Description

ALE Starter section contains a description of the keywords used in ALE applications.

Usual RADIOSS keywords will act on material at related grid points. All the parameters starting with /ALE will directly act on the grid points.

To activate ALE formulation with a given material law, add:

 

ALE formulation requires defining a grid formulation:

 

The Eulerian formulation can be defined in two ways. In this case, grid points remain fixed.

 

A modeling problem is well posed with boundary conditions on both material and grid velocities:

It is also possible to define Lagrangian nodes within an ALE part by using /ALE/BCS or merging a Lagrangian element.

Define links on grid velocities with:

This is often used in FSI modeling to window a moving free structure with an ALE grid. For example in ditching, a limited ALE domain can be linked to free interfaced structure. The advantage is that the water and air inlets are constant, since it is initial state with no material velocity.

 

To define inlet/outlet:

 

The initial velocity for material located at grid point is defined with:

 

The specific ALE interfaces are:

 

There are six material laws only compatible with ALE or EULER formulation:

Multi-material laws

Multi-Phase material law

Boundary material law

Thermal law

Besides the above ALE materials, the following material laws can be used in ALE/EULER analysis: LAW2, LAW3, LAW4, LAW5, LAW6, LAW10, LAW11, LAW16, LAW21, LAW37, LAW41, LAW46, LAW49, LAW51, LAW75 and LAW80.

The initial volumetric fractions of LAW51 sub-materials can also be defined with:

 

Specific rigid wall for ALE is:

 

Upwind coefficients are defined with the following card. They can also be updated in the Engine file with the same keyword:

 

Streamline upwind method for momentum advection can only be activated in Engine file with:

This method adds diffusion on the streamline direction instead of neighbor directions. It provides more accurate results when modeling phenomena is not consistent with the structure of the mesh. For example, a spherical blast wave evolving inside a parralelepipedic domain with a structured mesh.

 

Finite Volume formulation for internal force calculation can be activated with:

It provides more accurate results for non parallelepipedic shapes. See default formulation for under-integrated formulation in Theory Manual 5.1.4.1 “Reduced Integration Method”.

For detonics applications, the following keywords are available:

High Explosive material laws:

High Explosive Ignitions:

 

For laser matter interaction, the following keywords are available: