Dear all,
I am meshing an annular tube inside a fluid domain (attached images). This tube has fluid flowing through it. Also, there is fluid outside of it. My problem is: I am trying to generate a hexa meshing, so I cut the blocks so I got 4 domains which are:
(i) an inlet fluid domain
(ii) an outlet fluid domain
(iii) a solid "tube" domain
(iv) an inner fluid domain
There are 4 domains that meet at the entrance of the tube (the same situation happens at the exit of the tube). Since I need surfaces inside the fluid domain in order to mesh all the blocks faces meeting at the inlet of the tube, the inlet fluid has two surfaces while the tube and the inner fluid have another two surfaces (one surface each).
My question is: these faces have different sizes, how can I create an interface so that CFX-Pre may recognize them and let me put different boundary conditions for each side?
Hi Larissa Pinheiro,
you need to create body in each domain to create separate mesh (structural or tetra). Try to do the tutorial supplied by ICEM - hybrid mesh to understand the idea.
Damian
Hi Damian,
I Have already created the bodies and associated the block parts. My question is precisely about the interfaces. However, thanks for your reply.
Hi,
I believe you completed blocking and your mesh quality is good. Now you want separate the domain into different zones and create interfaces between them ?
Is that what you are looking for ?
Hi Hariharan,
You are almost right, the steps I took are:
1) I created the block;
2) Then cut it into 3 parts which were associated with the 3 bodies: inner fluid, outer fluid, and solid, so originating 3 domains
3) Meshed any of them separately
4) Now I have one surface of the fluid meeting 3 other surfaces (inner fluid, solid, and the fluid outside the solid --> second and third images)
The problem is that CFX-Pre does not allow me to have interfaces with different sizes. Should I break the fluid surface into minor surfaces in order to adequate to the other surfaces? It complicates the mesh and does not look very efficient.
Hi Larisa,
Try to save the bodies as separate meshes and import them into CFX one by one using cfx5 format. Once the meshes will be created as separate they must have their own surfaces and thus the interfaces can be created.
Damian
Hi Larissa,
I usually create the mesh for Ansys Fluent and, therefore, not sure about Cfx. Following are my questions/suggestions.
1. Why do you mesh each block separately? You mesh altogether and assign blocks to create zones and interfaces (inner, outer and solid).
2. I believe inner to outer you may create an internal boundary rather than an interface as both are fluid.
3. Interfaces are needed at the inner and outer curved surfaces of the cylinder.
4. Did you create the O-grid to improve mesh quality?
Please let me know if this helps.
Hi Larissa, there is more than one way
The first and easier is such as Damian. Obidowski said: Mesh each one separately and import inside CFX each mesh. The interfaces will be created automatically with the default interface condition: flux conservation. If not, you can create and give a boundary condition you want and be available to each kind of interface and domain...
The second is meshing all together in ICEM. You can mesh each part with a method you want ( tetra, hexa, etc)
Save this mesh file ( the *.uns) and close only the mesh.
Repeat each step for each domain.
After all bodies meshed, in Mesh, open each mesh file.
ICEM will ask you what to do when the 2nd mesh is load ( merge or not to merge?), so you choose MERGE.
ICEM will create a topology of booth meshes, and repeat till all meshes are loaded
The elements do not need to be one-to-one coincident. CFX or FLUEN will apply some algorithm to pass the fluxes to another side - such as a Generic Geometric Interface - GGI from CFX.
It is better if the elements are the same size and nodes are in the same position but doesn`t matter. The code will calculate.
There are more possibilities, but these are common practices. Try the first.
Hi,Iam maheedhar .I am also facing a similar problem as yours.I have a heated solid sphere inside a fluid domain,but in the fluent i can see only the fluid domain ,how to separate these zones and also how to assign interfaces.Please help if possible. thank you.
Maheedhar Reddy Hi, follow the ideas suggested by Damian and Ricardo. If in ICEM, mesh them separately (do not forget to assign the parts properly) and then import them all together in another ICEM project or directly into your solver.
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