127 citations · 764 across the 38 of their papers we have counts for
42 papers
Code Generation and Performance Engineering for Matrix-Free Finite Element Methods on Hybrid Tetrahedral Grids
Fabian Böhm, Daniel Bauer, Nils Kohl +5
This paper introduces a code generator designed for node-level optimized, extreme-scalable, matrix-free finite element operators on hybrid tetrahedral grids. It optimizes the local…
waLBerla-wind: a lattice-Boltzmann-based high-performance flow solver for wind energy applications
Helen Schottenhamml, Ani Anciaux-Sedrakian, Frédéric Blondel +2
This article presents the development of a new wind turbine simulation software to study wake flow physics. To this end, the design and development of waLBerla-wind, a new simulato…
Development of a central-moment phase-field lattice Boltzmann model for thermocapillary flows: Droplet capture and computational performance
Markus Holzer, Travis Mitchell, Christopher R. Leonardi +1
This study develops a computationally efficient phase-field lattice Boltzmann model with the capability to simulate thermocapillary flows. The model was implemented into the open-s…
Generalized Golub-Kahan bidiagonalization for nonsymmetric saddle point systems
Andrei Dumitrasc, Carola Kruse, Ulrich Ruede
The generalized Golub-Kahan bidiagonalization has been used to solve saddle-point systems where the leading block is symmetric and positive definite. We extend this iterative metho…
Deflation for the off-diagonal block in symmetric saddle point systems
Andrei Dumitrasc, Carola Kruse, Ulrich Ruede
Deflation techniques are typically used to shift isolated clusters of small eigenvalues in order to obtain a tighter distribution and a smaller condition number. Such changes induc…
Analysis and comparison of boundary condition variants in the free-surface lattice Boltzmann method
Christoph Schwarzmeier, Ulrich Rüde
The accuracy of the free-surface lattice Boltzmann method (FSLBM) depends significantly on the boundary condition employed at the free interface. Ideally, the chosen boundary condi…
Comparison of free-surface and conservative Allen-Cahn phase-field lattice Boltzmann method
Christoph Schwarzmeier, Markus Holzer, Travis Mitchell +3
This study compares the free-surface lattice Boltzmann method (FSLBM) with the conservative Allen-Cahn phase-field lattice Boltzmann method (PFLBM) in their ability to model two-ph…
A decoupled numerical method for two-phase flows of different densities and viscosities in superposed fluid and porous layers
Yali Gao, Daozhi Han, Xiaoming He +1
In this article we consider the numerical modeling and simulation via the phase field approach of two-phase flows of different densities and viscosities in superposed fluid and por…
Densification of Single-Walled Carbon Nanotube Films: Mesoscopic Distinct Element Method Simulations and Experimental Validation
Grigorii Drozdov, Igor Ostanin, Hao Xu +10
Nanometer thin single-walled carbon nanotube (CNT) films collected from the aerosol chemical deposition reactors have gathered attention for their promising applications. Densifica…
An improved lattice Boltzmann D3Q19 method based on an alternative equilibrium discretization
Martin Bauer, Ulrich Rüde
Lattice Boltzmann simulations of three-dimensional, isothermal hydrodynamics often use either the D3Q19 or the D3Q27 velocity sets. While both models correctly approximate Navier-S…
Direct simulation of liquid-gas-solid flow with a free surface lattice Boltzmann method
Simon Bogner, Jens Harting, Ulrich Rüde
Direct numerical simulation of liquid-gas-solid flows is uncommon due to the considerable computational cost. As the grid spacing is determined by the smallest involved length scal…
A stencil scaling approach for accelerating matrix-free finite element implementations
Simon Bauer, Daniel Drzisga, Marcus Mohr +3
We present a novel approach to fast on-the-fly low order finite element assembly for scalar elliptic partial differential equations of Darcy type with variable coefficients optimiz…
A Scalable Multiphysics Algorithm for Massively Parallel Direct Numerical Simulations of Electrophoresis
Dominik Bartuschat, Ulrich Rüde
In this article we introduce a novel coupled algorithm for massively parallel direct numerical simulations of electrophoresis in microfluidic flows. This multiphysics algorithm emp…
Extreme-Scale Block-Structured Adaptive Mesh Refinement
Florian Schornbaum, Ulrich Rüde
In this article, we present a novel approach for block-structured adaptive mesh refinement (AMR) that is suitable for extreme-scale parallelism. All data structures are designed su…
A comparative study of fluid-particle coupling methods for fully resolved lattice Boltzmann simulations
Christoph Rettinger, Ulrich Rüde
The direct numerical simulation of particulate systems offers a unique approach to study the dynamics of fluid-solid suspensions by fully resolving the submerged particles and with…
On the analysis of block smoothers for saddle point problems
Lorenz John, Ulrich Rüde, Barbara Wohlmuth +1
In this article, we discuss several classes of Uzawa smoothers for the application in multigrid methods in the context of saddle point problems. Beside commonly used variants, such…
Research and Education in Computational Science and Engineering
Ulrich Rüde, Karen Willcox, Lois Curfman McInnes +30
Over the past two decades the field of computational science and engineering (CSE) has penetrated both basic and applied research in academia, industry, and laboratories to advance…
A two-scale approach for efficient on-the-fly operator assembly in massively parallel high performance multigrid codes
Simon Bauer, Marcus Mohr, Ulrich Rüde +3
Matrix-free finite element implementations of massively parallel geometric multigrid save memory and are often significantly faster than implementations using classical sparse matr…
Highly sparse surface couplings for subdomain-wise isoviscous Stokes finite element discretizations
Markus Huber, Ulrich Rüde, Christian Waluga +1
The Stokes system with constant viscosity can be cast into different formulations by exploiting the incompressibility constraint. For instance the strain in the weak formulation ca…
Microswimming with inertia
Jayant Pande, Kristina Pickl, Oleg Trosman +2
Microswimmers, especially in theoretical treatments, are generally taken to be completely inertia-free, since inertial effects on their motion are typically small and assuming thei…
A Python Extension for the Massively Parallel Multiphysics Simulation Framework waLBerla
Martin Bauer, Florian Schornbaum, Christian Godenschwager +4
We present a Python extension to the massively parallel HPC simulation toolkit waLBerla. waLBerla is a framework for stencil based algorithms operating on block-structured grids, w…
Solution Techniques for the Stokes System: A priori and a posteriori modifications, resilient algorithms
Markus Huber, Lorenz John, Petra Pustejovska +3
This article proposes modifications to standard low order finite element approximations of the Stokes system with the goal of improving both the approximation quality and the paral…
A quantitative performance analysis for Stokes solvers at the extreme scale
Björn Gmeiner, Markus Huber, Lorenz John +2
This article presents a systematic quantitative performance analysis for large finite element computations on extreme scale computing systems. Three parallel iterative solvers for…
Curvature estimation from a volume of fluid indicator function for the simulation of surface tension and wetting with a free surface lattice Boltzmann method
Simon Bogner, Ulrich Rüde, Jens Harting
The free surface lattice Boltzmann method (FSLBM) is a combination of the hydrodynamic lattice Boltzmann method (LBM) with a volume of fluid (VOF) interface apturing technique for…