Learning Forum

[Malik]

Hy guys.
 I am a beginner in ansys simulation .
i am simulating concrete in a 3d pipe with length 38.50m and dia 0.125m.
this error occurs when i give inlet B:C as VElocity inlet or pressure inlet but it didnot occur when i give mass flow inlet B:C

 

 

 

  iter continuity x-velocity y-velocity z-velocity time/iter

3 7.5377e-01 3.1057e-02 3.1086e-02 2.6119e-01 0:10:48 500

 

reversed flow in 114 faces on pressure-outlet 6.

Stabilizing x-momentum to enhance linear solver robustness.

 

Divergence detected in AMG solver: x-momentum Stabilizing y-momentum to enhance linear solver robustness.

 

Divergence detected in AMG solver: y-momentum Stabilizing z-momentum to enhance linear solver robustness.

 

Divergence detected in AMG solver: z-momentum Stabilizing pressure correction to enhance linear solver robustness.

 

Divergence detected in AMG solver: pressure correction

Error at host: floating point exception

 

Error at Node 0: floating point exception

 

===============Message from the Cortex Process================================

 

Compute processes interrupted. Processing can be resumed.

 

==============================================================================

 

Error: floating point exception

Error Object: #f

 

 

[Amine Ben Hadj Ali]

Add more information about models used, grid, boundaries,.. Please insert the screenshots and do not attach them if you want that ANSYS Stuff have look into it.

[Malik]

i am using laminar model. Viscosity and density is defined by udf file. 
boundary coditions 
inlet mass flow 
outlet pressure outlet.i have attched screen short as well

[Keyur Kanade]

you are using udfs. so its difficult to predict why this error without looking udfs. also please note that we can not debug udfs for users. 

saying that, i can see there is some jump in the mesh from fine to coarse. can you please make sure that mesh is smooth. 

also what is min orthogonal quality of mesh? it should be above 0.1.

can you please reduce your mass flow rate and check? 

[Malik]

Dear KKanade,

I have make some changes in my meshing quality, but the problem is sam ewhen i give pressure inlet B.C or Velocity inlet condition.

i Attached my udf file and meshing detail again.
i am actually modeling bingham solution (concrete). I also have question how can i use single phase viscous model.

 

kind Regards 
Malik

[Rob]

If you're using a Bingham viscosity model why are you setting viscosity based on location? The UDF is working (otherwise it'd not run at all) so I'd start looking at viscosity etc just before the model fails: it's almost certainly due to an excessively high value or gradient. 

[Malik]

The UDF is working (otherwise it'd not run at all) so I'd start looking at viscosity etc just before the model fails: it's almost certainly due to an excessively high value or gradient. 

could you please explained, i did not understand.
while i am using viscosity udf file so i am not taking harshel balkely model.
i assume that it will take into account by reading the file.

 

[Amine Ben Hadj Ali]

What my colleague asked is correct: Why are you using a spatial dependent viscosity if you are obeying the Bingham law which would take care of everything ?

What are you trying to do? If the case does converge without UDF then you need to check your macros.