ANSYS gives different results for every identical simulation

  • Last Post 07 December 2017
sdeb31 posted this 06 December 2017

I am trying to solve the generic transport equation

for diffusion only. I made a UDF for the diffusion. This is a four-sided geometry.


#include "udf.h"

#include "mem.h"

DEFINE_DIFFUSIVITY(magfun, c, t, i)


real diff;

diff = -1/(NV_MAG(C_UDSI_G(c,t,0))+0.000000001);

return diff;


which I used in material properties of the fluid. I also have a source term which I used in cell zone conditions. When I run the simulation, not only do I get different answer each time I run the simulation, none of the results match what I should be getting.

When I save and close the file, and reopen it, I get this error

Can anyone help me out?

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Luca posted this 07 December 2017

I am new in this field, but a reasonable question could be: How much nodes has your mesh? Different results from the same simulation could come from a dipendence with the mesh. Try to refine your mesh and restart your job. (I had the same problem, without the error, and i solved it only refining the mesh).

I hope this could help you!


Raef.Kobeissi posted this 07 December 2017

Hello, I agree with Luca, any simple change in your setup, mesh, or even model will give you a different result.

Raef Kobeissi