Unsteady wave phenomena in high-speed compressible flows

高速可压缩流中的非定常波现象

• 批准号: RGPIN-2014-05427
• 负责人: Timofeev, Evgeny
• 金额: $ 1.75万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=611641
• 关键词: Unsteady; wave; phenomena; speed; compressible

The unifying theme of the proposed wide-scope research program is unsteady wave phenomena in high speed compressible flows. The key points here are high velocities, which make compressibility effects and wave-like nature of the phenomena under study prominent, and essential flow unsteadiness, which challenges researchers and is much less studied as compared to relevant steady gasdynamic flows. From the physico-mathematical point of view all these fluid phenomena are described by so-called hyperbolic systems of conservation laws, making it possible to treat, within the same framework of mathematical models and computer codes, the phenomena which at first superficial glance do not have much in common. In this spirit, the program encompasses four major research directions: (I) Fundamentals of essentially unsteady shock wave reflections from curved surfaces and transitions between different types of reflection: a number of issues related to physical mechanisms of these phenomena and interpretations of experimental observations have recently become a hot and contentious topic attracting many researchers; the proposed project is aimed at making crucial and decisive contributions to the debate; (II) Starting of air intakes for next-generation hypersonic air-breathing engines (scramjets): novel intake starting techniques based on unsteady effects (e.g., diaphragm-rupture induced) proposed earlier by the principal investigator will be further studied with more realistic models aiming at finding the ways of their practical implementation; an in-depth study and optimization of the widely used overboard spillage technique will be undertaken as well; (III) Shock wave phenomena in complex media as encountered in two application areas: the implosion-driven hypervelocity launcher for ground-based testing of orbital debris impact on satellites, and the shock wave propagation and cavitation bubble dynamics generated by laser pulse energy depositions in liquids as used in various medical applications of shock waves; (IV) Nonlinear magneto-acoustics: modelling of waves phase conjugation (time-reversal of acoustic signals) in heterogeneous media which has many applications in medical treatments and diagnostics, non-destructive testing and flow metrology. The main research tool of the program will be the set of high-resolution and efficient flow solvers developed earlier by the principal investigator. These numerical methods and codes are planned to be further elaborated for more accurate, efficient and reliable treatment of the above problems. Furthermore, the principal investigator forged very close collaborative ties with, arguably, world leaders in experimental diagnostics for the four research directions mentioned above (from Australia, Canada, France, Japan), who would supply their experimental data and additionally perform experiments suggested and designed by the principal investigator. Such worldwide collaboration, in the true spirit of our era of globalization, would ensure that all three modes of investigation - theoretical, experimental and numerical - are used in the most effective combination within the proposed research program. The major outcomes are expected to be discoveries of both fundamental and practical nature in the chosen research areas delivered to research and engineering community via refereed publications in archival journals; extensive training of graduate/undergraduate students in stimulating and in many aspects unique research environment, and further development of general computer codes for unsteady gasdynamics of shocked flows, which are already in use by many researchers worldwide and would undoubtedly serve as a solid base for future research undertakings and practical applications of their results.

所提出的广泛研究计划的统一主题是高速可压缩流中的非定常波现象。这里的关键点是高速，它使得所研究现象的压缩效应和波状性质变得突出，而基本流动的不稳定性则对研究人员提出了挑战，并且与相关的稳定气体动力学流动相比，研究较少。从物理数学的角度来看，所有这些流体现象都是由所谓的守恒定律双曲系统描述的，使得可以在相同的数学模型和计算机代码框架内处理乍一看没有太多共同点的现象。 本着这种精神，该计划涵盖四个主要研究方向：（一）曲面上本质上不稳定的冲击波反射和不同类型反射之间的转换的基础知识：与这些现象的物理机制和实验观察的解释相关的一些问题最近已成为吸引许多研究人员的热门和有争议的话题；拟议项目旨在为辩论做出关键和决定性的贡献； （二）下一代高超音速吸气式发动机（超燃冲压发动机）进气启动：课题组长之前提出的基于非定常效应（例如膜片破裂诱发）的新型进气启动技术将通过更真实的模型进行进一步研究，旨在寻找其实际实施的方法；还将对广泛使用的舷外溢漏技术进行深入研究和优化； (III) 两个应用领域中遇到的复杂介质中的冲击波现象：用于地面测试轨道碎片对卫星影响的内爆驱动超高速发射器，以及冲击波的各种医疗应用中使用的激光脉冲能量沉积在液体中产生的冲击波传播和空化气泡动力学； (IV) 非线性磁声学：异质介质中的波相位共轭（声信号的时间反转）建模，在医疗和诊断、无损检测和流量计量中有许多应用。 该项目的主要研究工具将是首席研究员早期开发的一套高分辨率和高效的流动求解器。这些数值方法和代码计划进一步细化，以便更准确、高效、可靠地处理上述问题。此外，首席研究员可以说与上述四个研究方向的实验诊断领域的世界领先者（来自澳大利亚、加拿大、法国、日本）建立了非常密切的合作关系，他们将提供他们的实验数据，并另外进行首席研究员建议和设计的实验。这种全球范围内的合作，本着全球化时代的真正精神，将确保所有三种研究模式——理论、实验和数值——在拟议的研究计划中以最有效的组合使用。 主要成果预计将是所选研究领域的基础性和实用性发现，并通过档案期刊上的参考出版物交付给研究和工程界；在刺激和在许多方面独特的研究环境中对研究生/本科生进行广泛的培训，并进一步开发冲击流非定常气体动力学的通用计算机代码，这些代码已经被世界各地的许多研究人员使用，无疑将为未来的研究工作和其成果的实际应用奠定坚实的基础。