Supercomputer model of dynamical dusty gas with intense momentum transfer between phases based on OpenFPM library

The paper considers the solution of model gas-dynamic problems (propagation of plane sound wave, one-dimensional shock tube problem, three-dimensional problem of a point explosion in a continuous medium) in the case of a gas-dust medium. The interaction of dust and gas was taken into account using the IDIC method within the SPH method used to solve gas-dynamic equations. An important feature of the work is the use of the open computational package OpenFPM, which makes it easy to carry out parallel computations. The main advantage of this package is the ready-made (implemented by the authors of the package) and intuitive, automatically parallelizable vector data structures, the use of which is identical both in the case of calculations on a personal computer and in the case of using supercomputer resources. The paper analyzes the efficiency of parallelization of numerical solutions of the considered problems.

Different-Scale Simulation of Flows in Porous Media

The paper considers the development of algorithms for an adequate description of processes of different scales in porous media. The choice of a computational technique is determined by the reference size of the problem being solved. Models of porous medium flow under Darcy’s law, neglecting the medium microstructure, are used for the simulation at macro-scale. While at micro-scale, a direct description of fluid flow in porous channels with complex geometry by means of gas dynamic equations is used. In the first case the proposed model of non-isothermal multiphase multicomponent flow in a porous medium includes the mass balance and total energy conservation equations modified by analogy to the known quasi-gas dynamic equations. The model features are the introduction of minimal reference scales in space and in time and the change of the system type from parabolic to hyperbolic to increase the stability of explicit difference schemes applied for approximation. In the second case the dimensionless form of the quasi-gas dynamic system with pressure decomposition, developed by the authors earlier, is adapted to the simulation of flows in the pore space. The fictitious domain method is proposed to reproduce the core microstructure. The developed approaches have been verified by test predictions.

Автоволновой импульс в среде с дисбалансом между тепловыделением и теплоотводом при произвольной величине тепловой дисперсии

An analytical method for determining the amplitude and velocity of an autowave pulse emerging in isentropically unstable heat-releasing media is presented. The method is suitable for any values of acoustic dispersion and growth rate and requires the knowledge of heat-loss function only without the need for a numerical solution of a complete system of gas-dynamic equations.

CFD Analysis of Aircraft Curved C-D Nozzle: Technical Note

A nozzle for the aircraft can be designed by considering the exit Mach number. In order to get a premeditated Mach number, we need to convert pressure energy into kinetic energy by using a nozzle. Convergent nozzles are utilized for subsonic flows while Convergent-Divergent (C-D) nozzle is utilized for supersonic flows. Curved nozzle flow is accelerated from low subsonic to sonic velocity at the throat and further expanded to supersonic velocities at the exit, in a C-D nozzle. This paper details the relevancies on designing a curved nozzle to attain super-sonic flow and maximizing the optimal thrust and devoid of flow separation due to shock waves. The navigation of the flow must be parallel to the axis of the nozzle for achieving extreme thrust and proficiency. Based on the fundamental gas dynamic equations, this study aims to develop a theoretical approach for the calculation of the flow properties along the axis of the C-D Nozzle. The flow conditions were selected in consideration of the pressure, temperature and gases accessible at the exit of the combustion chamber.

Forms of possible delamination of the liner in a metal composite high pressure vessel

The purpose of the paper was to study the effect of induced gas perturbations in the reservoir on the ballistic characteristics of single-stage gas guns. Two ways of waves generation at the initial moment are considered: by means of a non-uniform initial distribution of gas parameters and by creating a shock wave propagating from the bottom of the reservoir by external forces. The study is based on the numerical solution of one-dimensional gas-dynamic equations on a moving grid. Findings of research show that for relatively large (compared to the accelerating gas mass) mass of the projectiles, the wave processes induced by inhomogeneous filling lead to an increase in the muzzle velocity 1.4 times, and the shock waves generation by an external source — 1.8 times.