Pulsatile blood flow in arteries
 

Hi everyone,
I am a beginner in Fluent, but I am working in my final thesis in blood flow simulations through arteries.
I need to implement the pulsatile and sinusoidal blood velocity at inlet, similar as the attached image.
I have tried with the next code but, for instance, it doesn´t consider the retrograde flow (negative velocity).

/************************************************** *********************/
/* vinlet_udf.c
*/
/* UDFs for specifying time dependant velocity profile boundary condition
*/
/************************************************** *********************/

#include "udf.h"//file that contains definitions for define functions and fluent operations
#define PI 3.141592654

DEFINE_PROFILE(inlet_velocity,th,i)
{
face_t f;
begin_f_loop(f,th)
double t = (CURRENT_TIME*2-floor(CURRENT_TIME*2))/2; //t is the local time within each period

{
if(t <= 0.218)
F_PROFILE(f,th,i) = 0.5*sin(4*PI*(t+0.0160236));
else
F_PROFILE(f,th,i) = 0.1;
}
end_f_loop(f,th);
}

I know that I have to create a UDF code but, as I said, I am a rookie in Fluent.
Can anybody help me please??
Regards,
Rafa