P modeling
==============


Characteristics of modeling
------------------------

Elements MECA_HEXA20, MEFL_HEXA20, MEFL_PYRAM13, MESF_QUAD8

We resume the O modeling mesh by going from linear to quadratic and by creating a layer of fluid elements PYRAM13.

Boundary conditions:

In all the knots on the face :math:`M`

.. code-block:: text
 DDL_IMPO: (GROUP_NO): knot/surf PRES: 0. PHI :0.)

In all the nodes of the piston

.. code-block:: text
 (GROUP_NO: noeupist DY: 0. DZ:0.)


Characteristics of the mesh
----------------------------


.. csv-table::

    "Number of nodes:", "273"
    "Number of meshes and types:", "16 HEXA20, 48 PYRAM13, 8 QUAD8"



Tested values
---------------


.. csv-table::

    "**Frequency**", "**(** :math:`\mathrm{Hz}` **)**", ""
    "**Reference**", "**Aster**", "**Error (%)**"
    "13.8285", "13.8277", "-0.006"



notes
---------

Mode calculations performed by:

.. code-block:: text

    CALC_MODES
OPTION =' AJUSTE ',
CALC_FREQ =_F (FREQ =( 10.,20.))

The analytical solution of the first eigenvector is not known.

**Contents of the results file:**

Value of the first natural vibration frequency of the coupled system.