[mdsufiyan]

#include "udf.h"
#include "math.h"
#include

static real v_prev_y = 0.0;

DEFINE_CG_MOTION(flapping, dt, vel, omega, time, dtime)
{

Thread* t;
Domain* d;
FILE* fp;


real cg[3]; real force[3]; real moment[3];


real accl_y;
real dv_y;

real ured = 10;

real mass_y = 164.02;
real eta = 0.0001;
real ro = 1.0;

real c_y = 0.154;
real k_y = 16.09;

int i;
NV_S(vel, =, 0.0);

t = DT_THREAD(dt);
d = Get_Domain(1);

for (i = 0; i < 3; i++)
{
cg[1] = DT_CG(dt)[1];

Compute_Force_And_Moment(d, t, cg, force, moment, TRUE);

force[1] += -k_y * cg[1] - c_y * vel[1];


accl_y = force[1] / mass_y;


dv_y = accl_y * dtime;


v_prev_y += dv_y;


vel[1] = v_prev_y;
}

}

--------------------------------------------------------------------------------------------------------------------------------------------------

hello everyone,
I am trying to run a udf and it gives me the error as shown below not sure y. The UDF on top works the one at the bottom dosent. I already refined my mesh again and also reduced my convergence criteria to .1 and the time step to 0.001. however this didnt help.

the case is laminar, transient and set to SIMPLE.

I really need help asap thank you.



---------------------------------------------------------------------------------------------------------------------------------------------------
#include "udf.h"
#include "math.h"
#include

static real v_prev_y = 0.0;

DEFINE_CG_MOTION(flapping, dt, vel, omega, time, dtime)
{

#if !RP_HOST

Thread *t;
Domain *d;
FILE *fp;


real cg[3]; real force[3]; real moment[3];


real accl_y;
real dv_y;

real voltage;

real ured = 10;

real mass_y = 164.02;
real eta = 0.0001;
real ro = 1.0;

real c_y = 0.154;
real k_y = 16.09;

int i;
NV_S(vel, =, 0.0);

t = DT_THREAD(dt);
d = Get_Domain(1);

for (i = 0; i < 3; i++)

{
cg[1] = DT_CG(dt)[1];

Compute_Force_And_Moment(d, t, cg, force, moment, TRUE);

force[1] += -k_y * cg[1] - c_y * vel[1];


accl_y = force[1] / mass_y;


dv_y = accl_y * dtime;


v_prev_y += dv_y;


vel[1] = v_prev_y;

voltage = ((101.3 * accl_y) + (0.13 * vel[1]) + (39.5 * vel[1] * time));


#if !RP_HOST

fp = fopen ( "data.txt", "a");

fprintf (fp, "%g %g %g %g \n ", time, cg[1], vel[1], voltage );

fclose (fp);

#endif
}

#endif

}
------------------------------------------------------------------------------------------------------------------------------------------------------
Error: eval: unbound variable
Error Object:
Registering UdfSource, ("C:/Users/gheewale/Downloads/New folder20mm/New folder/PassiveplungingUDF.cpp")
Registering Udflib, ("C:/Users/gheewale/Downloads/New folder20mm/New folder/20_files/dp0/FLU/Fluent/libudf")

Error: eval: unbound variable
Error Object: