2007/03/31 by Satoshi Okuzumi, Masa-aki Sakagami, Masa‐aki Sakagami · 3 citations
Engineering · Physics and Astronomy · #Acoustic Wave Phenomena Research #Quantum Electrodynamics and Casimir Effect #Thermal Radiation and Cooling Technologies #astro-ph #gr-qc #physics.flu-dyn
paper · pdf · doi:10.1103/physrevd.76.084027
published as Phys.Rev.D76:084027,2007 · 9 pages, 8 figures, accepted for publication in Physical Review D
arxiv created 2007/08/29 · openalex publication_date 2007/10/22 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
Quasinormal ringing of acoustic black holes in Laval nozzles is discussed. The equation for sounds in a transonic flow is written into a Schr"odinger-type equation with a potential barrier, and the quasinormal frequencies are calculated semianalytically. From the results of numerical simulations, it is shown that the quasinormal modes are actually excited when the transonic flow is formed or slightly perturbed, as well as in the real black hole case. In an actual experiment, however, the purely-outgoing boundary condition will not be satisfied at late times due to the wave reflection at the end of the apparatus, and a late-time ringing will be expressed as a superposition of boxed quasinormal modes. It is shown that the late-time ringing damps more slowly than the ordinary quasinormal ringing, while its central frequency is not greatly different from that of the ordinary one. Using this fact, an efficient way for experimentally detecting the quasinormal ringing of an acoustic black hole is discussed.