The results of the study of an explosion point of supernova type Ia (SNIa) with using of mathematical modeling on supercomputers is given in the paper. Hydrodynamical model closed by the stellar equation of state and supplemented by Poisson equation for gravitational potential is used for modeling of a white dwarf. The nuclear combustion of carbon, for which the analytical solution is constructed, is accounted in the model. A multilevel organization of computations on nested grids is used in the solution. The new highorder accuracy numerical method based on the Godunov method, the Rusanov scheme and the piecewise parabolic method on local stencil, adapted for computations on nested grids, is built. The parallel implementation is based on the idea of distributed computations, where the architecture with shared memory is used for modeling of the hydrodynamic evolution of white dwarfs, when the critical values of temperature and density are reached, a new task is launched on the architecture with distributed memory, in which the evolution of hydrodynamic turbulence leading to supersonic nuclear combustion of carbon is simulated.
Many planets were detected in last few years, but there is no clear understanding of how they are formed. The fairly clear understanding of Solar system formation was founded with time, but there are some doubts yet because we don’t know what was at the beginning of the process, and what was acquired afterward. Moreover, formed ideas often couldn’t explain some features of other systems. Searching for Earth-like terrestrial planets is another very important problem. Even if any of found exoplanets will be similar to Earth, we couldn’t say that it is a “second Earth” exactly because its internal, geological, composition could be different – Venus is a vivid example. A new method for modelling of the planet formation process in a 3D2V formulation based on two-phase approach is presented in the paper. Fluids-in-cells method by Belotserkovskii-Davydov, modified with using the Godunov’s scheme, is used to model the gas component. The dust component is described by N-body system solved with the Particle-Mesh method. The method was accelerated by using of Nvidia CUDA technology. Gas-dust disk modelling results with the formation of sealing of gas and dust that could be interpreted as potential exoplanet are given.
We present implementation of a new vectorized high-order accuracy numerical method for solving gravitational hydrodynamics equations on supercomputers equipped with Intel Xeon Phi in the paper. Combination of the Godunov method, the Harten-Lax-Van Leer method and the piecewise parabolic method on the local stencil is at the basis of the method. It allows achieving high-order accuracy for smooth solutions and low dissipation on discontinuities. We present chemokinetic model of formaldehyde formation based on molecular hydrogen and carbon monoxide. We show the results of numerical simulation of interacting galaxies.
The complexity of astrophysical processes lies in the joint consideration of components of various nature. For example, in the collision problem of galaxies, the three-dimensional dynamics of an interstellar gas and a stellar component is considered. The modeling of these components can be based on completely different classes of numerical methods. One possible solution to this problem is to use the Eulerian-Lagrangian approach, in which physical quantities are concentrated at material points, which is typical for the SPH (Smoothed Particle Hydrodynamics) method, and the forces are calculated on an adaptive grid attached to a system of material points. This approach uniformly takes into account both the dynamics of a continuous medium and discrete particles, and also eliminates a number of drawbacks inherent in the original method. The calculation of gravitational interaction is carried out by solving the Poisson equation for the gravitational potential. In this case, all particles are projected onto the computational grid and the potential values in each cell are already calculated on it. The solution of the Poisson equation for the gravitational potential is performed using the fast Fourier transform. The article describes the new cuFFT code Virtual Planetarium for modeling astrophysical objects based on the SPH method, supplemented by the Godunov method for calculating pressure and momentum flows between particles, and the fast Fourier transform method for solving the Poisson equation for the gravitational potential. The paper describes the rationale for the transition to such a computational model, kinetic and hydrodynamic approaches are described in detail. Simulation of the collapse of an isothermal gas cloud is performed. Method to reproduce the evolution of instabilities in form of two density arms is realized.
The new code for numerical simulation of magnetic hydrodynamical astrophysical flows with consideration of chemical reactions is given in the paper. At the heart of the code -the new original low-dissipation numerical method based on a combination of operator splitting approach and piecewise-parabolic method on the local stencil. The details of the numerical method are described; the main tests and the scheme of parallel implementation are shown. The chemodynamics of the hydrogen while the turbulent formation of molecular clouds is modeled.
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