Jaroslav Hron | Charles University, Prague (original) (raw)
Papers by Jaroslav Hron
The 41st Annual SES Technical Meeting, 2004
In bioengineering applications problems of flow interacting with elastic solid are very common. W... more In bioengineering applications problems of flow interacting with elastic solid are very common. We formulate the problem of interaction between an incompressible fluid and an incompressible elastic material in the arbitrary Lagrangian-Eulerian formulation, including the possibility ...
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Brain Sciences
Computational fluid dynamics (CFD) has grown as a tool to help understand the hemodynamic propert... more Computational fluid dynamics (CFD) has grown as a tool to help understand the hemodynamic properties related to the rupture of cerebral aneurysms. Few of these studies deal specifically with aneurysm growth and most only use a single time instance within the aneurysm growth history. The present retrospective study investigated four patient-specific aneurysms, once at initial diagnosis and then at follow-up, to analyze hemodynamic and morphological changes. Aneurysm geometries were segmented via the medical image processing software Mimics. The geometries were meshed and a computational fluid dynamics (CFD) analysis was performed using ANSYS. Results showed that major geometry bulk growth occurred in areas of low wall shear stress (WSS). Wall shape remodeling near neck impingement regions occurred in areas with large gradients of WSS and oscillatory shear index. This study found that growth occurred in areas where low WSS was accompanied by high velocity gradients between the aneurys...
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Icarus
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Astrobiology
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Starting with a short introduction of the new nonconforming linear quadrilateral ˜ P1-finite elem... more Starting with a short introduction of the new nonconforming linear quadrilateral ˜ P1-finite element which has been recently proposed by Park ((13, 14)), we examine in detail the numerical behaviour of this element with special emphasis on the treatment of Dirichlet boundary conditions, efficient matrix assembly, solver aspects and the use as Stokes element in CFD. Furthermore, we compare the
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We investigate a monolithic algorithm to solve the problem of time dependent interaction between ... more We investigate a monolithic algorithm to solve the problem of time dependent interaction between an incompressible viscous fluid and an elastic solid. The continuous formulation of the problem and its discretization is done in a monolithic way, treating the problem as one continuum. The Q2/P dis 1 finite elements are used for the discretization and an approximate Newton method with
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We investigate a new method of solving the problem of fluid-structure interaction of an incompres... more We investigate a new method of solving the problem of fluid-structure interaction of an incompressible elastic object in laminar incompressible viscous flow. Our proposed method is based on a fully implicit, monolithic formulation of the problem in the arbitrary Lagrangian-Eulerian framework. High order FEM is used to obtain the discrete approximation of the problem. In order to solve the resulting
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In [13], we had performed numerical comparisons for different time stepping schemes for the incom... more In [13], we had performed numerical comparisons for different time stepping schemes for the incompressible Navier-Stokes equations. In this paper, we present the numerical analysis in the context of the Navier-Stokes equations for a new time-stepping θ-scheme which has been recently proposed by Glowinski [5]. Like the well-known classical Fractional-Step-θ-scheme which had been introduced by Glowinski [1], [4], too, and which is still one of the most popular time stepping schemes, with or without operator splitting techniques, this new scheme consists of 3 substeps with non-equidistant substepping to build one macro time step. However, in contrast to the Fractional-Step-θ-scheme, the second substep can be formulated as an extrapolation step for previously computed data only, and the two remaining substeps look like a Backward Euler step so that no expensive operator evaluations for the right hand side vector with older solutions, as for instance in the Crank-Nicolson scheme, have to...
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AJNR. American journal of neuroradiology, Jan 11, 2014
Rupture risk assessment for intracranial aneurysms remains challenging, and risk factors, includi... more Rupture risk assessment for intracranial aneurysms remains challenging, and risk factors, including wall shear stress, are discussed controversially. The primary purpose of the presented challenge was to determine how consistently aneurysm rupture status and rupture site could be identified on the basis of computational fluid dynamics. Two geometrically similar MCA aneurysms were selected, 1 ruptured, 1 unruptured. Participating computational fluid dynamics groups were blinded as to which case was ruptured. Participants were provided with digitally segmented lumen geometries and, for this phase of the challenge, were free to choose their own flow rates, blood rheologies, and so forth. Participants were asked to report which case had ruptured and the likely site of rupture. In parallel, lumen geometries were provided to a group of neurosurgeons for their predictions of rupture status and site. Of 26 participating computational fluid dynamics groups, 21 (81%) correctly identified the ...
