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Old   June 18, 2011, 05:05
Default Cyclic cg_motion
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Hi all! Thanks for everyone's help so far!

I want to implement a velocity set function in a udf over a period. Thus having a velocity over the first half and no velocity over the second.

This will simulate the velocity inlet during rowing

Here is my udf:

#include "udf.h"
#include "dynamesh_tools.h"

DEFINE_CG_MOTION(trans, dt, vel, omega, t, dtime)

float t;
face_t f;
float T;

T = 1.79; /*period of full cycle*/

/*reset velocities*/
NV_S(vel, =, 0.0);
NV_S(omega, =, 0.0);

if (!Data_Valid_P ())

Message0("\n\nNo data->No mesh motion\n\n");

while (t < 1000) /*will run until end specified in FLUENT*/
t = 0; /*set current time to zero*/

for (t < (T/2)) /*first half of period*/
vel[0] = 3;

for (t >= (T/2) && t < T ) /*second half of period*/
vel[0] = 0;


Any tips?

I am also struggling with negative cell volumes? Can anyone point me where I should look?

Thank you in advance
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