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"""
.. _openfoam_example:
Plot OpenFOAM data
~~~~~~~~~~~~~~~~~~
"""
from __future__ import annotations
import pyvista
from pyvista import examples
# %%
# This example uses data from a lid-driven cavity flow. It is recommended to
# use :class:`pyvista.POpenFOAMReader` for reading OpenFOAM files for more
# control over reading data.
#
# This example will only run correctly in versions of vtk>=9.1.0. The names
# of the patch arrays and resulting keys in the read mesh will be different
# in prior versions.
filename = examples.download_cavity(load=False)
reader = pyvista.POpenFOAMReader(filename)
# %%
# OpenFOAM datasets include multiple sub-datasets including the internal mesh
# and patches, typically boundaries. This can be inspected before reading the data.
print(f"All patch names: {reader.patch_array_names}")
print(f"All patch status: {reader.all_patch_arrays_status}")
# %%
# This data is represented as a :class:`pyvista.MultiBlock` object.
# The internal mesh will be located in the top-level MultiBlock mesh.
mesh = reader.read()
print(f"Mesh patches: {mesh.keys()}")
internal_mesh = mesh["internalMesh"] # or internal_mesh = mesh[0]
# %%
# In this case the internal mesh is a :class:`pyvista.UnstructuredGrid`.
print(internal_mesh)
# %%
# Additional Patch meshes are nested inside another MultiBlock mesh. The name
# of the sub-level MultiBlock mesh depends on the vtk version.
boundaries = mesh["boundary"]
print(boundaries)
print(f"Boundaries patches: {boundaries.keys()}")
print(boundaries["movingWall"])
# %%
# The default in OpenFOAMReader is to translate the existing cell data to point
# data. Therefore, the cell data arrays are duplicated in point data.
print("Cell Data:")
print(internal_mesh.cell_data)
print("\nPoint Data:")
print(internal_mesh.point_data)
# %%
# This behavior can be turned off if only cell data is required.
reader.cell_to_point_creation = False
internal_mesh = reader.read()["internalMesh"]
print("Cell Data:")
print(internal_mesh.cell_data)
print("\nPoint Data:")
print(internal_mesh.point_data)
# %%
# Now we will read in all the data at the last time point.
print(f"Available Time Values: {reader.time_values}")
reader.set_active_time_value(2.5)
reader.cell_to_point_creation = True # Need point data for streamlines
mesh = reader.read()
internal_mesh = mesh["internalMesh"]
boundaries = mesh["boundary"]
# %%
# This OpenFOAM simulation is in 3D with
# only 1 cell in the z-direction. First, the solution is sliced in the center
# of the z-direction.
# :func:`pyvista.DataSetFilters.streamlines_evenly_spaced_2D` requires the data
# to lie in the z=0 plane. So, after the domain sliced, it is translated to
# ``z=0``.
def slice_z_center(mesh):
"""Slice mesh through center in z normal direction, move to z=0."""
slice_mesh = mesh.slice(normal='z')
slice_mesh.translate((0, 0, -slice_mesh.center[-1]), inplace=True)
return slice_mesh
slice_internal_mesh = slice_z_center(internal_mesh)
slice_boundaries = pyvista.MultiBlock(
{key: slice_z_center(boundaries[key]) for key in boundaries.keys()},
)
# %%
# Streamlines are generated using the point data "U".
streamlines = slice_internal_mesh.streamlines_evenly_spaced_2D(
vectors='U',
start_position=(0.05, 0.05, 0),
separating_distance=1,
separating_distance_ratio=0.1,
)
# %%
# Plot streamlines colored by velocity magnitude. Additionally, the moving
# and fixed wall boundaries are plotted.
plotter = pyvista.Plotter()
plotter.add_mesh(slice_boundaries["movingWall"], color='red', line_width=3)
plotter.add_mesh(slice_boundaries["fixedWalls"], color='black', line_width=3)
plotter.add_mesh(streamlines.tube(radius=0.0005), scalars="U")
plotter.view_xy()
plotter.enable_parallel_projection()
plotter.show()
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