# Transient sinusoidal velocity inlet

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

 September 27, 2010, 11:07 Transient sinusoidal velocity inlet #1 Member   Join Date: Jun 2009 Posts: 31 Rep Power: 8 I'm trying to impose a sinusoidal velocity boundary condition in a cylinder, but instead of having the velocity magnitude changing in time (according to the sinusoidal eq), I only get my inlet profile to change into a sine wave. I tried using different equations for defining my transient boundary condition, but the result is always the same: a sine profile at the entrance. The UDF I'm using is below. Is this the correct way to impose a transient boundary condition? does anyone have any suggestions? Thanks! #include "udf.h" DEFINE_PROFILE(unsteady_velocity, thread, position) { face_t f; real t = CURRENT_TIME; real vel; vel= 0.2+0.1*sin(t); begin_f_loop(f, thread) { F_PROFILE(f, thread, position) = vel; } end_f_loop(f, thread) }

 September 27, 2010, 11:17 #2 Member   Neil Join Date: Jun 2009 Location: The Moon Posts: 42 Rep Power: 8 An easy way around this would be to get hold of the de laval nozzle 2D tutorial which has a UDF that imposes a transient sinusoidal velocity profile at the inlet. Then modify it for your problem or see how the code is structured then modify your UDF. Neil

 September 27, 2010, 12:03 #3 Member   Join Date: Jun 2009 Posts: 31 Rep Power: 8 Hi Trev, I actually have the same structure, but the only thing that I changed is that instead of using pressure I'm imposing velocity. To do this I'm just reading the UDF into the velocity inlet BC... but it doesn't work.

 Tags porfile, transient bc, udf, velocity

 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 anita OpenFOAM Running, Solving & CFD 7 September 25, 2012 05:35 chelvistero OpenFOAM 0 March 27, 2010 04:46 prapanj OpenFOAM 11 June 23, 2009 11:15 kapel OpenFOAM Running, Solving & CFD 3 June 6, 2006 10:03 Ronak Shah FLUENT 0 June 4, 2003 09:44

All times are GMT -4. The time now is 06:26.