Acoustic clouds: standing sound waves around a black hole analogue

Abstract

Under certain conditions sound waves in fluids experience an acoustic horizon with analogue properties to those of a black hole event horizon. In particular, a draining bathtub-like model can give rise to a rotating acoustic horizon and hence a rotating black hole (acoustic) analogue. We show that sound waves, when enclosed in a cylindrical cavity, can form stationary waves around such rotating acoustic black holes. These acoustic perturbations display similar properties to the scalar clouds that have been studied around Kerr and Kerr-Newman black holes; thus they are dubbed acoustic clouds. We make the comparison between scalar clouds around Kerr black holes and acoustic clouds around the draining bathtub explicit by studying also the properties of scalar clouds around Kerr black holes enclosed in a cavity. Acoustic clouds suggest the possibility of testing, experimentally, the existence and properties of black hole clouds, using analog models.

8 pages, 6 figures; v2. 11 pages, 8 figures, included analysis with Neumann boundary conditions and added more references

References in corpus (10)

• Kerr-Newman scalar clouds
• Kerr-Newman black holes with stationary charged scalar clouds
• A new spin on black hole hair
• Schwarzschild black holes can wear scalar wigs
• Non-linear Q-clouds around Kerr black holes
• Myers-Perry black holes with scalar hair and a mass gap
• Marginal scalar and Proca clouds around Reissner-Nordström black holes
• Onset of superradiant instabilities in the composed Kerr-black-hole-mirror bomb
• Ergoregion instability: The hydrodynamic vortex
• Quasinormal modes and Regge poles of the canonical acoustic hole

Cited by in corpus (10)

• Quasibound states of Schwarzschild acoustic black holes
• Black holes with synchronised Proca hair: linear clouds and fundamental non-linear solutions
• Acoustic black-hole bombs and scalar clouds in a photon-fluid model
• The Gravitational Bending of Acoustic Schwarzschild Black Hole
• Asymmetric wormholes in Palatini $f(\mathcal{R})$ gravity: Energy conditions, absorption and quasibound states
• No-short scalar hair theorem for spinning acoustic black holes in a photon-fluid model
• Stationary scalar clouds supported by rapidly-rotating acoustic black holes in a photon-fluid model
• Ergoregion instability in a fluid with vorticity
• Shadow and near-horizon characteristics of the acoustic charged black hole in curved spacetime
• Analytical investigation of wave absorption by a rotating black hole analogue