[Engineer12]

Hi everybody


I am carrying out the study of the pulsating flow of the intake of a 4-stroke engine. For this I have created this boundary condition (UDF) to simulate the suction of the engine, but when I run the Fluent simulation it does not recognize it and marks that the mass flow is 0 kg/s.


Can anyone suggest me what could be wrong?
I put the code below.


Thank you




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

DEFINE_PROFILE(unsteady_velocity, thread, position)
{
face_t f;
real time;
real m;
time=CURRENT_TIME;
m = 0;

begin_f_loop(f, thread)
{
if (time <= (0 + (0.00136 * m)) && time > (0.00136 + (0.00136 * m)))
F_PROFILE(f, thread, position) = 0.0;
else if (time <= (0.00136 + (0.00136 * m)) && time > (0.0027 + (0.00136 * m)))
F_PROFILE(f, thread, position) = 0.18382;
else if (time <= (0.0027 + (0.00136 * m)) && time > (0.0041 + (0.00136 * m)))
F_PROFILE(f, thread, position) = 0.0;
else if (time <= (0.0041 + (0.00136 * m)) && time > (0.0054 + (0.00136 * m)))
F_PROFILE(f, thread, position) = 0.0;
else if(time> (0.0054 + (0.00136 * m)))
m = m + 1;
}
end_f_loop(f, thread)
}

[AlexanderZ]

udf should be hooked properly
look into ansys fluent customization manual

also I'm expecting probles with this code as you have "m" in if condition
however m is changing inside the loop over faces -> means condition will be different at different location on the same stime moment, double check it