Modelling Interaction of Relativistic and Nonrelativistic Flows on Adaptive Grids

Abstract

We consider numerical aspects of the mathematical modeling of composite flows (relativistic and nonrelativistic) on adaptive computational grids applied to a double pulsar–optical star system. The pulsar is the source of an ultrarelativistic wind of the electron-positron plasma and the optical star is the source of a nonrelativistic wind. In the domains of relativistic and nonrelativistic flows, the plasma dynamics are described by different systems of equations. Moreover, the wind parameters are such that it is significantly difficult to model them in a similar way. Despite the fact that the distance between the partners of the binary system varies depending on the orbital phase, the flow is self-similar and is determined by the dimensionless parameters of the problem. The flow pattern can vary significantly under variations of these parameters. This requires the flexibility of the algorithm to construct a computational grid adaptable to the solution. In this work, we present the possibilities of use adaptive grids for modeling the above-mentioned class of composite flows.