[iamnotfajar]

Hello Everyone,

i got fatal error when i use 2 domain interface for outlet in Francis turbine. me and team are making new innovation about Francis turbine with 2 outlet flow. but when I use two outlet domain interface in different mesh of their draft tube I got Fatal overflow in linear solver. anyone have a solution?


thanks before,


fa

[Gert-Jan]

Should not be a problem. Probably there is something wrong in your settings. Please share your output file.

[iamnotfajar]

================================================== ====================
OUTER LOOP ITERATION = 590 ( 1) CPU SECONDS = 1.636E+05 (6.334E+01)
----------------------------------------------------------------------
| Equation | Rate | RMS Res | Max Res | Linear Solution |
+----------------------+------+---------+---------+------------------+

+--------------------------------------------------------------------+
| ERROR #004100018 has occurred in subroutine FINMES. |
| Message: |
| Fatal overflow in linear solver. |
+--------------------------------------------------------------------+

+--------------------------------------------------------------------+
| An error has occurred in cfx5solve: |
| |
| The ANSYS CFX solver exited with return code 1. No results file |
| has been created. |
+--------------------------------------------------------------------+

End of solution stage.

+--------------------------------------------------------------------+
| Warning! |
| |
| After waiting for 60 seconds, 1 solver manager process(es) appear |
| not to have noticed that this run has ended. You may get errors |
| removing some files if they are still open in the solver manager. |
+--------------------------------------------------------------------+

[Gert-Jan]

If you look on this forum, you will find that FINMES means "Final Message".
This brings us nothing. We need the complete output file.

I read that the error occured at the first iteration. What did you change? What happened in the previous 590 iterations?

[iamnotfajar]

first, i have 1 domain with 2 fluid model for outlet in left and right runner's turbine. but the result is weird. so I use two domain with 2 geometry. then I have try about 10th times but the solver still error like those message

[iamnotfajar]

================================================== ====================
OUTER LOOP ITERATION = 582 CPU SECONDS = 1.615E+05
----------------------------------------------------------------------
| Equation | Rate | RMS Res | Max Res | Linear Solution |
+----------------------+------+---------+---------+------------------+
| U-Mom | 0.97 | 7.8E-04 | 6.1E-02 | 1.0E-01 ok|
| V-Mom | 0.99 | 2.1E-03 | 1.5E-01 | 5.2E-02 OK|
| W-Mom | 1.00 | 2.1E-03 | 1.5E-01 | 5.0E-02 OK|
| P-Mass | 0.98 | 2.4E-04 | 8.8E-03 | 8.5 6.6E-02 OK|
+--------------------------------------------------------------------+
| ****** Notice ****** |
| A wall has been placed at portion(s) of an OUTLET |
| boundary condition (at 39.7% of the faces, 47.3% of the area) |
| to prevent fluid from flowing into the domain. |
| The boundary condition name is: Outlet. |
| The fluid name is: Fluid 1. |
| If this situation persists, consider switching |
| to an Opening type boundary condition instead. |
+--------------------------------------------------------------------+
+--------------------------------------------------------------------+
| ****** Notice ****** |
| A wall has been placed at portion(s) of an OUTLET |
| boundary condition (at 44.8% of the faces, 52.7% of the area) |
| to prevent fluid from flowing into the domain. |
| The boundary condition name is: Outlet 2. |
| The fluid name is: Fluid 1. |
| If this situation persists, consider switching |
| to an Opening type boundary condition instead. |
+--------------------------------------------------------------------+
+----------------------+------+---------+---------+------------------+
| H-Energy | 1.01 | 8.7E-04 | 1.0E-01 | 5.5 5.1E-02 OK|
+----------------------+------+---------+---------+------------------+
| K-TurbKE | 0.99 | 4.7E-04 | 8.2E-02 | 5.5 2.0E-02 OK|
| E-Diss.K | 1.00 | 9.8E-04 | 1.1E-01 | 7.5 2.8E-03 OK|
+----------------------+------+---------+---------+------------------+

