Post-processing =============== The easiest way to visualize the results is to use Tecplot or any other software that can read the files generated by Nemoh with the tecplot format. Most results are also output in a custom text format (``.dat`` files). Post-processing 2D data ----------------------- The results are stored in the `results` directory. The main files are: - ``RadiationCoefficients.tec``: added mass coefficients :math:`M_{a_{ij}}` (also in ``CM.dat``) and radiation damping coefficients :math:`B_{r_{ij}}` (also in ``CA.dat``) - ``FKForce.tec``: Froude-Krylov forces :math:`\vec{F}_{FK}` - ``DiffractionForce.tec``: diffraction forces :math:`\vec{F}_d` - ``ExcitationForce.tec``: excitation forces :math:`\vec{F}_e` Depending of the post-processing options, other files may be present in the `results` directory (such as Impulse Response Functions (IRF) and Response Amplitude Operators (RAO)). Loading a file in Tecplot ^^^^^^^^^^^^^^^^^^^^^^^^^ To load a file in Tecplot, click on ``File -> Load Data...`` and select the file you want to load. Alternatively, directly click the ``Load Data`` button on the top left. .. subfigure:: AB :name: fig:tecplot_load_data .. image:: figures/tecplot_load_data.png :alt: Load data through the file menu .. image:: figures/tecplot_load_data2.png :alt: Load data through the button Two ways of loading data in Tecplot The file will be loaded in Tecplot and you can visualize the results in the main window. .. image:: figures/tecplot_2d_data_display.png :alt: Loaded data in Tecplot The Nemoh output files each contain data for all requested body Degrees of Freedom (DoF) and/or forces, as functions of the wave frequency. Some files also have data for different wave directions. To select the data you want to display, click on the ``Mapping Style...`` button on the left. .. image:: figures/tecplot_open_mapping_style.png :alt: Open the mapping style In the small window that appears, navigate to the ``Definitions`` tab and check the box in the ``Show Map`` column for the data you want to display. You can check several curves to display them all on the same plot. .. image:: figures/tecplot_select_data.png :alt: Select data to display .. hint:: After changing the plotted data in the ``Mapping Style`` window, click on ``View -> Fit to Full Size`` (or hit ``Ctrl+F``) to update the scales to the new data. The other tabs in the ``Mapping Style...`` window allow you to customize the display of the data. .. hint:: The ``Zone`` column allows you to switch between different wave directions. Comparing results from different files ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ To open other results for comparison, click on ``File -> Load Data...`` (or the ``Load Data`` button) again and select the file you want to load. In the following prompt, select ``Append data to active frame`` to add the new data to the existing plot. .. image:: figures/tecplot_append_data.png :alt: Append data to the active frame .. warning:: Appending data is trivial when the files contain the same data fields, as is most often the case when one wants to compare. However, if the files contain different data fields, Tecplot will prompt you to merge some fields and add others. This can be confusing and is not recommended. A new ``Zone`` has been added, which can be selected in the ``Zone`` column in the ``Mapping Style`` window. .. image:: figures/tecplot_select_zone.png :alt: Select zone to display In order to compare the same data from different files, make sure that the relevant field is selected in the ``Y-Axis`` column. .. image:: figures/tecplot_select_y_axis.png :alt: Select Y-axis Displaying a legend ^^^^^^^^^^^^^^^^^^^ To display a legend, click on ``Plot -> Line Legend...`` and check the ``Show Line Legend`` box (and the ``Show Mapping Names`` box). .. subfigure:: AB :name: fig:tecplot_show_legend .. image:: figures/tecplot_line_legend_menu.png :alt: Open the line legend menu .. image:: figures/tecplot_show_line_legend.png :alt: Check the button Displaying the line legend You can edit the names displayed in the legend in the ``Mapping Style`` window. .. image:: figures/tecplot_set_curve_name.png :alt: Edit the legend The legend will be displayed in the plot, and can be moved around by clicking and dragging it. .. image:: figures/tecplot_move_line_legend.png :alt: Displayed legend Post-processing 3D data ----------------------- Two types of 3D data can be output by Nemoh (only if specicied in the ``Nemoh.cal`` file): - The pressure distribution on the body, in ``pressure..dat`` files. - The free surface elevation around the body, in ``freesurface..dat`` files. .. hint:: Keep in mind that Nemoh's results are in the frequency domain. Thus, you won't be able to see the `waves` as you could expect in the time domain. The displayed data is the amplitude or phase shift of a physical quantity. .. warning:: Outputting the free surface elevation significantly increses the execution time of Nemoh. To load a 3D file in Tecplot, click on ``File -> Load Data...`` and select the file you want to load (see last section). Instead of ``XY Line``, select ``3D cartesian`` in the dropdown menu on the left. .. image:: figures/tecplot_select_3d_cartesian.png :alt: Select a 3D view in Tecplot You can that select the type of data you want to display. Check the ``Mesh`` and ``Contour`` boxes to display the mesh and the surfacic data, respectively. .. image:: figures/tecplot_select_mesh_and_contour.png :alt: Select Mesh and Contour Click on the button next to ``Contour`` to select the surfacic fields you want to display. .. image:: figures/tecplot_select_contour_field.png :alt: Select the contour field The surfacic data will be displayed on the mesh. .. image:: figures/tecplot_FS_display.png :alt: 3D data displayed in Tecplot You can choose another colormap in the ``Contour`` options window. You can also choose a continuous colormap rather than a banded one. .. subfigure:: AB :name: fig:tecplot_colormap_options .. image:: figures/tecplot_select_colormap.png :alt: Select a different colormap .. image:: figures/tecplot_select_continuous_colormap.png :alt: Choose a continuous colormap Colormap options