Accurate, Robust Simulations of Aerodynamics Flows, Especially Wakes and Shocks

准确、稳健的空气动力学流动模拟，尤其是尾流和冲击

• 批准号: RGPIN-2020-04503
• 负责人: OllivierGooch, Carl
• 金额: $ 2.84万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=760255
• 关键词: Accurate; Robust; Simulations; Aerodynamics; Flows

My research area is the development of more accurate, efficient, and robust algorithms for computational fluid dynamics (CFD) and mesh generation. My medium term research goal for my group is to bring together our work in algorithms for flow solution, mesh generation and adaptation, error analysis, and numerical stability to more consistently produce reliable simulation results for analysis and design in external aerodynamics. The technical challenge here is not just to obtain a numerical solution for a particular flow problem, but to reduce as much as possible the need for a human user to intervene and iterate during this process, while at the same time providing tight quantitative bounds on the error in output quantities of engineering interest, including for example forces and heat fluxes. These advances will improve the CFD analysis tools engineers use to design quieter, more fuel efficient aircraft and land transportation vehicles. Our strategic objectives during the term of the proposed Discovery Grant are: 1. Meshing. While adaptive meshing is poised to take over CFD, there is still a need in computational aerodynamics for better non-adaptive meshing, especially for complex configurations like high-lift systems. We will continue our current work on a fully anisotropic 3D mesh generator which maximizes internal structure throughout the mesh. 2. Highly-Accurate Flow Solvers. The Reynolds-averaged Navier-Stokes equations are a sometimes maligned model for turbulent flow, but remain the only feasible alternative for large-scale aerodynamic simulations. Even though the model is not an exact representation of the flow physics, simulations should not compound that problem with numerical error. We will complete work on our fourth-order accurate unstructured mesh finite-volume RANS flow solver, and demonstrate its usefulness, accuracy, and efficiency for aircraft in cruise and high-lift configurations. 3. Numerical Treatment of Shock Waves. Modern numerical methods in CFD rely for accuracy on the assumption of smooth solutions, which breaks down for transonic and supersonic flows with shock waves. Shock fitting is a paradigm that treats such flows explicitly as discontinuous. We are developing meshing tools for shock fitting for 3D flows, including complex shock-shock and shock-boundary interaction. We will also begin work in-house on developing a high-order shock-fitting scheme. 4. Steady-State Convergence. Most commercial CFD software requires hundreds or thousands of iterations to reach full convergence to steady state. We will leverage what we have learned about eigensystems and convergence for unstructured mesh flow solvers in our stability work to improve convergence rates by an order of magnitude. Taken together, these capabilities will have a significant impact on the reliability and robustness of CFD simulations, which in turn will open their use to a wider range of industrial analysis and design applications.

我的研究领域是开发更准确、更高效、更稳健的计算流体动力学 (CFD) 和网格生成算法。我的团队的中期研究目标是将我们在流动求解、网格生成和自适应、误差分析和数值稳定性算法方面的工作结合起来，以便更一致地产生可靠的模拟结果，用于外部空气动力学的分析和设计。这里的技术挑战不仅仅是获得特定流量问题的数值解，而是尽可能减少人类用户在此过程中干预和迭代的需要，同时提供严格的定量界限工程感兴趣的输出量的误差，包括例如力和热通量。这些进步将改进工程师用来设计更安静、更省油的飞机和陆地运输车辆的 CFD 分析工具。在拟议的发现补助金期限内，我们的战略目标是： 1. 网格化。虽然自适应网格划分即将取代 CFD，但计算空气动力学仍然需要更好的非自适应网格划分，特别是对于高升力系统等复杂配置。我们将继续目前的工作，开发完全各向异性 3D 网格生成器，最大限度地提高整个网格的内部结构。 2. 高精度流动求解器。雷诺平均纳维-斯托克斯方程有时是一个被诟病的湍流模型，但仍然是大规模空气动力学模拟的唯一可行的替代模型。尽管该模型并不是流动物理学的精确表示，但模拟不应将该问题与数值误差混合在一起。我们将完成四阶精确非结构化网格有限体积 RANS 流求解器的工作，并展示其对于巡航和高升力配置飞机的实用性、准确性和效率。 3.冲击波的数值处理。 CFD 中的现代数值方法的准确性依赖于平滑解的假设，而对于带有冲击波的跨音速和超音速流来说，该假设会失效。冲击拟合是一种将此类流动明确视为不连续的范例。我们正在开发用于 3D 流冲击拟合的网格划分工具，包括复杂的冲击-冲击和冲击-边界相互作用。我们还将开始内部开发高阶减震方案。 4.稳态收敛。大多数商业 CFD 软件需要数百或数千次迭代才能完全收敛到稳定状态。我们将在稳定性工作中利用我们所学到的关于特征系统和非结构化网格流求解器收敛的知识，将收敛速度提高一个数量级。总而言之，这些功能将对 CFD 仿真的可靠性和稳健性产生重大影响，进而将其用于更广泛的工业分析和设计应用。