[Alwaysabeginner]

Hey!
ICEM beginner here. I'm trying to mesh a small cavity (to be used as a jet) on the surface of a NACA0015 aerofoil (Picture attached). I want the cavity region to be ideally filled with an all tri mesh and a structured mesh outside.
I'm using a standard C-grid mesh for the aerofoil.
While I can do both individually(as separate files), I'm not able to mesh the complete geometry. Couple of methods which I tried out were:
1) Mesh the cavity in a separate block, and later convert it into a free block. In this method I can't seem to merge the two meshes at the interface.
2) Mesh only the aerofoil separately and the cavity separately(using the inbuilt unstructured mesh option). Here, the interface still acts as a wall, and hence there is no interaction between the outer field and the cavity.
In another case, I also tried creating two interfaces (as curves) b/w the two parts (vis. external field and cavity) and tried to give them the interface BOCO in Fluent - but that does not work (solution is diverging)
3) I tried using a single block to capture the entire geometry - however, the cavity is not getting captured at all ( I can't seem to "bend" the mesh to capture the details of the cavity.

I'm at a loss on how to proceed now. I hence have two questions:
1) Can a edge associated on a curve have no BOCO explicitly mentioned (i.e. can I make it a part of the fluid flow itself)?
2) What's the best strategy on how to proceed?

Thanks in advance!

[Far]

You can do it in the following way. :


Method 1:

1. From the block inside the airfoil (usually solid), split it three locations : two vertical and one horizontal (at bottom of jet).

2. Associate the vertices to corresponding points and edges to curves. You will also need curve at the airfoil and jet intersection.

3. As the mesh inside the jet will distorted during different events of ejecting and suction, I would recommend using tri mesh inside cavity. You can convert blocking into free mesh, as you have already mentioned.


Method 2:

1. Create the hexa mesh for airfoil as usual.

2. Create tri mesh inside the jet along with prism layers.

3. Merge them in ICEM CFD (see my tutorial on 2d hybrid meshing on forum)

[Alwaysabeginner]

Nice! Thanks a lot!

I have a follow up question. This curve that you mention at the interface : It still carries over to fluent as a separate entity. What boundary condition should I give on the same (it should ideally not be there). In other words, I want the fluid to interact in both the quad-dominant and tri-dominant parts - the curve is preventing me from doing so (Deleting the curve results in the mesh going awry). Is there a way to link the two "fluid" regions - outside the jet and inside the jet together?

[Far]

Originally Posted by Alwaysabeginner

Nice! Thanks a lot!

I have a follow up question. This curve that you mention at the interface : It still carries over to fluent as a separate entity. What boundary condition should I give on the same (it should ideally not be there). In other words, I want the fluid to interact in both the quad-dominant and tri-dominant parts - the curve is preventing me from doing so (Deleting the curve results in the mesh going awry). Is there a way to link the two "fluid" regions - outside the jet and inside the jet together?

define it interior

[Alwaysabeginner]

Thanks a lot for your inputs!

[alirez]

Originally Posted by Far

You can do it in the following way. :


Method 1:

1. From the block inside the airfoil (usually solid), split it three locations : two vertical and one horizontal (at bottom of jet).

2. Associate the vertices to corresponding points and edges to curves. You will also need curve at the airfoil and jet intersection.

3. As the mesh inside the jet will distorted during different events of ejecting and suction, I would recommend using tri mesh inside cavity. You can convert blocking into free mesh, as you have already mentioned.


Method 2:

1. Create the hexa mesh for airfoil as usual.

2. Create tri mesh inside the jet along with prism layers.

3. Merge them in ICEM CFD (see my tutorial on 2d hybrid meshing on forum)

where is the tutorial on 2d hybrid meshing?