How to set property to change over time?

1

Dear all,
I want to set a property that varies over time (such as density) by Curve, but how should I set “curve_name_coords</independent variable>” (Independent variable needs to point to Time)? It seems that “curve_name_coords” is not present in Curve struct block and OGS cannot recognize the variable “Time”.

<property>
    <name>property_name</name>
    <type>Curve</type>
    <independent_variable>curve_name_coords</independent_variable>
    <curve>curve_name</curve>
</property>

<curves>
    <curve>
        <name>CurveName</name>
        <coords>
            x_1 x_2 ... x_n
        </coords>
        <values>
            y(x_1) y(x_2) ... y(x_n)
        </values>
    </curve>
</curves>

error: The variable name 'time' does not correspond to any known variable

I have tried using the <type>Parameter</type> method and then setting the Curve in the Parameter block. Although it can run successfully, the actual propoerty will not change over time

2

Hi,

here, you have a list of all tests using <curve>s, some for time dependent parameters, some for excavation modelling:

And here you have a simple specific example:

        <parameter>
            <name>p_Dirichlet_right_spatial</name>
            <type>Constant</type>
            <value>1</value>
        </parameter>
        <parameter>
            <name>p_Dirichlet_right</name>
            <type>CurveScaled</type>
            <curve>p_Dirichlet_right_temporal</curve>
            <parameter>p_Dirichlet_right_spatial</parameter>
        </parameter>
    </parameters>
    <curves>
        <curve>
            <name>p_Dirichlet_right_temporal</name>
            <coords>0.0 10.0</coords>
            <values>0.0 10.0</values>
        </curve>
    </curves>

The curve’s value is multiplied with the “spatial” value. I.e., in this example the values of p_Dirichlet_right will range between 0 and 10.

Best regards,
Christoph

3

Sorry, I just saw that you were asking for material properties, not for parameters.

Apparently, we don’t have a test example where time is the independent variable.

You could try t as the independent variable (maybe it works, I didn’t test it):

<independent_variable>t</independent_variable>

Or you could fall back to a parameter (I didn’t try that either):

                        <property>
                            <name>viscosity</name>
                            <type>Parameter</type>
                            <parameter_name>YourCurveScaledParameter</parameter_name>
                        </property>
4

Dear Chelh
Thank you very much for your patient reply. I would like to express my sincerest gratitude to you.
Unfortunately, I have tried both of the methods you proposed and have failed. The first method will be displayed error: The variable name 't' does not correspond to any known variable . Although the second method (fall back to a parameter) can run successfully, the material property dose not change over time.

5

Which version of OGS are you using?

AFAICS <independent_variable>t</independent_variable> should work as of OGS 6.5.5.

Could you provide example files (prj, meshes) to reproduce the errors, please?

6

You’re right. Thank you so much for your help! I truly appreciate your support and the time you took to assist me.
I used 6.5.3 before. After upgrading to 6.5.5, OGS successfully recognized <independent variable>t</independent variable>.
But I found that the material parameters still do not change over time. Is this method applicable to all material properties of all Process? I tested longitudinal_dispersivity in ComponentTransport.

<property>
    <name>longitudinal_dispersivity</name>
    <type>Curve</type>
    <independent_variable>t</independent_variable>
    <curve>aL_with_time</curve>
</property>

 <curves>
     <curve>
         <name>aL_with_time</name>
         <coords>0.0 3600.0</coords>
         <values>0.0 0.5</values>
     </curve>
 </curves>

After testing, longitudinal_dispersivity at all times is equal to 0. Even if <values> y(x_1) y(x_2) ... y(x_n) </values> are changed (such as ‘0.5 0.0’ or ‘0.5 0.5’) , the result will not change.

7

It looks like for medium properties such as dispersivity only constants are supported, as opposed to phase and component properties:

            auto const& retardation_factor =
                component[MaterialPropertyLib::PropertyType::retardation_factor]
                    .template value<double>(vars, pos, t, dt);

            auto const& solute_dispersivity_transverse = medium.template value<
                double>(
                MaterialPropertyLib::PropertyType::transversal_dispersivity);

            auto const& solute_dispersivity_longitudinal =
                medium.template value<double>(
                    MaterialPropertyLib::PropertyType::
                        longitudinal_dispersivity);

            auto const density =
                phase[MaterialPropertyLib::PropertyType::density]
                    .template value<double>(vars, pos, t, dt);

That seems to be a design choice. The MaterialPropertyLib::Medium class even lacks a value() method taking t as an argument.

1 Like
8

Got it. Perhaps I should dive deeper into learning the development of OGS source code and contribute to the OGS community just like you. Thank you so much for your patient guidance and invaluable help these past few days. I have truly benefited a lot!