Acoustic metric of the compressible draining bathtub
Acoustic metric of the compressible draining bathtub
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可压缩排水浴缸的声学指标
DOI：
10.1103/physrevd.84.084027
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发表时间：
2011
影响因子：
5
通讯作者：
S. Filippi
中科院分区：
文献类型：
--
作者：
C. Cherubini;S. Filippi
排水浴缸流是声黑洞理论的基石，本文将其推广到以多向状态方程为特征的可压缩非粘性流的精确解的情况。对所选多向性指数的解析构形进行研究，发现它们在所谓的极限圆处都是非物理的。通过研究相应声线元的零测地线结构，表明该几何轨迹与声事件视界重合。这个区域的特征还在于时空曲率的无穷大，因此声学类比在这里就失效了。最后讨论了人工和自然涡旋的可能应用。
The draining bathtub flow, a cornerstone in the theory of acoustic black holes, is here extended to the case of exact solutions for compressible nonviscous flows characterized by a polytropic equation of state. Investigating the analytical configurations obtained for selected values of the polytropic index, it is found that each of them becomes nonphysical at the so called limiting circle. By studying the null geodesics structure of the corresponding acoustic line elements, it is shown that such a geometrical locus coincides with the acoustic event horizon. This region is characterized also by an infinite value of space-time curvature, so the acoustic analogy breaks down there. Possible applications for artificial and natural vortices are finally discussed.