Learning Forum

[Elir]

Hi.

I interpret my udf and start simulating.

My udf just defines a velocity inlet boundary condition in terms of wall shear stress and static pressure. Then I get this error after two iterations. Is there any idea how I can fix it? My udf is as below.

#include "udf.h"

#define Lpn 1.19e-11

#define Rw 2.83333333e11

#define Padv 2333.13486

DEFINE_PROFILE(velocity_outlet,t,i)

 {

real wall_shear_force, area, wss, P_lumen_endothelial, deltaP, A[ND_ND];

real SI, MC, LC, phi, Re, Lpl, Rt;

face_t f;

  begin_f_loop(f,t)

   {

F_AREA(A,f,t);

area = NV_MAG(A);

wall_shear_force = NV_MAG(F_STORAGE_R_N3V(f,t, SV_WALL_SHEAR));

wss = wall_shear_force/area;

SI=0.38*exp(-0.79*wss)+0.225*exp(-0.043*wss);

MC=0.003797*exp(14.75*SI);

LC=0.307+0.805*MC;

phi=LC*1.10446617e-3;

Lpl=phi*3.55555556e-10;

Rt=pow((Lpn+Lpl),-1)+Rw;  

F_PROFILE(f,t,i) =-pow((Rt),-1)*52.5*133.32;

   }

  end_f_loop(f,t)

 } 

Thank you for your attentions. 

[Karthik R]

Hello:
It seems to me that you do not really need a UDF for this. You should be able to use Fluent expressions for these analytical expressions. Can you try using this?
Karthik