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Old   April 26, 2014, 06:51
Default How to set rotating monitor point
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Hi guys,
I want to calculate rotating compressors and set some monitor points. Now i met some troubles. A the blade is rotating, the monitor point should rotate along with the blade. So how to set the monitor points? How to let the monitor points rotate along with the computational domain?
Looking forward to your help!
Thank you !
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Old   June 2, 2014, 23:48
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Does anybody konw? How to let the monitor point rotate along with the blade? Thanks!
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Old   June 5, 2014, 05:38
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This worked for me:
-create a Source Point from Cartesian Coordinates in CFX (e.g. SP1)
-write an expression like XSP1=probe(Global X Coordinate)@SP1
-monitor the created expression XSP1

-->this is quite handy, since you can probe whatever pleases you (and as long as itīs available @ runtime)

Any better solutions are welcome!

Matthias
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Old   June 5, 2014, 06:52
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What version of ANSYS CFX are you using ?

Up until version 14.0, the monitor points in rotating domains always move with the domain (Local option in later releases). I understand this is what you are asking for, correct ?

From version 14.5, you can select the location of the monitor point to be interpreted as stationary, or local to the reference frame in the domain. That is, for the new option Stationary, the domain is passing while the point remains stationary.

Hope the above helps
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Old   June 5, 2014, 11:14
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Quote:
Originally Posted by Opaque View Post
What version of ANSYS CFX are you using ?

Up until version 14.0, the monitor points in rotating domains always move with the domain (Local option in later releases). I understand this is what you are asking for, correct ?

From version 14.5, you can select the location of the monitor point to be interpreted as stationary, or local to the reference frame in the domain. That is, for the new option Stationary, the domain is passing while the point remains stationary.

Hope the above helps
Thanks for your reply!

The version of ANSYS CFX that I use is 13.0. Are you sure that the monitor point in rotating domains will move with the domain without doing anything special? I think that in version 13.0, the monitor point is default local to the reference frame. But the default reference is a stationary cartesian coordinate system. The monitor point is set by given xyz coordinates reference to the stationary cartesian coordinate system. Through the domain is rotating, will the coordinate fixed monitor point move will it ?

Hope your further reply.
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Old   June 5, 2014, 13:24
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Recall that ANSYS CFX never moves the meshes in the rotating frame. The equations are written in the rotating frame; therefore, the mesh points remain on the same location.

On the new feature, the points moves backwards (counter rotating) to probe a different location in the domain.

You should be fine.

It is very easy to verify by looking at the signal generated by the probe. If the probe is in front of the rotating boundary you should see a sine wave with the frequency of the rotation and the pitch that separates the next passing if the point is in the stationary frame. Otherwise, you see the value in the rotating frame.
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Old   June 5, 2014, 22:51
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Quote:
Originally Posted by mvoss View Post
This worked for me:
-create a Source Point from Cartesian Coordinates in CFX (e.g. SP1)
-write an expression like XSP1=probe(Global X Coordinate)@SP1
-monitor the created expression XSP1

-->this is quite handy, since you can probe whatever pleases you (and as long as itīs available @ runtime)

Any better solutions are welcome!

Matthias
Thanks for your kindest reply!

I have tried your method, but I have some questions. What's the meaning of probe(Global X Coordinate)? How can I set the variables I want to monitor (as I want to know the pressure change with the time); How to set the rotating speed?

Opaque says that the monitor point will move with the domain without doing anything special. Do you agree?

Hope your further reply! Thank you !
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