# UDF Unsteady velocity parabolic profile

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 February 27, 2008, 15:05 UDF Unsteady velocity parabolic profile #1 Rashad Guest   Posts: n/a Hi Is it possible to give parabolic unsteady velocity inlet with the help of UDF. I tried UDf in given in the documentation it works but when i incorporate space variable x in the unsteady UDF it does not work. Any help Regards Rashad

 February 28, 2008, 12:27 Re: UDF Unsteady velocity parabolic profile #2 Paolo Lampitella Guest   Posts: n/a Just substitute your velocity components to these ones /************************************************** ******************** UDF for specifying a transient velocity profile boundary condition ************************************************** ********************/ #include "udf.h" DEFINE_PROFILE(x_velocity, t, i) { real x[ND_ND]; real x0, y0, time; face_t f; time = CURRENT_TIME; begin_f_loop(f, t) { F_CENTROID(x,f,t); x0 = x[0]; y0 = x[1]; F_PROFILE(f, t, i) = -cos(x0)*sin(y0)*exp(-2.0*time); } end_f_loop(f, t) } DEFINE_PROFILE(y_velocity, t, i) { real x[ND_ND]; real x0, y0, time; face_t f; time = CURRENT_TIME; begin_f_loop(f, t) { F_CENTROID(x,f,t); x0 = x[0]; y0 = x[1]; F_PROFILE(f, t, i) = cos(y0)*sin(x0)*exp(-2.0*time); } end_f_loop(f, t) }

 February 29, 2008, 02:36 Re: UDF Unsteady velocity parabolic profile #3 Rashad Guest   Posts: n/a Thankyou Dear Paolo Lampitella Rashad

 October 1, 2018, 15:27 #4 New Member   ismail demirkıran Join Date: Jul 2017 Posts: 4 Rep Power: 8 thanks guys, I have a similiar problem with transient parabolic velocity proflie but i need 3D version. -How can i modify this code? -Is there a reference paper or definition for given equation above? Regards, ismail