# [boundary condition] logarithmic velocity profile

 User Name Remember Me Password
 Register Blogs Members List Search Today's Posts Mark Forums Read

 LinkBack Thread Tools Search this Thread Display Modes
 April 17, 2009, 16:14 [boundary condition] logarithmic velocity profile #1 New Member   Join Date: Apr 2009 Posts: 14 Rep Power: 17 Hello, I have a problem that involves boundary condition in fluent. My boundary condition is a logarithmic velocity profile, that enters in the domain, and I don’t know how to do this in fluent. With velocity inlet I can create a regular velocity profile, but I can’t create a logarithmic velocity profile in boundary condition. So I wonder if anyone can tell me how I define a logarithmic velocity profile in boundary condition with fluent. Thanks and sorry for my bad English Last edited by cfdworker; April 17, 2009 at 17:33.

 April 17, 2009, 17:40 #2 New Member   mark Join Date: Apr 2009 Posts: 5 Rep Power: 17 define a profile file and call the profile in the bc file or for more flexibility use a udf for spatial variation definition using log relationship. see udf guide and define profile macro for example.

 April 17, 2009, 23:36 #3 New Member   Join Date: Apr 2009 Posts: 14 Rep Power: 17 Hello, thanks for the answer. I tried to make an udf file, like you suggested, that defines the logarithmic profile, but when I interpreted or compiled the file, fluent report an error and can’t read the file. I wonder if the udf file I make is wrong. My udf is this file: #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) = 3.*log(y/((10.)^(-2.)))/log(10./((10.)^(-2.))); } end_f_loop(f, thread) } My domain is 3d and my simulation consists in analyze the wind in a terrain. So I ask anyone if can tell me what is wrong with my udf file. I would appreciate any suggestions.

 Thread Tools Search this Thread Search this Thread: Advanced Search Display Modes Linear Mode

 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 OffTrackbacks are Off Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post Sing FLUENT 12 August 7, 2017 06:25 Morten Andersen CFX 1 January 8, 2007 11:37 Alan Main CFD Forum 10 October 28, 2005 12:14 R P CFX 2 October 26, 2004 02:13 Murat Main CFD Forum 0 December 30, 2003 00:45

All times are GMT -4. The time now is 20:42.

 Contact Us - CFD Online - Privacy Statement - Top