[Nek5000-users] **ERROR**: Failed in HMHOLTZ (axisymmetric)

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

Dear Neks,

I have run into this convergence error in PRES while testing an 
axisymmetric case (**ERROR**: Failed in HMHOLTZ...). See below:

=============================================================================================
Step  51118, t= 5.1118000E+01, DT= 1.0000000E-03, C=  0.081 4.9673E+02 
5.6732E-03
              Solving for heat
  Solving for fluid T T T
       51118    Hmholtz TEMP:      1   3.1921E-17   2.8762E-14   
5.0000E+00
       51118   5.1118E+01  2.6393E-04 Heat done
    51118   7.62673E-01   2.44737E-03   3.11629E+02   8 PRES   PROJECT
  51118   100 **ERROR**: Failed in HMHOLTZ: PRES   1.0006E-04   
3.9093E-04   1.0000E-04
       51118    Hmholtz VELX:      3   8.2217E-09   4.2588E-02   
1.0000E-06
       51118    Hmholtz VELY:      3   1.0309E-08   3.8505E-02   
1.0000E-06
                L1/L2 DIV(V)    :  -1.5406E-09   2.6956E-03
                L1/L2 QTL       :   0.0000E+00   0.0000E+00
                L1/L2 DIV(V)-QTL:  -1.5406E-09   2.6956E-03
       51118   5.1118E+01  8.4209E-03 Fluid done
     51118  5.1118E+01  4.0915E-03  5.2924E+00 ubar
  dump history points
  done :: dump history points
=============================================================================================

Time step is so small due to the domain's substantial changes in size, 
which make the CFL go over 1 and crash otherwise. Velocity is 
oscillating
  periodically so CFL will take very low values (such as the one above) 
and then reach higher values overtime (0.4 or 0.5). Even raising 
tolerances
past a reasonable extreme will not make it converge. Any hints?

Best regards,

MViturro






-- 
MAURO VITURRO BALUFO
Universidad Politecnica de Madrid