Creating a zero-thickness wall in a 3D channel (Spaceclaim + Ansys Meshing + Fluent)

  • Last Post 14 December 2018
  • Topic Is Solved
highhopes posted this 06 December 2018

Dear everyone,

I am trying to create a zero-thickness obstacle in a 3D flow geometry. You can see a simplified example of what I mean attached to this message. 

Creating something like this was possible in Icem but I have to use Spaceclaim and Ansys Meshing and Ansys Meshing does not either accept or recognize the 2D wall. I cannot be sure what exactly the problem is.

If anyone has ever been able to do it, I would be very happy if you could walk me through the solution.

Kindest regards

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kkanade posted this 07 December 2018

as ansys employee we can not download any attachments. please insert some images. 

as i imagine you have a fluid body and a surface body in spaceclaim. please create a single part from them and use sharetopology options as shown in following video. if this solves your issue, please mark this as 'is solution' to help others on forum. 

highhopes posted this 07 December 2018

Thank you for your answer. However I cannot see the video or a link in your post.

Here is the image of the case I mentioned:

kkanade posted this 07 December 2018


highhopes posted this 14 December 2018

Thank you for your answer, @kkanade. For my specific case, "Share" option did not work but "Merge" did, maybe simply because it was a combination of a volume/body and a plane/shell/surface/face element. 

To all the users, this was the method I followed for my specific case:

1. Generate the 3D tunnel as a body element

2. Generate the 2D/zero-thickness obstacle inside the tunnel

3. Click on the parent element in the structure tree - change "Share topology" option to "merge" in the properties menu (See the video example in the previous post)

4. Save project

5. Open Ansys Meshing on Workbench

6. Create inflation on 2D surface

7. Generate mesh

   - Get ready for the warning "Pre-inflation layer generation has stopped because of side face limitation, proximity collisions and quality." Even though I entered 5 maximum layers for inflation, there seemed to be only 1 on both sides of the obstacle as shown below

Here, if you pick the option "post" instead of "pre", you get the number of layers you want but the quality is still low and you still get the warning "Post inflation with layer compression has generated non continuous inflation layers. Please review the geometry and/or the meshing parameters."

I must say as an experienced Icem CFD user, quite a learning curve is required to migrate to the combination of Spaceclaim and Ansys Meshing because if you want to create high-quality inflation layers / boundary layer mesh on this 2D element for example, I think you have to follow a method more detailed than I mentioned above.

kkanade posted this 14 December 2018

as you have zero thickness, the prism at both end will have stairstepping. if it tries to create prism at both end then a prism cell will have two faces in a plane which will give very bad mesh quality at the both end. you can try to draw prisms on zero thickness on paper and you would easily see this.

if you want prisms on both sides, you may want to give some thickeness to that plate.