Collaborative Research: Simulation and Analysis of Turbulent Jet Noise Using Arbitrary-Order Hermite Methods

哈格斯特罗姆和科隆纽斯根据2009年《美国复苏和再投资法案》(公法111-5)资助该奖项。研究人员与他们的学生和博士后一起，追求一个有三个主要目标的跨学科项目。第一个目标是开发、优化和传播基于任意阶Hermite近似的新的计算方法，这种方法可以有效地利用Petascale工具来求解复杂的、多尺度的、依赖时间的偏微分方程组。其次，将Hermite方法应用于雷诺数超过一个数量级的湍流喷流噪声的直接模拟，为未来工程设计相关流动条件下的模拟铺平了道路。最终目标是开发和应用后处理技术，使用模拟数据来发现导致喷气噪声的基本物理机制，改进工程模型的输入，并提供降噪策略。Hermite方法的独特性质使其成为在高性能计算平台上进行高分辨率模拟的理想选择。这是他们第一次全力以赴地解决一个难题。这些方法本身可以在任何需要高精度的应用中有益地使用，并创建了一个优化构建块的库以及用于其应用的模板，并向科学界免费提供。理解喷气式飞机噪音是一个巨大的科学挑战。辐射声只携带极小部分的流动能量，既是小尺度湍流的结果，也是大尺度相干结构复杂动力学的结果。硬件的异构性阻碍了下一代高性能计算系统的有效利用。这个项目专注于新的方法，既对复杂的体系结构足够灵活，又足够强大，以提供高分辨率的近似。喷气噪声是一个环境问题，在世界各地受到越来越严格的监管。为了实现正在讨论的雄心勃勃的降噪目标，需要大大加强对基础物理学的理解。研究人员将要完成的模拟和后续分析使我们更接近发现导致声辐射的微妙物理机制的目标，并更接近合理设计抑制它的方法。

Hagstrom and Colonius This award is funded under the American Recovery andReinvestment Act of 2009 (Public Law 111-5). The investigators, with their students and postdocs, pursue an interdisciplinary project with three primary aims. The first aim is the development, optimization, and dissemination of novel computational methods based on arbitrary-order Hermite approximations that efficiently utilize petascale facilities to solve complex, multiple-scale, time-dependent systems of partial differential equations. Secondly, Hermite methods are applied to the direct simulation of turbulent jet noise at Reynolds numbers more than an order of magnitude beyond those currently available, paving the way for future simulations under flow conditions relevant to engineering design. The final goal is the development and application of post-processing techniques to use the simulation data to discover the basic physical mechanisms responsible for the jet noise, improve the inputs to engineering models, and inform strategies for noise reduction. The unique properties of Hermite methods make them ideal for high-resolution simulations on high-performance computing platforms. This is the first instance where they are fully exercised to attack a difficult problem. The methods themselves can be profitably used in any application requiring high accuracy, and a library of optimized building blocks along with templates for their application is created and made freely available to the scientific community. To understand jet noise is an immense scientific challenge. The radiated sound, which carries only a minuscule fraction of the flow energy, results from both small-scale turbulence and the complex dynamics of larger-scale coherent structures. The efficient utilization of the next generation of high-performance computing systems is hindered by the heterogeneous nature of the hardware. This project is focused on new methods that are both flexible enough for complex architectures, and powerful enough to deliver high-resolution approximations. Jet noise is an environmental problem subject to increasingly severe regulation throughout the world. To meet the ambitious noise reduction goals under discussion, a greatly enhanced understanding of the basic physics is needed. The simulations and follow-up analysis to be completed by the investigators bring us much closer to the goal of discovering the subtle physical mechanisms responsible for the acoustic radiation and to the rational design of methods to suppress it.