# Local coordinate systems for 2 inlets

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April 22, 2022, 09:09
Local coordinate systems for 2 inlets
#1
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Hello,

I'm quite new to STARCCM and I didn't find the solution to my problem anywhere, forum or doc.

Here is the issue: I have a simulation with 2 circular shaped velocity inlet boundaries, representing 2 fans: inlet_left and inlet_right. I need to set up a specific velocity profile for each fan, and I tried to do it with the Table(r) method. Only velocity magnitude must vary, not flow direction (for now).
I created 2 new local cylindrical coordinate systems, respectivelly centered at the left and right inlets. I can't manage to link these coordinate systems to both inlets at the same time.

In short: I can't have the desired velocity profiles at both inlets at the same time using the Table(r) method, because I can't assign coordinate systems to both inlets independently.

The only way I kind of managed to do it is by assigning the left (or right) coordinate system to the entire region in Physics Values > Axis (cf. image1). But this only allow me to get the desired velocity profile on the left (or right) inlet, not on both at the same time.

I also tried defining 2 new reference frames respectively associated to the 2 local cylindrical coordinate systems, but this doesn't seem to work at all (cf. image2).

Thank you very much for helping!
Attached Images
 image1.png (64.1 KB, 6 views) image2.png (71.7 KB, 6 views)

 April 25, 2022, 09:25 #2 Senior Member   Chaotic Water Join Date: Jul 2012 Location: Elgrin Fau Posts: 322 Rep Power: 15 Yeah, looks like multiple coordinate systems cannot be used in case of Table(R). The only solution I can suggest - is to use Table(XYZ), coordinate system can be set per inlet in that case.

April 26, 2022, 07:43
#3
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Quote:
 Originally Posted by cwl Yeah, looks like multiple coordinate systems cannot be used in case of Table(R). The only solution I can suggest - is to use Table(XYZ), coordinate system can be set per inlet in that case.
Ok, I've tried with table(xyz) and it does work. It's quite annoying though, as you have to define theta and z values even when the velocity profile is only dependent upon r. It's weird that coordinate system per inlet does not exist with table(r).

Anyways, thank you, problem solved!

 Tags coordinate frame-, coordinate system, starccm+, table inlet