[Roland R]

Hello CFX Users,

I’m calculating a 2D wing (NACA 0012) with SST. Re = ~3e6 so based on the help the Yplus has to be in range 20-100. This condition is OK but the solver shows during the run the next :

----------------------------------------------------------------------
| Equation | Rate | RMS Res | Max Res | Linear Solution |
+----------------------+------+---------+---------+------------------+
| Wallscale | 0.73 | 3.2E-07 | 8.6E-06 | 23.9 6.5E-01 ok|
+----------------------+------+---------+---------+------------------+
| U-Mom | 0.83 | 2.8E-04 | 1.2E-02 | 1.0E+00 F |
| V-Mom | 1.51 | 8.3E-04 | 3.0E-02 | 1.5E+00 F |
| W-Mom | 1.06 | 8.9E-22 | 8.3E-20 | 1.6E+14 * |
| P-Mass | 0.95 | 1.9E-04 | 5.0E-03 | 9.0 2.0E+00 F |
+----------------------+------+---------+---------+------------------+
| H-Energy | 1.93 | 1.6E-03 | 1.2E-01 | 5.7 7.8E-03 OK|
+----------------------+------+---------+---------+------------------+
| K-TurbKE | 0.80 | 4.3E-04 | 1.5E-02 | 5.7 3.6E-02 OK|
| O-TurbFreq | 0.69 | 7.3E-04 | 5.8E-02 | 11.7 1.4E-03 OK|


I think that the mesh quality is correct. (2D stuctured hexahedral mesh). I don’t understand cause of the „ F and * ”.

Thanks
Roland

[ghorrocks]

This means the linear solver is not converging. You need to improve the stability of the simulation. The big problem is the W-mom equation - you say this is a 2D simulation but have you considered the issues mentioned here http://www.cfd-online.com/Wiki/Ansys..._simulation.3F

[Roland R]

Hello Glann,

OK, based on the document cause of the error is unambiguous.

Thank you for your help;

Roland