
[Sponsors] 
October 13, 2011, 05:21 

#41 
New Member
Join Date: Sep 2011
Posts: 8
Rep Power: 6 
Sorry Marjan, that's about the limit of my knowledge on the subject. Let us know if you find a solution!


March 15, 2012, 03:58 

#42  
Senior Member
Safia
Join Date: Oct 2010
Location: Australia
Posts: 161
Rep Power: 7 
Quote:
Update Loop = TRANS_LOOP] added to additional variable commands?? need more explaintions please, ASAP 

April 5, 2012, 03:08 

#43 
Senior Member
Safia
Join Date: Oct 2010
Location: Australia
Posts: 161
Rep Power: 7 

April 5, 2012, 08:51 

#44 
Senior Member
Edmund Singer P.E.
Join Date: Aug 2010
Location: Minneapolis, MN
Posts: 510
Rep Power: 11 
What do you want to know?


April 6, 2012, 01:27 
how I can add update loop into my AV?&How we apply derivative at B.Cs

#45  
Senior Member
Safia
Join Date: Oct 2010
Location: Australia
Posts: 161
Rep Power: 7 
Quote:
Hi singer 1812 Actually, I would like to apply derivative w. r. t. distance at my b.Cs for u, v,w,E, and K. So does I can apply that using your advices into this thread? if so, how we can handle this without using user fortran into CFX solver? Thanks in advance 

April 6, 2012, 09:11 

#46 
Senior Member
Edmund Singer P.E.
Join Date: Aug 2010
Location: Minneapolis, MN
Posts: 510
Rep Power: 11 
You are trying to get d/dx not d/dt?
You dont need this method (update loop) to do that, that data is in already in solution. 

April 8, 2012, 18:51 
yes as you said

#47 
Senior Member
Safia
Join Date: Oct 2010
Location: Australia
Posts: 161
Rep Power: 7 

April 9, 2012, 00:13 
misunderstand me

#48  
Senior Member
Safia
Join Date: Oct 2010
Location: Australia
Posts: 161
Rep Power: 7 
Quote:
Actually U misunderstand me because you talked about d /dx,y,z into post stage but what I'm looking for is set d../dx, d../dy &d../dz=0 at the boundary consitions (outlets) into set up stage. any input can help Regards 

April 9, 2012, 08:57 

#49 
Senior Member
Edmund Singer P.E.
Join Date: Aug 2010
Location: Minneapolis, MN
Posts: 510
Rep Power: 11 
Dont need transloop. Just setup a CEL expression for the derivative and put it into the BC under flow direction.


April 9, 2012, 09:02 

#50 
Senior Member
Edmund Singer P.E.
Join Date: Aug 2010
Location: Minneapolis, MN
Posts: 510
Rep Power: 11 
Ahh, I didnt read your message carefully enough. You need it on the outlet.
To what purpose are you forcing the derivatives on the outlet? 

April 9, 2012, 21:10 
my model

#51  
Senior Member
Safia
Join Date: Oct 2010
Location: Australia
Posts: 161
Rep Power: 7 
Quote:
Any input can help. regards 

April 9, 2012, 21:17 
how I input my neumann BC through flow dirrection

#52  
Senior Member
Safia
Join Date: Oct 2010
Location: Australia
Posts: 161
Rep Power: 7 
Quote:
Regards 

April 10, 2012, 09:50 

#53 
Senior Member
Edmund Singer P.E.
Join Date: Aug 2010
Location: Minneapolis, MN
Posts: 510
Rep Power: 11 
I dont understand why you are trying to force an outlet to have a certain gradient. Is this purely to match something in liturature?
The opening will only apply those conditions to the flow coming into the domain, not the flow leaving it. The conditions of the flow leaving the domain are a function of what takes place inside. If you need the gradient to be zero wrt the boundary, use a symmetry BC. If it is non zero, I think you will need to use User Fortran to enforce that. 

