[schwaral]

Hi all,

Can someone explain me what I messed up? I think I missunderstood something fundamental here. It compails without error. The UDF works without the loops. Also using only the inner loop is not working. Without the DEFINE_ONDEMAND all other UDFs in the file compiled work fine. When it runs I get this error:

Error: received a fatal signal (Segmentation fault).

Error: received a fatal signal (Segmentation fault).
Error Object: #f

DEFINE_ON_DEMAND(find_othercell)
{
Domain *d= Get_Domain(22);
int ID = 12;
Thread* f =Lookup_Thread(d, ID); // is pointer to thread
face_t f; //face_t is an integer data type that identifies a particular face within a face thread.
int n_faces; //number of faces

thread_loop_f(f, d)
{
begin_f_loop(f, t)
{
n_faces = n_faces + 1;
//C_CENTROID(air_c_centroid, c_cell, t_mark);
}
end_f_loop(f, t)
}
Message0("n_faces: %i \n", n_faces);
}

I think maybe the ID is wrong. I have a conformal mesh and there are multiple domains. 22 refers to one domain of my porous domain, that is connceted to other domains. ID 12 refers to the Intrior that represents the face between the domain(22) and domain(24). I tried 22 and 24 and both gives me same error. I think the "interior face" with ID 12 belongs to both of the domains but this is not possible?! If you can trust CFD-Post the name of 12 suggest, that it belongs to the domain 22

[schwaral]

for example this is not working as well. I really do not understand why this error happens. All I can read in the internet, is that mostly a variable is not initialized or the UDM is not set or the UDF is not compiled correclty. But for me all this is not the case

[schwaral]

for example this is not working as well.


DEFINE_ON_DEMAND(findothercell)
{
Domain *d= Get_Domain(24);
int ID = 32;
Thread* tf;
face_t f;
tf =Lookup_Thread(d, ID);

begin_f_loop(f, tf)
{
printf("n_faces\n");
}
end_f_loop(f, tf)
}




I really do not understand why this error happens. All I can read in the internet, is that mostly a variable is not initialized or the UDM is not set or the UDF is not compiled correclty. But for me all this is not the case

[pakk]

It can mean that domain 24 does not exist, or that cell zone 32 does not exist.

And my first guess would be domain 24... Why did you put 24 there? Where does this number come from?

[schwaral]

Originally Posted by pakk

It can mean that domain 24 does not exist, or that cell zone 32 does not exist.

And my first guess would be domain 24... Why did you put 24 there? Where does this number come from?

It is what I read in the fluent setup tree under cell-zone-conditions. I thought the number there is the number of the domain?

[pakk]

Originally Posted by schwaral

It is what I read in the fluent setup tree under cell-zone-conditions. I thought the number there is the number of the domain?

No, you misunderstood the help. GET_DOMAIN refers to the phase. Normally it is 1, if you have a mixture then higher values refer to the other mixture components.

The number 24 that you saw is the THREAD_ID of the interior, you don't need that here.

Summary : just use GET_DOMAIN(1).

[schwaral]

aaah okay thanks! that makes sense now

[schwaral]

I have another question regarding the internal walls. When I use c0=F_C0(f,ft) and loop over all faces of internal wall, Fluent finds all the cells on the left side of the internal wall. When I use c1=F_C1(f,ft) fluent finds all the nodes right of the internal wall.

I thougth that c1 should be the cell thread even further away from the boundary (2nd cell row next to boundary).

Do you have an idea how to find the 2nd row of cells next to internal wall?
I want to find the first two cells on the right side of internal wall. So somehow the c0 has to be on the other side (right) of the wall and c1 should be on the right side as well.

	begin_f_loop(f, tf)
	{
		/* c0 and t0 identify the adjacent cell */
		c0 = F_C0(f, tf);
		c1 = F_C1(f, tf);
		t0 = THREAD_T0(tf);
		t1 = THREAD_T1(tf);			

			C_UDMI(c0, t0, 0) = 1.0;
			C_UDMI(c1, t1, 1) = 2.0;
	
	}
	end_f_loop(f, tf)

PS: The way I tried it now is to use normal face vector from c0 to c1 and since I know the distance to my 2nd cell row I can do a simple sum of normalvector*distance+ c1=new point in 2nd cell row. However I am am unable to find a soution to find the Cell Centroid by only knowing the coordinates in a cell.
If I use interpolation for reading solution data, do I need to know the cell centroid or will Fluent automatically detect the cell centroid, when I give x,y,z of a cell?