[Shilpa]

I am doing fluid structure interaction of blood flow through artery in the case of asymmetrical fusiform aneurysm (abdominal aortic). Im using ansys workbench 15. i have udf for velocity and pressure written in a c file. My analysis is showing error for pressure values above 50 pascal while i need to run the coupling analysis for 10000-17000 pascal range.
do we need to give a pressure constant value along with udf velocity as inlet boundary condition in setup of fluid flow(fluent). Please share any information regarding this.
Thank you

[naikpk]

Hey,
I think you should give udf velocity profile as an inlet with constant/fixed pressure.
What error are you getting? Can you show your udf ?
What boundary condition are you using for outlet ?

[Shilpa]

the following is my inlet and outlet boundary conditions as functions in the same c program. after i interpret this c program in the ansys workbench, i assign velocity udf as inlet boundary and pressure 101325 Pa. then i assign pressure udf as outlet boundary. thats how i tried to do. I'm using i7 computer with 8gb ram and 3.4GHz.
Thanks for the reply



#include "udf.h"
DEFINE_PROFILE(inlet_velocity,th,i)
{
face_t f;
begin_f_loop(f,th)
double t=(CURRENT_TIME*2-floor(CURRENT_TIME*2))/2;
{
if(t<=0.0586)
{F_PROFILE(f,th,i)=0.0064;}

else if((t>0.0586)&&(t<=0.234))
{F_PROFILE(f,th,i)=(((2239*t*t*t)-(814.3*t*t)+(73.01*t)-1.4099)/100);}

else if((t>0.234)&&(t<=0.3049))
{F_PROFILE(f,th,i)=(((5327.9*t*t)-(2433.3*t)+277.94)/100);}


else if((t>0.3049)&&(t<=0.5202))
{F_PROFILE(f,th,i)=(((-5947.8*t*t*t)+(7368.3*t*t)-(3146.8*t)+474.48)/100);}

else if((t>0.5202)&&(t<=0.6836))
{F_PROFILE(f,th,i)=(((-48372*t*t*t*t)+(120715*t*t*t)-(112868*t*t)+(46881*t)-7301.2)/100);}

else if((t>0.6836)&&(t<=0.8705))
{F_PROFILE(f,th,i)=(((3252.7*t*t*t)-(7381*t*t)+(5543.3*t)-1377.3)/100);}

else if((t>0.8703)&&(t<0.8892))
{F_PROFILE(f,th,i)=(((-368.44*t*t)+(644.33*t)-281.05)/100);}


else if((t>0.8892)&&(t<=1))
{F_PROFILE(f,th,i)=0.005714;}

}
end_f_loop(f,th);
}

DEFINE_PROFILE(outlet_pressure,th,i)
{
face_t f;
begin_f_loop(f,th)
double t=(CURRENT_TIME*2-floor(CURRENT_TIME*2))/2;
{
if(t<=0.1979)
{F_PROFILE(f,th,i)=(101325+((27943*t*t*t*t)-(11166*t*t*t)+(1236.2*t*t)-(77.561*t)+80.944)*133.3223);}

else if((t>0.1979)&&(t<=0.3756))
{F_PROFILE(f,th,i)=(101325+((-27358*t*t*t)+(24083*t*t)-(6556.3*t)+636.68)*133.3223);}

else if((t>0.3756)&&(t<=0.5729))
{F_PROFILE(f,th,i)=(101325+((12473*t*t*t)-(17029*t*t)+(7485.9*t)-946.66)*133.3223);}


else if((t>0.5729)&&(t<=1))
{F_PROFILE(f,th,i)=(((-223.03*t*t*t)+(620.47*t*t)-(592.34*t)+275.83)*133.3223);}

}
end_f_loop(f,th);
}

[robogrady]

Shilpa
I would really appreciate if you can tell me what solution you came up with for this problem? Or if anyone else knows? Thank you.