================================================== ====================
OUTER LOOP ITERATION = 583 CPU SECONDS = 1.618E+05
----------------------------------------------------------------------
| Equation | Rate | RMS Res | Max Res | Linear Solution |
+----------------------+------+---------+---------+------------------+
| U-Mom | 0.99 | 7.8E-04 | 6.8E-02 | 1.1E-01 ok|
| V-Mom | 1.00 | 2.1E-03 | 1.4E-01 | 5.2E-02 OK|
| W-Mom | 0.99 | 2.1E-03 | 1.6E-01 | 5.1E-02 OK|
| P-Mass | 0.96 | 2.3E-04 | 9.1E-03 | 8.5 6.6E-02 OK|
+--------------------------------------------------------------------+
| ****** Notice ****** |
| A wall has been placed at portion(s) of an OUTLET |
| boundary condition (at 39.7% of the faces, 47.3% of the area) |
| to prevent fluid from flowing into the domain. |
| The boundary condition name is: Outlet. |
| The fluid name is: Fluid 1. |
| If this situation persists, consider switching |
| to an Opening type boundary condition instead. |
+--------------------------------------------------------------------+
+--------------------------------------------------------------------+
| ****** Notice ****** |
| A wall has been placed at portion(s) of an OUTLET |
| boundary condition (at 44.8% of the faces, 52.7% of the area) |
| to prevent fluid from flowing into the domain. |
| The boundary condition name is: Outlet 2. |
| The fluid name is: Fluid 1. |
| If this situation persists, consider switching |
| to an Opening type boundary condition instead. |
+--------------------------------------------------------------------+
+----------------------+------+---------+---------+------------------+
| H-Energy | 0.98 | 8.5E-04 | 1.0E-01 | 5.5 5.1E-02 OK|
+----------------------+------+---------+---------+------------------+
| K-TurbKE | 1.01 | 4.8E-04 | 5.1E-02 | 5.5 2.1E-02 OK|
| E-Diss.K | 1.06 | 1.0E-03 | 1.3E-01 | 7.5 3.0E-03 OK|
+----------------------+------+---------+---------+------------------+

================================================== ====================
OUTER LOOP ITERATION = 584 CPU SECONDS = 1.621E+05
----------------------------------------------------------------------
| Equation | Rate | RMS Res | Max Res | Linear Solution |
+----------------------+------+---------+---------+------------------+
| U-Mom | 1.02 | 7.9E-04 | 7.7E-02 | 1.0E-01 ok|
| V-Mom | 0.99 | 2.1E-03 | 1.5E-01 | 5.2E-02 OK|
| W-Mom | 1.00 | 2.1E-03 | 1.7E-01 | 5.0E-02 OK|
| P-Mass | 1.04 | 2.4E-04 | 1.3E-02 | 8.5 6.5E-02 OK|
+--------------------------------------------------------------------+
| ****** Notice ****** |
| A wall has been placed at portion(s) of an OUTLET |
| boundary condition (at 39.7% of the faces, 47.3% of the area) |
| to prevent fluid from flowing into the domain. |
| The boundary condition name is: Outlet. |
| The fluid name is: Fluid 1. |
| If this situation persists, consider switching |
| to an Opening type boundary condition instead. |
+--------------------------------------------------------------------+
+--------------------------------------------------------------------+
| ****** Notice ****** |
| A wall has been placed at portion(s) of an OUTLET |
| boundary condition (at 44.8% of the faces, 52.7% of the area) |
| to prevent fluid from flowing into the domain. |
| The boundary condition name is: Outlet 2. |
| The fluid name is: Fluid 1. |
| If this situation persists, consider switching |
| to an Opening type boundary condition instead. |
+--------------------------------------------------------------------+
+----------------------+------+---------+---------+------------------+
| H-Energy | 1.02 | 8.7E-04 | 8.7E-02 | 5.5 4.9E-02 OK|
+----------------------+------+---------+---------+------------------+
| K-TurbKE | 1.00 | 4.8E-04 | 6.3E-02 | 5.5 1.9E-02 OK|
| E-Diss.K | 0.97 | 1.0E-03 | 8.8E-02 | 7.5 2.9E-03 OK|
+----------------------+------+---------+---------+------------------+

