1. Discretization#

1.1. Degrees of freedom#

Finite element

Degrees of freedom (at each vertex node)

MEFL_xxx (3D_ FLUIDE)

PRES: pressure PHI: potential for fluid movement

MEFL_FACE (3D_ FLUIDE)

PHI: fluid displacement potential

MEFS_xxx (FLUI_STRU)

DX, DY, DZ: structural displacement components PHI: potential for fluid movement

MEFP_FACE (2D_ FLUI_PESA)

DZ: free surface deflection PHI: potential for fluid movement

1.2. Support mesh for stiffness matrices#

Modeling

Mesh

Finished Element

Remarks

3D_ FLUIDE

TETRA4

MEFL_TETRA4

TETRA10

MEFL_TETRA10

PENTA6

MEFL_PENTA6

PENTA15

MEFL_PENTA15

HEXA8

MEFL_HEXA8

HEXA20

MEFL_HEXA20

HEXA27

MEFL_HEXA27

FLUI_STRU

TRIA3

MEFS_FACE3

TRIA6

MEFS_FACE6

QUAD4

MEFS_FACE4

QUAD8

MEFS_FACE8

QUAD9

MEFS_FACE9

2D_ FLUI_PESA

TRIA3

MEFP_FACE3

TRIA6

MEFP_FACE6

QUAD4

MEFP_FACE4

QUAD8

MEFP_FACE8

QUAD9

MEFP_FACE9

Note 1:

Coupling with a mesh structure of elements COQUE_3Dimpose to mesh the fluid-structure interface with elements QUAD8 (and not QUAD9) elements. The fluid massive domain is therefore meshed in HEXA20 (and not HEXA27). In fact, fluid-structure coupling takes place on the degrees of freedom of movement only, for the solid.

Note 2:

It is imperative that the normal outside the fluid domain is always oriented from the fluid to the structure, for all fluid-structure interface models, in particular FLUI_STRU.

1.3. Cargo support mesh#

Modeling

Mesh

Finished Element

Remarks

3D_ FLUIDE

TRIA3

MEFL_FACE3

TRIA6

MEFL_FACE6

QUAD4

MEFL_FACE4

QUAD8

MEFL_FACE8

QUAD9

MEFL_FACE9

2D_ FLUI_PESA

TRIA3

MEFP_FACE3

TRIA6

MEFP_FACE6

QUAD4

MEFP_FACE4

QUAD8

MEFP_FACE8

QUAD9

MEFP_FACE9