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Numerical simulation of the Rayleigh–Taylor instability in a plain layer of argon over a layer of helium in a field of gravitational force was performed using continuum and kinetic approaches. Continuum model is based on the Navier–Stokes equations for a gas mixture, kinetic approach is on the Direct Simulation Monte Carlo method. The onset of large-scale movement and mixing processes are investigated. Quantitative characteristics of the evolution of the Rayleigh–Taylor instability in a rarefied mode are obtained. [ABSTRACT FROM AUTHOR]

In the present work, HyCFS-R numerical code is used for the numerical simulation of heterogeneous detonation in plane and 3D channels with rectangular and circular crossections based on the Euler-Euler approach. Computations were performed for the Al/O2 gas-particle suspension with 10 µm particles. Obtained data is used for the basic analysis of spatial effects on the detonation wave propagation regimes and flow pattern in general. [ABSTRACT FROM AUTHOR]

In the current work the preliminary results of numerical simulations of detonation wave propagation with detailed hy- drocarbon chemical mechanisms are presented. 1D and 2D cases are investigated. All simulations are conducted using an in-home code solving the chemically reacting Euler equations on supercomputers with GPUs. Four chemical models are considered: AFRL model, Singh–Jachimowski model, Varatharajan–Williams model and GRI-Mech 3.0 model. Due to complexity of GRI-Mech 3.0 model it is not used for 2D numerical simulations of detonation wave propagation. For all chemical models the Chapman-Jouguet velocity is obtained, the ignition delay is determined and the Zeldovich–Neumann–Doering solution is obtained in order to compare how suitable they are for numerical simulations of detonations. The 2D Euler equations are solved for an ethylene/oxygen/nitrogen mixture using high-order shock-capturing TVD schemes and a finite-rate chemistry solver. The sizes of detonation cells obtained with different models are compared with each other and experimental data. [ABSTRACT FROM AUTHOR]

Module of HyCFS-R numerical code for the simulation of chemically reacting gas/particle suspensions based on the Euler–Euler approach is verified on the problem of detonation wave propagating in channel. The grid convergence and 3D effects are studied. Numerical simulation results are compared with data available in the literature. [ABSTRACT FROM AUTHOR]

Numerical simulations of detonation wave propagation in a channel are performed and the formation of the detonation wave multifront structure is studied. An in-house numerical code running on hybrid supercomputers is employed for the numerical simulations. The code is written in C++ with the use of MPI, OpenMP and CUDA parallel technologies. Four different chemical reaction mechanisms for description of hydrogen/oxygen mixture combustion are considered. The mechanisms are compared in terms of the Chapman-Jouguet detonation speed, the predicted number of detonation cells and the shape of detonation wave front. [ABSTRACT FROM AUTHOR]

In the present work a computer code HyCFS-R for numerical simulation of chemically reacting compressible flows on hybrid CPU/GPU supercomputers is developed. It solves unsteady Euler equations for multispecies chemically reacting flows in general curvilinear coordinates using shock-capturing TVD schemes. The developed code is verified by comparing results of numerical simulation with the solutions obtained using ANSYS Fluent software coupled with the user-defined functions for taking into account the thermo-chemical non-equilibrium. [ABSTRACT FROM AUTHOR]

The viscous shock tube problem is studied using two different solvers, 5th order WENO solver and a 13th order hybrid scheme. The possibility to reach a grid-convergent solution for the Reynolds number Re = 2500 is investigated and an analysis of shock wave / boundary layer interaction details and flow dynamics inside the viscous shock tube is presented. Specific features and accuracy of the used solvers are discussed. [ABSTRACT FROM AUTHOR]

The Kelvin–Helmholtz instability developing in the compressible mixing layer is simulated numerically using both the kinetic and continuum approaches. The computations are performed for a spatially periodic mixing layer at subsonic convective Mach numbers and low Reynolds numbers. The main part of the kinetic simulations are carried out with the Shakhov model kinetic equation but the simulations based on the Boltzmann equation are also conducted. A deterministic numerical method that directly solves the kinetic equations on a finite-difference grid in the multidimensional phase space is used. The computational code is adapted for implementation on hybrid computational clusters combining CPUs and GPUs. Navier–Stokes simulations of the Kelvin–Helmholtz instability are also performed and their results are compared with those of kinetic simulations. [ABSTRACT FROM AUTHOR]

In the present work a computer code RCFS for numerical simulation of chemically reacting compressible flows on hybrid CPU/GPU supercomputers is developed. It solves 3D unsteady Euler equations for multispecies chemically reacting flows in general curvilinear coordinates using shock-capturing TVD schemes. Time advancement is carried out using the explicit Runge- Kutta TVD schemes. Program implementation uses CUDA application programming interface to perform GPU computations. Data between GPUs is distributed via domain decomposition technique. The developed code is verified on the number of test cases including supersonic flow over a cylinder. [ABSTRACT FROM AUTHOR]

The possibility of adaptation of a Multi-GPU, CUDA-based code for parallel computations on CPUs with the OpenMP technology is considered. By applying macros of the preprocessor of the C++ language and compiler options, the source code can be translated the GPU/CUDA, CPU/OpenMP, and Xeon Phi/OpenMP executable files. The operability of this technology is illustrated by an example of adaptation of the HyCFS code. The computational efficiency for various platforms is compared. [ABSTRACT FROM AUTHOR]

In the present work a computer code RCFS for numerical simulation of chemically reacting compressible flows on hybrid CPU/GPU supercomputers is developed. It solves 3D unsteady Euler equations for multispecies chemically reacting flows in general curvilinear coordinates using shock-capturing TVD schemes. Time advancement is carried out using the explicit Runge- Kutta TVD schemes. Program implementation uses CUDA application programming interface to perform GPU computations. Data between GPUs is distributed via domain decomposition technique. The developed code is verified on the number of test cases including supersonic flow over a cylinder. [ABSTRACT FROM AUTHOR]

There are various methods for calculating rarefied gas flows, in particular, statistical methods and deterministic methods based on the finite-difference solutions of the Boltzmann nonlinear kinetic equation and on the solutions of model kinetic equations. There is no universal method; each has its disadvantages in terms of efficiency or accuracy. The choice of the method depends on the problem to be solved and on parameters of calculated flows. Qualitative theoretical arguments help to determine the range of parameters of effectively solved problems for each method; however, it is advisable to perform comparative tests of calculations of the classical problems performed by different methods and with different parameters to have quantitative confirmation of this reasoning. The paper provides the results of the calculations performed by the authors with the help of the Direct Simulation Monte Carlo method and finite-difference methods of solving the Boltzmann equation and model kinetic equations. Based on this comparison, conclusions are made on selecting a particular method for flow simulations in various ranges of flow parameters. [ABSTRACT FROM AUTHOR]