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Interfaces between blade channel and casing treatment

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Old   September 18, 2017, 01:56
Default Interfaces between blade channel and casing treatment
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Nate Lau
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Dear all,

I made a 'One-channel' simulation in CFX to check the effect of casing treatment and the configuration is showed in the Pic1 in attachment. I want to link the two interfaces highlighted by green color with different configuration, by 'General Connection ''Frozen Rotor'. The whole mesh is completed in Numeca.

Firstly, there is a tip in CFX-Pre:
In Analysis 'Flow Analysis 1' - Domain Interface 'Boutlet_Outlet': Pitch Change option 'Automatic' is not valid if side 1 or 2 of the interface has a 360 degree or greater pitch angle, zero radius, mesh faces normal and parallel to the rotation axis, or mesh faces at the hub curve (low radial or axial position) which are thin in the radial or axial direction.

So, I set pitch ratio to be 1 then. But in CFX there is also error message, showed in the Fig2 in attachment.

Until now I cannot find the mistake... I do not know how to set Pitch Change in CFX-Pre for my case.
Attached Images
File Type: png CasingTreatment.png (88.5 KB, 10 views)
File Type: png 1505714053(1).png (11.5 KB, 11 views)
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Old   September 18, 2017, 07:27
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Glenn Horrocks
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Have you read the FAQ: https://www.cfd-online.com/Wiki/Ansy...do_about_it.3F

The floating point error might have nothing to do with your question about pitch ratio.
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Old   September 20, 2017, 07:27
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AHMAD
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I think your casing treatment domain and rotor domain should perfectly overlap if you choose pitch ratio = 1.

Try reading the manual again.
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Old   September 20, 2017, 22:36
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Nate Lau
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Thank you. The suggestion helps me.
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casing treatment, pitch change, rotor-stator

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