AIM (Advanced Instability Methods) for industry

在过去的十年里，人们对将非模态分析应用于基础流体力学中的标准问题的兴趣激增。即使在简单的流动中，这些非模式分析预测的行为也可能与传统分析预测的行为完全不同，而且比传统分析预测的更准确，特别是对于工业环境中的流动类型。非模式分析在标准问题中的成功应用为工程实践中的阶段性变化奠定了基础。然而，必须克服一些非常重大的挑战。首先，标准方法不能处理工程中经常发现的非线性问题。其次，标准方法计算量大，不能处理多个自由度的问题。第三，标准方法涉及简单的测量，如动能密度，而其他测量通常更适用于工业情况。令人鼓舞的是，应用数学家和工程师在所有这些领域都取得了重大进展。这一进展表明，根据约束最优化和变分方法对问题进行一般化描述，采用和应用控制和计算社区的方法，将弥合标准流程和工程问题之间的差距。我们的愿景是，未来一代的工程计算流体动力学(CFD)工具将包含能够执行非模态分析的模块。如果这种分析变得可行，它们肯定会改变工程师设计流体机械系统的方式，如燃烧室、涡轮叶片、反应室和喷墨打印机。此外，它们可以很容易地处理瞬变效应和非周期时变基流，这在工程环境中通常是特别相关的。这项研究将使依赖流体力学和热声学的建模和控制的英国工业受益。例如，制药行业将受益于更好地了解生理流动中向湍流和再透明化的转变，这对通过鼻子和上呼吸道应用药物很重要；燃气轮机行业将受益于能够对其燃料喷射器进行即时敏感性分析，并将其与导致燃烧不稳定的热声学更好地理解相结合；而风力涡轮机行业将受益于对翼型对湍流转变和暴露于阵风或前一机翼尾迹的结果的敏感性的改进预测。这项提案中的调查人员都是EPSRC资助的高级不稳定性方法(AIM)网络的创始成员，该网络成立于2009年1月，目的是探索非正态分析与工业问题的相关性。通过学术界和工业界的大师班和研讨会以及越来越多的基于网络的资源，该网络为传播和利用这项研究提供了一条途径。总而言之，这项建议的目标是弥合基础工作和工程实践之间的差距，将这些技术嵌入工程设计周期，并加强英国在这一领域日益壮大的英才中心。这里提出的通用框架，结合两个具有挑战性的工程实例和AIM网络的资源，将使这一点成为可能，并向更广泛的工程界进行演示。

In the last ten years there has been a surge of interest in non-modal analysis applied to standard problems in fundamental fluid mechanics. Even in simple flows, the behaviour predicted by these non-modal analyses can be completely different from - and far more accurate than - that predicted by conventional analyses, particularly for the types of flows found in industrial situations.The successful application of non-modal analysis to standard problems sets the scene for step changes in engineering practice. Nevertheless, some very significant challenges must be overcome. Firstly, the standard approach cannot handle the non-linear problems often found in engineering. Secondly, the standard approach is computationally expensive and cannot handle problems with many degrees of freedom. Thirdly, the standard approach deals with simple measures, such as kinetic energy density, while other measures are usually more pertinent for industrial situations. Encouragingly, applied mathematicians and engineers have made significant progress in all of these areas. This progress has revealed that a generalized formulation of the problem in terms of constrained optimization and variational methods, adapting and applying methods from the control and computational communities, will bridge the gap between standard flows and engineering problems.Our vision is that future generations of engineering Computational Fluid Dynamics (CFD) tools will contain modules that can perform non-modal analysis. If and when such analyses can be made practicable they are certain to change the way that engineers design fluid mechanical systems, such as combustion chambers, turbine blades, reaction chambers and ink jet printers. Furthermore, they can readily deal with transient effects and non-periodic time-varying base flows, which are often particularly relevant in engineering situations.This research will benefit UK industries that rely on the modelling and control of fluid mechanics and thermoacoustics. For example, the pharmaceutical industry will benefit from a better understanding of transition to turbulence and relaminarization in physiological flows, which is important for the application of drugs via the nose and upper airways; The gas turbine industry will benefit from being able to perform instant sensitivity analyses of their fuel injectors and to combine this with greater understanding of the thermo-acoustics that leads to combustion instability; and the wind turbine industry will benefit from an improved prediction of the sensitivity of an aerofoil to turbulence transition and results of exposure to a gust or to the wake of the preceding aerofoil.The investigators in this proposal are all founder members of the EPSRC-funded Advanced Instability Methods (AIM) Network, which was set up in January 2009 to explore the relevance of non-normal analysis to industrial problems. Through masterclasses and workshops in academia and industry and an increasing number of web-based resources, the network provides a route for dissemination and exploitation of this research.In summary, the objectives of this proposal are to bridge the gap between fundamental work and engineering practice, to embed these techniques in the engineering design cycle and to reinforce a growing centre of excellence within the UK in this area. The generalized framework proposed here, combined with two challenging engineering examples and the resources of the AIM Network, will make this possible and demonstrate it to a wider engineering community.