Научная статья на тему 'Hierarchical basis on tetrahedra for mixed finite element formulation of the Darcy problem'

Hierarchical basis on tetrahedra for mixed finite element formulation of the Darcy problem Текст научной статьи по специальности «Математика»

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Текст научной работы на тему «Hierarchical basis on tetrahedra for mixed finite element formulation of the Darcy problem»

References

1. Cerna D. Cubic spline wavelets with four vanishing moments on the interval and their applications to option

pricing under Kou mode // International J. of wavelets, multiresolution and information processing. 2019. V. 17, N. 1.

Article N. 1850061.

2. Koro K., Abe K. Non-orthogonal spline wavelets for boundary element analysis // Engineering analysis with

boundary elements. 2001. V. 25. P. 149-164.

3. Shumilov B. M. Algorithm with splitting for cubic spline wavelets with two zero moments on an interval // Siberian

electronic mathematical reports. 2020. V. 17. P. 2105-2121.

4. Pissanetzky S. Sparse matrix technology. London: Academic press, 1984.

5. Shumilov B. M. Semi-orthogonal spline-wavelets with derivatives and the algorithm with splitting // Numerical

analysis and applications. 2017. V. 10, N. 1. P. 90-100.

On seven-diagonals splitting for cubic spline wavelets with six vanishing moments on an interval

B. M. Shumilov

Tomsk State University of Architecture and Building

Email: sbm@tsuab.ru

DOI 10.24412/cl-35065-2021-1-00-55

In this study, we use a zeroing property of the first six moments for constructing a splitting algorithm for

cubic spline wavelets. First, we construct a new system of cubic basic spline-wavelets, realizing orthogonal

conditions to all polynomials up to fifth degrees [1]. Then, using the homogeneous Dirichlet boundary condi-

tions [2], we adapt spaces to the closed interval. The originality of the study consists of obtaining implicit rela-

tions connecting the coefficients of the spline decomposition at the initial scale with the spline coefficients and

wavelet coefficients at the nested scale by a tape system of linear algebraic equations with a non-degenerate

matrix. After excluding the even rows of the system, in contrast to the case with two zero moments [3], the

resulting transformation matrix has five or seven (instead of three) diagonals. For a seven-diagonal matrix, the

presence of a strict diagonal dominance over the columns [4] is proved. The comparative results of numerical

experiments on approximating and calculating the derivatives of a discrete function are presented.

References

1. Koro K., Abe K. Non-orthogonal spline wavelets for boundary element analysis // Engineering Analysis with

Boundary Elements. 2001. V. 25. P. 149-164.

2. Cerna D. Cubic spline wavelets with four vanishing moments on the interval and their applications to option

pricing under Kou mode // International J. of Wavelets, Multiresolution and Information Processing. 2019. V. 17, N. 1.

Article N. 1850061.

3. Shumilov B. Algorithm with splitting for cubic spline wavelets with two zero moments on an interval // Siberian

Electronic Mathematical Reports. 2020. V. 17. P. 2105-2121.

4. Pissanetzky S. Sparse Matrix Technology. London: Academic Press, 1984.

Hierarchical basis on tetrahedra for mixed finite element formulation of the Darcy problem

E. P. Shurina1,2, N. B. Itkina2, S. A. Trofimova1,2

1Trofimuk Institute of Petroleum Geology and Geophysics SB RAS

2Novosibirsk State Technical University

Email: svetik-missy@mail.ru, TrofimovaSA@ipgg.sbras.ru, itkina.nat@yandex.ru, shurina@online.sinor.ru

DOI 10.24412/cl-35065-2021-1-00-57

The solution of a certain class of applied problems in the oil industry involves the use of mathematical

models that describe complex processes associated with the intensification and development of hydrocarbon

fields. Mixed variational formulation turn out to be effective for determining the explicit behavior of the nor-

mal velocity component at the boundary of the modeling domain, however, they involve finding a solution in

two spaces [1]. In this paper the problem of constructing a specialized hierarchical basis systems on tetrahe-

dral finite elements in the H1-space for pressure and in the Hdiv-space for velocity is investigated and also the

influence of this basis on the properties of a matrix of a discrete analogue of a non-conformal mixed formula-

tion based on the discontinuous Galerkin method is studied [2].

This work was supported by the Project No. 0266-2019-0007.

References

1. F. Brezzi, T.J.R. Hughes, L.D. Marini, A. Masud. Mixed discontinuous Galerkin methods for Darcy flow // J. of

Scientific Computing. 2005. V. 22, No. 1. P. 119-225.

2. P. Solin, K. Segeth, I. Dolezel. High-order finite element methods, ChapmananHall, CRC, 2004. 388 p.

Particle motions for the gas dynamics equations with the special state equation

D. T. Siraeva1

1Mavlyutov Institute of Mechanics UFRC RAS

Email: sirdilara@gmail.com

DOI 10.24412/cl-35065-2021-1-00-59

The gas dynamics equations with the state equation of special form are considered. The state equation is

a pressure equal to the sum of two functions. The first function depends on density, and the second function

depends on entropy [1]. The system admits a 12-dimensional Lie algebra. An optimal system of dissimilar sub-

algebras of the Lie algebra was constructed in [2]. Invariant submodels are calculated for 2- and 3-dimensional

subalgebras. Exact solutions were found for some submodels.

The motion of particles and volumes according to the exact solutions is considered due to using the com-

puter mathematics system Maple.

The work was supported by the Russian Foundation for Basic Research (project no. 18-29-10071) and partially from

the Federal Budget by the State Target (project no. 0246-2019-0052).

References

1. Ovsyannikov L.V. The �podmodeli� program. Gas dynamics // J. of Appl. Math. and Mechan. 1994. V. 58, N. 4.

P. 601-627. Doi:10.1016/0021-8928(94)90137-6.

2. Siraeva D.T. Optimal system of non-similar subalgebras of sum of two ideals // Ufa Mathematical J.. 2014. V. 6,

N. 1. P. 90-103. Doi:10.13108/2014-6-1-90.

The coupling of the vectorial and scalar boundary element methods

S. A. Sivak, M. E. Royak, I. M. Stupakov

Novosibirsk State Technical University

Email: siwakserg@yandex.ru

DOI 10.24412/cl-35065-2021-1-00-60

The vectorial boundary element method is a tool applied to solve electromagnetic problems in a media

with consideration of eddy currents [1]. It�s also known as the boundary element method for eddy current

problems [2, 3]. The use of this method brings certain difficulties, one of which is the problem of zero wave

number in the subdomains adjacent to the domain where the eddy currents should be considered. As a means

to mitigate the computational difficulty, we present in this paper the coupling with the scalar potential. The

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