Search results for: Martin Kronbichler

Items from 1 to 20 out of 76 results

article

On the role of tissue mechanics in fluid–structure interaction simulations of patient‐specific aortic dissection

Richard Schussnig, Malte Rolf‐Pissarczyk, Kathrin Bäumler, Thomas‐Peter Fries, more

International Journal for Numerical Methods in Engineering > 125 > 14 > n/a - n/a

Modeling an aortic dissection represents a particular challenge from a numerical perspective, especially when it comes to the interaction between solid (aortic wall) and liquid (blood flow). The complexity of patient‐specific simulations requires a variety of parameters, modeling assumptions and simplifications that currently hinder their routine use in clinical settings. We present a numerical framework...

article

Loss, gain and choice difficulty in gambling patients: Neural and behavioural processes

Daniel Freinhofer, Philipp Schwartenbeck, Natasha Thon, Wolfgang Aichhorn, more

Addiction Biology > 29 > 5 > n/a - n/a

Impaired decision‐making is often displayed by individuals suffering from gambling disorder (GD). Since there are a variety of different phenomena influencing decision‐making, we focused in this study on the effects of GD on neural and behavioural processes related to loss aversion and choice difficulty. Behavioural responses as well as brain images of 23 patients with GD and 20 controls were recorded...

article

Recognition and perception of emotions in juvenile myoclonic epilepsy

Lucas Johannes Rainer, Giorgi Kuchukhidze, Eugen Trinka, Mario Braun, more

Epilepsia > 64 > 12 > 3319 - 3330

Objective Perception and recognition of emotions are fundamental prerequisites of human life. Patients with juvenile myoclonic epilepsy (JME) may have emotional and behavioral impairments that might influence socially desirable interactions. We aimed to investigate perception and recognition of emotions in patients with JME by means of neuropsychological tests and functional magnetic resonance imaging...

article

A matrix‐free approach for finite‐strain hyperelastic problems using geometric multigrid

Denis Davydov, Jean‐Paul Pelteret, Daniel Arndt, Martin Kronbichler, more

International Journal for Numerical Methods in Engineering > 121 > 13 > 2874 - 2895

This work investigates matrix‐free algorithms for problems in quasi‐static finite‐strain hyperelasticity. Iterative solvers with matrix‐free operator evaluation have emerged as an attractive alternative to sparse matrices in the fluid dynamics and wave propagation communities because they significantly reduce the memory traffic, the limiting factor in classical finite element solvers. Specifically,...

article

High‐order cut discontinuous Galerkin methods with local time stepping for acoustics

Svenja Schoeder, Simon Sticko, Gunilla Kreiss, Martin Kronbichler

International Journal for Numerical Methods in Engineering > 121 > 13 > 2979 - 3003

We propose a method to solve the acoustic wave equation on an immersed domain using the hybridizable discontinuous Galerkin method for spatial discretization and the arbitrary derivative method with local time stepping (LTS) for time integration. The method is based on a cut finite element approach of high order and uses level set functions to describe curved immersed interfaces. We study under which...

article

On the role of (weak) compressibility for fluid‐structure interaction solvers

Andrea La Spina, Christiane Förster, Martin Kronbichler, Wolfgang A. Wall

International Journal for Numerical Methods in Fluids > 92 > 2 > 129 - 147

In the present study, a weakly compressible formulation of the Navier‐Stokes equations is developed and examined for the solution of fluid‐structure interaction (FSI) problems. Newtonian viscous fluids under isothermal conditions are considered, and the Murnaghan‐Tait equation of state is employed for the evaluation of mass density changes with pressure. A pressure‐based approach is adopted to handle...

article

Modern discontinuous Galerkin methods for the simulation of transitional and turbulent flows in biomedical engineering: A comprehensive LES study of the FDA benchmark nozzle model

Niklas Fehn, Wolfgang A. Wall, Martin Kronbichler

International Journal for Numerical Methods in Biomedical Engineering > 35 > 12 > n/a - n/a

This work uses high‐order discontinuous Galerkin discretization techniques to simulate transitional and turbulent flows through medical devices. Flows through medical devices are characterized by moderate Reynolds numbers and typically involve different flow regimes such as laminar, transitional, and turbulent flows. Previous studies for the FDA benchmark nozzle model revealed limitations of Reynolds‐averaged...

article

High‐order DG solvers for underresolved turbulent incompressible flows: A comparison of L² and H(div) methods

Niklas Fehn, Martin Kronbichler, Christoph Lehrenfeld, Gert Lube, more

International Journal for Numerical Methods in Fluids > 91 > 11 > 533 - 556

The accurate numerical simulation of turbulent incompressible flows is a challenging topic in computational fluid dynamics. For discretisation methods to be robust in the underresolved regime, mass conservation and energy stability are key ingredients to obtain robust and accurate discretisations. Recently, two approaches have been proposed in the context of high‐order discontinuous Galerkin (DG)...

article

A multiscale approach to hybrid RANS/LES wall modeling within a high‐order discontinuous Galerkin scheme using function enrichment

