CFX error

- July 4, 2024 at 1:26 pm
  
  Stephen Orritt
  Subscriber
  
  Hi all,
  I am getting an error when running a transient simulation which is as follows:
  -------------------------------------------------------------------+
  | ERROR #004100018 has occurred in subroutine FINMES. |
  | Message: |
  | Fatal overflow in linear solver.
  The simulation is modelling a wind turbine using a momentum source, the simulations run well and seem to agree with literature data when run as a steady-state frozen rotor simulation (image below). However, when switching over to a transient simulation I get the error stated at the first timestep. Can momentum sinks be used for rotating transient simulations? I have looked at the documentation which does not point to anything obvious other than rechecking the physics and mesh. I believe the mesh is of suitable detail and quality for this initial simulation. I have also looked at changing the timestep down to E-5 seconds and that does not solve the issue. One thing I have noticed in the output file is the wallscale residual seems to fail initially, could this be the issue and how could I solve this?
  SOLVING : Wall Scale |
  ----------------------------------------------------------------------
  | Equation | Rate | RMS Res | Max Res | Linear Solution |
  +----------------------+------+---------+---------+------------------+
  | Wallscale | 0.00 | 2.4E-05 | 1.2E-03 | 9.6 2.8E+01 F |
  +----------------------+------+---------+---------+------------------+
  | Wallscale |99.99 | 6.8E+13 | 1.2E+15 | 9.6 8.3E-02 OK|
  +----------------------+------+---------+---------+------------------
  Many thanks
- July 9, 2024 at 4:56 am
  
  Bhargav Desai
  Ansys Employee
  
  Hi Stephen,
  Generally this error is received when the boundary conditions are set incorrectly or if the initial values are inappropriate.
  Since you are running a transient case, please make sure the interface definition are correct and the initial values you are using for simulation are reasonable.