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makaero April 7, 2010 15:31

Connecting volumes
3 Attachment(s)

In a mesh of wing geometry, i have a problem with connecting volumes. I assigned the faces between volumes as 'interface' BC in gambit and exported the mesh.

After mesh file read into fluent a note appeared as
Note: Separating interface zone 3 into zones 3 and 1.
interface -> interface (3) and interface:001 (1)

and when asked for grid check in fluent it shows up a warning

"WARNING: Unassigned interface zone detected for interface 1
WARNING: Unassigned interface zone detected for interface 3"

I coudnt figure out whats wrong with the interface faces.
I meshed the all volumes (has 3 small volumes on wing and 3 volumes in domain, as shown in figure) seperately, should i unite or merge the volumes after meshing?

Do i loose the volume mesh if i unite all volumes?

All help appreciated!

-mAx- April 12, 2010 01:03

*if you unite the volumes, you will loose the volume mesh.
*if you set surfaces as Interfaces, your volumes have to be disconnected. Then after you imported your mesh into fluent, you have to define the couple of interfaces (define/interfaces). That's why you get warnings regarding unassigned interfaces

makaero April 12, 2010 13:26

Thanks for the reply.

The problem is resolved now.

As you can see in the grid file, the root and tip of the wing are attached to the faces to minimize the 3d effects, how does it effect Cl and Cd values?

Chris D April 13, 2010 00:32

If you're trying to minimize 3D effects, why not just solve a 2D problem? I'm just curious. Also, you might have some problems converging your solution due to the large changes in cell volume in the cross stream direction.

makaero April 15, 2010 19:18

Wing leading edge is sinusoidal wave, so icant do a 2d geometry.
yes i do have problem with solution convergence at high AOA.

A mesh with 1.2 million cells working well up to 12deg AoA, but i need the Cl and Cd values at 16 and 18deg of AoA.

How to avoid the convergence problem? i have given a try by under relaxing factors, but it dint fix the problem.


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