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Journal of Scientific Computing, 2006
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Journal of Computational and Applied Mathematics, 2006
Starting with a short introduction of a new non-conforming linear quadrilateral View the MathML s... more Starting with a short introduction of a new non-conforming linear quadrilateral View the MathML source -finite element which has been recently proposed by Park [A study on locking phenomena in finite element methods, Ph.D. Thesis, Seoul National University, February 2002] and ...
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Applied Numerical Mathematics, 2012
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Starting with a short introduction of the new nonconforming linear quadrilateral P1-finite eleme... more Starting with a short introduction of the new nonconforming linear quadrilateral P1-finite element which has been recently proposed by Park ([13, 14]), we examine in detail the numerical behaviour of this element with special emphasis on the treatment of Dirichlet boundary conditions, ...
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Journal of neurological surgery. Part A, Central European neurosurgery, 2017
Computational fluid dynamics (CFD) has been studied as a tool for the stratification of aneurysm ... more Computational fluid dynamics (CFD) has been studied as a tool for the stratification of aneurysm rupture risk. We performed CFD analysis in a patient operated on for a ruptured anterior communicating artery aneurysm. The point of rupture was identified during surgery. The aneurysm and blood vessels were segmented from computed tomography angiography to prepare a model for simulations. We found that the streamlines showed a concentrated inflow jet directed straight at the rupture point, and high wall shear stress was found at the point of rupture in the aneurysm sac. Thus specific local hemodynamics may be indicative of the aneurysm rupture site.
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Nonlinear Analysis: Real World Applications, 2011
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Numerical techniques for solving the problem of fluid-structure interaction with an elastic mater... more Numerical techniques for solving the problem of fluid-structure interaction with an elastic material in a laminar incompressible viscous flow are described. An Arbitrary Lagrangian-Eulerian (ALE) formulation is employed in a fully coupled monolithic way, considering the problem as one continuum. The mathematical description and the numerical schemes are designed in such a way that more complicated constitutive relations (and more
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The 41st Annual SES Technical Meeting, 2004
In bioengineering applications problems of flow interacting with elastic solid are very common. W... more In bioengineering applications problems of flow interacting with elastic solid are very common. We formulate the problem of interaction between an incompressible fluid and an incompressible elastic material in the arbitrary Lagrangian-Eulerian formulation, including the possibility ...
Bookmarks Related papers MentionsView impact
Brain Sciences
Computational fluid dynamics (CFD) has grown as a tool to help understand the hemodynamic propert... more Computational fluid dynamics (CFD) has grown as a tool to help understand the hemodynamic properties related to the rupture of cerebral aneurysms. Few of these studies deal specifically with aneurysm growth and most only use a single time instance within the aneurysm growth history. The present retrospective study investigated four patient-specific aneurysms, once at initial diagnosis and then at follow-up, to analyze hemodynamic and morphological changes. Aneurysm geometries were segmented via the medical image processing software Mimics. The geometries were meshed and a computational fluid dynamics (CFD) analysis was performed using ANSYS. Results showed that major geometry bulk growth occurred in areas of low wall shear stress (WSS). Wall shape remodeling near neck impingement regions occurred in areas with large gradients of WSS and oscillatory shear index. This study found that growth occurred in areas where low WSS was accompanied by high velocity gradients between the aneurys...