Benjamin Krank, Martin Kronbichler, Wolfgang A. Wall

International Journal for Numerical Methods in Fluids > 90 > 2 > 81 - 113

We present a novel approach to hybrid Reynolds‐averaged Navier‐Stokes (RANS)/ large eddy simulation (LES) wall modeling based on function enrichment, which overcomes the common problem of the RANS‐LES transition and enables coarse meshes near the boundary. While the concept of function enrichment as an efficient discretization technique for turbulent boundary layers has been proposed in an earlier...

article

eXtended hybridizable discontinuous Galerkin for incompressible flow problems with unfitted meshes and interfaces

Ceren Gürkan, Martin Kronbichler, Sonia Fernández‐Méndez

International Journal for Numerical Methods in Engineering > 117 > 7 > 756 - 777

The eXtended hybridizable discontinuous Galerkin (X‐HDG) method is developed for the solution of Stokes problems with void or material interfaces. X‐HDG is a novel method that combines the hybridizable discontinuous Galerkin (HDG) method with an eXtended finite element strategy, resulting in a high‐order, unfitted, superconvergent method, with an explicit definition of the interface geometry by means...

article

A matrix‐free high‐order discontinuous Galerkin compressible Navier‐Stokes solver: A performance comparison of compressible and incompressible formulations for turbulent incompressible flows

Niklas Fehn, Wolfgang A. Wall, Martin Kronbichler

International Journal for Numerical Methods in Fluids > 89 > 3 > 71 - 102

Both compressible and incompressible Navier‐Stokes solvers can be used and are used to solve incompressible turbulent flow problems. In the compressible case, the Mach number is then considered as a solver parameter that is set to a small value, M ≈0.1, in order to mimic incompressible flows. This strategy is widely used for high‐order discontinuous Galerkin (DG) discretizations of the compressible...

article

Robust and efficient discontinuous Galerkin methods for under-resolved turbulent incompressible flows

Niklas Fehn, Wolfgang A. Wall, Martin Kronbichler

Journal of Computational Physics > 2018 > 372 > C > 667-693

We present a robust and accurate discretization approach for incompressible turbulent flows based on high-order discontinuous Galerkin methods. The DG discretization of the incompressible Navier–Stokes equations uses the local Lax–Friedrichs flux for the convective term, the symmetric interior penalty method for the viscous term, and central fluxes for the velocity–pressure coupling terms. Stability...

article

Matrix‐Free Locally Adaptive Finite Element Solution of Density‐Functional Theory With Nonorthogonal Orbitals and Multigrid Preconditioning

Denis Davydov, Timo Heister, Martin Kronbichler, Paul Steinmann

physica status solidi (b) > 255 > 9 > n/a - n/a

In this paper, we propose a new numerical method to find the ground state energy of a given physical system within the Kohn–Sham density functional theory. The h‐adaptive finite element method is adopted for spatial discretization and implemented with matrix‐free operator evaluation. The ground state energy is found by performing unconstrained minimization with non‐orthogonal orbitals using the limited...

article

Functional magnetic resonance imaging under anaesthesia of a patient with severe chronic disorders of consciousness

Betty Wutzl, Axel Friedrich Unterrainer, Martin Kronbichler, Frank Rattay, more

Clinical Neurology and Neurosurgery > 2018 > 172 > C > 96-98

We report on a 19-year old male patient who is recovering from near-drowning. The patient was admitted for re-evaluation in a Minimally Conscious State.A regular functional Magnetic Resonance Imaging was not possible due to complex motor tics of the patient with sudden flexion and extension movements of arms and legs as well as opisthotonic retroflexion of the head and trunk. Thus, the patient was...

article

Efficiency of high‐performance discontinuous Galerkin spectral element methods for under‐resolved turbulent incompressible flows

Niklas Fehn, Wolfgang A. Wall, Martin Kronbichler

International Journal for Numerical Methods in Fluids > 88 > 1 > 32 - 54

The present paper addresses the numerical solution of turbulent flows with high‐order discontinuous Galerkin methods for discretizing the incompressible Navier‐Stokes equations. The efficiency of high‐order methods when applied to under‐resolved problems is an open issue in the literature. This topic is carefully investigated in the present work by the example of the three‐dimensional Taylor‐Green...

article

Direct Numerical Simulation of Flow over Periodic Hills up to ReH=10,595 $\text {Re}_{H}= 10{,}595$

Benjamin Krank, Martin Kronbichler, Wolfgang A. Wall

Flow, Turbulence and Combustion > 2018 > 101 > 2 > 521-551

We present fully resolved computations of flow over periodic hills at the hill-Reynolds numbers ReH=5,600 $\text {Re}_{H}= 5{,}600$ and ReH=10,595 $\text {Re}_{H}= 10{,}595$ with the highest fidelity to date. The calculations are performed using spectral incompressible discontinuous Galerkin schemes of 8th $8^{\text {th}}$ and 7th $7^{\text {th}}$ order spatial accuracy, 3rd $3^{\text {rd}}$ order temporal...

