[SAM S]

I had compiled and hooked my mass transfer udf into fluent but while initializing am getting the error
Node 0: Process 3636: Received signal SIGSEGV.

Node 1: Process 2608: Received signal SIGSEGV.

Node 2: Process 3328: Received signal SIGSEGV.

Node 3: Process 3600: Received signal SIGSEGV.

MPI Application rank 0 exited before MPI_Finalize() with status 2
The fl process could not be started.

I learnt that it is a memory error but how to rectify it. Can anyone help me.

Thank you.

[`e`]

What is the UDF code you're compiling?

[SAM S]

Please find the mass transfer source udf

#include "udf.h"
DEFINE_MASS_TRANSFER(liq_gas_source,cell,thread,fr om_index,from_species_index,to_index, to_species_index)
{
real m_lg;
real T_SAT = 373.15;
real vof_cutoff = 0.05;
C_R(cell,liq) = 0.0;
C_R(cell,gas) = 0.0;
Thread *liq = THREAD_SUB_THREAD(thread, from_index);
Thread *gas = THREAD_SUB_THREAD(thread, to_index);
m_lg = 0.0;
if ( (C_VOF(cell,thread) > vof_cutoff ) && (C_VOF(cell,thread) < (1 - vof_cutoff) ))
{
if ((m_lg == 0.0) && (C_T(cell,liq) >= T_SAT))
{
m_lg = -0.1*C_VOF(cell,liq)*C_R(cell,liq)*fabs(C_T(cell,li q)-T_SAT)/T_SAT;
}
if (C_T(cell, gas) <= T_SAT)
{
m_lg = 0.1*C_VOF(cell,gas)*C_R(cell,gas)*fabs(T_SAT-C_T(cell,gas))/T_SAT;
}
}
return (m_lg);
}

[pakk]

What are you trying to do here:

C_R(cell,liq) = 0.0;
C_R(cell,gas) = 0.0;

Is this an attempt to set the density to zero? This is not the correct way to do this.

Fluent (probably) does not allow you to overwrite the stored densities, only to read the values.

[`e`]

First, check that your DEFINE_MASS_TRANSFER statement is not broken into two lines:

DEFINE_MASS_TRANSFER(liq_gas_source,cell,thread,fr
om_index,from_species_index,to_index, to_species_index)

From copying and pasting your code, there appears to be a space in the 'from_index' variable. Instead, this statement should be on one line of code:

DEFINE_MASS_TRANSFER(liq_gas_source,cell,thread,from_index,from_species_index,to_index, to_species_index)

If you're still getting the errors, then eliminate lines of code until you find the problem line.

[SAM S]

Thank you for your replies. As you suggested initializing density to zero gave me errors while compiling. So removed those two lines. DEFINE statement is in a single line. I dont have any compilation error but while initializing I am getting the above mentioned error.

[pakk]

So the code that you showed here was not exactly the code that you were using... That makes it difficult for us to find mistakes in your code!

To check something else: do you get warnings when you don't use the udf?
(And did you restart Fluent after getting this error?)

[SAM S]

Sorry for not providing the exact code earlier. Then without udf there is no problem in initializing or running (though simulation wont converge). Yes I tried restarting but same error appears everytime