[WhiteW]

Hi,
I'm trying to run the axialTurbine_mixingPlane tutorial of OpenFoam extend 4.0 installed on Ubuntu 18.04, however I'm facing some difficulties.
I get a core dump error after 47 iterations. I did not change anything in the setting I only run the Allrun script.
These are the latest iterations of my log file.

Time = 46

BiCGStab:  Solving for Ux, Initial residual = 0.698405, Final residual = 8.08864e-08, No Iterations 1
BiCGStab:  Solving for Uy, Initial residual = 0.698188, Final residual = 2.4243e-07, No Iterations 1
BiCGStab:  Solving for Uz, Initial residual = 0.698477, Final residual = 2.48043e-07, No Iterations 1
BiCGStab:  Solving for p, Initial residual = 1, Final residual = 455.851, No Iterations 1000
time step continuity errors : sum local = 3.56365e+38, global = -4.76599e+35, cumulative = -4.76599e+35
BiCGStab:  Solving for epsilon, Initial residual = 3.67211e-09, Final residual = 3.67211e-09, No Iterations 0
bounding epsilon, min: 2.58173e-21 max: 1.03353e+55 average: 6.74374e+51
BiCGStab:  Solving for k, Initial residual = 0.0227964, Final residual = 0.000761749, No Iterations 1
bounding k, min: -7.73614e+48 max: 9.10391e+49 average: 9.26692e+46
ExecutionTime = 6.04 s  ClockTime = 6 s

Cyclic GGI pair (RUCYCLIC1, RUCYCLIC2)
Area: 0.00221581 0.00221581 Diff = 3.09219e-14 or 1.39551e-09 %
Flux: 2.31736e+33 2.31736e+33 Diff = -8.2108e+23 or 3.54318e-08 %
Cyclic GGI pair (DTCYCLIC1, DTCYCLIC2)
Area: 0.0035 0.0035 Diff = 8.85771e-14 or 2.53078e-09 %
Flux: 4.31601e+32 4.31601e+32 Diff = -1.34661e+23 or 3.12004e-08 %
Mixing plane pair (GVOUTLET, RUINLET) : 1.86941e+32 2.23911e+30 Diff = 1.8918e+32 or 101.198 %
Mixing plane pair (RUOUTLET, DTINLET) : 5.33053e+32 -8.3258e+31 Diff = 4.49795e+32 or 84.3809 %
Time = 47

BiCGStab:  Solving for Ux, Initial residual = 0.633442, Final residual = 0.000583272, No Iterations 1
BiCGStab:  Solving for Uy, Initial residual = 0.574022, Final residual = 0.00464318, No Iterations 1
BiCGStab:  Solving for Uz, Initial residual = 0.53716, Final residual = 0.00227515, No Iterations 1
BiCGStab:  Solving for p, Initial residual = 1, Final residual = 16429.4, No Iterations 1000
time step continuity errors : sum local = 1.20783e+44, global = 4.76424e+40, cumulative = 4.76419e+40
Floating point exception (core dumped)

Is it a foam extend problem or there is something I can do to make the analysis converge (I notice the pressure equation and continuity diverge)?
Thanks,
WhiteW

[WhiteW]

Dear all,
I succeeded in running the tutorial of axialTurbine, however I had to double the mesh elements and decrease the relaxation factors.
I notice that the same error also occurs in MRFSimpleFoam/mixerVessel2D tutorial and, as previous, it can be avoided by doubling the mesh size and decreasing the relaxation factors.


My impression is that foam extend is a little more unstable than the other two version, sometime it suddenly appears the floating point exception (core dump) error, even if the residuals are decreasing without apparent problems.
This is the first time I'm using it, I'm not expert of foam extend but have you also noticed the same?



WhiteW