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[ANSYS Meshing] Define a Interface between a Rotary Domain and a Stationary Domain

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Old   July 22, 2014, 13:36
Default Define a Interface between a Rotary Domain and a Stationary Domain
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Hi Guys,
I have already searched the Internet and didnt find a Tutorial/Explaniation etc...

For Meshing i have the Option Hypermesh and ICEM CFD15.

I just dont get it. I have a Rotating Domain and a Stationary Domain. Between I need a Interface. Do I need only ONE 2D Interface mesh? One Surface?
I have tried it with one Surface and than I had these Shadow Walls in CFX...

Or do I need to mesh both Surfaces? Contact Surface of Rotating Domain + Contact Surface of Stationary Domain?
But than those 2 Interface Meshes are not equal.

Trying it for 8 hours now...

Best greetings

Benjamin
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Old   July 22, 2014, 14:33
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The way that I always do it is to have two solid bodies that meet at some interface. The interface needs to have either the same radial or axial extent. The surface that defines the interface on both sides needs to touch. Think of having one solid body and cutting it with a very thin knife. Then you mesh each part independently and then define the interface in fluent or cfx or whatever by picking both sides of the interface.
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Old   July 22, 2014, 14:37
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Quote:
Originally Posted by khoopes View Post
The way that I always do it is to have two solid bodies that meet at some interface. The interface needs to have either the same radial or axial extent. The surface that defines the interface on both sides needs to touch. Think of having one solid body and cutting it with a very thin knife. Then you mesh each part independently and then define the interface in fluent or cfx or whatever by picking both sides of the interface.
That means, I only need one 2D Interface between those two Domains?
Because I have also 2 Solids. That means I have 2 times the same Surface. So I can delete one of those Surfaces, connect with my other Surface those two solids and I am done?
I am confused. Because that guy in that Video defined Interface1_1 & Interface1_2 in Fluent. Later he combined them...
https://www.youtube.com/watch?v=P2vaj70ATZs

Greetings
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Old   July 22, 2014, 14:43
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I am not as familiar with fluent. In CFX, you need two meshed surfaces with each one defining one side of the interface.
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Old   July 22, 2014, 14:55
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Quote:
Originally Posted by khoopes View Post
I am not as familiar with fluent. In CFX, you need two meshed surfaces with each one defining one side of the interface.
And must those surface meshes look 1:1 ? so do they need to have the exactly same mesh? i mean the nodes need not to be at the same locations?

Thank you so much for your help already!
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Old   July 22, 2014, 14:57
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CFX can do it both ways, look up "Mesh Connection Options" in the CFX Help (section 5.4 in the modeling guide)
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Old   July 22, 2014, 17:30
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Ok went through it. I did not understand what that Pitch Change is. For my Interface Rotating + Stationary, they have the same dimension, just the mesh is not equal.
There was a error and I had to choose None. It simulates know, tomorrow I know more... Can u tell me in easy words what that Pitch Change is? I am from Austria and i googled for some German Translation... However I didnt get it...
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Old   July 23, 2014, 10:27
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Pitch is the amount of the full 360 covered by a component. So a component with 10 passages would have a 36 degree pitch. Pitch change is when one component has a different number of passages per 360 than another component. This is common between rotors and stators. A rotor may have 10 passages and a stator 12 or something. There would be a pitch change between these two components. You can either model more than one passage per component to get equal pitch between them, or live with the pitch change. Anytime there is a pitch change it has to be modeled. CFX has several ways to model pitch change and they all have their advantages and disadvantages.
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