# Velocity profile UDF

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

 May 8, 2012, 18:29 Velocity profile UDF #1 Member   Join Date: Jan 2011 Posts: 42 Rep Power: 6 Hi, I'm trying to create a tranverse velocity profile UDF to use it as velocity inlet boundary condition to simulate flow in a water tank. The UDF is as follows: ######################################## DEFINE_PROFILE(Velocity_Profile_Z, thread, index) { real x[ND_ND]; /* this will hold the position vector */ real z; face_t f; begin_f_loop(f, thread) /* loops over all faces in the thread passed in the DEFINE macro argument */ { F_CENTROID(x,f,thread); z = x[1]; if (z < 0) z = z*(-1); else F_PROFILE(f, thread, index) = 1*pow((z/(12.8)),0.142857); } end_f_loop(f, thread) } ############################################ When I run the simulation, once it converges I plot a XY Plot, see attached figure . In my case the Z-axis represents the abscissa and the velocity magnitude the ordinate. The plot shows that even do the function represents the desire velocity profile, there is almost none velocity magnitude variation!!! Does anyone have an idea of why is that happening?? Thanks in advance. [/URL]

 May 9, 2012, 04:11 #2 Member   Daniel Tanner Join Date: Apr 2009 Posts: 54 Rep Power: 8 You have set z = x[1]. This is the y direction on your mesh, is that correct? The x vector is given by: (x[0], x[1], x[2]) which is equivalent to (x,y,z). Worth checking this.

 May 10, 2012, 13:03 #3 Member   Join Date: Jan 2011 Posts: 42 Rep Power: 6 Thanks Daniel!! That was the problem!!!!!

 Thread Tools 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 On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post Oli Fluent UDF and Scheme Programming 4 September 30, 2013 15:39 cfdworker Fluent UDF and Scheme Programming 0 April 23, 2009 19:09 Anant FLUENT 1 February 27, 2008 15:54 William177 FLUENT 1 February 3, 2008 07:47 Alan Main CFD Forum 10 October 28, 2005 12:14

All times are GMT -4. The time now is 01:30.