Summary of ALE Keywords

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

Description

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:
  • /BCS (constraining material velocity on nodes)
  • /ALE/BCS (constraining grid velocity on nodes)
  • /EBCS (constraining elementary state)

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.

The specific ALE interfaces are:
  • /INTER/TYPE1 (ALE nodes on a Lagrangian surface)
  • /INTER/TYPE9 (interfacing a Lagrangian surface with a given ALE free surface)
  • /INTER/TYPE12 (enables the transmission of flow between 2 ALE surfaces (main and secondary side))
  • /INTER/TYPE18 (coupling with Lagrange structure)
  • /INTER/TYPE22 (cut cell method, BETA software release)
There are seven material laws compatible with the ALE or EULER formulation:
Multi-material laws
/MAT/LAW37 (BIPHAS) (bi-material liquid gas)
/MAT/LAW20 (BIMAT) (general 2D bi-material law)
/MAT/LAW51 (MULTIMAT) (general 3D multi-material law, scattered scheme)
Multi-Phase material law
/MAT/LAW26 (SESAM) (SESAME-Johnson-Cook material)
/MAT/LAW151 (MULTIFLUID) (general 3D multi-material law, collocated scheme)
Boundary material law
/MAT/LAW11 (BOUND) (Inlet/Outlet material)
Thermal law
/MAT/LAW18 (THERM) (Thermal material)
Besides the above ALE materials, the following material laws can be used in ALE/EULER analysis:
The second order MUSCL scheme for reconstruction of volumetric fractions can be invoked through:
To define inlet/outlet:
The initial velocity for material located at grid point is defined with:
The initial velocity for collocated scheme (LAW151) can be defined with:
Non-reflecting outlet boundary condition for material LAW151 can be setup with:
Inlet boundary condition for material LAW151 can be setup with:
The hydrostatic pressure field, due to gravity, can be initialized with:
The initial volumetric fractions of materials LAW51 and LAW151 sub-materials can also be defined with:
Velocities and thermodynamic values can be mapped into the ALE domain by using:
Specific rigid wall for ALE is:
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 Reduced Integration Method in the Theory Manual.

For detonics applications, the following keywords are available:
High Explosive material laws
/MAT/LAW5 (JWL)
/MAT/LAW41 (LEE_TARVER)
/MAT/LAW51 (MULTIMAT)
/MAT/LAW151 (MULTIFLUID)
High Explosive Ignitions
/DFS/DETLINE (detonation line)
/DFS/DETPLAN (planar wave)
/DFS/DETPOINT (detonation point)
/DFS/WAV_SHA (wave shaper)
For laser matter interaction, the following keywords are available:
The following equation of states are available in Radioss:
Specified parts can be activated or deactivated from ALE computations with: