F modeling
==============

Fluid behavior: THMC = LIQU_GAZ_ATMavec a constant saturation :math:`S=1`


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


* Plane modeling


* 1 mesh DPQ8 from the D_ PLAN_THM modeling: THM_ DPQ8


.. image:: images/100010E20000159A000013A3E04FB40CCC36EFED.svg
    :width: 288
    :height: 288


.. _RefImage_100010E20000159A000013A3E04FB40CCC36EFED.svg:


Tested sizes and results
------------------------------

Discretization in time: Several time steps (16) to study the evolution of pressure during the transition phase until it stabilizes. The time pattern is implicit (:math:`\theta =1`).

List of calculation times in seconds:

:math:`\mathrm{1,}\mathrm{5,}\mathrm{10,}\mathrm{50,}\mathrm{100,}\mathrm{500,}{10}^{3},{5.10}^{3},{10}^{4},5.{10}^{4},{10}^{5},5.{10}^{5},{10}^{6},5.{10}^{6},{10}^{7},{10}^{10}`

The nodal fluid pressure unknowns evaluated in Code_Aster are variations from the initial reference pressures defined under the keyword THM_INIT, which is why this table shows pressure variations in our comparison between the Code_Aster calculation and the reference solution.


.. csv-table::

    "**Node/point**", "**Order Number**", "**Press**", "**Reference**"
    :math:`(\mathrm{Pa})` ", "**Tolerance**
    :math:`(\text{\%})`"
    ":math:`\mathrm{N1}/A` ", "1 (t=1 s)", ":math:`\mathrm{PRE1}` "," -3,98.10-2", "1.0"
    "", "2 (t=5s)", ":math:`\mathrm{PRE1}` "," -1,99.10-1", "1.0"
    "", "3 (t=10 s)", ":math:`\mathrm{PRE1}` "," -3,98.10-1", "1.0"
    "", "4 (t=50s)", ":math:`\mathrm{PRE1}` "," -1.99", "1.0"
    "", "8 (t=5.103s)", ":math:`\mathrm{PRE1}` "," -1,95.10+2", "1.0"
    "", "16 (t=1010s)", ":math:`\mathrm{PRE1}` "," -5.10+3", "1.0"
    ":math:`\mathrm{N3}/B` ", "1 (t=1 s)", ":math:`\mathrm{PRE1}` "," 3.98.10-2", "1.0"
    "", "2 (t=5s)", ":math:`\mathrm{PRE1}` ", "1,99.10-1", "1.0"
    "", "3 (t=10 s)", ":math:`\mathrm{PRE1}` ", "3,98.10-1", "2.0"
    "", "4 (t=50 s)", ":math:`\mathrm{PRE1}` ", "1.99", "2.0"
    "", "8 (t=5.103s)", ":math:`\mathrm{PRE1}` ", "1,95.10+2", "1.0"
    "", "16 (t=1010s)", ":math:`\mathrm{PRE1}` ", "5.10+3", "1.0"



notes
---------

Note that the pressures calculated for the two previous behaviors (THMC = LIQU_SATU (model :math:`E`) and THMC = LIQU_GAZ_ATM (model :math:`F`)) are equal in absolute values. The difference in signs is due to the fact that:


* the pressure :math:`\mathrm{PRE1}` evaluated in the code is the water pressure for the behavior THMC = LIQU_SATU,


* :math:`\mathrm{PRE1}` is equal to the capillary pressure for the behavior THMC = LIQU_GAZ. Capillary pressure is equal to the difference between gas pressure and liquid pressure. In the particular case where the dry air pressure is atmospheric pressure (THMC = LIQU_GAZ_ATM), the capillary pressure has the opposite value of the liquid pressure.