[Nek5000-users] An abrupt error of "unconverged Helmh3 fluid"

[nek5000-users at lists.mcs.anl.gov]

Dear Neks,

I am using the moving mesh to simulate surface gravity waves with some random heat flux at the surface.
The codes ran well for a while, but it suddenly pop out an error of unconverged Helmh3 fluid, as shown in the below log file (Step 14650).

Could anyone give me a hint on this kind of error?

Thank you,
Peng


Step  14647, t= 7.3235000E+01, DT= 5.0000000E-03, C=  0.036 2.8716E+04 1.9695E+00
             Solving for Hmholtz scalars
      14647  Hmholtz TEMP       4   6.0654E-16   1.4699E-01   1.0000E-12
      14647  Scalars done  7.3235E+01  3.9568E-02
             Solving for fluid
      14647  Helmh3 fluid       4   1.9934E-13   8.0532E-04   1.0000E-12
      14647  U-PRES gmres      14   4.5296E-11   2.2779E-03   1.0000E-10   8.2958E-02   2.5954E-01
      14647  Fluid done  7.3235E+01  3.7241E-01
Step  14648, t= 7.3240000E+01, DT= 5.0000000E-03, C=  0.035 2.8718E+04 1.9642E+00
             Solving for Hmholtz scalars
      14648  Hmholtz TEMP       4   6.0987E-16   1.4701E-01   1.0000E-12
      14648  Scalars done  7.3240E+01  3.9551E-02
             Solving for fluid
      14648  Helmh3 fluid       4   1.9904E-13   8.0535E-04   1.0000E-12
      14648  U-PRES gmres      14   4.5647E-11   2.2779E-03   1.0000E-10   8.3140E-02   2.5985E-01
      14648  Fluid done  7.3240E+01  3.7297E-01
Step  14649, t= 7.3245000E+01, DT= 5.0000000E-03, C=  0.034 2.8720E+04 1.9658E+00
             Solving for Hmholtz scalars
      14649  Hmholtz TEMP       4   6.1309E-16   1.4704E-01   1.0000E-12
      14649  Scalars done  7.3245E+01  3.9058E-02
             Solving for fluid
      14649  Helmh3 fluid       4   1.9875E-13   8.0535E-04   1.0000E-12
      14649  U-PRES gmres      14   4.5884E-11   2.2778E-03   1.0000E-10   8.3552E-02   2.5956E-01
      14649  Fluid done  7.3245E+01  3.7226E-01
Step  14650, t= 7.3250000E+01, DT= 5.0000000E-03, C=  0.033 2.8722E+04 1.9614E+00
             Solving for Hmholtz scalars
      14650  Hmholtz TEMP       4   6.1615E-16   1.4707E-01   1.0000E-12
      14650  Scalars done  7.3250E+01  3.9481E-02
             Solving for fluid
 14650   201 Unconverged Helmh3 fluid rbnorm =          NaN 0.100000E-11
      14650  U-PRES gmres     120          NaN          NaN   1.0000E-10   7.0555E-01   2.3985E+00
      14650  Fluid done  7.3250E+01  5.4078E+00
Step  14651, t= 7.3255000E+01, DT= 5.0000000E-03, C=    NaN 2.8729E+04 7.0068E+00
             Solving for Hmholtz scalars
      14651  Error Hmholtz TEMP     200          NaN          NaN   1.0000E-12
      14651  Scalars done  7.3255E+01  1.0293E+00
             Solving for fluid
 14651   201 Unconverged Helmh3 fluid rbnorm =          NaN 0.100000E-11
      14651  U-PRES gmres     120          NaN          NaN   1.0000E-10   7.0602E-01   2.4098E+00
      14651  Fluid done  7.3255E+01  5.3955E+00
Step  14652, t= 7.3260000E+01, DT= 5.0000000E-03, C=    NaN 2.8738E+04 9.1272E+00
             Solving for Hmholtz scalars
      14652  Error Hmholtz TEMP     200          NaN          NaN   1.0000E-12
      14652  Scalars done  7.3260E+01  1.0415E+00
             Solving for fluid
 14652   201 Unconverged Helmh3 fluid rbnorm =          NaN 0.100000E-11
      14652  U-PRES gmres     120          NaN          NaN   1.0000E-10   7.0562E-01   2.3933E+00
      14652  Fluid done  7.3260E+01  5.3900E+00