Grid Adaptive LES/DNS

燃烧是目前最广泛使用的能量转换方法，为现代工业和社会提供动力。这种能量是由化石燃料的燃烧提供的，化石燃料是一种全球有限的资源，每天都在减少。化石燃料燃烧产生的排放物也会导致全球变暖等环境问题。为了更有效地转换能量并且对环境的危害更小，期望获得对燃烧过程的透彻理解。真实的燃烧应用的开发通常需要一系列实验来测试设计或理论。随着计算资源和数值技术的快速发展，计算机模拟测试也可以用于设计过程中的一小部分的成本相比，一个等效的实验。此外，计算机模拟可以通过同时扫描不同的配置，在较短的时间内提供有关拟议设计的更广泛的信息。目前的方法，如雷诺平均纳维尔斯托克斯（RANS），其中的时间波动流方程求解的平均形式，和大涡模拟（LES），其中只有较小尺度的运动建模正在被用来模拟工业问题。然而，这两种方法都需要模型提供额外的信息，这些信息由于存在局限性而丢失。拟议的工作将通过开发一种结合LES和直接数值模拟（DNS）的混合方法，将这些计算模拟提升到一个新的水平，其中所有运动尺度都是明确计算的，而不依赖于任何建模。据研究人员所知，这将是首次尝试将联合收割机和DNS结合起来模拟燃烧，然后与成本更高的全DNS进行比较。从这项工作的结果，预计将提供一个更好地了解大尺度湍流燃烧问题，而不损失的准确性。最后，这种方法可以形成一个强大而准确的模拟方法的基础，燃烧设计师可以使用它来探索新的配置，以提供更便宜，更安全，更环保的下一代能源。

Combustion is currently the most widely used method of energy conversion that powers modern industry and society. This energy is provided from the combustion of fossil fuels that are a global finite resource which is diminishing on a daily basis. Emissions from the combustion of fossil fuels can also lead to environmental problems such as global warming. In order to convert energy more efficiently and less harmfully to the environment, it is desirable to gain a thorough understanding of the combustion process. The development of real combustion applications generally requires a series of experiments to test a design or theory. With the rapid growth in computing resources and numerical techniques, computer simulation testing can also be used in the design process at a fraction of the cost compared with an equivalent experiment. In addition, computer simulations can provide a wider range of information on a proposed design in a shorter time frame by sweeping through different configurations simultaneously. Current methods such as Reynolds Averaged Navier Stokes (RANS), where the time fluctuating flow equations are solved in an average form, and Large Eddy Simulations (LES), where only the smaller scales of motion are modelled are being used to simulate industrial problems. However, both of these methods require models to provide additional information that is lost due to there limitations. The proposed work will take these computational simulations to the next level by developing a hybrid method that combines LES and Direct Numerical Simulation (DNS), where all scales of motion are computed explicitly without recourse to any modelling. To the investigators knowledge, this will be the first attempt to combine LES and DNS to simulate combustion, and then compare to a much more costly full DNS. The results from this work are expected to give a better understanding of large scale turbulent combustion problems without a loss in accuracy. Finally, this method could form the basis for a robust and accurate simulation method that combustion designers can use to explore new configurations with confidence to provide the next generation of energy cheaper, safer and more environmentally friendly.