Shock wave interactions in unsteady high-speed compressible flows

拟议的大范围研究计划的统一主题是带有激波的高速非定常可压缩流动，它的长期目标是利用最先进的流动解算器研究涉及非定常冲击波现象的重要基本和应用问题，并根据所研究问题的要求继续发展这些数值模拟工具。该程序包括三个主要研究方向：(I)非定常激波从不同表面反射的基本原理和不同类型反射之间的过渡：与这些现象的物理机制和实验观测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；拟议的项目旨在对这场辩论作出关键和决定性的贡献；(Ii)多流体介质中的冲击波现象，用于两个应用领域：液体中会聚的冲击波驱动的气腔内爆，这与基于所谓的磁化目标聚变的未来核聚变反应堆高度相关；以及在冲击波的医疗应用中遇到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；(3)下一代高超声速吸气式发动机(超燃冲压发动机)进气口的启动：将用更现实的模型进一步研究新的进气启动技术，如基于薄隔膜破裂或所谓的“拖拉机-火箭”想法的进气启动技术，旨在找到其实际实施的方法。该计划的主要研究工具将是首席研究员早些时候开发的一套高分辨率和高效的流动解算器。为更准确、高效、可靠地处理上述问题，计划进一步开发。此外，首席研究员还与上述研究方向中的一些实验诊断领域的世界领先者建立了密切的合作关系，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。因此，科学调查的所有三个节点都将得到充分参与。预计主要成果将是通过档案期刊上的参考出版物向研究和工程界提供选定研究领域的基础性和实用性的发现；在激励和许多方面独特的研究环境方面对研究生/本科生进行广泛的培训，以及进一步开发激波流动的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。

The unifying theme of the proposed wide-scope research program is high-speed unsteady compressible flows with shock waves, which are much less studied as compared to their steady counterparts. Its long-term objectives are to study important basic and applied problems involving unsteady shock wave phenomena using the state-of-the-art flow solvers and to continue further development of these numerical tools as would be dictated by the problems under study.  The program encompasses three major research directions: (I) Fundamentals of unsteady shock wave reflections from various 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) Shock wave phenomena in multi-fluid media for two application areas: the implosion of a gas cavity driven by converging shock waves in liquid, which is highly relevant to the prospective nuclear fusion reactors based on the so-called magnetized target fusion;  and the shock wave propagation and cavitation bubble dynamics generated by laser pulse energy depositions in liquids, as encountered in medical applications of shock waves; (III) Starting of air intakes for next-generation hypersonic air-breathing engines (scramjets): novel intake starting techniques such as the ones based on the ideas of thin diaphragm rupture or so called "tractor-rocket" will be further studied with more realistic models aiming at finding the ways of their practical implementation. The main research tool of the program will be the set of high-resolution and efficient flow solvers developed earlier by the principal investigator. It is planned to be further developed for more accurate, efficient, and reliable treatment of the above problems. Analytical models will be developed as well. Furthermore, the principal investigator forged close collaborative ties with, arguably, world leaders in experimental diagnostics for some of the above research directions, who would supply their experimental data and additionally perform experiments suggested and designed by the principal investigator. Thus, all three nodes of scientific investigation will be fully engaged. 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.