[Shomaz ul Haq]

Dear all,

Hello. Hope all are well. My question is how can I create an inner o grid? I did and knew it a while back but have forgotten it now. Would be grateful for help. My first O grid has been made. Hope to hear from someone soon. Thanks.

[Shomaz ul Haq]

Hello everyone. Would be grateful if someone could help me out in creating an o grid within another o grid. I have made the first o grid but when I try to make the second o grid my cells are not curved but squares in the middle. Would be grateful for help. Thanks.

[bluebase]

Hello Shomaz,

i assume, you know how to build the 2-layered o-grid structure, but happen to have straight inner edges instead of curved ones matching the outer layer.
I suggest you to use "Link Edge" if you want to have a edge explizitely matching the form of another edge. It can be found in Blocking > Edit Edge > Link Edge.

With regards,
Sebastian

[Shomaz ul Haq]

Thanks Sebastian Engel. I understand what you are saying. I made an o grid by making a 3D bounding block, applying edge to curve association, snapping the vertices, and split blocking i.e. making the o grid by choosing the face option (I chose the inlet and outlet faces). It generated a good o grid. My question is before making the second o grid I need to do edge curve association again. Right? The problem is I don't have a second curve to associate the inner o grid edge with. What is the easiest and best way to go about making the second o grid? I'll look in the link edge option too. Hope to hear from someone soon. Thanks.

[shereez234]

Like sebastian said split the First O grid and then link the edges of inner O grid to the outer grid (outer O grid edges being the reference edges)

[Shomaz ul Haq]

Thanks a lot Sebastian and Shereez.

[Shomaz ul Haq]

Hello Sebastian and Shereez. Hope you guys are well. Sorry for late reply I was busy in some other stuff. I have made the second o grid inside now am trying to use the link edge option. Shereez you said select outer o grid edges as reference edge. What does that mean? In ICEM nomenclature there is a "source edge" and a "target edge." Do you mean the "target edge?" Also the mesh I am getting is shown in picture 1 whereas I need a mesh like the one in picture 2. The grid is fine when I don't make the second o grid inside. But I need it to correct corners inside o grid to improve quality as you can see. Hope to hear from soon. Thanks.

[shereez234]

Originally Posted by Shomaz ul Haq

Hello Sebastian and Shereez. Hope you guys are well. Sorry for late reply I was busy in some other stuff. I have made the second o grid inside now am trying to use the link edge option. Shereez you said select outer o grid edges as reference edge. What does that mean? In ICEM nomenclature there is a "source edge" and a "target edge." Do you mean the "target edge?" Also the mesh I am getting is shown in picture 1 whereas I need a mesh like the one in picture 2. The grid is fine when I don't make the second o grid inside. But I need it to correct corners inside o grid to improve quality as you can see. Hope to hear from soon. Thanks.

reference edge is source edge. Here is what you should do.

1. Go to split edge and use spline to project the edges to the curves for the first O grid.
2. Go to mesh parameters and add some nodes in the second O grid layer. It is 2 nodes at the moment
3. Go to link edge and link the second o grid edges to the parallel first O grid edges (green ones). source edge is first o grid edges and target is second inner o grid edges.

[Shomaz ul Haq]

Thanks. I don't understand how to do the first step. Can you kindly explain a little bit more. Which edge(s) of outer o grid should I select. Also you are not talking about the edges(s) in green right? Confused. Would be grateful for help. Thanks.

[Shomaz ul Haq]

I did exactly as you told me but after following the three steps I am getting the following mesh. The quality is even worse now as the mesh is very bad. Please help. Thanks.

[shereez234]

https://www.dropbox.com/sh/wrra1bj3f...oJ6wGaXqa?dl=0


Download these images and have a look. Is this what you are looking for

[Shomaz ul Haq]

I have attached my first o grid picture (without any internal o grid like previous images). As you can see they are good. But I want to improve corner block elements so want to have another o grid inside. Actually my O grid is like the one in the images. But I think maybe its improved in your images. Not sure. What do you think?

Also can you please tell me why aren't those three steps giving me a two o grids with better corners.

Thanks.

[bluebase]

Hello Shomaz,
do you happen to have access to the tutorials comming with icem? Until V16 they where included in the manuals.
If you have them included, i suggest you to do the tutorials to get more familiar with the process of using icem.

For some time there are also free video tutorials available. check it out: https://www.learncax.com/courses/by-...cem-cfd-detail


Taking your last picture (~4.png) as current state to you question.
When you create another o-grid layer, then the outer blocks will have better quality (because you moved the problem to the inner layer)
Then, when the elements in the new layer are not automatically follow the form of the outer layer then use Link Edge. Read the Manual about a feature you don't know about. And mind the difference between Split Edge and Link Edge.
And Play! Don't just try it once! and then say it doesn't work. see what changes with different settings.(here: see what happens when you change the scaling facor). It's not like you can break anything (as long as you save often )
I am sure you are capable to find a solution yourself with this guidance.

with regards,
Sebastian

[Shomaz ul Haq]

You're absolutely right Sebastian. Thanks for your support. Appreciate it But I have really read about the link edge and split edge options. I don't understand why I am not getting a good quality double o grid. Also I agree when I define the second o grid the quality of the outer elements improve but don't understand how to improve corners. In short I don;t want to just create a second o grid but one that has improved corners and similar edges as that of the outer o grid. Thanks.

[Shomaz ul Haq]

Did it! Thanks a lot for your support. I just added two circular curves. One at the inlet and one at the outlet. at the inner edges of the outer o grid layer. That worked like a charm. Quality is much better now You were absolutely right Sebastian. One should have patience and try try again before seeking help.