[sumitaero]

Hello Friend,
I have been working on ANSYS Transient Thermal for a purely conduction problem.
It would be a great help if anyone can suggest as to how the solution methodology works in the case of a Transient Thermal module of ANSYS.

In ANSYS Fluent module, it is clearly visible in the solution part as to what scheme is used or what methodlogy is used to solve a particular problem. It is not the same in case of Transient Thermal module.

[suraj9735]

Hello everyone,

I have also something similar conceptual problem regarding ANSYS Mechanical vs. Fluent.

I am solving a pure conduction problem in solid, And I test the results in both ANSYS Mechanical and Fluent too.

I have to share something.

ANSYS Mechanical-
1) Gives very good/appropriate/relevant result in automatic mode.
2) I am not familiar with scripting/command in the workbench Mechanical (WM). So I switch to Fluent and easy to use UDF for my model.
3)Very less access of solver through GUI in workbench Mechanical. And I also don't know how to check convergence plot in WM like Fluent shows at every iteration.


Fluent-
1)It's very hard to let the solution converged and doesn't change much with iterations. So it gives bad result comparing to WM.
2)Fluent has very much access to solver through GUI and can set so many things easily about convergence, reports, etc.
3) I think UDF in Fluent is relatively easier than workbench Mechanical scripting or APDL command.


I have two pictures of results given by Mechanical and Fluent of the same case for comparison but have too much difference, Even energy equation is converged till e-14 in Fluent.....

How can I make my result better in Fluent?
How can I study quickly to write command in the workbench Mechanical?

[Gert-Jan]

What mesh did you use in WB and in fluent? Same tet mesh?

[suraj9735]

Originally Posted by Gert-Jan

What mesh did you use in WB and in fluent? Same tet mesh?

I use the same tet mesh in both Mechanical and Fluent.

Mesh size= approx 300000 elements

[Gert-Jan]

What Type? Tet mesh?

[suraj9735]

Originally Posted by Gert-Jan

What Type? Tet mesh?

That mesh was automatically generated within the Mesh module of ANSYS.

[suraj9735]

Here is the picture of tet mesh. I am new to the CFD, have very less experience with meshing.

[Gert-Jan]

Mechanical is a FEM package. That will treat tet-mesh properly.
Fluent is a FVM Package. That will not treat tet-mesh properly. To get better results, I suggest to:
- create a uniform tet mesh;
- even better: convert it to poly mesh in fluent;
- best: create a hex mesh.