udf for finding coordinate of last cell of water on vertical line in domain domain
 

Hello experts,
I have 2 phase flow(water and air) and I generated waves. after a while I want to find water elevation on the vertical line defined in the domain (located at 2m from the inlet boundary), I have the ID of the line, but I don't know how to find the water elevation and save it on file to reuse it in the next steps? can anyone help me with it?

how did you make that line?
make a sketch

my vision:
to find the coordinate of water you may make a loop over cells and check C_VOF (in case you are using VOF to simulate water)

if C_VOF = 1 (or close to 1) you may consider it as water, so now you may check it's coordinates and get the max along the axis you need

thanks, AlexanderZ
I wrote to UDF, but only the first one gives me the output and the second one always shows 0 value for C_VOF .
-------------------------
the first UDF is:
==============
#include "udf.h"
#include "sg_mphase.h"
/* domain passed to Adjust function is mixture domain for multiphase*/
FILE *fp;
DEFINE_ADJUST(report_VOF, domain)
{
/* "Parallelized" Sections */
#if !RP_HOST /* Compile this section for computing processes only (serial and node) since these variables are not available on the host */

Thread *t;
cell_t c;
real xc[ND_ND],x0=2.4327,dx=0.2;
real max1=0.0;

fp = fopen("output.txt","w");
thread_loop_c(t,domain)
{
begin_c_loop(c,t){
C_CENTROID(xc, c, t);
if(xc[0]<x0+dx && xc[0]>x0-dx && max1<xc[1] && C_R(c,t)>900.0){
max1=xc[1];
}

}
end_c_loop(c,t)
}
fprintf(fp,"%f\n",max1);
fclose(fp);

}
#endif /* !RP_HOST */
}



-------------------------------------------------------------------
and the second udf is:
=========================================

DEFINE_ADJUST(max_value, domain)
{
#if !RP_HOST
real FC[2],Max=0.0;
cell_t c; //Cell thread
face_t f;
Thread *t_air; // Phase level thread
///domain = Get_Domain(2);
///int ID = 11;
//Domain *subdomain;
//subdomain = Get_Domain(2); /* returns phase with ID=2 domain pointer
// and assigns to variable
// Zone ID for wall-1 zone from Boundary Conditions task page
Thread *thread = Lookup_Thread(domain, 2);
t_air = THREAD_SUB_THREAD(thread, 1);
begin_f_loop(f, thread)
{
//c = F_C0(f,thread);
c = F_C0(f,thread);
F_CENTROID(FC,f,thread);
if(Max<FC[1] && C_R(c,t_air)>100.0 ){
Max=FC[1];
}
///if (C_VOF(c,t_air) <0.2) {
// C_VOF(c,t_air)=0;
// printf("x-coord = %f y-coord = %f phi=%f\n", FC[0], FC[1],C_VOF(c,t_air));
//printf("x-coord = %f y-coord = %f phi=%f\n", FC[0], FC[1],C_VOF(c,domain));
// }

}
end_f_loop(f,thread)

printf("max=%f \n",Max);
#endif
}

you may see Max=0 as output in two cases:
1. your condition is never true
2. max y-coordinate of our boundary (with ID 2) is 0, in other words all other coordinates of boundary are negative

test if C_R(c,t_air) macro returns you correct value