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

Time-Varying Inlet Velocity

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   January 27, 2010, 12:25
Default Time-Varying Inlet Velocity
  #1
New Member
 
CFDFSI
Join Date: Dec 2009
Posts: 4
Rep Power: 16
cfdfsi is on a distinguished road
I'm trying to impose time-varying velocity at the inlet. Can someone guide me on how to impose the bc ?

Thanks.
cfdfsi is offline   Reply With Quote

Old   January 27, 2010, 17:00
Default
  #2
Senior Member
 
Join Date: Nov 2009
Posts: 411
Rep Power: 19
DoHander is on a distinguished road
Use a UDF - you will find an example of a an unsteady velocity boundary condition in the Fluent UDF manual.

Do
DoHander is offline   Reply With Quote

Old   January 27, 2010, 17:18
Default
  #3
New Member
 
CFDFSI
Join Date: Dec 2009
Posts: 4
Rep Power: 16
cfdfsi is on a distinguished road
thanks for the reply.

for example: if i want v(t) = 0.1*t for 0< t < 1 at the inlet,
is the following UDF correct ?

Code:
#include "udf.h"

DEFINE_PROFILE(transient_velocity, thread, position)
{

  float t, velocity;
  face_t f;

  t = RP_Get_Real("flow-time");

  velocity = 0.1*t;

  begin_f_loop(f, thread)
  {
   F_PROFILE(f, thread, position) = velocity;
  }
  end_f_loop(f, thread)

}
cfdfsi is offline   Reply With Quote

Old   January 27, 2010, 20:25
Default
  #4
Senior Member
 
Join Date: Nov 2009
Posts: 411
Rep Power: 19
DoHander is on a distinguished road
Looks OK (I didn't tested your code in Fluent), however if you want to apply this only for 0< t < 1 ... you've missed a test condition.

Do
DoHander is offline   Reply With Quote

Old   September 24, 2010, 17:26
Default
  #5
Member
 
Join Date: Jun 2009
Posts: 31
Rep Power: 16
mrestrepo30 is on a distinguished road
dear cfdfsi,

I was using your UDF to impose a time varying velocity inlet on a 3D cylinder. However, I'm not getting a plug profile with it.

Did anything similar happened to you?




Thanks!
mrestrepo30 is offline   Reply With Quote

Reply

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
Floating point exception error Alan OpenFOAM Running, Solving & CFD 11 July 1, 2021 22:51
How to set a time varying velocity field as a BC? Mikro OpenFOAM Pre-Processing 5 March 19, 2009 05:38
UDF paraboloid velocity inlet Ronak Shah FLUENT 0 June 4, 2003 10:44
velocity more than INLET velocity neu FLUENT 3 May 13, 2003 05:56
Terrible Mistake In Fluid Dynamics History Abhi Main CFD Forum 12 July 8, 2002 10:11


All times are GMT -4. The time now is 05:42.