Shock wave interactions in unsteady high-speed compressible flows

提出的大范围研究计划的统一主题是高速非定常激波可压缩流动，与稳定流动相比，对其的研究要少得多。其长期目标是使用最先进的流动求解器研究涉及非定常激波现象的重要基础和应用问题，并根据所研究的问题继续进一步发展这些数值工具。本项目包括三个主要研究方向：(1)不同表面非定常激波反射的基本原理和不同类型反射之间的转换：有关这些现象的物理机制和实验观测的解释的一些问题近年来成为吸引许多研究人员的热点和有争议的话题；拟议的项目旨在为辩论作出关键和决定性的贡献；（二）多流体介质中激波现象的两个应用领域：一是液体中激波汇聚驱动的气腔内爆，这与基于所谓磁化靶聚变的未来核聚变反应堆高度相关；以及激光脉冲能量在液体中沉积所产生的激波传播和空化泡动力学，如在医学应用中遇到的激波；（三）下一代高超声速吸气式发动机（超燃冲压发动机）进气道启动：新型进气道启动技术，如基于薄隔膜破裂或所谓的“拖拉机-火箭”的思想，将进一步研究与更现实的模型，旨在寻找其实际实施的途径。该项目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。为了更准确、高效、可靠地处理上述问题，计划进一步开发。分析模型也将被开发。此外，在上述一些研究方向上，首席研究员与实验诊断领域的世界领导者建立了密切的合作关系，他们将提供他们的实验数据，并进行由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充分参与。主要成果预计将是在所选研究领域的基础和实际性质的发现，通过档案期刊上的评审出版物提交给研究和工程界；广泛培养研究生/本科生，在许多方面营造独特的研究环境，并进一步开发激波流动非定常气体动力学通用计算机代码，这些代码已经被世界上许多研究人员使用，无疑将为今后的研究事业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.