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-   -   sliding meshes with periodic BC's (http://www.cfd-online.com/Forums/fluent/31610-sliding-meshes-periodic-bcs.html)

Dan Brozozowski June 9, 2003 03:33

sliding meshes with periodic BC's
 
Section 9.5.3 of the User's Guide says the following: "If you are modelling a rotor/stator geometry using periodicity, the periodic angle of the mesh around the rotor blade(s) must be the same as that of the mesh around the stationary vane(s)."

I'm trying to model a single rotor/stator section of an axial pump in Fluent 6 using the sliding mesh technique. (Right now I'm just doing a 2D model at the midspan of the blades.)

My sliding mesh consists of a single channel from the rotor section and a single channel from the stator section.

The problem is that the rotor and stator have different numbers of blades (i.e. the rotor blades are spaced farther apart than the stator blades) so the interfacing boundaries of the two meshes have different lengths. So, for the reasons listed above from ing user's manual, Fluent does not accept this mesh.

It seems like there must be a way to solve this without modelling all the rotor/stator blades. Any suggestions?

Thanks!

Dan

senthil June 26, 2003 04:35

Re: sliding meshes with periodic BC's
 
hi, Before answering your question, could you plese tell me why you choose sliding mesh theroy. Its for unsteady case and moreover to capture the stong interaction of stator and rotor. I don't know much about the sliding mesh theory. But i'm also working on rotor stator problem using mixing plane theroy. THis you can try out, but only this is this is steady state anlalysis. And this will take care of diffenent interface lenghts (mixing plane).

senthil.

Dan Brzozowski June 26, 2003 15:01

Re: sliding meshes with periodic BC's
 
Senthil,

Yes, we are looking specifically at strong rotor-stator interaction. This page contains a good description of the machine I'm modelling:

http://www.me.jhu.edu/~lefd/turbo/turbo.htm

As I said before it's an axial turbopump with 12 rotor blades and 17 stator blades. The animations on the page are from the actual experimental data observed using Particle Image Velocimety (but this is a CFD forurm so I'll just leave it at that...)

Should I consider using the mixing plane approach? Can I still do unsteady analysis with that?

Dan

senthil June 27, 2003 08:10

Re: sliding meshes with periodic BC's
 
Dan, I look at the site you mentioned. Its great work.

Since you are intrested in rotor-stator interaction, Mixing plane will not work, as it is a steadt state asumption. The sliding mesh model is appropriate model to capture the interaction.

Senthil.



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