UNS: Collaborative Research: Spectral Energy Transfer in Turbulent Flames: From its Characterization to Subgrid Scale Models

1512214/EGolfopoulos，Fokion N.1512771/BlanQuart，Guillaum首席调查人员建议调查如何通过使用最先进的计算机模拟技术并借助先进的基于激光的测量来更好地模拟流体流动(通常在发动机和发电厂的燃烧室中使用)。这项研究的潜在好处包括更好地理解和设计燃烧器，以及更高的效率和更低的污染物排放。研究生和本科生都将参与研究，并为未来的研究人员和工程师做好准备。这项建议侧重于研究放热对小尺度湍流结构的影响，旨在为发展基于物理的湍流反应模型提供洞察力和机制，而不是基于特别的假设。实验部分包括新的速度测量，采用了一种类似于层析成像的方法，即速度测量覆盖了场的深度，而不是传统的真正三维流动的二维截面。关于科尔莫戈洛夫关于湍动能级联的平衡假设是否有效，以及如果不成立，放热反应应该在多大程度上和以什么方式对该假设进行修正，也将提供一些见解。与通常使用PIV解决的问题相比，测量跨越了更广泛的动态范围。所提出的直接数值模拟和分析主要集中在热释放对湍流能谱的影响以及不同尺度之间的能量传递。

1512214 / Egolfopoulos, Fokion N.1512771 / Blanquart, GuillaumeThe principal investigators propose to investigate how fluid flows (typical in devices such as combustor in engines and power plants) can be better modelled by using the state-of-art computer simulation techniques with the help of advanced laser-based measurements. The potential benefits of the study include better understanding and design of combustors and higher efficiency and lower pollutant emissions. Both graduate and undergraduate students will be involved in the research and be prepared as future researchers and engineers. This proposal focuses on fundamental investigation of the effects of heat release on small scale turbulent structure and aims to provide insight and mechanisms for developing physics-based turbulent reacting models, rather than based on ad-hoc assumptions. The experimental components include novel velocity measurements, adopting an approach similar to tomography in that the velocity measurements cover the depth of the field instead of the traditional two-dimensional section in truly three-dimensional flows. Some insight will also be shed on whether Kolmogorov's equilibrium assumption for turbulent kinetic energy cascade is valid and, if not, to what extent and in what manner the assumption should be modified by the heat-releasing reactions. The measurements span over a broader dynamic range of scales than is normally addressed using PIV. The proposed direct numerical simulations (DNS) and analysis are well focused on questions of the effects of heat release on turbulent energy spectra and energy transfer between different scales.