Field Function Question. Need help writing it :(((

kj878 · February 6, 2012, 16:44

So I'm fairly knew to StarCCM and I need to set up my initial wall temperature such that it decreases as it goes along the length. I believe i need to write a field function for this but unfortunately I have zero experience in writing programs/codes and I have no idea how to write field function formula for my problem.

Wont someone be kind enough to help me write a field function?

My problem statement is a fluid flowing through a pipe, length say 1m and the temperature of the wall varies through the length.

From L=0 to L=.5 I need my wall temp to be at 150C. From L=.5 to L=.75, the wall temp needs to drop from 150C to 70C, linearly. Similarly, from L=.75 to L=1m, the wall temp needs to drop from 70C to 35C, linearly as well.

Can someone please help me with this??
Many thanks in advance!

ThomasZiegenhein · February 14, 2012, 18:30

Another option is to create an extern Table and read it in Star-ccm+.

With Field Functions it should work also. You get the values of the standard Field Functions through their names, e.g. $$Position[0] gives the i-th coordinate (x in Cartesian). IF-ELSE is like the short form in java, (Expression) ? statement1(if true) : statement2(if false) . You can make the linear drop in an extra Field Function and use it as statement. For further information take a look in the help.

February 6, 2012, 16:44	Field Function Question. Need help writing it :(((	#1
kj878 New Member kj878 Join Date: Feb 2012 Posts: 10 Rep Power: 14	So I'm fairly knew to StarCCM and I need to set up my initial wall temperature such that it decreases as it goes along the length. I believe i need to write a field function for this but unfortunately I have zero experience in writing programs/codes and I have no idea how to write field function formula for my problem. Wont someone be kind enough to help me write a field function? My problem statement is a fluid flowing through a pipe, length say 1m and the temperature of the wall varies through the length. From L=0 to L=.5 I need my wall temp to be at 150C. From L=.5 to L=.75, the wall temp needs to drop from 150C to 70C, linearly. Similarly, from L=.75 to L=1m, the wall temp needs to drop from 70C to 35C, linearly as well. Can someone please help me with this?? Many thanks in advance! Last edited by kj878; February 7, 2012 at 11:34.

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February 14, 2012, 18:30		#2
ThomasZiegenhein New Member Thomas Ziegenhein Join Date: Feb 2012 Posts: 8 Rep Power: 14	Another option is to create an extern Table and read it in Star-ccm+. With Field Functions it should work also. You get the values of the standard Field Functions through their names, e.g. $$Position[0] gives the i-th coordinate (x in Cartesian). IF-ELSE is like the short form in java, (Expression) ? statement1(if true) : statement2(if false) . You can make the linear drop in an extra Field Function and use it as statement. For further information take a look in the help.