We have developed a new computer program in Fortran 90, in order to obtain numerical solutions of a system of Relativistic Magnetohydrodynamics partial differential equations with predetermined gravitation (GRMHD), capable of simulating the formation of relativistic jets from the accretion disk of matter up to his ejection. Initially we carried out a study on numerical methods of unidimensional...

We are concerned with central differencing schemes for solving scalar hyperbolic conservation laws arising in the simulation of multiphase flows in heterogeneous porous media. We compare the Kurganov-Tadmor (KT) (Kurganov and Tadmor, 2000) semi-discrete central scheme with the Nessyahu-Tadmor (NT) (Nessyahu and Tadmor, 1990) central scheme. The KT scheme uses more precise information about the ...

Here, we indicate how to integrate the set of conservation equations for mass, momentum and energy for a two-fluid plasma coupled to Maxwell’s equations for the electromagnetic field, written in a composite conservative form, by means of a recently modified non-staggered version of the staggered second order central difference scheme of Nessyahu and Tadmor [H. Nessyahu, E. Tadmor, Non-oscillato...

A class of non-oscillatory numerical methods for solving nonlinear scalar conservation laws in one space dimension is considered. This class of methods contains the classical Lax-Friedrichs and the second order Nessyahu-Tadmor scheme. In the case of linear flux, new l2 stability results and error estimates for the methods are proved. Numerical experiments confirm that these methods are one-side...

Here we outline a modification of the second order central difference scheme based on staggered spatial grids due to Nessyahu and Tadmor [H. Nessyahu, E. Tadmor, Non-oscillatory central differencing for hyperbolic conservation laws, J. Comput. Phys. 87 (1990) 408] to a non-staggered scheme for one-dimensional hyperbolic systems which can additionally include source terms. With this modification...

Several models in mathematical physics are described by quasi-linear hyperbolic systems with source term and in several cases the production term can become stiff. Here suitable central numerical schemes for such problems are developed and applications to the Broadwell model and extended thermodynamics are presented. The numerical methods are a generalization of the Nessyahu–Tadmor scheme to th...

A hydrodynamical model based on the theory of extended thermodynamics is presented for carrier transport in semiconductors. Closure relations for fluxes are obtained by employing the maximum entropy principle. The production terms are modeled by fitting the Monte Carlo data for homogeneously doped semiconductors. The mathematical properties of the model are studied. A suitable numerical method,...

In this paper, we consider several high order schemes in one space dimension. In particular, we compare the second order relaxation (<<1) or "relaxed" (=0) schemes of Jin-Xin 4], with the second order Lax-Friedrichs scheme of Nessyahu-Tadmor 6], and with higher order ENO and WENO schemes. This comparison is rst made on Sod shock tube, and then on a very pathological example of a p-system constr...

We show the discrete lip+-stability for a relaxation scheme proposed by Jin and Xin [Comm. Pure Appl. Math., 48 (1995), pp. 235–277] to approximate convex conservation laws. Equipped with the lip+-stability we obtain global error estimates in the spaces W s,p for −1 ≤ s ≤ 1/p, 1 ≤ p ≤ ∞ and pointwise error estimates for the approximate solution obtained by the relaxation scheme. The proof uses ...