We derive and analyze a simplified formulation of the numerical viscosity terms appearing in the expression of the numerical fluxes associated to several High-Resolution Shock-Capturing schemes. After some algebraic preprocessing, we give explicit expressions for the numerical viscosity terms of two of the most widely used flux formulae, which implementation saves computational time in multidim...

We investigate advection dominated accretion flows of matter in the vicinity of black holes, using the fully relativistic description in the frame of disk approximation. We also include some effects of the quasi-sphericity of the flow. We are interested in the spectra emitted by such flows and specifically, in the relativistic effects accompanying propagation of light. Using the ray shooting me...

Dynamics of stationary axisymmetric configuration of the viscous accreting fluids surrounding a non-rotating compact object in final stages of accretion flow is presented here. For the special case of thin disk approximation, the relativistic fluid equations ignoring self-gravity of the disk are derived in Schwarzschild geometry. For two different state equations, two sets of self-consistent an...

Jets and outflows are known to form out of advective accretion flows around black holes. Hard photons from the centrifugal barrier directly hit the electrons and deposit momentum on them. For optically thick flows such deposition is not efficient, but for optically thin flows matter could be accelerated to relativistic speed. In fact, even bound matter could be made free through successive depo...

We study the Casimir force on a single surface immersed in an inhomoge-neous medium. Specifically we study the vacuum fluctuations of a scalar field with a spatially varying squared mass, m 2 + λ∆(x − a) + V (x), where V is a smooth potential and ∆(x) is a unit-area function sharply peaked around x = 0. ∆(x − a) represents a semi-penetrable thin plate placed at x = a. In the limits {∆(x−a) → δ(...