[cfd_Matrix]

Hi all,
I am modeling Sun heating oil layer on top of water in three phase vof model (air as primary phase).. the solar flux (w/m2) is incorporated as heat source at the interface for oil vof >=0.5. I using DEFINE ADJUST to store VOF gradiant in C_UDMI; Display C_UDMI shows both interfaces (air/oil and water/oil). when I Run the calculation seem like it don't apply the heat source at all.
my question is why the CUDMI save both interfaces a,d how to force the SOURCE term at the air/oil interface (F(oil) >= 0.5.
Thanks in advance

#include "udf.h"
#include "sg_mphase.h"

#define Sun_flux 1120 /* average solar heat flux on earth surface (W/m2) */



DEFINE_ADJUST(my_adjust, mixture_domain)
{
int phase_domain_index=0.;
Thread *t;

cell_t c;

mixture_domain= Get_Domain(2);

thread_loop_c (t,mixture_domain)
if (THREAD_STORAGE(t,SV_UDM_I)!=NULL)

begin_c_loop (c,t)
{

/*To store gradient of volume fraction in a user defined memory*/
C_UDMI(c,t,0)=sqrt((C_VOF_G(c,t)[0])*(C_VOF_G(c,t)[0])+(C_VOF_G(c,t)[1])*(C_VOF_G(c,t)[1]));
}
end_c_loop (c,t)
}


DEFINE_SOURCE(heat, cell, mix_th, dS, eqn)
{
Thread *pri_th, *sec_th;
real source;

pri_th = THREAD_SUB_THREAD(mix_th, 0);
sec_th = THREAD_SUB_THREAD(mix_th, 1);

if (C_VOF(cell,pri_th)>0.05 && C_VOF(cell,pri_th)<0.5)
{

source= Sun_flux*C_UDMI(cell,mix_th,0);
dS[eqn] = 0.0;
}
return source;
}

[AlexanderZ]

if you defined domain in header

DEFINE_ADJUST(my_adjust, mixture_domain)

you don't need to reinitialize it

mixture_domain= Get_Domain(2);

compile code and you will see errors

[cfd_Matrix]

Originally Posted by AlexanderZ

if you defined domain in header

DEFINE_ADJUST(my_adjust, mixture_domain)

you don't need to reinitialize it

mixture_domain= Get_Domain(2);

compile code and you will see errors

Dear AlexanderZ Thank you for your reply, I compilE the UDF, and it compile with no error, the problem i am facing is with DEFINE SOURCE, which describe the absorbed heat at the oil/air interface (heat flux * mag(grad(F)), either it apply the eat source to both interfaces or it does not apply it at all, the problem is with :
if (C_VOF(cell,pri_th)>0.05 && C_VOF(cell,pri_th)<0.5)
how to force the SOURCE term at the air/oil interface and for (F(oil) >= 0.5
any clue on how to solve this problem ?

[AlexanderZ]

I can hardly understand what you a talking about

if (C_VOF(cell,pri_th)>0.05 && C_VOF(cell,pri_th)<0.5)
{

source= Sun_flux*C_UDMI(cell,mix_th,0);
dS[eqn] = 0.0;
}
return source;

there is no else statement for C_VOF(cell,pri_th)> 0.5 actually

if (C_VOF(cell,pri_th)>0.05 && C_VOF(cell,pri_th)<0.5)
{
..........
}
else
{
.............
}
return source;

[cfd_Matrix]

Originally Posted by AlexanderZ

I can hardly understand what you a talking about

if (C_VOF(cell,pri_th)>0.05 && C_VOF(cell,pri_th)<0.5)
{

source= Sun_flux*C_UDMI(cell,mix_th,0);
dS[eqn] = 0.0;
}
return source;

there is no else statement for C_VOF(cell,pri_th)> 0.5 actually

if (C_VOF(cell,pri_th)>0.05 && C_VOF(cell,pri_th)<0.5)
{
..........
}
else
{
.............
}
return source;

Dear AlexanderZ; what i mean by if statament is to force the heat source at the air/oil interface (not oil/water interface ) and it should be applied for cells belong to the interface with F(oil) >= 0.5 / Then the if statemnt should be like this:

if (C_VOF(cell,sec_th)>0.5) /* oil is the first secondary phase*/
{

source= Sun_flux*C_UDMI(cell,mix_th,0);
dS[eqn] = 0.0;
}
else
{

source= 0.0;
dS[eqn] = 0.0;
}
return source;