================================================== ====================
OUTER LOOP ITERATION = 585 CPU SECONDS = 1.624E+05
----------------------------------------------------------------------
| Equation | Rate | RMS Res | Max Res | Linear Solution |
+----------------------+------+---------+---------+------------------+
| U-Mom | 1.02 | 8.1E-04 | 7.1E-02 | 1.0E-01 ok|
| V-Mom | 1.00 | 2.1E-03 | 1.8E-01 | 5.1E-02 OK|
| W-Mom | 1.01 | 2.1E-03 | 1.5E-01 | 5.0E-02 OK|
| P-Mass | 1.01 | 2.4E-04 | 1.0E-02 | 8.5 6.5E-02 OK|
+--------------------------------------------------------------------+
| ****** Notice ****** |
| A wall has been placed at portion(s) of an OUTLET |
| boundary condition (at 39.7% of the faces, 47.3% of the area) |
| to prevent fluid from flowing into the domain. |
| The boundary condition name is: Outlet. |
| The fluid name is: Fluid 1. |
| If this situation persists, consider switching |
| to an Opening type boundary condition instead. |
+--------------------------------------------------------------------+
+--------------------------------------------------------------------+
| ****** Notice ****** |
| A wall has been placed at portion(s) of an OUTLET |
| boundary condition (at 44.8% of the faces, 52.7% of the area) |
| to prevent fluid from flowing into the domain. |
| The boundary condition name is: Outlet 2. |
| The fluid name is: Fluid 1. |
| If this situation persists, consider switching |
| to an Opening type boundary condition instead. |
+--------------------------------------------------------------------+
+----------------------+------+---------+---------+------------------+
| H-Energy | 1.00 | 8.7E-04 | 6.2E-02 | 5.5 5.3E-02 OK|
+----------------------+------+---------+---------+------------------+
| K-TurbKE | 0.99 | 4.7E-04 | 4.9E-02 | 5.5 2.2E-02 OK|
| E-Diss.K | 0.98 | 9.9E-04 | 1.4E-01 | 7.5 2.9E-03 OK|
+----------------------+------+---------+---------+------------------+

================================================== ====================
| Timescale Information |
----------------------------------------------------------------------
| Equation | Type | Timescale |
+----------------------+-----------------------+---------------------+
| U-Mom-Draft Tube | Auto Timescale | 1.59155E-03 |
| V-Mom-Draft Tube | Auto Timescale | 1.59155E-03 |
| W-Mom-Draft Tube | Auto Timescale | 1.59155E-03 |
| U-Mom-Runner | Auto Timescale | 1.59155E-03 |
| V-Mom-Runner | Auto Timescale | 1.59155E-03 |
| W-Mom-Runner | Auto Timescale | 1.59155E-03 |
| U-Mom-Spiral | Auto Timescale | 1.59155E-03 |
| V-Mom-Spiral | Auto Timescale | 1.59155E-03 |
| W-Mom-Spiral | Auto Timescale | 1.59155E-03 |
+----------------------+-----------------------+---------------------+
| H-Energy-Draft Tube | Auto Timescale | 1.59155E-03 |
| H-Energy-Runner | Auto Timescale | 1.59155E-03 |
| H-Energy-Spiral | Auto Timescale | 1.59155E-03 |
+----------------------+-----------------------+---------------------+
| K-TurbKE-Draft Tube | Auto Timescale | 1.59155E-03 |
| E-Diss.K-Draft Tube | Auto Timescale | 1.59155E-03 |
| K-TurbKE-Runner | Auto Timescale | 1.59155E-03 |
| E-Diss.K-Runner | Auto Timescale | 1.59155E-03 |
| K-TurbKE-Spiral | Auto Timescale | 1.59155E-03 |
| E-Diss.K-Spiral | Auto Timescale | 1.59155E-03 |
+----------------------+-----------------------+---------------------+

[ghorrocks]

I trust you have covered the basic stuff discussed in the FAQ: https://www.cfd-online.com/Wiki/Ansy...do_about_it.3F

[iamnotfajar]

fyi guys. i have fix this problem using inflation on meshing.


thanks before, and thanks for helping me ^^

[ghorrocks]

OK, that's great. But normally refining the mesh makes convergence harder, not easier, so do not think this is always the solution to this problem. Your original mesh probably had some really poor quality elements.

[Gert-Jan]

I agree with Glenn. A fatal overflow, at the first iteration is not cause by presence or absense of inflation. Probably it has to do with your settings e.g. BC, or interfaces settings.
Nevertheless, success with your project.