[`e`]

We're both trying to help you out here Ondrej, and have both read your problem, understood it and given guidance. I agree with pakk that these forums are for learning and troubleshooting Fluent issues, not simply doing the work for you. It appears you ignored my comment on the domain pointer solution back in this post, and I had to repeat myself before you fixed that issue. For every solution we provide in threads, I'm sure there's a number of others who stumble across the same issue and find these threads through search engines.

That being said, I think the key issue you face is that computers like to start from zero; for example, you access the fourth element of an array with x[3] and not with x[4]. Applying this logic to your C_UDMI macro: try accessing C_UDMI(c,t,0).

[perun333]

Originally Posted by `e`

We're both trying to help you out here Ondrej, and have both read your problem, understood it and given guidance. I agree with pakk that these forums are for learning and troubleshooting Fluent issues, not simply doing the work for you. It appears you ignored my comment on the domain pointer solution back in this post, and I had to repeat myself before you fixed that issue. For every solution we provide in threads, I'm sure there's a number of others who stumble across the same issue and find these threads through search engines.

That being said, I think the key issue you face is that computers like to start from zero; for example, you access the fourth element of an array with x[3] and not with x[4]. Applying this logic to your C_UDMI macro: try accessing C_UDMI(c,t,0).

I know sorry for this. I tried to apply your recomendations but with the same result:

Updating solution at time level N... done.
iter energy delta_time time time/iter

Error: received a fatal signal (Segmentation fault).

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


This is my updated code:
#include "udf.h"

DEFINE_ADJUST(teste, domain)
{
Thread *t;
cell_t c;

thread_loop_c(t, domain)
{
begin_c_loop_all(c, t)
{
C_UDMI(c,t,0) = NV_MAG(C_T_G(c,t));
}
end_c_loop_all(c, t)
}
}



Then I tried it from another side, but with same resault:

#include "udf.h"
DEFINE_ADJUST(max_C_T_G, domain)
{
cell_t c;
Thread *ct;
real maxT;
maxT = 0.0;
thread_loop_c(ct,domain)
{
begin_c_loop(c,ct)
{
if (C_T_G(c,ct)[0] > maxT)
{
maxT = C_T_G(c,ct)[0];
}
}
end_c_loop(c,ct)
}
printf("Maximum temperature = %f \n", maxT);
}
Sorry for it.

[`e`]

Try emptying your DEFINE_ADJUST UDF and only have a message, for example:

#include "udf.h"
DEFINE_ADJUST(max_C_T_G, domain)
{
    Message("Hello...\n");
}

If you're not receiving the message above to your screen then you're not re-compiling the UDF correctly and should read my post on how to re-compile UDFs.

Lastly, use Message() instead of printf().

[perun333]

Originally Posted by `e`

Try emptying your DEFINE_ADJUST UDF and only have a message, for example:

#include "udf.h"
DEFINE_ADJUST(max_C_T_G, domain)
{
    Message("Hello...\n");
}

If you're not receiving the message above to your screen then you're not re-compiling the UDF correctly and should read my post on how to re-compile UDFs.

Lastly, use Message() instead of printf().

I tried your example and it works, so Im compiling correctly. I think that problem is somewhere inside code...

[`e`]

Work through your code line by line (adding one by one from the working simple message UDF) until you determine which line is causing your error and then fix it, good luck!

[perun333]

Originally Posted by `e`

Work through your code line by line (adding one by one from the working simple message UDF) until you determine which line is causing your error and then fix it, good luck!

I think thats correct:

#include "udf.h"
DEFINE_ADJUST(max_C_T_G, domain)
{
cell_t c;
Thread *ct;
real maxT;
maxT = 0.0;
thread_loop_c(ct,domain)
{
begin_c_loop(c,ct)
{
if (C_T_G(c,ct)[0] > maxT)
{
maxT = C_T_G(c,ct)[0];
}
}
end_c_loop(c,ct)
}
printf("Maximum temperature = %f \n", maxT);
}

But problem is maybe with axisymetric definition.

[pakk]

The problem could be that your temperature gradient is not yet defined. Is this on the first iteration? If so, let your simulation run for a few time steps before you use this UDF.

And a minor detail: replace

printf("Maximum temperature = %f \n", maxT);

by

Message("Maximum temperature gradient = %f K/m.\n", maxT);

[perun333]

Originally Posted by pakk

The problem could be that your temperature gradient is not yet defined. Is this on the first iteration? If so, let your simulation run for a few time steps before you use this UDF.

And a minor detail: replace

printf("Maximum temperature = %f \n", maxT);

by

Message("Maximum temperature gradient = %f K/m.\n", maxT);

Hi Pakk,

I tried your opinions:
-change the line for message in udf
-run transient calculate >>calculation converget
-compiled upgraded udf
-Adjust hook
-calculate
-error:
Updating solution at time level N... done.
iter energy delta_time time time/iter
! 45 solution is converged
45 5.6044e-07 1.0000e+01 1.3000e+02 0:00:02 20

Error: received a fatal signal (Segmentation fault).

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

[pakk]

Hmm, then I don't know...

You could try to see if the gradient is the problem by replacing C_T_G(c,ct)[0] by C_T(c,ct). But if the gradient is really the problem, I would not know how to solve that.

If C_T(c,ct) also does not work, the axisymmetry might be the problem. But then, I also would not know how to solve that.

[perun333]

Originally Posted by pakk

Hmm, then I don't know...

You could try to see if the gradient is the problem by replacing C_T_G(c,ct)[0] by C_T(c,ct). But if the gradient is really the problem, I would not know how to solve that.

If C_T(c,ct) also does not work, the axisymmetry might be the problem. But then, I also would not know how to solve that.

With maximal temperature macro C_T it works

[perun333]

Originally Posted by pakk

It is bad that you see it that way. The way I see it, I am trying to help you understand the problem, and help you get to a solution.

You give the impression that you don't want to understand anything, but that you just want to hear what you should do to get rid of your error. Is that what you want? In that case, you'll have to hire me, I don't do those jobs for free.

Hi pakk,

I try to compiled and adjusted udf (which have to work) from ansys forum.
Here is code:
#include "udf.h"
DEFINE_ADJUST(total_dissipation, domain)
{
cell_t c;
Thread *ct;
real total_diss;

total_diss = 0.0; /* Initialise total_diss before the loop */

thread_loop_c(ct,domain)
{
begin_c_loop(c,ct)
{
total_diss += C_D(c,ct) * C_VOLUME(c,ct); /* Use += to sum up values */
}
end_c_loop(c,ct)
}
Message("Volume integral of turbulent dissipation = %f \n", total_diss);
}



And I have still same resault:

fatal error (segmentation fault)

I tried to compiled simple udf which contains only hello world and it works. Have you any idea where is problem?

[bmahnic]

Hi!

I think that the solution to your problem is defining the thread value as equal to DT_THREAD(dt).
The reason is in the fact that you are using the dynamic mesh. In that case normal thread definition does not work. Consequentially, your face looping macro aborts the simulation.

Regards, Marko.

[wiki123]

@OP.

Actually what was being conveyed to you was that by default the first memory location is 0 in Ansys fluent. You defined one memory means you defined 0 serial number memory. It starts with 0.

But you were storing the gradient in the user defined memory 1 which was not existing.