[ijama]

Hello,

I would like to seek help on making udf to calculate the torque (from pressure and viscous force) acting on a 2D blade. I know that the value can be easily obtained using Monitor but I need to get the torque value for each time-step so I can use it to adjust the angular velocity later(not in the code yet). I keep on getting error on line 30 "NV_S(force_v, =, F_STORAGE_R_NV(f,t,SV_WALL_SHEAR),*,-1.0);".

I pasted the code below, thank you in advance for your help.

# include "udf.h"

DEFINE_EXECUTE_AT_END(torque_time)
{
Domain *d = Get_Domain(1);
Thread *t = Lookup_Thread(d,5);
face_t f;
real NV_VEC(A);
real NV_VEC(force_p);
real NV_VEC(force_v);
real NV_VEC(torque_p);
real NV_VEC(torque_v);
real x[ND_ND];
real NV_VEC(radius);
real NV_VEC(torque_final);
real tor;
NV_S(force_p,= ,0.0);
NV_S(force_v,=,0.0);
NV_S(torque_final,=,0.0);
NV_S(torque_p,=,0.0);
NV_S(torque_v,=,0.0);

begin_f_loop(f,t)
{
F_AREA(A,f,t);
F_CENTROID(x,f,t);
NV_S(force_p,= , F_AREA(A,f,t), * , F_P(f,t));
NV_D(radius,= ,x[0],x[1],x[2]);
NV_CROSS(torque_p,radius,force_p);
NV_S(force_v, =, F_STORAGE_R_NV(f,t,SV_WALL_SHEAR),*,-1.0);
NV_CROSS(torque_v,radius,force_v);

NV_VV(torque_final,= ,torque_final,+, torque_p,+,torque_v);
tor= NV_MAG(torque_final);
}
end_f_loop(f,t)

printf("Torque is = %g", tor );
}

[pakk]

Make sure to compile it ("build"), not interpret.

[ijama]

Originally Posted by pakk

Make sure to compile it ("build"), not interpret.

Hello pakk,

Thank you for your reply. Yes I did both compiled and interpret but did not work.

[pakk]

And which error do you see exactly when you compile?