Direct Numerical and Large-eddy Simulation of Supersonic Transverse Jets Using a Novel Numerical Method

使用新型数值方法对超音速横向射流进行直接数值和大涡模拟

• 批准号: 0828162
• 负责人: Krishnan Mahesh
• 金额: $ 25.91万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0828162&HistoricalAwards=false
• 关键词: Direct; Numerical; Large; eddy; Simulation

CBET - 0828162 Mahesh, Krishnan The PI plans use of direct numerical and large-eddy simulation to study transverse jets in high-speed cross flow and compare to existing experimental data. The objectives of the proposed research are to develop a high-fidelity Direct Navier-Stokes (DNS) database at low Reynolds numbers, and Large-Eddy Simulation (LES) capability at experimental Reynolds numbers for transverse jets in supersonic cross flow. Specific studies will concern penetration, entrainment and mixing characteristics of this flow and developing a novel numerical methodology using this challenging problem as a testbed. The simulations use a novel numerical method and subgrid model developed by the PI's group for unstructured grids. The algorithm ensures robustness and accuracy without numerical dissipation. It rescales the governing equations and ensures that the discrete equations analytically reduce to the incompressible equations in the limit of low Mach number. Discrete operators are derived to be accurate on highly skewed unstructured grids and a shock-capturing scheme is applied in a corrector step. The subgrid model solves an evolution equation for the subgrid kinetic energy with no adjustable coefficients. If successful, this numerical methodology will have significant impact on a wide class of problems beyond the scope of this work. High-speed transverse jets are central to enabling sustained combustion inside scramjet engines which represent the next frontier in aviation propulsion. Another important application of high-speed transverse jets is thrust vector control under re-entry conditions. The physical understanding developed from the simulations will help develop practical scaling laws, while the unstructured LES methodology will allow actual prediction and design of these systems. The study also seeks to expand knowledge of turbulent mixing to high speeds. There is a lack of consensus on fundamental issues such as what affects jet trajectories, penetration and mixing. This study will be performed by one PhD student and one undergraduate student. The undergraduate student will be chosen from the Minnesota Supercomputing Institute's summer internship program which draws students from across the country. The PI will also participate in another outreach program of the Super-computing Institute involving high school students from the Twin Cities area. The proposed work will form part of the PI's teaching material, and presentations and articles intended for a broad audience.

CBET - 0828162 Mahesh, Krishnan PI 计划使用直接数值和大涡模拟来研究高速横流中的横向射流，并与现有实验数据进行比较。拟议研究的目标是开发低雷诺数下的高保真直接纳维斯托克斯（DNS）数据库，以及超音速横流中横向射流实验雷诺数下的大涡模拟（LES）能力。具体研究将涉及该流动的渗透、夹带和混合特性，并使用这一具有挑战性的问题作为测试平台开发一种新颖的数值方法。模拟使用了 PI 小组针对非结构化网格开发的新型数值方法和子网格模型。该算法确保了鲁棒性和准确性，没有数值耗散。它重新调整了控制方程，并确保离散方程在低马赫数限制下解析地简化为不可压缩方程。离散算子被推导为在高度倾斜的非结构化网格上准确，并且在校正器步骤中应用冲击捕获方案。子网格模型求解无可调系数的子网格动能演化方程。如果成功，这种数值方法将对超出本工作范围的广泛问题产生重大影响。高速横向喷气发动机是实现超燃冲压发动机内部持续燃烧的核心，而超燃冲压发动机代表了航空推进的下一个前沿领域。高速横向喷流的另一个重要应用是再入条件下的推力矢量控制。从模拟中获得的物理理解将有助于制定实用的标度定律，而非结构化 LES 方法将允许对这些系统进行实际预测和设计。该研究还试图将湍流混合的知识扩展到高速。对于影响射流轨迹、穿透和混合等基本问题缺乏共识。这项研究将由一名博士生和一名本科生进行。本科生将从明尼苏达超级计算研究所的暑期实习计划中选拔，该计划吸引了来自全国各地的学生。 PI 还将参加超级计算研究所的另一个外展项目，该项目涉及双城地区的高中生。拟议的工作将成为 PI 教材、面向广大受众的演示文稿和文章的一部分。