3. Modeling A

3.1. Characteristics of modeling

Two modeling variants are carried out:

• a \((p,\mathrm{\Phi },z)\) modeling of the free surface with 57 elements MEFP_FACE4 (2D modeling _ FLUI_PESAsur the group of elements MASURF) quadrangles with 4 knots while the fluid volume is modeled by 513 fluid elements \((p,\mathrm{\Phi })\) (3D modeling _ FLUIDEsur the group of elements MAFLUIDE) cubic to 8 knots. This modeling gives access to sloshing modes and acoustic modes;

• a fluid volume modeling that is modeled by 513 fluid elements \((p,\mathrm{\Phi })\) (3D modeling_ FLUIDEsur the group of elements MAFLUIDE) cubic at 8 knots, while the free surface (group of nodes: NOSURF) is affected by a Dirichlet condition: PRES =0.0, PHI =0.0. This Dirichlet condition is performed successively in two ways: by dualization (AFFE_CHAR_MECA (DDL_IMPO)), then by elimination (AFFE_CHAR_CINE (MECA_IMPO)). This modeling gives access to only acoustic modes.

In both cases, no boundary conditions are affected on the side walls and the bottom: this is a natural boundary condition: \(\vec{\nabla p}\mathrm{.}\vec{n}=0\).

3.2. Characteristics of the mesh

The mesh contains: 513 HEXA8; 57 QUAD4.

3.3. Tested values

Identification	Reference (\(\mathit{Hz}\))
Slope mode 1, 0	0.898250
Casual mode 2, 0	1.38452
Joggle mode3, 0	1.70952
Joggle Mode4, 0	1.97551
Slope mode 5, 0	2.20885
Acoustic mode 0, 0, 0	1166.67
Acoustic mode 1, 0, 0	1458.33