.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "auto_how_to/example_iso_surface_area.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        :ref:`Go to the end <sphx_glr_download_auto_how_to_example_iso_surface_area.py>`
        to download the full example code.

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_auto_how_to_example_iso_surface_area.py:


Measure the interface area of a VOF free surface
================================================

In a volume-of-fluid simulation, the ``alpha.water = 0.5`` iso-surface is a
good proxy for the liquid–gas interface. Its area is a useful diagnostic:
it grows during breakup, collapses on coalescence. pyOFTools' ``iso_surface``
builder + ``Sum`` gives you the number in one line.

.. GENERATED FROM PYTHON SOURCE LINES 12-14

Open the case
-------------

.. GENERATED FROM PYTHON SOURCE LINES 14-37

.. code-block:: Python


    import os
    import subprocess

    import pyOFTools.patch_pybfoam  # noqa: F401
    from pyOFTools import clone_example

    CASE = clone_example("damBreak")
    subprocess.run(
        ["./Allrun"],
        cwd=CASE,
        check=True,
        env={**os.environ},
        capture_output=True,
        text=True,
    )

    from pybFoam import Time, fvMesh, volScalarField

    time = Time(str(CASE.parent), CASE.name)
    mesh = fvMesh(time)
    volScalarField.read_field(mesh, "alpha.water")





.. rst-class:: sphx-glr-script-out

 .. code-block:: none


    <pybFoam.pybFoam_core.volScalarField object at 0x7f46cba33a90>



.. GENERATED FROM PYTHON SOURCE LINES 38-43

Iso-surface area
----------------
``iso_surface`` returns a ``WorkFlow`` seeded with a ``SurfaceDataSet``
whose field slot is *empty*. Pipe into ``area()`` to populate the field
with face-area magnitudes, then ``Sum`` to reduce.

.. GENERATED FROM PYTHON SOURCE LINES 43-51

.. code-block:: Python


    from pyOFTools.aggregators import Sum
    from pyOFTools.builders import area, iso_surface

    result = (iso_surface(mesh, iso_field="alpha.water", iso_value=0.5) | area() | Sum()).compute()
    interface_area = result.values[0].value
    print(f"interface area at t=0: {interface_area:.6g} m^2")





.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    interface area at t=0: 0.00687285 m^2




.. GENERATED FROM PYTHON SOURCE LINES 52-68

Over time, wire this into a @Table
----------------------------------
In-situ, you register the computation once and the framework calls it
each write step:

.. code-block:: python

   from pyOFTools.postprocessor import PostProcessorBase
   postProcess = PostProcessorBase()

   @postProcess.Table("interface_area.csv")
   def interface_area(mesh):
       return iso_surface(mesh, "alpha.water", 0.5) | area() | Sum()

See :doc:`/how-to/configure_controlDict` for the ``system/controlDict``
wiring.


.. rst-class:: sphx-glr-timing

   **Total running time of the script:** (0 minutes 10.628 seconds)


.. _sphx_glr_download_auto_how_to_example_iso_surface_area.py:

.. only:: html

  .. container:: sphx-glr-footer sphx-glr-footer-example

    .. container:: sphx-glr-download sphx-glr-download-jupyter

      :download:`Download Jupyter notebook: example_iso_surface_area.ipynb <example_iso_surface_area.ipynb>`

    .. container:: sphx-glr-download sphx-glr-download-python

      :download:`Download Python source code: example_iso_surface_area.py <example_iso_surface_area.py>`

    .. container:: sphx-glr-download sphx-glr-download-zip

      :download:`Download zipped: example_iso_surface_area.zip <example_iso_surface_area.zip>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_