This paper presents a quasi-local method of studying the physics of dynamical black holes in numerical simulations. This is done within the dynamical horizon framework, which extends the earlier work on isolated horizons to time-dependent situations. In particular: (i) We locate various kinds of marginal surfaces and study their time evolution. An important ingredient is the calculation of the ...

SANDIP K. CHAKRABARTI, D. DEBNATH, P.S. PAL, A. NANDI, R. SARKAR, M.M. SAMANTA, P.J. WIITA, H. GHOSH and D. SOM S. N. Bose National Centre for Basic Sciences, JD-Block, Sector III, Salt Lake, Kolkata, 700 098, India. E-mail:[email protected] 2 Centre for Space Physics, Chalantika 43, Garia Station Rd., Kolkata 700084, India. 3 Department of Physics & Astronomy, Georgia State University, PO B...

Non-axisymmetric simulations verify and extend the results from a previous linear Floquet stability analysis of the wakes of rings. The wakes corresponding to the saturated state of each predicted non-axisymmetric instability mode over the entire aspect ratio range are successfully computed, and isosurface plots are presented elucidating the vortical wake structures. The existence of three non-...

We present first results of the non-linear evolution of rotating relativistic stars obtained with an axisymmetric relativistic hydrodynamics code in a fixed spacetime. As initial data we use stationary axisymmetric and perturbed configurations. We find that, in order to prevent (numerical) angular momentum loss at the surface layers of the star a high-resolution grid (or a numerical scheme that...

We consider the equilibrium and stability of rotating axisymmetric fluid drops by appealing to a variational principle that characterizes the equilibria as stationary states of a functional containing surface energy and rotational energy contributions, augmented by a volume constraint. The linear stability of a drop is determined by solving the eigenvalue problem associated with the second vari...

In this paper an upwind algorithm based on Roe’s scheme is presented for solution of PNS equations. Non iterative-implicit method using finite volume technique is used. The main advantage of this approach, in comparison with similar upwind methods, is reduction of oscillations around sonic line. This advantage causes the present method to be able to analyze supersonic flows with free stream Mac...