CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > FLUENT > Fluent UDF and Scheme Programming

UDF steady state to transient

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   December 20, 2012, 12:55
Default UDF steady state to transient
  #1
New Member
 
Vcent
Join Date: Nov 2012
Posts: 5
Rep Power: 13
Vcent is on a distinguished road
Hi,

After successfully using a UDF for a nonlinear velocity profile at an inlet in a steady state mode, I would like to run it in a transient mode. I added the factor time. However the function only runs with constants for "q" (see red part). Otherwise I get a error "divergence detected in AMG solver x-momentum".

After testing several parts, I think it has probably something to do with y=x[1] (see blue part). Does anyone know a solution?

#include "udf.h"

DEFINE_PROFILE(inlet_x_velocity, thread, index)
{
real x [ND_ND];
real y;
face_t f;
real t = CURRENT_TIME;
real q;

begin_f_loop(f,thread)
{
F_CENTROID(x,f,thread);
y=x[1];
if (CURRENT_TIME <= 100000.0)
q = 2.0*pow((y/3.0),0.4);
else
q = 1;
F_PROFILE(f, thread, index)=q;
}
end_f_loop(f, thread);
}

thanks,

Vcent
Vcent is offline   Reply With Quote

Reply

Tags
state, steady, transient, udf, velocity

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Steady State Vs Transient answers Kushagra CFX 25 July 23, 2017 04:20
Steady or Transient noobies FLUENT 1 February 17, 2012 14:38
Constant velocity of the material Sas CFX 15 July 13, 2010 09:56
Transient vs Steady State Adam CFX 1 April 12, 2007 12:34
About the difference between steady and unsteady problems Lisa Main CFD Forum 11 July 5, 2000 15:37


All times are GMT -4. The time now is 21:58.