[shedo]

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?

[AlexanderZ]

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

[shedo]

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
}

[AlexanderZ]

you may see Max=0 as output in two cases:
1. your condition is never true

f(Max<FC[1] && C_R(c,t_air)>100.0 ){

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