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-   -   Rotating plate. (https://www.cfd-online.com/Forums/cfx/81728-rotating-plate.html)

 farrr November 4, 2010 18:07

Rotating plate.

Hi everyone,
I'm trying to model two rotating discs with some radial plates between them, with axial flow.
The picture shown here:

http://lh4.ggpht.com/_t22jHS_B_7A/TN.../s800/CFXp.JPG

http://lh4.ggpht.com/_t22jHS_B_7A/TN.../s800/CFX2.jpg

Inlet mass flow is used in the bottom, outlet pressure in the end and rotational periodic in each side. All the walls are rotating around the x axis.
I have no problem with modeling just two rotating discs but when I add the radial plate to the geometry, I get this error at the the first step of solver.

| ERROR #002100080 has occurred in subroutine CHECK_NORMV.
| Message:
| The specified velocity vector on the boundary patch
| |
| Default Domain Default
| |
| has a significant normal component at one or more faces. One of
| these face locations is

| (x,y,z) = ( 4.43340E-03, 3.68905E-02, 5.00000E-04).

| The angle between the specified velocity and the element surface is
| 89.217 degrees at this face. This is considered an error because
| it implies that the mesh is moving. The following are possible
| reasons for the error message:
| 1. There is a setup error; for example, an incorrect axis of
| rotation.
| 2. There may be a meshing problem; for example, the nodes on a
| rotating surface might not lie on the surface of revolution.
3. The boundary is curved and the mesh is very coarse. In this
| case, you may increase the tolerance for this check by
| increasing the expert parameter 'tangential vector tolerance'
| from its default of 20 degrees.

The location (x,y,z) refers to the a point at the end of the plate.

P.S. I refined the mesh in that spot but it didn't work.

 stumpy November 5, 2010 11:47

What's your rotation axis? I assume you need to use MFR for this. In a rotating domain, any counter-rotating walls must be tangential to the rotation direction. In a stationary domain, any rotating walls must be tangential to the specified velocity direction.

 michael_owen November 5, 2010 11:49

You need to put the system in a rotating frame of reference and apply counter-rotating wall velocities to the fixed walls, instead of attempting to apply a rotating wall velocity to the rotating plate. The wall velocity has to be tangent to the wall, otherwise the system is not stationary.

 farrr November 5, 2010 13:03

Thank you folks. I'll try that.

 flilk October 17, 2011 22:53

is it work ?
now i have a same problem,and have no idea

 farrr October 19, 2011 18:30

It was long time a go. But I think it worked.

 flilk October 20, 2011 02:48

toaday ,i use the rotating frame and counter-rotating wall to define the simulation,but the same problem is occour.i want to know what you did in your work.

 jthiakz July 20, 2015 14:24

counter rotating wall's mesh is coarse hence surface normal are >25 (cfx default). Refining could be an option or removing 3D features

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