Natural frequency analysis of a cylinder
----------------------------------------

The figure below shows the first vibration mode of a cylindrical shell with CC2
boundary conditions. The figure was generated using ``refinement=2`` and
running the script directly.

.. image:: ./ex_natural_frequency_cylinder.jpg

The code used to generate this figure is extracted from one of ``pyfe3d`` unit
tests:

.. literalinclude:: ../../tests/test_quad4_natural_freq_cylinder.py
    :encoding: latin-1