We present an analog model for the Ba\~nados, Teitelboim, Zanelli (BTZ) black hole based on a hydrodynamical flow. numerically solve fully nonlinear hydrodynamic equations of motion and observe excitation decay BTZ quasinormal modes in process. consider both small perturbation steady state configuration fluid large perturbation; latter could be regarded as example formation (acoustic) hole.

Using cold working fastener holes is a simple life enhancement procedure that strengthens metallic components by retarding crack growth around a hole. In the present paper, the residual stress field that is induced by the hole expansion process is obtained based on different material models namely elastic perfect plastic, isotropic hardening and kinematic hardening using three-dimensional finit...

Accretion onto black holes in wind-fed binaries and in collapsars forms small rotating discs with peculiar properties. Such “mini-discs” accrete on the free-fall time without help of viscosity and nevertheless can have a high radiative efficiency. The inviscid mini-disc model was previously constructed for a non-rotating black hole. We extend the model to the case of a spinning black hole, calc...

Black hole evaporation is investigated in a (1+1)-dimensional model of quantum gravity. Quantum corrections to the black hole entropy are computed, and the fine-grained entropy of the Hawking radiation is studied. A generalized second law of thermodynamics is formulated, and shown to be valid under suitable conditions. It is also shown that, in this model, a black hole can consume an arbitraril...

In this thesis properties and the origin of black hole entropy are investigated from various points of view. First, laws of black hole thermodynamics are reviewed. In particular, the first and generalized second laws are investigated in detail. It is in these laws that the black hole entropy plays key roles. Next, three candidates for the origin of the black hole entropy are analyzed: the D-bra...

We show that the model proposed by Esin, McClintock, & Narayan for the low state, intermediate state, and high state of the black hole soft X-ray transient, Nova Muscae 1991, is consistent with the spectral evolution of the black hole X-ray binary, Cyg X-1, during the hard-to-soft state transition observed in 1996. We also apply the model to the outbursts of two other black hole X-ray transient...

The study of rotary steering drilling technology is currently one of the hot topics in the drilling engineering field. It requires accurate well trajectory control instructions when rotary steerable tools are applied to achieve the well trajectory control goal. A drilling trajectory prediction model will benefit this progress. According to the continuous beam theory, a mechanical model of push-...