UDF for Dynamic mesh

guido_88 · April 2, 2013, 11:51

Hi, I'm trying to simulate a 2D flow over a moving cylinder or over an inclined plate. I have to describe a vertical motion that follow a sinusoidal law for my cylinder/plate, so can anyone write a simple UDF to use? Thanks!

vasava · April 3, 2013, 01:51

Here is UDF from fluent tutorial. You can edit it to your specifications.

/************************************************** *******************/
/* UDF to compute the orientation of a rotating valve, based on a
specified rotational speed.

Christoph Hiemcke, Fluent Inc., 12 Feb 2004

butterlfy_flex_UDF = name shown in Fluent GUI
dt = thread
cg_vel = cg velocity (global)
cg_omega = angular velocity (global)
time = current time
dtime = time step
*/
/************************************************** *******************/
#include "udf.h"

#define omega 10.0 /* rotational speed, rad/sec */

DEFINE_CG_MOTION(butterfly_flex_UDF, dt, cg_vel, cg_omega, time, dtime)
{
cg_vel[0] = 0.0;
cg_vel[1] = 0.0;
cg_vel[2] = 0.0;

cg_omega[0] = 0.0;
cg_omega[1] = omega;
cg_omega[2] = 0.0;
}

April 2, 2013, 11:51	UDF for Dynamic mesh	#1
guido_88 New Member Guido Join Date: Dec 2009 Posts: 17 Rep Power: 15	Hi, I'm trying to simulate a 2D flow over a moving cylinder or over an inclined plate. I have to describe a vertical motion that follow a sinusoidal law for my cylinder/plate, so can anyone write a simple UDF to use? Thanks!

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April 3, 2013, 01:51		#2
vasava Senior Member Paritosh Vasava Join Date: Oct 2012 Location: Lappeenranta, Finland Posts: 732 Rep Power: 22	Here is UDF from fluent tutorial. You can edit it to your specifications. /************************************************ ****************/ / UDF to compute the orientation of a rotating valve, based on a specified rotational speed. Christoph Hiemcke, Fluent Inc., 12 Feb 2004 butterlfy_flex_UDF = name shown in Fluent GUI dt = thread cg_vel = cg velocity (global) cg_omega = angular velocity (global) time = current time dtime = time step / /*********************************************** ****************/ #include "udf.h" #define omega 10.0 / rotational speed, rad/sec */ DEFINE_CG_MOTION(butterfly_flex_UDF, dt, cg_vel, cg_omega, time, dtime) { cg_vel[0] = 0.0; cg_vel[1] = 0.0; cg_vel[2] = 0.0; cg_omega[0] = 0.0; cg_omega[1] = omega; cg_omega[2] = 0.0; }