[arkie87]

Is it possible to assign values to a user-defined-memory using a defined "profile" in Fluent? Or is it only possible via UDF?

[vinerm]

UDMs are accessible only via UDF; both C based and Scheme based.

[arkie87]

Originally Posted by vinerm

UDMs are accessible only via UDF; both C based and Scheme based.

Thank you (for the bad news :P)

[vinerm]

May I know the objective of using UDM if UDF is not being used?

You can access the profiles defined in the Fluent within a UDF and assign the values to UDM.

[arkie87]

Originally Posted by vinerm

May I know the objective of using UDM if UDF is not being used?

You can access the profiles defined in the Fluent within a UDF and assign the values to UDM.

I want to define porosity and inverse permeability via profile file. I have the profile file and it hooks properly, but want to plot it to see if it looks as expected. Fluent does not let me contour plot porosity or inverse permeability, so i thought I could copy porosity to a UDM, since Fluent lets me contour plot UDMs.

[vinerm]

You can certainly plot profiles, except those are not contour plots. To plot contours, you have to apply those to UDMs. But if its a profile then the values are already known and you can use some external tool to plot it, such as matlab, octave, gnuplot, tecplot, etc. Furthermore, Fluent will only plot the interpolated profile and not the actual profile when you assign those to UDMs and plot the contours. But it certainly is doable using UDF.

There is a small hack that you can do. Enable Fixed Values in Fluent's cell zone. Then, assign the profiles as any of the field variables. Initialize the simulation. If you assign profiles as velocity, then you can just plot the velocity, and voila.

[arkie87]

Originally Posted by vinerm

You can certainly plot profiles, except those are not contour plots. To plot contours, you have to apply those to UDMs. But if its a profile then the values are already known and you can use some external tool to plot it, such as matlab, octave, gnuplot, tecplot, etc. Furthermore, Fluent will only plot the interpolated profile and not the actual profile when you assign those to UDMs and plot the contours. But it certainly is doable using UDF.

There is a small hack that you can do. Enable Fixed Values in Fluent's cell zone. Then, assign the profiles as any of the field variables. Initialize the simulation. If you assign profiles as velocity, then you can just plot the velocity, and voila.

I have created profile file in matlab, so i am confident that it is correct, but i want to verify that fluent is reading it as expected.

I was trying to apply it to velocity, like you say, and plotting it, but i can only apply it as a boundary condition on the inlet. I was trying to initialize velocity field using it, but it wouldnt let me. Your suggestion to fix the field variables sounds like it will work though. Thanks!

[arkie87]

Originally Posted by vinerm

You can certainly plot profiles, except those are not contour plots. To plot contours, you have to apply those to UDMs. But if its a profile then the values are already known and you can use some external tool to plot it, such as matlab, octave, gnuplot, tecplot, etc. Furthermore, Fluent will only plot the interpolated profile and not the actual profile when you assign those to UDMs and plot the contours. But it certainly is doable using UDF.

There is a small hack that you can do. Enable Fixed Values in Fluent's cell zone. Then, assign the profiles as any of the field variables. Initialize the simulation. If you assign profiles as velocity, then you can just plot the velocity, and voila.

Unfortunately, fixing values doesnt appear to be working. Initializing overwrites the values, and running 1 iteration doesnt work either...

any ideas what i might be doing wrong?

[vinerm]

Initializing always sets the initial values, however, after running a couple of iterations, it should be able to show the fixed values. And you may have to deselect node values while plotting contours.

[arkie87]

Originally Posted by vinerm

Initializing always sets the initial values, however, after running a couple of iterations, it should be able to show the fixed values. And you may have to deselect node values while plotting contours.

Yes, this worked. I think during troubleshooting i turned off flow from the equations list. Flow has to be enabled for it to assign fixed values.

Thanks again!

[vinerm]

Nice to know that the hack worked.