[Linas]

I wrote a UDF to specify density as a function of* temperature for a multi-species, multiphase model. This is the error I get.


* step* flow-time* * *p-inlet
* * *0* 0.0000e+00 -1.0553e-14


Updating solution at time level N...
*done.


* iter* continuity* x-velocity* y-velocity* z-velocity* * * energy* ch44-p* ch3oh-pha* n2-phase-a* co2-phase-* vf-phase-a* * *time/iter
* * * * Stabilizing pressure coupled to enhance linear solver robustness.
* * * * Stabilizing pressure coupled using GMRES to enhance linear solver robustness.


Experiencing convergence difficulties - temporarily relaxing and trying again...


Experiencing convergence difficulties - temporarily relaxing and trying again...


Experiencing convergence difficulties - temporarily relaxing and trying again...


Experiencing convergence difficulties - temporarily relaxing and trying again...
* * * * Stabilizing pressure coupled to enhance linear solver robustness.
* * * * Stabilizing pressure coupled using GMRES to enhance linear solver robustness.


Experiencing convergence difficulties - temporarily relaxing and trying again...


Divergence detected in AMG solver: pressure coupled temperature limited to 3.273150e+03 in 387997 cells on zone 1231 in domain 1
* * * * *Stabilizing vof-1 to enhance linear solver robustness.
* * * * Stabilizing vof-1 using GMRES to enhance linear solver robustness.


Divergence detected in AMG solver: vof-1
Divergence detected in AMG solver: pressure coupled
Divergence detected in AMG solver: vof-1
Divergence detected in AMG solver: pressure coupled
Divergence detected in AMG solver: vof-1
Divergence detected in AMG solver: pressure coupled
Divergence detected in AMG solver: vof-1
Divergence detected in AMG solver: pressure coupled
Divergence detected in AMG solver: vof-1
Divergence detected in AMG solver: pressure coupled
Divergence detected in AMG solver: vof-1
Divergence detected in AMG solver: pressure coupled
Divergence detected in AMG solver: vof-1
Divergence detected in AMG solver: pressure coupled
Divergence detected in AMG solver: vof-1
Divergence detected in AMG solver: pressure coupled
Divergence detected in AMG solver: vof-1
Divergence detected in AMG solver: pressure coupled
Divergence detected in AMG solver: vof-1
Divergence detected in AMG solver: pressure coupled
Divergence detected in AMG solver: vof-1
Divergence detected in AMG solver: pressure coupled
Divergence detected in AMG solver: vof-1
Error at host: floating point exception


Error: floating point exception
Error Object: ()


Error at Node 5: floating point exception


Error at Node 4: floating point exception


Error at Node 6: floating point exception


Error at Node 3: floating point exception


Error at Node 10: floating point exception


Error at Node 7: floating point exception


Error at Node 0: floating point exception


Error at Node 9: floating point exception


Error at Node 8: floating point exception


Error at Node 1: floating point exception


Error at Node 11: floating point exception


Error at Node 2: floating point exception


Error: floating point exception

Would someone be able to review my UDF (below) and tell me if there is an obvious mistake.



#include "udf.h"
/* Define the UDF to specify temperature-dependent density */
DEFINE_PROPERTY(temperature_dependent_density, cell, thread)
{
* * real T;* /* Temperature */
* * real density;* /* Density */
* * real vol_frac;* /* Volume fraction of phase A */


* * /* Loop over all cells in the thread */
* * begin_c_loop(cell, thread)
* * {
* * * * /* Get the volume fraction of phase A in the cell */
* * * * vol_frac = C_VOF(cell, thread);


* * * * /* Check if the volume fraction of phase A is greater than 50% */
* * * * if (vol_frac > 0.5)
* * * * {
* * * * * * /* Get the temperature of the cell */
* * * * * * T = C_T(cell, thread);


* * * * * * /* Calculate the density based on the given relationship */
* * * * * * density = 1.4811 - 0.0007 * T;


* * * * * * /* Set the density for the cell */
* * * * * * C_R(cell, thread) = density;
* * * * }
* * }
* * end_c_loop(cell, thread)


* * return density;
}

[rewol]

Hello,

Are you sure you need cell looping in DEFINE_PROPERTY macro?

From what i remember it is called for each individual cell and all you have to do is extract arguments (temp, vol fractions etc.) from cell, calculate what you want and assign it.

[cbooks77]

I think you might need to get the pointer for the phase thread you are trying to loop over first. As an example C_VOF(cell,thread) would be C_VOF(cell, liq) or C_VOF(cell, gas) where liq and cell are pointers to the liquid and gas phase cell threads.