Two phase interface area
 

Hello all,

I am trying to get a UDF to find the surface area of the interface at the first row of cells adjacent to the wall. If my interface stretches across 3 cells, will I have to obtain the area of each of those cell? I am not sure on how to go about doing this. My case is 2D axisymmetric where I have vapor as my primary phase and liquid water as my secondary phase. I have posted my UDF below. If anyone can let me know if this is a good way to go about it or if I need to try a different approach, I would be greatly appreciative.

Thank you very much.
Bradley

#include "udf.h"
#include "sg.h"
#include "sg_mphase.h"
#include "flow.h"
#include "mem.h"

DEFINE_ADJUST(interface_area,d)
{
Thread *t;
Thread **pt;
cell c;
face f;
int Zone_ID = 6; /* Base Wall Boundary Condition ID = 6 */
d = Get_Domain(4); /* Interface Domain */
t = Lookup_Thread(d,Zone_ID); /* Thread Pointer to Base Wall */
real NV_VEC(A); /* Vector of Face Area */
real total_area = 0.0; /* Initializing the total area */

begin_f_loop(f,t)
{
F_AREA(A,f,t);
total_area += 2*3.14*NV_MAG(A); /* 2D Axisymmetric needs 2*pi */
}
end_f_loop(f,t)
}