Software for Modeling Flows with Large Deformations
Developing of Three-Dimensional Code for Flows with Large Deformations Modeling Using Irregular Grids
Tech Area / Field
- INF-COM/High Performance Computing and Networking/Information and Communications
- PHY-NGD/Fluid Mechanics and Gas Dynamics/Physics
8 Project completed
Senior Project Manager
Alexandrov K A
VNIITF, Russia, Chelyabinsk reg., Snezhinsk
- Institute of Mathematical Modelling, Russia, Moscow
- Universität Hannover / Institut für Werkstoffkunde, Germany, Hannover\nFOA, Sweden, Stockholm
Project summaryThe continuous increasing power of modern computers leads to arising of new problems in computer modeling. One of the most difficult ones is the problem of producing codes, which may be used for a wide class of problems simulating without special knowledge of numerical mathematics. The main difficulties in modeling appear usually while one tries to simulate flows with large deformations in moving grid. These difficulties are connected with the well-known fact, that in such kind of flows lagrangian volumes, which were close one to another may in some time appear to be very far one from another. Thus commonly used lagrangian methods on regular grids can’t be used without special methods of grid reconstructing. Euler methods are free from this drawback, but their usage for simulating are restricted to the flows, in which one type of matter is present. To model more complicated flows one may use different techniques, such as multigrid methods, methods with concentration and so on. Only a person, who understands their restrictions and has a significant experience in modeling, may use all these techniques, otherwise the result could be unpredictable. Often the lagrangian irregular grid methods (such as tetrahedral finite element methods) are used for flows with large deformations modeling. These methods may be applied to a wider class of problems, but the genetic drawback of lagrangian methods (that is the ability of close lagrangian point to move far one from another) is not overcame in them.
This proposal is devoted to the development of a perspective three-dimensional method for flows with large deformations modeling.
It is the irregular grid method, based on the presentation of the flow region by the Voronoi cells. Such methods were first elaborated by Prof. Sofronov et al. Then, after a long delay, these methods were discussed at the conference on Free Lagrangian Methods in Albuquerque, NM, 1984. After that conference these methods received the name: «Free Lagrangian Methods». These methods allow lagrangian point to move free, and after each time step the Voronoi grid is reconstructed according to the actual disposition of the points. The main drawback of these methods was the large non-monotonicity of the receiving numerical solution.
In 1996-1997 the group from Russian Federal Nuclear Center – All-Russian Institute for Technical Physics (RFNC-VNIITF), Snezhinsk with the support of Lawrence Livermore National Laboratory, created 2D Irregular Grid Code (IGM), based on Voronoi grid. The difference scheme of TVD type, which was used there, led to monotonicity of the solution received. IGM code contains the explicit gas dynamic solver, implicit heat transfer solver, and implicit Maxwell equation solver. General algorithms of 2D grid constructing and reconstructing have been implemented.
The work, proposed in this paper will be the generalization of the created 2D code.