Vortex loops are compact toroidal structures wherein fluid rotation forms a closed loop around a fictitious axis, manifest in many natural occurrences. These phenomena result from brief impulses through vents or apertures in fluid systems, such as in caves, volcanic crusts, downbursts, or the descent of liquid droplets. The majority of naturally occurring and laboratory-generated vortex loops, studied for fundamental research on their formation, growth, instability, and dissolution, are classified as incompressible. This categorisation denotes negligible alterations in thermodynamic properties within the vortex loop. However, a distinct category of vortex loops emerges from processes involving artillery, shock tubes, explosions, chemical interactions, and combustion. This class primarily constitutes compressible vortex loops. Their presence in flow fields spans over a century, and they have been observed since the application of open-ended shock tubes to explore phenomena like diffracting shock waves, blast wave interactions with objects, and noise mitigation. The study and comprehension of compressible vortex loops and their interactions have historically relied heavily on optical techniques, lacking comprehensive insight into the intricate flow dynamics. Nevertheless, the advancements in flow visualisation tools and computational capabilities in the 21st century have significantly aided scientists in scrutinising and characterising these vortex loops and their interactions in intricate detail. Unfortunately, a comprehensive review of the literature addressing compressible vortex loops originating from shock tubes, their evolution, and interactions with shockwaves and various objects, including walls, appears lacking. This review article aims to address this gap.

中文翻译：

---

可压缩涡旋循环及其相互作用


涡流环是紧凑的环形结构，其中流体旋转围绕虚构轴形成一个闭合环，这在许多自然事件中都有体现。这些现象是由流体系统中的通风口或孔隙的短暂冲动引起的，例如在洞穴、火山地壳、暴流或液滴下降中。大多数自然发生的和实验室生成的涡流环，为了对其形成、生长、不稳定性和溶解进行基础研究而进行研究，被归类为不可压缩。这种分类表示涡旋回路内热力学性质的变化可以忽略不计。然而，涉及火炮、激波管、爆炸、化学相互作用和燃烧的过程会出现一类独特的涡流环。此类主要构成可压缩的涡旋环。它们在流场中的存在跨越了一个多世纪，自从应用开口激波管来探索衍射激波、爆炸波与物体的相互作用和噪声缓解等现象以来，人们一直观察到它们。历史上，对可压缩涡旋环及其相互作用的研究和理解在很大程度上依赖于光学技术，缺乏对错综复杂的流动动力学的全面了解。尽管如此，21 世纪流动可视化工具和计算能力的进步极大地帮助了科学家仔细检查和描述这些涡流回路及其相互作用的复杂细节。不幸的是，似乎缺乏对源自激波管的可压缩涡流环、它们的演变以及与冲击波和各种物体（包括墙壁）的相互作用的文献的全面回顾。本综述文章旨在解决这一差距。