April 11, 2012, 22:20 

#54  
Senior Member
Safia
Join Date: Oct 2010
Location: Australia
Posts: 161
Rep Power: 7 
Quote:
If I required any further recomments I will reask you 

April 12, 2012, 04:19 

#55 
New Member
lihui
Join Date: Jun 2010
Posts: 12
Rep Power: 7 
This method is right, frist you must run the fortan in your computer.


July 14, 2014, 18:06 
TRANS_LOOP operations

#56 
Banned
Join Date: Feb 2013
Posts: 16
Rep Power: 0 
Hello,
I am tring to use the TRANS_LOOP operation to solve the following equation in a CFX Domain: XX=1(1/((1XXold)^a+B*exp(C/(D*T[K]))*F*n))^a I am doing the following steps: · Create an additional variable XX which is defined by the expression : XX value: 1(1/((1XXold)^a+B*exp(C/(D*T[K]))*F*n))^a The variable is function of temperature. · Create another additional variable XXold which defined by the expression: XXold value: ave(XXold)@domain+XX()@domain*Time Step Size. · Initially, I run a simulation with initial values in Additional Variable Models XX=0 and XXold=0. But when I set for each variable its CEL expression I am getting this following message: "Bad expression value 'XXold val' detected in parameter 'Additional Variable Value' in object '/FLOW:Flow Analysis 1/DOMAIN:domain/SOLID MODELS/ADDITIONAL VARIABLE:XXold'. CEL error: The following unrecognised name was referenced: XX." Is there anyone who can help me to overcome this problem please? Thank you in advance for your advices and suggestions 

July 15, 2014, 08:37 

#57 
Banned
Join Date: Feb 2013
Posts: 16
Rep Power: 0 
Hello,
I am tring to use the TRANS_LOOP operation to solve the following equation in a CFX Domain: XX=1(1/((1XXold)^a+B*exp(C/(D*T[K]))*F*n))^a I am doing the following steps: · Create an additional variable XX which is defined by the expression : XX value: 1(1/((1XXold)^a+B*exp(C/(D*T[K]))*F*n))^a The variable is function of temperature. · Create another additional variable XXold which defined by the expression: XXold value: ave(XXold)@domain+XX()@domain*Time Step Size. LIBRARY:· Initially, I run a simulation with initial values in Additional Variable Models XX=0 and XXold=0. But when I set for each variable its CEL expression I am getting this following message: "Bad expression value 'XXold val' detected in parameter 'Additional Variable Value' in object '/FLOW:Flow Analysis 1/DOMAIN:domain/SOLID MODELS/ADDITIONAL VARIABLE:XXold'. CEL error: The following unrecognised name was referenced: XX." Is there anyone who can help me to overcome this problem please? Thank you in advance for your advices and suggestions 

July 15, 2014, 17:48 

#58 
New Member
Join Date: Sep 2011
Posts: 8
Rep Power: 6 
Hi emotep, I could be wrong, but on first glance, you have ave(XXold) and XX().
I think the issue amy be here....... 

July 15, 2014, 21:17 

#59 
Banned
Join Date: Feb 2013
Posts: 16
Rep Power: 0 
what do you suggest me. I am not using a variable such MASSFLOW or velocity for the variable I want to calculate. It is in fact independent. To calculate this I have already set an additional variable and express a CEL.
Thank you for your answer 

July 16, 2014, 23:31 

#60 
New Member
Join Date: Oct 2012
Posts: 8
Rep Power: 5 
this is covered here: http://www.edr.no/blogg/ansys_blogge...rations_in_cfx


Thread Tools  
Display Modes  


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Cel expressions  RAMAN6089  CFX  13  December 1, 2009 00:17 
junction box routine and CEL function  bornspur  CFX  2  February 3, 2009 03:24 
Cel expressions for trasient problem  Jervds  CFX  0  March 4, 2008 11:03 
Cel expressions Time dependent  Juan Maria Campos  CFX  8  December 27, 2007 19:16 
CEL Expressions  Nick  CFX  3  September 25, 2007 14:54 