# how to determine the C0 and C1 on interior wall in fluent UDF

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 April 14, 2015, 04:04 how to determine the C0 and C1 on interior wall in fluent UDF #1 New Member   zhouxman Join Date: Dec 2014 Posts: 12 Rep Power: 8 Hi,everybody, how to determine the C0 and C1 on interior wall in fluent UDF?

April 15, 2015, 18:39
#2
Senior Member

A-A Azarafza
Join Date: Jan 2013
Posts: 226
Rep Power: 11
Quote:
 Originally Posted by zhouxman Hi,everybody, how to determine the C0 and C1 on interior wall in fluent UDF?

Dear Friend,

c0 = F_C0(f,t) and c1 = F_C1(f,t) are actually two macros are used to access to adjacent cell thread for faces (walls or interior). For wall faces, only c0 is available; however, for interior faces both c0 and c1 can be accessed via the right-hand rule. To determine the c0 and c1 thread on interior faces, you need to find the area normal vector. The cells out of which the area normal vector is pointing to is defined as c0 thread and the ones into which the area normal vector is pointing to is called c1 thread. So to get the right c0 and c1, first you should get the pertinent face thread using face look_up macro ant then employ the right-hand rue. To make it clear, see the schematic in attachment.

I hope it helps
Attached Images
 111.JPG (10.3 KB, 85 views)
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Regard yours

April 15, 2015, 22:12
#3
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zhouxman
Join Date: Dec 2014
Posts: 12
Rep Power: 8
Quote:
 Originally Posted by A CFD free user Dear Friend, c0 = F_C0(f,t) and c1 = F_C1(f,t) are actually two macros are used to access to adjacent cell thread for faces (walls or interior). For wall faces, only c0 is available; however, for interior faces both c0 and c1 can be accessed via the right-hand rule. To determine the c0 and c1 thread on interior faces, you need to find the area normal vector. The cells out of which the area normal vector is pointing to is defined as c0 thread and the ones into which the area normal vector is pointing to is called c1 thread. So to get the right c0 and c1, first you should get the pertinent face thread using face look_up macro ant then employ the right-hand rue. To make it clear, see the schematic in attachment. I hope it helps
dear,

best regard

April 17, 2015, 04:35
how to determine the 'area normal vector'
#4
New Member

zhouxman
Join Date: Dec 2014
Posts: 12
Rep Power: 8
Quote:
 Originally Posted by A CFD free user Dear Friend, c0 = F_C0(f,t) and c1 = F_C1(f,t) are actually two macros are used to access to adjacent cell thread for faces (walls or interior). For wall faces, only c0 is available; however, for interior faces both c0 and c1 can be accessed via the right-hand rule. To determine the c0 and c1 thread on interior faces, you need to find the area normal vector. The cells out of which the area normal vector is pointing to is defined as c0 thread and the ones into which the area normal vector is pointing to is called c1 thread. So to get the right c0 and c1, first you should get the pertinent face thread using face look_up macro ant then employ the right-hand rue. To make it clear, see the schematic in attachment. I hope it helps
dear,
how to determine the 'area normal vector'

 April 17, 2015, 04:45 #5 Senior Member   Join Date: Nov 2013 Posts: 1,629 Rep Power: 22 To answer your question, it would help what you mean with "determine". Do you want to know how to calculate the area normal vector in a script? Or do you want to know what "area normal vector" means? Or something else?

April 18, 2015, 07:32
Dear pakk，
#6
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zhouxman
Join Date: Dec 2014
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Quote:
 Originally Posted by pakk To answer your question, it would help what you mean with "determine". Do you want to know how to calculate the area normal vector in a script? Or do you want to know what "area normal vector" means? Or something else?
Dear pakk，
I want to know how to calculate the area normal vector in a script and the means of "area normal vector" .
Thanks

 April 20, 2015, 03:57 #7 Senior Member   Join Date: Nov 2013 Posts: 1,629 Rep Power: 22 Probably the words "area normal vector" did not appear out of nowhere into your brain. You must have read it somewhere. In fact, the only place I know where these words are used is in the Fluent manual. So I suggest you look there.

 April 26, 2018, 11:11 THREAD_SHADOW(t) flluent udf #8 New Member   Morteza Join Date: Aug 2016 Posts: 2 Rep Power: 0 Hello all I would like to know what is the functionality of THREAD_SHADOW(t) macro? I have searched little bit but i did not find any useful information. Can anybody demonstrate above macro in a UDF?

 April 26, 2018, 17:51 THREAD_SHADOW(t) flluent udf #10 New Member   Morteza Join Date: Aug 2016 Posts: 2 Rep Power: 0 Thank you very much pakk Could you please make an example of fluid-solid domain? the solid domain should be part of simulation and don't necessary have to be a wall. am I right? like gas in vicinity of porous media?

September 1, 2019, 09:36
Determine F_C0 and F_C1 on an interior wall
#11
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Jason FANG
Join Date: Aug 2019
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Hi everyone!
I am also wondering how to determine the macros of adjacent cells, F_C0 and F_C1, on an interior wall (interface between fluid and solid zones) as illustrated in Fig. I heard of the right-hand law, but I do not know how to use it. Is there any simple way to solve this problem?
Thanks for any help!
Attached Images
 interface.jpg (11.3 KB, 31 views)