Yes (102)
Number of found documents:
102
Published from
to
Analytical solution of Stokes flow near corners and applications to numerical solution of Navier-Stokes equations with high precision
Burda, P.; Novotný, Jaroslav; Šístek, Jakub
2012 - English
We present analytical solution of the Stokes problem in 2D domains. This is then used to find the asymptotic behavior of the solution in the vicinity of corners, also for Navier-Stokes equations in 2D. We apply this to construct very precise numerical finite element solution.
Keywords:
Stokes flow; singularities; corners; asymptotic solution
Fulltext is available at external website.
Analytical solution of Stokes flow near corners and applications to numerical solution of Navier-Stokes equations with high precision
We present analytical solution of the Stokes problem in 2D domains. This is then used to find the asymptotic behavior of the solution in the vicinity of corners, also for Navier-Stokes equations in ...
Numerical comparison of different choices of interface weights in the BDDC method
Čertíková, M.; Burda, P.; Šístek, Jakub
2012 - English
Balancing Domain Decomposition by Constraints (BDDC) belongs to the class of primal substructuring Domain Decomposition (DD) methods. DD methods are iterative methods successfully used in engineering to parallelize solution of large linear systems arising from discretization of second order elliptic problems. Substructuring DD methods represent an important class of DD methods. Their main idea is to divide the underlying domain into nonoverlapping subdomains and solvemany relatively small, local problems on subdomains instead of one large problem on the whole domain. In primal methods, it has to be specified how to distribute interface residuals among subdomains and how to obtain global, interface values of solution from local values on adjacent subdomains. Usually a weighted average is used with some simple choice of weights.
Keywords:
BDDC; domain decomposition; iterative substructuring; averaging
Fulltext is available at external website.
Numerical comparison of different choices of interface weights in the BDDC method
Balancing Domain Decomposition by Constraints (BDDC) belongs to the class of primal substructuring Domain Decomposition (DD) methods. DD methods are iterative methods successfully used in engineering ...
Some practical aspects of parallel adaptive BDDC method
Šístek, Jakub; Mandel, J.; Sousedík, B.
2012 - English
We describe a parallel implementation of the Balancing Domain Decomposition by Constraints (BDDC) method enhanced by an adaptive construction of coarse problem. The method is designed for numerically difficult problems, where standard choice of continuity of arithmetic averages across faces and edges of subdomains fails to maintain the low condition number of the preconditioned system. Problems of elasticity analysis of bodies consisting of different materials with rapidly changing stiffness may represent one class of such challenging problems. The adaptive selection of constraints is shown to significantly increase the robustness of the method for this class of problems. However, since the cost of the set-up of the preconditioner with adaptive constraints is considerably larger than for the standard choices, computational feasibility of the presented implementation is obtained only for large contrasts of material coefficients.
Keywords:
substructuring methods; BDDC; Feti methods
Available in digital repository of the ASCR
Some practical aspects of parallel adaptive BDDC method
We describe a parallel implementation of the Balancing Domain Decomposition by Constraints (BDDC) method enhanced by an adaptive construction of coarse problem. The method is designed for numerically ...
Algebraic classification of the Weyl tensor
Pravdová, Alena
2012 - English
Alignment classification of tensors on Lorentzian manifolds of arbitrary dimension is summarized. This classification scheme is then applied to the case of the Weyl tensor and it is shown that in four dimensions it is equivalent to the well known Petrov classification. The approaches using Bel-Debever criteria and principal null directions of the superenergy tensor are also discussed.
Keywords:
algebraic classification of tensors; Lorentzian manifolds
Fulltext is available at external website.
Algebraic classification of the Weyl tensor
Alignment classification of tensors on Lorentzian manifolds of arbitrary dimension is summarized. This classification scheme is then applied to the case of the Weyl tensor and it is shown that in four ...
Algebraic classification of the Weyl tensor : selected applications
Pravda, Vojtěch
2012 - English
Selected applications of the algebraic classification of tensors on Lorentzian manifolds of arbitrary dimension are discussed. We clarify some aspects of the relationship between invariants of tensors and their algebraic class, discuss generalization of Newman-Penrose and Geroch-Held-Penrose formalisms to arbitrary dimension and study an application of the algebraic classification to the case of quadratic gravity.
