/ALE/GRID
Block Format Keyword This card enables you to define grid formulation for ALE modeling. ALE domain can have moving boundaries.
Grid must also be updated on each cycle to map the new geometrical domain. This update is not unique and can be arbitrary. Grid points are updated on each cycle depending on formulation type provided by you.
Format
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
|---|---|---|---|---|---|---|---|---|---|
| /ALE/GRID/FormulationType | |||||||||
Definitions
- Formulation Type
- Description
- ZERO
- Grid is not updated.
- DONEA
- Donea Formulation.
- DISP
- Average Displacement.
- SPRING
- Spring are introduced on cell edges to avoid locally small mesh size.
- STANDARD
- Advanced formulation with edge spring and anti-shear spring to avoid small mesh size and flat cells.
Comments
- ALE formulation is activated for a given material using /ALE/MAT card.
- By default grid velocity is not computed. This is equivalent to /ALE/GRID/ZERO. This formulation also enables to switch to an Eulerian formulation.
- The purpose of grid formulation is to
update grid points with evolution of the ALE
domain caused by moving boundaries (illustrated
below). Grid velocities are also computed with a
dependency on Lagrangian node velocities. Material
inside the domain is not affected since it is
remapped inside the new grid configuration at each
cycle. Some domain evolution may lead to small
cell and then numerical strategies can be
introduced to prevent time step to decrease
(example:/ALE/GRID/STANDARD).
Figure 1. - Specific rules for grid velocity of given points can also be defined by introducing links (/ALE/LINK/VEL). This enables to link grid velocity to specific master nodes.
- A given point from ALE domain can be defined as a Lagrangian node (/ALE/BCS).
- A given grid point can be fixed in all or specific directions (/ALE/BCS).
- To fix material at a given point in a specified direction (/BCS).