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GPU-accelerated LBM-VOF two-phase flow simulations with grid refinement
Citation Link: https://doi.org/10.15480/882.2049
Publikationstyp
Conference Presentation
Date Issued
2017-05
Sprache
English
Author(s)
Institut
TORE-DOI
TORE-URI
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 inter-
grid 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.
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 inter-
grid 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.
Subjects
Lattice Boltzmann Method
Grid Refinement Scheme
Volume of Fluid Interface Capturing Method
Free Surface Flows
Wave Propagation
GPU Computing with Nvidia CUDA
DDC Class
620: Ingenieurwissenschaften
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