Keywords:
Einstein spacetimes; algebraic classification
Fulltext is available at external website.
Algebraic classification of the Weyl tensor : selected applications
Selected applications of the algebraic classification of tensors on Lorentzian manifolds of arbitrary dimension are discussed. We clarify some aspects of the relationship between invariants of tensors ...
On the motion of rigid bodies in a compressible viscous fluid under the action of gravitational forces
Ducomet, B.; Nečasová, Šárka
2012 - English
The global existence of weak solution is proved for the problem of the motion of several rigid bodies in a barotropic compressible fluid, under the influence of gravitational forces.
Keywords:
compressible viscous fluid; motion
Fulltext is available at external website.
On the motion of rigid bodies in a compressible viscous fluid under the action of gravitational forces
The global existence of weak solution is proved for the problem of the motion of several rigid bodies in a barotropic compressible fluid, under the influence of gravitational forces.
Recent development of the DML-CZ and its current state
Rákosník, Jiří
2011 - English
The project DML-CZ: The Czech Digital Mathematics Library has been implemented since 2005 and in 2010 switched over to routine operation. This report describes progress, growth and usage of the DML-CZ, the experience from cooperation with content providers in the designed editorial workflow, some newly implemented features, adjustments of the workflow following from both the ongoing practical experience and the requirements of the advancing EuDML project, the general public acceptance and attendance and the suggested economic model for sustainable development.
Keywords:
digital mathematics library; retrodigitization; DML-CZ
Available in digital repository of the ASCR
Recent development of the DML-CZ and its current state
The project DML-CZ: The Czech Digital Mathematics Library has been implemented since 2005 and in 2010 switched over to routine operation. This report describes progress, growth and usage of the ...
A comparison of some a posteriori error estimates for fourth order problems
Segeth, Karel
2010 - English
In this survey contribution, we present and compare, from the viewpoint of adaptive computation, several recently published error estimation procedures for the numerical solution of biharmonic and some further fourth order problems including computational error estimates.
Keywords:
a posteriori error estimate; finite element method; fourth order problem
Available in digital repository of the ASCR
A comparison of some a posteriori error estimates for fourth order problems
In this survey contribution, we present and compare, from the viewpoint of adaptive computation, several recently published error estimation procedures for the numerical solution of biharmonic and ...
Programs and Algorithms of Numerical Mathematics 15
Vejchodský, Tomáš; Chleboun, J.; Přikryl, Petr; Segeth, Karel; Šístek, Jakub
2010 - English
The book contains papers presented at the international seminar Programs and algorithms of numerical Mathematics 15 (PANM 15), held in Dolni Maxov, Czech Republic, June 6-11, 2010. It is the fifteen volume in the series of the PANM proceedings. The topics of contributions include numerical methods for fluid flow modelling, the finite element method, a posteriori error estimates, topics from numerical linear atgebra, etc.
Keywords:
algorithms; numerical mathematics
Available in digital repository of the ASCR
Programs and Algorithms of Numerical Mathematics 15
The book contains papers presented at the international seminar Programs and algorithms of numerical Mathematics 15 (PANM 15), held in Dolni Maxov, Czech Republic, June 6-11, 2010. It is the fifteen ...
Some remarks on averaging in the BDDC method
Čertíková, M.; Burda, P.; Novotný, J.; Šístek, Jakub
2010 - English
In this paper, we introduce a general framework for derivation of the averaging operator, from hich the standard choices are recovered by simplifications. Then, an alternative approach derived by another simplification is proposed and tested on a 2D example.
Keywords:
BDDC method
Available in digital repository of the ASCR
Some remarks on averaging in the BDDC method
In this paper, we introduce a general framework for derivation of the averaging operator, from hich the standard choices are recovered by simplifications. Then, an alternative approach derived by ...
NRGL provides central access to information on grey literature produced in the Czech Republic in the fields of science, research and education. You can find more information about grey literature and NRGL at service web
Send your suggestions and comments to nusl@techlib.cz
Provider
Other bases