[ana86]

Hello,



I have a problem with using dynamic mesh and species transport at the same time.

When I run a simulation without species transport, my mesh moves, but when I enable the species transport model fluent crashes. Can anybody help me with this problem?

For the dynamic mesh motion I used the example from the udf-guide.


Thank you :-)

[vinerm]

Does the simulation work the other way around, i.e., if you enable species transport but not the dynamic mesh?

It is possible that the species transport setup has a problem.

Furthermore, if you are using a UDF from an example, ensure that it is compatible with the species transport model. Usually, a dynamic mesh UDF has got nothing to do with a species or material properties but in case the UDF accesses any such parameter, then it would require little modifications.

[ana86]

Yes, I tried to run only the species transport, and it also works fine.

I just tried a very simple udf. The mesh is moving only in x-direction with

NODE_X(v) += 1.0e-8;


So it is independent from species transport, and I thought I can use both at the same time, because there is no coupling, or something like that...
But maybe I have to enable something in fluent, or I have to include some *.h files, but I don't know...

[vinerm]

Is that the complete UDF source? You need to include udf.h. Furthermore, NODE_X does not provide motion. It returns position of the node.

[ana86]

No, this is not the complete udf.



It is what I wrote in the f_node_loop.

The udf works fine, if I don't use the species transport.

For other fluent cases I also use udfs for moving mesh, and I don't have any problems, if I don't use species transport...

And as I said, I also tried the udf from the udf-user-guide for the grid motion. Without species it works fine...

[vinerm]

There's no compatibility issues between dynamic mesh and species transport. However, sometimes the order matters. Does the successfully running dynamic mesh case has species transport enabled but equations disabled for solving or does it not have species transport enabled at all and when the species transport is enabled, Fluent crashes?

[vinerm]

I'd recommend using dynamic mesh without the UDF for debugging the case. Enable species transport and dynamic mesh but use a profile instead of a UDF for the motion. Profile format for dynamic mesh is simple; similar to a transient file except the names for the variables are hard coded. So, for velocity along x-coordinate, use v_x. If this works, then, most likely, the issue is with the UDF.

[AlexanderZ]

Originally Posted by ana86

No, this is not the complete udf.



It is what I wrote in the f_node_loop.

The udf works fine, if I don't use the species transport.

For other fluent cases I also use udfs for moving mesh, and I don't have any problems, if I don't use species transport...

And as I said, I also tried the udf from the udf-user-guide for the grid motion. Without species it works fine...

it means problem is in your species transport settings, isn't it?

[ana86]

Originally Posted by vinerm

I'd recommend using dynamic mesh without the UDF for debugging the case. Enable species transport and dynamic mesh but use a profile instead of a UDF for the motion. Profile format for dynamic mesh is simple; similar to a transient file except the names for the variables are hard coded. So, for velocity along x-coordinate, use v_x. If this works, then, most likely, the issue is with the UDF.

Thank you, I will try this

[ana86]

Originally Posted by AlexanderZ

it means problem is in your species transport settings, isn't it?

I think, the problem is in the species transport setting, but I don't know... I can run a case with only moving mesh, and a case with only species transport, but I can't run a case with both together...

[vinerm]

If there is nothing proprietary in the code, I'd recommend you share it in full and we can have a look. Having a problem in Species transport is a possibility but if it runs without dynamic or moving mesh, it should run with it as well until unless there is a conflict. And that seems to be the reason here.

[ana86]

Now I solved the problem. I reset the fluent case and startet over. Now I can run the simulation with species transport and moving mesh.



Thank you for your help!

[vinerm]

Nice to know that it works now. Good experience, I suppose.