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

SOS.udf inlet parabolic velocity for aerodynamic analysis

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

Reply
 
LinkBack Thread Tools Display Modes
Old   March 4, 2015, 12:00
Default SOS.udf inlet parabolic velocity for aerodynamic analysis
  #1
New Member
 
achilles
Join Date: Feb 2015
Location: paris
Posts: 2
Rep Power: 0
ashkan39t323 is on a distinguished road
Send a message via Skype™ to ashkan39t323
Hi guys,
How can i create udf for a wind tunnel simulation in architecture using LES model. The parameters are:
H=320m (wind tunnel height in y direction)
h(building)=200m (building height in the wind tunnel (y direction))

Wind Profile (x_velocity) calculation is:

v2=v1 * (ln[h2/0.8]) / (ln[h1/0.8))
The reference wind speed v1 is measured at height h1. v2 is the wind speed at height h2.

Considering v1=1m/s in h1=1m
what is the problem of this udf.
Tnx alot

#include "udf.h"

DEFINE_PROFILE(inlet_x_velocity, thread, position)
{
real x[ND_ND];
real y;
face_t f;

begin_f_loop(f, thread)
{
F_CENTROID(x,f,thread);
y = x[1];
F_PROFILE(f, thread, position) = (log10(y/0.8))/(0.223143);
}
end_f_loop(f, thread)
}
ashkan39t323 is offline   Reply With Quote

Old   March 4, 2015, 12:05
Default
  #2
Senior Member
 
Join Date: Nov 2013
Posts: 689
Rep Power: 9
pakk is on a distinguished road
Quote:
Originally Posted by ashkan39t323 View Post
what is the problem of this udf.
It would be better if you would tell the problem you have with this UDF. So that we don't have to guess what you are talking about. Compile error? Run error? Unexpected results? I am sure you have tried this UDF, tell us what came out of it.

But even without that information, I guess some unexpected results can be caused by the fact that you don't tell Fluent what x should be. For me it is clear that you mean x to be the position of cell f, but the compiler cannot guess that.
pakk is offline   Reply With Quote

Reply

Thread Tools
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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
VOF Volume fraction in Velocity inlet aruelle FLUENT 1 March 18, 2010 12:53
How to define a parabolic velocity inlet of particles with UDF zumaqiong FLUENT 2 February 22, 2010 10:46
udf parabolic velocity inlet with unsteady case Faruk Beyca FLUENT 3 November 28, 2005 15:25
UDF paraboloid velocity inlet Ronak Shah FLUENT 0 June 4, 2003 09:44
Terrible Mistake In Fluid Dynamics History Abhi Main CFD Forum 12 July 8, 2002 09:11


All times are GMT -4. The time now is 15:27.