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-   -   Rotor-Stator interface boundary condition (http://www.cfd-online.com/Forums/edge/98018-rotor-stator-interface-boundary-condition.html)

AlesP March 1, 2012 11:07

Rotor-Stator interface boundary condition
 
Hi,

I don't know if this is the correct place to solve implementation issues, but let's try it :)

1) The way it is implemented in Edge now is that the interface boundary averaging is done in the radial direction (at least there must be some nontrivial variation in the radial component of the boundary coordinates).
Do you think that it would be useful to have the possibility of having the interface boundary averaging done in axial direction (i.e., boundaries with constant radial coordinate)? It is not difficult and I can do it - just want to know if it is useful for somebody.

2) I am almost sure (at least have some doubts) that conservation as it is implemented in econsbc_m.f90 and gcorrotstat_m.f90 is not working properly in some cases, at least if rotor and stator are rotational periodic (e.g., one blade modeled).

I have run some tests and the results were different for different relative positions of rotor and stator (which corresponds for instance to the fact that I pick different period). I used the trunk version but used the area weighting instead of mass flux weighting in econsbc_m.f90.

If I force FLSUM(2:4)=0 (don't use conservation for momentum equations) the results were ok - the same radial distribution of variables for both configurations.

I think that
FLSUM(1) = Integral RO * REL.VELOCITY DOT NORMAL
is independent of the position (this number remains the same if you rotate the mesh and velocities accordingly), and so is the conservation term for energy equation and probably also for turbulence (at least k, omega)
BUT
FLSUM(2) = Integral RO * REL.VELOCITY DOT NORMAL * U + P*N1
FLSUM(3) = Integral RO * REL.VELOCITY DOT NORMAL * V + P*N2
FLSUM(4) = Integral RO * REL.VELOCITY DOT NORMAL * W + P*N3
are not.

Somebody having problem with this? Do you think this could be some bug?

Thanks!
Ales


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