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Icarus
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Astrobiology
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Starting with a short introduction of the new nonconforming linear quadrilateral ˜ P1-finite elem... more Starting with a short introduction of the new nonconforming linear quadrilateral ˜ P1-finite element which has been recently proposed by Park ((13, 14)), we examine in detail the numerical behaviour of this element with special emphasis on the treatment of Dirichlet boundary conditions, efficient matrix assembly, solver aspects and the use as Stokes element in CFD. Furthermore, we compare the
Bookmarks Related papers MentionsView impact
We investigate a monolithic algorithm to solve the problem of time dependent interaction between ... more We investigate a monolithic algorithm to solve the problem of time dependent interaction between an incompressible viscous fluid and an elastic solid. The continuous formulation of the problem and its discretization is done in a monolithic way, treating the problem as one continuum. The Q2/P dis 1 finite elements are used for the discretization and an approximate Newton method with
Bookmarks Related papers MentionsView impact
We investigate a new method of solving the problem of fluid-structure interaction of an incompres... more We investigate a new method of solving the problem of fluid-structure interaction of an incompressible elastic object in laminar incompressible viscous flow. Our proposed method is based on a fully implicit, monolithic formulation of the problem in the arbitrary Lagrangian-Eulerian framework. High order FEM is used to obtain the discrete approximation of the problem. In order to solve the resulting
Bookmarks Related papers MentionsView impact
In [13], we had performed numerical comparisons for different time stepping schemes for the incom... more In [13], we had performed numerical comparisons for different time stepping schemes for the incompressible Navier-Stokes equations. In this paper, we present the numerical analysis in the context of the Navier-Stokes equations for a new time-stepping θ-scheme which has been recently proposed by Glowinski [5]. Like the well-known classical Fractional-Step-θ-scheme which had been introduced by Glowinski [1], [4], too, and which is still one of the most popular time stepping schemes, with or without operator splitting techniques, this new scheme consists of 3 substeps with non-equidistant substepping to build one macro time step. However, in contrast to the Fractional-Step-θ-scheme, the second substep can be formulated as an extrapolation step for previously computed data only, and the two remaining substeps look like a Backward Euler step so that no expensive operator evaluations for the right hand side vector with older solutions, as for instance in the Crank-Nicolson scheme, have to...
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Bookmarks Related papers MentionsView impact
AJNR. American journal of neuroradiology, Jan 11, 2014
Rupture risk assessment for intracranial aneurysms remains challenging, and risk factors, includi... more Rupture risk assessment for intracranial aneurysms remains challenging, and risk factors, including wall shear stress, are discussed controversially. The primary purpose of the presented challenge was to determine how consistently aneurysm rupture status and rupture site could be identified on the basis of computational fluid dynamics. Two geometrically similar MCA aneurysms were selected, 1 ruptured, 1 unruptured. Participating computational fluid dynamics groups were blinded as to which case was ruptured. Participants were provided with digitally segmented lumen geometries and, for this phase of the challenge, were free to choose their own flow rates, blood rheologies, and so forth. Participants were asked to report which case had ruptured and the likely site of rupture. In parallel, lumen geometries were provided to a group of neurosurgeons for their predictions of rupture status and site. Of 26 participating computational fluid dynamics groups, 21 (81%) correctly identified the ...
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Journal of Scientific Computing, 2006
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Journal of Computational and Applied Mathematics, 2006
Starting with a short introduction of a new non-conforming linear quadrilateral View the MathML s... more Starting with a short introduction of a new non-conforming linear quadrilateral View the MathML source -finite element which has been recently proposed by Park [A study on locking phenomena in finite element methods, Ph.D. Thesis, Seoul National University, February 2002] and ...
Bookmarks Related papers MentionsView impact
Applied Numerical Mathematics, 2012
Bookmarks Related papers MentionsView impact
Starting with a short introduction of the new nonconforming linear quadrilateral P1-finite eleme... more Starting with a short introduction of the new nonconforming linear quadrilateral P1-finite element which has been recently proposed by Park ([13, 14]), we examine in detail the numerical behaviour of this element with special emphasis on the treatment of Dirichlet boundary conditions, ...
Bookmarks Related papers MentionsView impact
Journal of neurological surgery. Part A, Central European neurosurgery, 2017
Computational fluid dynamics (CFD) has been studied as a tool for the stratification of aneurysm ... more Computational fluid dynamics (CFD) has been studied as a tool for the stratification of aneurysm rupture risk. We performed CFD analysis in a patient operated on for a ruptured anterior communicating artery aneurysm. The point of rupture was identified during surgery. The aneurysm and blood vessels were segmented from computed tomography angiography to prepare a model for simulations. We found that the streamlines showed a concentrated inflow jet directed straight at the rupture point, and high wall shear stress was found at the point of rupture in the aneurysm sac. Thus specific local hemodynamics may be indicative of the aneurysm rupture site.
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Nonlinear Analysis: Real World Applications, 2011
Bookmarks Related papers MentionsView impact
Numerical techniques for solving the problem of fluid-structure interaction with an elastic mater... more Numerical techniques for solving the problem of fluid-structure interaction with an elastic material in a laminar incompressible viscous flow are described. An Arbitrary Lagrangian-Eulerian (ALE) formulation is employed in a fully coupled monolithic way, considering the problem as one continuum. The mathematical description and the numerical schemes are designed in such a way that more complicated constitutive relations (and more
Bookmarks Related papers MentionsView impact