# 7. Results

Now that we have run the case, we must check the results. Previously we downloaded all
the macroscopics from the case, and now we will visualize them in ParaView.

```{note}
The results shown in this chapter come from a slightly different setup, so you can expect
different values and plots from the ones you get by following this workshop. The
inspection is done the same way.
```

## Processing the Lines

For lines, we can visualize them in the domain by adding the geometries as well, which
makes it easier to check the positions.

```{eval-rst}
.. figure:: /_static/img/workshops/first-abl-simulation/07-lines-ux.png
    :align: center

    The three line exports loaded alongside the plane and roughness geometries, coloured
    by :math:`u_x`.
```

To process the average velocity in them and see how it changes, we add **Temporal
Statistics**, and then **Plot Data** on the line, using the z position as x and `ux` as
y.

```{eval-rst}
.. figure:: /_static/img/workshops/first-abl-simulation/07-lines-avg.png
    :align: center

    Mean :math:`u_x` profiles for the three lines, plotted against `Points_Z`.
```

We can also add a turbulence intensity **Calculator** (`ux_stddev/ux_average`) on top of
the temporal statistics and plot it.

```{eval-rst}
.. figure:: /_static/img/workshops/first-abl-simulation/07-lines-turb-intens.png
    :align: center

    Turbulence intensity profiles for the three lines.
```

We compare the results against the Eurocode values using the script below. It reads the
line exports directly from their HDF5 files and plots both profiles against
EN 1991-1-4 for terrain category II.

```{note}
The script requires [h5py](https://www.h5py.org/), [NumPy](https://numpy.org/) and
[Matplotlib](https://matplotlib.org/). Run it from the folder holding the downloaded line
exports: `python plot_abl_eurocode.py --dir <results folder>`.
```

{download}`Download plot_abl_eurocode.py </_static/scripts/plot_abl_eurocode.py>`

```{eval-rst}
.. figure:: /_static/img/workshops/first-abl-simulation/abl_cat2_vs_eurocode.png
    :align: center

    Mean velocity and turbulence intensity from the three lines, against EN 1991-1-4
    terrain category II.
```

For the average velocity, the plot is pretty spot on. For the turbulence intensity, the
values are lower than Eurocode CAT 2. To improve this we could go back to the setup and,
for example, try to increase the elements height, increase the K multiplier in the
advanced properties of SEM, increase the roughness category, or other tweaks. Even
changing the resolution may affect this. It's a process of trial and error.

## Visualizing the Domain

For domain visualization we will use the XZ plane as an example: we open the XDMF file
and just check its visualization.

```{eval-rst}
.. figure:: /_static/img/workshops/first-abl-simulation/07-plane-visualization.png
    :align: center

    The XZ debug plane coloured by :math:`u_x`.
```

We can see that the field seems to be developed.

It's also interesting to create animations from these, so that we can see the flow
evolving overall. By setting the camera, changing colormaps and configuring the lighting,
it's possible to create great animations.

```{raw} html
<figure style="display: flex; flex-direction: column; align-items: center;">
  <video controls style="max-width: 100%; width: 100%;">
    <source src="/_static/img/workshops/first-abl-simulation/plane_xz_ux.mp4" type="video/mp4">
  </video>
  <figcaption style="display: flex; justify-content: center;">Streamwise velocity on the XZ plane, animated over the acquisition window.</figcaption>
</figure>
```

A similar process can be done for the other exports, such as the volume debug, the
statistics export, and the other plane exports.

Now we have a basic ABL case, from end to end.