article

An adaptive hybridizable discontinuous Galerkin approach for cardiac electrophysiology

Julia M. Hoermann, Cristóbal Bertoglio, Martin Kronbichler, Martin R. Pfaller, more

International Journal for Numerical Methods in Biomedical Engineering > 34 > 5 > n/a - n/a

Cardiac electrophysiology simulations are numerically challenging because of the propagation of a steep electrochemical wave front and thus require discretizations with small mesh sizes to obtain accurate results. In this work, we present an approach based on the hybridizable discontinuous Galerkin method (HDG), which allows an efficient implementation of high‐order discretizations into a computational...

article

Arbitrary High-Order Explicit Hybridizable Discontinuous Galerkin Methods for the Acoustic Wave Equation

Svenja Schoeder, Martin Kronbichler, Wolfgang A. Wall

Journal of Scientific Computing > 2018 > 76 > 2 > 969-1006

We propose a new formulation of explicit time integration for the hybridizable discontinuous Galerkin (HDG) method in the context of the acoustic wave equation based on the arbitrary derivative approach. The method is of arbitrary high order in space and time without restrictions such as the Butcher barrier for Runge–Kutta methods. To maintain the superconvergence property characteristic for HDG spatial...

article

The Importance of the Left Occipitotemporal Cortex in Developmental Dyslexia

Lisa Kronbichler, Martin Kronbichler

Current Developmental Disorders Reports > 2018 > 5 > 1 > 1-8

Purpose of Review Developmental dyslexia is characterized by an impaired acquisition of fluent and skilled reading ability. Numerous studies have explored the neural correlates of this neurodevelopmental disorder, with most classic accounts strongly focussing on left temporoparietal regions. We will review recent findings from structural and functional MRI studies that suggest a more important role...

article

On the stability of projection methods for the incompressible Navier–Stokes equations based on high-order discontinuous Galerkin discretizations

Niklas Fehn, Wolfgang A. Wall, Martin Kronbichler

Journal of Computational Physics > 2017 > 351 > C > 392-421

The present paper deals with the numerical solution of the incompressible Navier–Stokes equations using high-order discontinuous Galerkin (DG) methods for discretization in space. For DG methods applied to the dual splitting projection method, instabilities have recently been reported that occur for small time step sizes. Since the critical time step size depends on the viscosity and the spatial resolution,...

Publication date

Last year (3)
Last 3 years (3)

Close

Date range setting

Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.

From:

To:
Set your own date range

INFONA - science communication portal

Search results for: Martin Kronbichler

On the role of tissue mechanics in fluid–structure interaction simulations of patient‐specific aortic dissection

Loss, gain and choice difficulty in gambling patients: Neural and behavioural processes

Recognition and perception of emotions in juvenile myoclonic epilepsy

A matrix‐free approach for finite‐strain hyperelastic problems using geometric multigrid

High‐order cut discontinuous Galerkin methods with local time stepping for acoustics

On the role of (weak) compressibility for fluid‐structure interaction solvers

Modern discontinuous Galerkin methods for the simulation of transitional and turbulent flows in biomedical engineering: A comprehensive LES study of the FDA benchmark nozzle model

High‐order DG solvers for underresolved turbulent incompressible flows: A comparison of L² and H(div) methods

A multiscale approach to hybrid RANS/LES wall modeling within a high‐order discontinuous Galerkin scheme using function enrichment

eXtended hybridizable discontinuous Galerkin for incompressible flow problems with unfitted meshes and interfaces

A matrix‐free high‐order discontinuous Galerkin compressible Navier‐Stokes solver: A performance comparison of compressible and incompressible formulations for turbulent incompressible flows

Robust and efficient discontinuous Galerkin methods for under-resolved turbulent incompressible flows

Matrix‐Free Locally Adaptive Finite Element Solution of Density‐Functional Theory With Nonorthogonal Orbitals and Multigrid Preconditioning

Functional magnetic resonance imaging under anaesthesia of a patient with severe chronic disorders of consciousness

Efficiency of high‐performance discontinuous Galerkin spectral element methods for under‐resolved turbulent incompressible flows

Direct Numerical Simulation of Flow over Periodic Hills up to ReH=10,595 $\text {Re}_{H}= 10{,}595$

An adaptive hybridizable discontinuous Galerkin approach for cardiac electrophysiology

Arbitrary High-Order Explicit Hybridizable Discontinuous Galerkin Methods for the Acoustic Wave Equation

The Importance of the Left Occipitotemporal Cortex in Developmental Dyslexia

On the stability of projection methods for the incompressible Navier–Stokes equations based on high-order discontinuous Galerkin discretizations

Filter options

Publication date

Publication type

Keywords

Data set

Journal

INFONA - science communication portal

Search results for: Martin Kronbichler

Add recipient

Sending message cancelled

Are you sure you want to cancel sending this message?

Send message

Filter options

Publication date

Date range setting

Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.

Publication type

Keywords

Data set

Journal

Reporting an error / abuse

Sending the report failed

Accessibility options