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4programs. In particular it is important for systems and tools for automatic parallel programs construction,
since a program can be reconstructed according to profiling and trace information automatically. In the work
we propose facilities for LuNA system, capable of optimizing fragmented programs efficiency based on trace
information. Experimental results are presented.
Research on the numerical method and grid parameters as they influence the simulation accuracy
for the floating bodies
K. S. Plygunova, V. V. Kurulin, D. A. Utkin
FSUE �Russian Federal Nuclear Center � All-Russia Research Institute of Experimental Physics� Nizhny Novgorod
Region, Sarov
Email: xenia28_94@mail.ru
DOI 10.24412/cl-35065-2021-1-01-79
The work studies the grid parameters, the time step size, the order of approximation by space and time as
they influence the accuracy of the problem solution with damped free vibrations of the cylinder on the water
surface [1, 2]. The numerical simulation method of the floating bodies is based on the solution of a system of
Navier-Stokes equations together with VOF method [3, 4]. The motion of the body is accounted for by the de-
formation of the computational grid [5]. CFS model is used to account for the surface tension forces [6]. The
method is realized on the basis of the home LOGOS software package [7].
References
1. Maskell S. J., Ursell F. The transient motion of a floating body // J. Fluid Mech., 1970. N. 44. P. 303-313.
2. Soichi Ito. Study of the transient heave oscillation of a floating cylinder // Massachusetts institute of technology.
1977.
3. Hirt C.W., Nichols B.D. Volume of fluid (VOF) method for the dynamics of free boundaries // J. Comput. Phys. 1981.
V. 39. P. 201-225.
4. Kozelkov A.S., Meleshkina D.P., Kurkin A.A., Tarasova N.V., Lashkin S.V., Kurulin V.V. Completely implicit method to
solve Navier-Stokes equations to compute multiphase flows with free surface // Computational technologies. 2016. Vol.
21. � 5. pp. 54-76.
5. Edward Luke, Eric Collins, Eric Blades, A fast mesh deformation method using explicit interpolation // Journal of
Computational Physics. 2012. N. 231. P. 586�601.
6. Brackbill J.U., Kothe D.B., Zemach C. A continuum method for modeling surface tension // J. Comput. Phys. 1992.
N.100. P. 335-354.
7. Kozelkov A.S., Kurulin V.V., Lashkin S.V., Shagaliev R.M., Yalozo A.V., Investigation of supercomputer capabilities
for the scalable numerical simulation of computational fluid dynamics problems in industrial applications //
Computational mathematics and mathematical physics. 2016. V. 56. N. 8. P. 1524�1535.
Optimizations of computations on manycore processors and accelerators for elastic waves simulation
A. F. Sapetina
Institute of Computational Mathematics and Mathematical Geophysics SB RAS
Email: afsapetina@gmail.com
DOI 10.24412/cl-35065-2021-1-01-80
The solution of compute-intensive problems of mathematical modeling requires the development of par-
allel programs. The choice of various mathematical methods, algorithms and computational architectures for
solving such problems, as well as the development of high-performance codes is a complex task. In solving it,
the researcher can be helped by the developed system of intellectual support based on the ontological ap-
proach [1]. In this system, it is necessary to lay the knowledge about the impact of different approaches to or-
ganizing computations and working with memory on the final performance for different types of codes.
In this work, finite-difference 3D modeling of the propagation of elastic waves is considered [2]. Using the
example of solving this problem founded wide application, the influence of various optimization strategies for
parallel programs for various manycore architectures is investigated. Specific optimizations for different types
of architectures are considered, including improving the cache memory usage, balancing the computational
load, vectorization and accelerator memory usage.
Based on the research carried out, the software has been developed for various computing systems with
high rates of strong and weak scalability.
This research was supported by the Russian Foundation for Basic Research (grants No. 19-07-00085).
References
1. Glinskiy B.�., Zagorulko Yu.A., Zagorulko G.B., Kulikov I.M., Sapetina A.F., Titov P. A., Zhernyak G.F. Building
ontologies for solving compute-intensive problems // J. of Physics: Conference Series. 2021. V. 1715, Article Number
012071.
2. Sapetina A.F., Glinskiy B.�., Martynov V.N. Numerical modeling results for vibroseismic monitoring of volcanic
structures with different shape of the magma chamber // J. of Physics: Conference Series. 2021. V. 1715, Article Number
012057.
Solution approaches to numerical gas-dynamic problems with changing boundaries in LOGOS software
package
A. V. Sarazov, A. S. Kozelkov, D. K. Zelensky, R. N. Zhuchkov
FSUE �Russian Federal Nuclear Center � All-Russia Research Institute of Experimental Physics� Nizhny Novgorod
Region, Sarov
Email: avsarazov@vniief.ru
DOI 10.24412/cl-35065-2021-1-01-81
Approaches in simulation of the gas dynamic processes are of both scientific and practical interest. Transi-
ent modes in operation of engineering equipment that come from the motion of the element constituents of
the unit cause growing attention in the engineering practice. Numerical simulation of this class of problems in
LOGOS engineering software package [1] is available using two approaches different in the ideology: compu-
ting method on the deforming grids preserving links topology [2] and computing technology on overlapping
grids [3].
The choice of a particular approach comes from the immediate task setting. Nevertheless, there are some
problems where it is not possible to prefer either of the alternatives because it is impossible to describe com-
pletely the physical processes using one approach only.
The work reviews the realized physical-mathematical models for the problems of numerical gas dynamics
with moving structural components. It provides the examples of characteristic problems in aviation industry
that show operability of the realized models of the LOGOS software package.
References
1. M. A. Pogosjan, E. P. Savelevskikh, R. M. Shagaliev, A. S. Kozelkov, D. Yu. Strelets, A. A. Ryabov, A. V. Kornev, Yu. N.
Deryugin, V. F. Spiridonov, K. V. Tsiberev Application of Russian supercomputer technologies to develop the advanced
models of aviation technology VANT. Ser.: Mat. Mod. Fiz. Proc. 2013. No 2. P. 3-18.
2. E. Luke, E. Collins, E. Blades. A fast mesh deformation method using explicit interpolation, Journal of
Computational Physics 231 (2012) 586�601.
