t8code - the open-source library for extremely efficient simulations with adaptive grids
t8code - the open-source library for extremely efficient simulations with adaptive grids
Geometric representation of scalable adaptive meshes
Advection of a concentration around a cylinder. The underlying hybrid mesh is adaptively refined and fed with data from the underlying geometry. In this way, it will better represent the geometry with each new level of refinement.
Aircraft geometry created using the t8code software library
The aeroplane geometry is meshed with curved tetrahedral elements. The elements on level 0 show the curved input grid. A 1:8 refinement takes place between each ascending level. A level 2 refinement plane moves along the axis of the aircraft, demonstrating the adaptivity of the grid management.
A representation of mantle convection on Mars using the GAIA framework. a) The original data. The cold temperature is shown in blue, the hot regions in red. b) The adaptive mesh resulting from the original data set. As the variance increases, the cells are refined more often, so that we see finer resolution at the boundaries between hot and cold regions. The coarse cells are refined up to 6 times depending on the variance of the data associated with each cell. c) Data interpolation of the original dataset onto the adaptive network.
t8code is a software library for efficient management of dynamic adaptive grids and data on them. Any simulation software that uses grids can benefit from t8code as a plugin, because it supports and enhances various simulation applications. t8code is very general-purpose because it supports just about any grid needed by numerical simulation software.
the software library t8code enables efficient management of dynamic adaptive grids and data on them
t8code extends successful technologies, which were previously only available for quadrilateral and hexahedral grids, to general element shapes
the software library can be used as a tool for all simulation codes
t8code scales on supercomputers and significantly reduces computation times
t8code is developed at the DLR Institute for Software Technology with the participation of the University of Bonn
t8code (written in lower case and pronounced "tetcode") is a software library for efficient management of dynamic adaptive grids and data on them. Any simulation software that uses grids can benefit from t8code as a plugin, because it supports and enhances various simulation applications. t8code is very general-purpose because it supports just about any grid needed by numerical simulation software.
t8code is being developed by the department of High-Performance Computing at the Institute for Software Technology, with the participation of the University of Bonn. At the German Aerospace Center (DLR), t8code is already successfully used in several projects. The current areas of application range from earth system modeling and the simulation of atmospheric chemistry to the improvement of 3D printing processes.
Aircraft cross section modelled with scalable adaptive meshes
The animation shows the cross section of an aircraft modelled using the t8code software library. The software library supports the efficient management of dynamically adaptive grids and the data on them. t8code enhances various simulation applications as a plug-in and can be used for any simulation software that uses grids.
Computer simulations of weather forecasts, climate models, or flows often use grids as the basis for calculations. The computational domain is first divided into a grid of different geometric shapes such as triangles, quadrilaterals, hexahedra, or tetrahedra. The finer the resolution of this grid, the more accurate the results of the simulation.
Adaptive grids in a simulation of flows in the Earth's atmosphere
By refining and coarsening the calculation cells, computing time and memory requirements can be significantly reduced.
However, finer resolution also increases computation time and memory requirements. A grid can be called adaptive when they selectively refine only in places where fine resolution is needed, and remain coarser in other places. Grid refinement is useful in the example of a weather simulation along a cold front. If the grid resolution changes during the simulation - the cold front moves - this is called dynamic adaptive grids. The subdivision into fine and coarse computational domains allows to deal extremely efficiently with the available computational capacity.
t8code extends successful technologies
The simulation was performed with the CFD code Trixi.jl. The framework was extended with the so-called three-equation model. The model includes a simplified two-phase flow of the Baer-Nunziato equations for compressible multiphase fluids. The simulation shown is the result of a joint research project between DLR and the University of Cologne. The aim is to develop and implement computer models for sloshing dynamics in liquid hydrogen tanks on moving platforms such as cars, ships and aircraft. Particular emphasis is placed on the most detailed resolution possible of the boundary layer between the gas and liquid phases. This is achieved using an adaptive grid from t8code that dynamically adapts to the changing boundary layer.
2D tank sloshing simulation in a moving circular tank
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2D tank sloshing simulation in a moving circular tank
The simulation was performed with the CFD code Trixi.jl. The framework was extended with the so-called three-equation model. The model includes a simplified two-phase flow of the Baer-Nunziato equations for compressible multiphase fluids. The simulation shown is the result of a joint research project between DLR and the University of Cologne. The aim is to develop and implement computer models for sloshing dynamics in liquid hydrogen tanks on moving platforms such as cars, ships and aircraft. Particular emphasis is placed on the most detailed resolution possible of the boundary layer between the gas and liquid phases. This is achieved using an adaptive grid from t8code that dynamically adapts to the changing boundary layer.
t8code is extremely efficient and works even with the extremely large processor counts of current supercomputers. In practical applications with up to one million parallel processes and grids with more than one trillion (10 to the power of 12) elements, t8code has demonstrated its efficiency. t8code achieves this efficiency by using a tree-based approach with the help of space-filling curves. These data structures are both highly computationally and memory efficient and geometrically very flexible. t8code extends this successful technology, which was previously only available for quadrilateral and hexahedral lattices, to general element shapes. Thus, t8code in 3D supports the particularly frequently used shapes tetrahedron, hexahedron, prisms and pyramids and also allows the combination of different shapes within one grid.
Potential for the industry
t8code is ideally suited as a scalable alternative to the unstructured grids commonly used in industry. t8code promises shorter runtimes - and thus lower costs - better resolutions, and universally applicable code for simulation software.
