Property Presets

Section author: Florian Zill (Helmholtz Centre for Environmental Research GmbH - UFZ)

ogstools.propertylib provides classes (Scalar, Vector, Matrix) which encapsulate unit handling and data transformation for simplified processing of mesh data. There are several predefined properties stored under the module ogstools.propertylib.presets.

from ogstools.meshplotlib import examples, plot
from ogstools.propertylib import Scalar, presets

presets.get_dataframe()

	data_name	data_unit	output_unit	output_name	type
preset
heatflowrate	HeatFlowRate			HeatFlowRate	Scalar
massflowrate	MassFlowRate			MassFlowRate	Scalar
material_id	MaterialIDs			MaterialIDs	Scalar
nodal_forces	NodalForces			NodalForces	Vector
...	...	...	...	...	...
fluid_pressure_crit	sigma	Pa	MPa	fluid_pressure_criterion	Scalar
stress	sigma	Pa	MPa	stress	Matrix
temperature	temperature	K	°C	temperature	Scalar
velocity	velocity	m/s	m/s	darcy_velocity	Vector

17 rows × 5 columns

Scalar, Vector and Matrix inherit from the class Property with its transform() function. This function converts the argument from data_unit to output_unit and applies a function if specified. In this case we convert from K to °C:

presets.temperature.transform(273.15)

0.0

You can also create your own properties by creating a Scalar, Vector or Matrix property. The following doesn’t do any unit conversion.

custom_temperature = Scalar(
    data_name="temperature", data_unit="K", output_unit="K"
)
custom_temperature.transform(273.15)

array(273.15)

Or use existing presets as a template and replace some parameters:

custom_temperature = presets.temperature.replace(output_unit="°F")
custom_temperature.transform(273.15)

31.999999999999936

Components of Vector properties and Matrix properties can be accessed with bracket indexing. Vector properties should be of length 2 or 3 corresponding to the dimension. Matrix properties likewise should be of length 4 [xx, yy, zz, xy] or 6 [xx, yy, zz, xy, yz, xz].

presets.displacement[1].transform([0.01, 0.02, 0.03])

array(0.02)

presets.strain["xx"].transform([0.01, 0.02, 0.03, 0.04, 0.05, 0.06])

1.0

Magnitude of a 2D displacement vector:

presets.displacement.magnitude.transform([0.03, 0.04])

0.05

We suggest specifying the properties and their transformations once. These can be reused in different kind of post processing. When plotting with ogstools.meshplotlib we can use these presets to simplify the task of processing the data (e.g. calculate the von Mises stress):

fig = plot(examples.mesh_mechanics, presets.stress.von_Mises)

Have a look at How to use meshplotlib for more examples.