Computational methods for ill-posed problems of gravitational gasodynamics

Abstract

A new numerical model of a galaxy interaction in gasodynamical approach is considered. In this model the equations of a gas dynamics with a cold function and the Poisson equation for a gravity potential are solved. A total system of equations is illposed. It allows us to describe a gravitational instability of astrophysical processes. As an example, the results of the collapse simulation are presented. The gas dynamic system of equations is solved by the Fluids-in-Cell method with the energy balance correction. Using the 3D Cartesian simulation a rotation, a self-consistent gravitational field, a complex central body geometry and a gas temperature were taken into account. A parallel implementation of the method for the simulation of various galaxy interaction scenarios was used in the model. Also, a research of the numerical model application range for various collision velocities and a mass relation of gas and star components was made here.

AstroPhi: A code for complex simulation of the dynamics of astrophysical objects using hybrid supercomputers

“…This technique is more suitable for computation with GPUs and Intel Xeon Phi accelerators than the previously used flow computation technique [48]. At each time step the energy balance is verified and corrected [50]. The energy balance correction procedure includes renorming of scheme velocities for the transfer of mass, impulse, and two energy types during the Lagrangian stage.…”

“…Our research group has been developing the Lagrangian-Eulerian approach on the basis of the fluids in cells (FlIC) and Godunov methods for several years [3,22,[48][49][50][51]. The AstroPhi code proposed here is based on an equation solver for gas dynamics comprising two stages.…”

The numerical modelling of MHD astrophysical flows with chemistry

“…Magnetic field plays a key role in formation and dynamics of astrophysical objects. Thus, on cosmological scales the influence of weak magnetic field, with order µG, on the dynamics of hydrodynamical instabilities and ram-pressure mechanism in galactic clusters (Bruggen 2013) was studied; primarily radial orientation of the magnetic field in Virgo cluster outside the central area was defined (Pfrommer & Dursi 2010), and comparison of magnetic field with radio observation was carried out (Xu et al 2012). The structure of magnetic field in spiral arms of the M51 galaxy was investigated (Fletcher et al 2011), and the evolution of the disk galaxy with consideration of influence of magnetic field was modeled (Pakmor & Springel 2013).…”