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Item type:Publication, Access status: with files , GPU-accelerated LBM-VOF two-phase flow simulations with grid refinement(2017-05); ; ; The contribution is devoted to a novel grid refinement technique for GPU-accelerated Lattice Boltzmann Method (LBM) dedicated to free surface flow simulations in marine applications. LBM implementations are mostly based on homogeneous isotropic Cartesian discretizations of the computational domain. Challenges occur when a refined spatial and temporal resolution is locally required. To efficiently address this demand, local grid refinement is often deployed to regions featuring small scale structures and effects to be resolved. Within the LBM the spatial and temporal discretizations are strongly coupled. Hence, LBM solvers featuring local grid refinement are suitable for the simulation of transient, turbulent and free surface flows. The present LBM involves a Volume of Fluid (VOF) strategy to model two-phase flows. Herein, the advection of a mixture volume fraction serves to advance the free-surface in time. The employed grid refinement is based on overlapping grids with different resolution. The bidirectional information exchange between the grids is managed via bi[tri]-linear interpolations for two[three]-dimensional simulations. For single-phase flows this synchronisation step comprises the exchange of LBM specific variables solely. When attention is directed to two-phase flows, the intergrid coupling of the mixture fraction poses a special algorithmic problem. The suggested coupling approach is based on a Piecewise Linear Interface Construction (PLIC) method. Accordingly, the information about the surfaces orientation and position is employed to compute the fill level more accurate within the overlapping regimes. Examples included refer to two- and three-dimensional test cases and reveal that the proposed method is able to reproduce accurate results at fairly moderate computational effort.Publicationtype: Conference Presentation387 440 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Towards online visualization and interactive monitoring of real-time CFD simulations on commodity hardware(Multidisciplinary Digital Publishing Institute (MDPI), 2015-09-11); ; Real-time rendering in the realm of computational fluid dynamics (CFD) in particular and scientific high performance computing (HPC) in general is a comparably young field of research, as the complexity of most problems with practical relevance is too high for a real-time numerical simulation. However, recent advances in HPC and the development of very efficient numerical techniques allow running first optimized numerical simulations in or near real-time, which in return requires integrated and optimized visualization techniques that do not affect performance. In this contribution, we present concepts, implementation details and several application examples of a minimally-invasive, efficient visualization tool for the interactive monitoring of 2D and 3D turbulent flow simulations on commodity hardware. The numerical simulations are conducted with ELBE, an efficient lattice Boltzmann environment based on NVIDIA CUDA (Compute Unified Device Architecture), which provides optimized numerical kernels for 2D and 3D computational fluid dynamics with fluid-structure interactions and turbulence.Publicationtype: Journal ArticleScopus© Citations 5 394 533 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Validation of the GPU-accelerated CFD solver ELBE for free surface flow problems in civil and environmental engineering(Multidisciplinary Digital Publishing Institute (MDPI), 2015-07-07); ; ; ; This contribution is dedicated to demonstrating the high potential and manifold applications of state-of-the-art computational fluid dynamics (CFD) tools for free-surface flows in civil and environmental engineering. All simulations were performed with the academic research code ELBE (efficient lattice boltzmann environment, http://www.tuhh.de/elbe). The ELBE code follows the supercomputing-on-the-desktop paradigm and is especially designed for local supercomputing, without tedious accesses to supercomputers. ELBE uses graphics processing units (GPU) to accelerate the computations and can be used in a single GPU-equipped workstation of, e.g., a design engineer. The code has been successfully validated in very different fields, mostly related to naval architecture and mechanical engineering. In this contribution, we give an overview of past and present applications with practical relevance for civil engineers. The presented applications are grouped into three major categories: (i) tsunami simulations, considering wave propagation, wave runup, inundation and debris flows; (ii) dam break simulations; and (iii) numerical wave tanks for the calculation of hydrodynamic loads on fixed and moving bodies. This broad range of applications in combination with accurate numerical results and very competitive times to solution demonstrates that modern CFD tools in general, and the ELBE code in particular, can be a helpful design tool for civil and environmental engineers.Publicationtype: Journal ArticleScopus© Citations 35 282 296 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Prediction of cavitation erosion for marine applicationsThe paper presents the development of a cavitation erosion prediction method. The approach is tailored to marine applications and embedded into a VoF-based procedure for the simulation of turbulent flows. Supplementary to the frequently employed Euler-Euler models, Euler-Lagrange approaches are employed to simulate cavitation. The study aims to convey the merits of an Euler-Lagrange approach for erosion simulations. Accordingly, the erosion model is able to separate different damage mechanisms, e.g. micro-jets, single and collective bubble collapse, and also quantifies their contribution to the total damage. Emphasis is devoted to the prediction of the cavitation extend, the influence of compressible effects and the performance of the material damage model in practical applications. Examples included refer to 2D validation test cases and reveal a fair predictive accuracy.Publicationtype: Journal ArticleScopus© Citations 1 274 309 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Forschungsschwerpunkt Maritime Systeme - Zukunft gestalten - Forschung und wissenschaftliche Ausbildung(Forschungsschwerpunkt Maritime Systeme der TUHH, 2014-08); ; ; ; Brochure of the Research Cluster Maritime Systems on the research orientation of the participating institutes.Publicationtype: Book1342 2118 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Fünfter Interdisziplinärer Workshop Maritime Systeme : aktuelle Ergebnisse aus laufenden Promotionsprojekten an der TUHH(Forschungsschwerpunkt Maritime Systeme der TUHH, 2014-02-02); ; ; Florian Tietze, Hermann Lödding Produktivitätsanalyse in der Unikatfertigung mit mobilen Endgeräten Wolfgang Fricke, Bjarne Gerlach, Matthias Guiard Investigation on the load carrying behaviour of windows subjected to dynamic loads Xiaojing Luo, Thomas Rung Viscous Multi-Body Hydrodynamics for Offshore Applications David Osthoff Numerical Simulation of Ship Collision with Gravity Base Foundation of Offshore Wind Turbine Edwin Kreuzer, Eugen Solowjow, Gang Qiu, Thorben Hamann, Jürgen Grabe Leg-Seabed Interactions of Jack-Up Vessels Marcel König, Eyke Höft, Alexander Düster Numerical Simulation of the Berthing Manoeuvre of Service Vessels to Offshore Wind Turbine Plants Daniel Ferreira González Numerical Simulations of Ship Motions during Landing Manoeuvres at Offshore Wind Turbine Plants Philipp Sebastian Halata, Axel Friedewald, Hermann Lödding Ein szenariobezogenes Auswahlverfahren für Augmented-Reality-Komponenten Hendrik Dankowski Fast Numerical Calculation Methods for the Investigation of Real Ship AccidentsPublicationtype: Conference Proceedings2499 1251 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Viscous-Inviscid Coupling Methods for Advanced Marine Propeller Applications(Hindawi Publishing Corporation, 2012); ; ; The paper reports the development of coupling strategies between an inviscid direct panel method and a viscous RANS method and their application to complex propeller ows. The work is motivated by the prohibitive computational cost associated to unsteady viscous flow simulations using geometrically resolved propellers to analyse the dynamics of ships in seaways. The present effort aims to combine the advantages of the two baseline methods in order to reduce the numerical effort without compromising the predictive accuracy. Accordingly, the viscous method is used to calculate the global flow field, while the inviscid method predicts the forces acting on the propeller. The corresponding reaction forces are employed as body forces to mimic the propeller influence on the viscous flow field. Examples included refer to simple verification cases for an isolated propeller blade, open-water validation simulations for a complete propeller, and more challenging investigations of a manoeuvring vessel in seaways. Reported results reveal a fair predictive agreement between the coupled approach and fully viscous simulations and display the efficiency of the coupled approach.Publicationtype: Journal ArticleScopus© Citations 14 366 559