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: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=638816
• 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.

建议的大范围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度，这使得研究中的现象的可压缩性效应和波状性质突出，以及基本的流动不稳定性，这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，研究得少得多。从物理数学的观点来看，所有这些流体现象都是由所谓的双曲守恒律系统来描述的，这使得在数学模型和计算机代码的同一框架内处理这些现象成为可能，这些现象乍一看并没有太多共同之处。在这种精神下，该计划包括四个主要研究方向：（I）基本上非定常的激波从曲面反射的基本原理和不同类型的反射之间的过渡：与这些现象的物理机制和实验观察的解释有关的一些问题最近已成为吸引许多研究人员的热点和有争议的话题;所提出的这个项目的目的，是要对这场辩论作出关键的、决定性的贡献;（II）下一代高超音速空气助燃式发动机（超音速燃烧冲压式喷气发动机）进气道的起动：基于非定常效应的新型进气道起动技术（例如，（三）复杂介质中的冲击波现象，主要有两个应用领域：（1）复杂介质中的冲击波现象;（2）复杂介质中的冲击波现象;（3）复杂介质中的冲击波现象;（4）复杂介质中的冲击波现象;（5）复杂介质中的冲击波现象;内爆驱动超高速发射器，用于轨道碎片撞击卫星的地面测试，以及冲击波的各种医疗应用中所用的液体中激光脉冲能量沉积所产生的冲击波传播和空泡动力学;（四）非线性磁声：非均匀介质中波的相位共轭（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方面有许多应用。该计划的主要研究工具将是由首席研究员早些时候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完善，以更准确，有效和可靠地处理上述问题。此外，首席研究员与上述四个研究方向的实验诊断领域的世界领导者（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，并额外执行首席研究员建议和设计的实验。这种全球性的合作，在我们的全球化时代的真正精神，将确保所有三种调查模式-理论，实验和数值-在拟议的研究计划中使用的最有效的组合。主要成果预计将是在选定的研究领域的基础和实践性质的发现，提供给研究和工程界通过参考出版物在档案期刊;对研究生/本科生进行广泛的培训，使其在许多方面具有独特的研究环境，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，这些方法已经被世界各地的许多研究人员使用，无疑将为今后的研究工作和实际应用其成果奠定坚实的基础。