Learning Forum

[Paul Stephen]

Greetings ANSYS community,

I hope this post finds you all in good health. I am relatively new to ANSYS Fluent and I've encountered an error message that has left me a bit puzzled. I'm reaching out here seeking guidance and insight into this issue, as it seems to be related to both sliding interfaces and moving reference frames.

During my simulation in Fluent, a message appeared in the console window stating: "Cannot Create Surface from sliding interface zone, Create empty surface." As a newcomer to this problem, I'm eager to understand what this error message indicates and how it can be resolved.

Interestingly, I came across a similar issue in one of the Ansys innovation course PDFs, but there's a slight difference. The problem in the PDF arose while performing the sliding mesh operation, whereas in my case, I am utilizing a moving reference frame. Could this be a factor contributing to the error?

I would greatly appreciate any insights or experiences you can share regarding this error message. Has anyone else encountered it while working with a moving reference frame, or could you provide suggestions on troubleshooting steps to resolve this issue?

Your expertise and assistance would be invaluable as I work to navigate and overcome this challenge. Thank you for taking the time to read my post, and I'm looking forward to learning from your experiences.

Best regards,

Paul Stephen

[Federico Alzamora Previtali]

Hello Paul, 

When does this message appear? You said during your simulation. Do you have animation for contour plots or orther displays?

This message typically appears when you select a boundary in a mesh or contour that was automatically created when you set the Mesh Interface.

If you do not set any specific options when setting the Mesh Interface, the following boundary will be created automatically.
1. When connecting fluids with the Mesh Interface
　・Common part: interior
　・Non-shared parts: Non-overlapping wall
2. When connecting fluids and solids, or solids and solids with the Mesh Interface
　・Common part: Double-sided wall
　・Non-shared part: Non-overlapping single-sided wall

Boundaries created in these intershared and non-shared parts can exist as zones and have boundary conditions. However, since there is no actual state as a mesh, if you try to display it with a mesh or contour, the above message will be displayed.
In post-processing, etc., please select the original interface plane to display instead of the automatically created boundary.

[Paul Stephen]

Subject: Clarification on Console Message during Mesh Interface Setup

Hello,

Thank you for the detailed explanation regarding the message.

Just to confirm, I encountered this message in the console window during the setup condition, specifically after assigning the Mesh Interface with periodic boundary conditions. In the context of my work, I am analyzing the external flow around an object.

In ANSYS 2023 R1, when I assigned the periodic boundary condition, I noticed that an option called "matching" was automatically selected, and I couldn't find a way to deselect it. Consequently, I observed the following automatically created boundaries:

1. When connecting fluids with the Mesh Interface
   • Common part: interior
   • Periodic

This behavior differs from my experience in the 2021 version. In ANSYS 2021, I had the flexibility to both select and unselect the "matching" option, which resulted in two different conditions:

1. When the matching option under periodic boundary conditions is unselected

   • Common part: interior
   • Non-shared parts: Non-overlapping wall

2. When the matching option under periodic boundary conditions is selected

   • Common part: interior
   • Period

As I prepare to run the simulation, I'm seeking further clarification on what this message means and how it might affect the simulation results. Understanding the implications of these automatically created boundaries is crucial for the accuracy of my analysis.

Your assistance in shedding light on this matter would be greatly appreciated. If you could provide insights into the impact of these automatically created boundaries on the simulation results and any best practices for working with them, it would be of immense help.

Thank you once again for your support, and I look forward to your guidance.

Best regards,

Paul

[Federico Alzamora Previtali]

The Fluent user guide has these options documented 6.6. Non-Conformal Meshes (ansys.com)