Physics-based Scale Enrichment for Eddy-Resolving Turbulence Simulations

计算模型被广泛用于设计和分析，以支持航空航天、能源和交通部门的新技术。这些应用中的许多都需要对具有复杂几何形状的湍流流动进行准确的预测。例如，改进的航空航天飞行器的空气动力学设计要求对飞行器表面的湍流阻力进行预测和管理。作为基础科学研究的重要工具，涡旋分辨湍流模拟在很大程度上才刚刚开始用于工程应用，原因是它们的成本非常高。该项目将开发一种基于物理的建模方法，以成本效益的方式显著改进湍流模拟。新方法将为非定常载荷、疲劳、表面振动和声辐射的高性价比预测提供巨大的潜力。所提出的方法基于涡旋解析湍流模拟，例如大涡模拟，尽管带宽有限，并在每个计算单元应用高效的、基于物理的尺度丰富方案。丰富方案在本地产生物理上一致的细小尺度涡旋的实现，其动态地响应所解析的较大尺度，并且使得能够以大得多的带宽对物理量进行统计预测，从而使得能够对先前不可访问的量进行预测。提出了一种新的计算建模策略，可应用于风能、结构振动和疲劳的航空航天设计/优化等领域。除此之外，拟议的方法可能会在更广泛的领域应用，如动态气象学和海洋和大气科学。正在开发的工具和软件将是开源的，预计将在计算科学界的不同群体之间展开合作和使用。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Computational models are widely used in design and analysis to support new technologies in aerospace, energy and transportation sectors. Many of these applications require accurate prediction of turbulent fluid flows often with complex geometries. For example, improved aerodynamic designs for aerospace vehicles require prediction and management of the drag force of turbulent flow on the vehicle surfaces. Eddy-resolving turbulence simulations, which are an important tool for fundamental scientific research, are only beginning to be used in engineering applications largely due to their very high cost. This project will develop a physics-based modeling approach to significantly improve turbulence simulations in a cost-effective manner. The new method should provide significant potential for cost-effective predictions of unsteady loads, fatigue, surface vibrations, and acoustic radiation.The proposed approach is based on combining eddy-resolving turbulence simulation, such as large-eddy simulation, albeit of limited bandwidth, with an efficient, physics-based scale-enrichment scheme applied at each of the computational cells. The enrichment scheme generates a physically consistent realization of the finer-scale eddies locally which dynamically respond to the resolved larger scales and enable statistical predictions of physical quantities with a substantially larger bandwidth, thus enabling predictions of quantities not accessible previously. A novel computational modeling strategy is proposed with potential applications to diverse fields such as wind energy, and aerospace design/optimization involving structural vibration and fatigue. Beyond these, the proposed approach may have applications in broader fields such as dynamic meteorology and ocean and atmospheric sciences. The tools and software being developed will be open source and is expected to initiate collaborations and use across diverse groups from the computational science community.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.