I'm currently working on the UDF of a VOF model involving water and oil phase. The code is really simple which is trying to patch a oil droplet in the 2d domain. The code shows as following
#include "udf.h"
DEFINE_INIT(my_init_func,d)
{
cell_t c;
Thread *t;
real xc[ND_ND];
/* loop over all cell threads in the domain */
thread_loop_c(t,d)
{
/* loop over all cells */
begin_c_loop_all(c,t)
{
C_CENTROID(xc,c,t);
if (sqrt(ND_SUM(pow(xc[0] - 2.,2.),
pow(xc[1] - 2.,2.),
pow(xc[2] - 2.,2.))) < 1.)
C_VOF(c,1) = 1.;
else
C_VOF(c,1) = 0.;
}
end_c_loop_all(c,t)
}
}
During interpretation, no error was reported while the "segmentation fault " shows after the initialization.
What's more, if i compiled the code, something is wrong with the problem of ‘xcopy'. Load the C file, "The UDF library you are trying to load (libudf) is not compiled for 2d on the current platform (win64)." is presented.
If anybody can help me? Thank you so much!!!
segfaults (174) occur when the program tries to use memory/resources that are not accessible for it.
1) try to increase the stack, core, and memory during runtime (ulimit -s unlimited, ulimit -c unlimited, ulimit -m unlimited)
2) recompile with (for intel fortran) -heap arrays 64 .
This problem is solved.
The solver can only pass the pointer of the mixture domain but not subdomains'. So the volume fraction of sundomain cannot be defined as a property like temperature. In order to define the volume fraction of secondary phase, a domain_id and a pointer pointing to the subdomain must be set.
I have the same problem while simulating PEM fuel cell and I don't know what to do. please guide me
Chris Zhong Drahomir Chovan Mohamadreza Beygifard
Dear all thanks for the discussion, it gives me such insight about my project.
Still, I have to ask since I couldn't manage to run it properly.
My system is composed of 3 bodies, and the middle body will be the host of a reaction. All those three systems have the porous zone option activated. I want the water liquid which flows through the undermost body and arriving the porous jump boundary, passing through this boundary, reacting with the chemicals I designated in the middle body, creating those other products, and finally once again those products for this time passing through the second porous jump boundary and reaching to the uppermost body.
I hope you could imagine the system. Now I created 2 cell zones just above these porous jump boundaries with a width of 1 grid cell which was 8 m for my case, and also set the Y velocities of those interior cell zones as 0. Logically, since they are just above the porous jump boundaries they are actually in-situ of the reaction area(the middle body). So, I did activate the porous zone and reaction options for my cell zones, and set '0' value for the Y velocities in the fixed values tab (A researcher who encountered the same problem proposed this method, so I wanted to give it a try.).
Now, as for porous jump boundaries, I still set them as porous jump boundaries which I believe where the problem arises. When I didn't create a namedselections for them in mesh section, ANSYS Fluent gives the error for example:
Error: Species are not solved in neighbor cell threads (14 and 16)\n of interior zone 6. \n
Error Object: #f
but when I set them as porous jump boundaries, this time it gives an error of segmentation fault, no flow detected at porous jump 7(exp.).
One more thing, the properties of the porous jump condition:
FACE PERMEABILITY: 1e+10(default) How do I set it, I have a mesh system of 5000x5000 m and 40000 elements(grids) in this system
POROUS MEDIUM THICKNESS: 0 it is.
PRESSURE-JUMP COEFFICIENT: 0(default) I saw some calculations for cylindirical studies but I don't know how to calculate it or what are the values for 2D planar structures(systems).
What is it that I'm doing completely wrong and/or fail to notice?
Any comment would be much appreciated. Thanks in advance.
Cheers,
Selvi
let me wrap it up:
segmentation fault error that I kept receive while I was trying to solve my problem was due to failing assignment of contact regions in mesh in the process of transfering the data to the setup section of ANSYS Fluent. I don't know how and why at sometimes these contact regions are defined well, sometimes not at all. So once I watched these tutorials, I noticed the failure:
1- https://www.youtube.com/watch?v=1pxvdwEWc5Q&list=LLQyexlKy3Y4osmrpyI3yqmQ&index=8&t=0s
2- https://www.youtube.com/watch?v=lJ3aNj9Y9j0&list=LLQyexlKy3Y4osmrpyI3yqmQ&index=3&t=0s
Following instructions from these tutorials(especially the first one) I managed to solve the error. I didn't need to define any other boundary layers between those packed beds including porous jump boundary. I don't have great knowledge about the implementations of ANSYS Fluent(keep learning) but once I tried "ADD FROZEN" method in the first link I shared, I just got rid of the error.
So, problem is solved.
Cheers,
Selvi
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