Improved accuracy general remapping algorithm
Most numerical methods in fluid dynamics can be classified as being either Lagrangian or Eulerian. An important group of methods, however, is a combination of both. These methods generally derive from the ALE (Arbitrary-Lagrangian-Eulerian) method of Hirt et al. A computational cycle in these methods is divided into two main phases: a lagrangian phase and a rezone or remap phase (these two terms are used interchangeably). The remapping phase conservtively transfers quantities, calculated in the Lagrangian phase, from the Lagrangian mesh to some other specified mesh. For example, in a given time step the remap phase may be omitted, in which case the computation is purely Lagrangian, or the remapping may be back to the original mesh, in which case the computation is Eulerian. The remapping step, therefore, corresponds to the effect of the advection terms in Eulerian equations. It may also be viewed as a conservative interpolation procedure from one mesh to another, and so it is also useful in other more general applications, such as in adaptive mesh computations. In this paper a new method is extended to the case of a more accurate density distribution: the density distribution within a cell is allowed to be linear, while preserving the average value of density over the cell. The orientation of this planar surface is given by the average local density gradient. Such a linear distribution, while more accurate in general, can cause undershoots or overshoots in regions of rapidly changing densities. This is avoided by placing monotonicity limits on the allowable gradients, similar to those used by Van Leer in one-dimension.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 6894571
- Report Number(s):
- LA-UR-83-3549; CONF-840650-1; ON: DE84004320
- Resource Relation:
- Conference: 9. international conference on numerical methods in fluid dynamics, Saclay, France, 25 Jun 1984
- Country of Publication:
- United States
- Language:
- English
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