研究成果，以及通过对麻省大学洛厄尔分校西班牙裔专业工程师协会的指导，将代表性不足的本科STEM学生推广到应用学术研究中，从而产生教育影响。

Multi-Scale Approach for the Comprehensive Modeling and Simulation of Non-Equilibrium Atmospheric-Pressure Turbulent Plasma FlowsThe project will explore the novel use of Variational Multi-Scale Large Eddy Simulation (VMS-LES) as a consistent, complete, and computationally feasible, modeling and simulation approach for turbulent plasma flows. Three main tasks will be pursued: (i) formulation of a VMS-LES model of plasma flows based on a monolithic treatment of fluid conservation and electromagnetic field evolution equations, together with a novel description of the small scales (computationally unresolvable flow features); (ii) implementation of the model within a software infrastructure for the simulation of industrially-relevant non-equilibrium atmospheric-pressure plasma flows; and (iii) validation of the approach with Direct Numerical Simulation (DNS) of model problems and with experimental data from collaborators from the Academy of Sciences of the Czech Republic. The comprehensiveness of the VMS-LES approach will allow the seamless exploration of laminar, transitional, and turbulent non-equilibrium plasma flow regimes. The monolithic formulation is expected to provide increased robustness and computational efficiency with respect to prevailing solution methods. The project will test the hypothesis of the universality of the small scales, at the core of LES approaches, which will lead to broader understanding of the physics of plasma turbulence and to increased predictive capabilities of turbulence models.The project will impact diverse modern technologies based on non-equilibrium atmospheric-pressure plasma flows, such as fuel reforming, assisted combustion, gasification, toxics remediation, and materials processing, for which no comprehensive turbulence modeling and simulation methodology exist. The project has the potential to impact a wide range of subfields of Plasma Science and Engineering by providing a turbulence modeling and simulation approach applicable to different types of plasma models, and therefore enabling the computational investigation of diverse natural (e.g., astrophysical jets, solar flares, earth's magnetosphere, lightning) and technological (e.g., confined fusion, planetary entry, processing of materials) plasma flows for which DNS is unfeasible with current and foreseeable computational resources. The project promotes international collaborative research, and has educational impacts by the training of a Ph.D. student, the dissemination of research outcomes through journal publications, and by the outreach of underrepresented undergraduate STEM students into applied academic research through mentorship to the Society of Hispanic Professional Engineers at UMass Lowell.