Sub-skill of openfoam: 3.1 Solver Log Residual Format (+5).
Each iteration produces lines in this format:
smoothSolver: Solving for Ux, Initial residual = 0.0118755, Final residual = 0.000302581, No Iterations 1
GAMG: Solving for p, Initial residual = 0.150883, Final residual = 0.00896498, No Iterations 3
Regex for extraction:
import re
pattern = r'^(\w+):\s+Solving for (\w+), Initial residual = ([0-9.e+-]+), Final residual = ([0-9.e+-]+), No Iterations (\d+)'
# Groups: solver_name, field_name, initial_residual, final_residual, iterations
Time step markers:
Time = 150 # steady: iteration number
Time = 0.0345 # transient: physical time
Courant number (transient only):
Courant Number mean: 0.123 max: 0.987
Continuity errors:
time step continuity errors : sum local = 1.23e-07, global = -2.34e-15, cumulative = -5.67e-14
Convergence marker (SIMPLE):
SIMPLE solution converged in 285 iterations
End marker: End
foamLog log.simpleFoam
# Creates logs/ directory with per-field residual files:
# logs/p_0 — initial residual for p
# logs/Ux_0 — initial residual for Ux
# logs/k_0 — initial residual for k
# logs/contLocal_0 — local continuity error
# logs/contGlobal_0 — global continuity error
# Format: two columns (iteration, value)
import re
from pathlib import Path
def parse_openfoam_log(log_path):
"""Parse OpenFOAM solver log and extract residuals per field."""
residuals = {}
time_step = 0
pattern = re.compile(
r'(\w+):\s+Solving for (\w+), '
r'Initial residual = ([0-9.e+-]+), '
r'Final residual = ([0-9.e+-]+), '
r'No Iterations (\d+)'
)
time_pattern = re.compile(r'^Time = ([0-9.e+-]+)')
for line in Path(log_path).read_text().splitlines():
time_match = time_pattern.match(line)
if time_match:
time_step = float(time_match.group(1))
continue
match = pattern.search(line)
if match:
field = match.group(2)
if field not in residuals:
residuals[field] = []
residuals[field].append({
'time': time_step,
'initial': float(match.group(3)),
'final': float(match.group(4)),
'iterations': int(match.group(5)),
})
return residuals
Function objects write to postProcessing/<name>/<startTime>/:
| Function Object | Output File | Content |
|---|---|---|
yPlus | yPlus/0/yPlus.dat | Wall y+ values |
solverInfo | solverInfo/0/solverInfo.dat | Residuals per timestep |
forceCoeffs | forceCoeffs/0/coefficient.dat | Cd, Cl, Cm vs time |
probes | probes/0/p, probes/0/U | Field values at probe points |
fieldMinMax | fieldMinMax/0/fieldMinMax.dat | Min/max per field |
Key lines to parse:
Max aspect ratio = 5.08 OK.
Mesh non-orthogonality Max: 45.2 average: 12.3
Max skewness = 0.127 OK.
Min volume = 4.2e-11. Max volume = 1.68e-09.
Mesh OK. # or: Failed N mesh checks.
| Code | Meaning |
|---|---|
| 0 | Success (End printed) |
| 1 | FOAM FATAL ERROR or FOAM FATAL IO ERROR |
| 134 | SIGABRT — assertion failure |
| 136 | SIGFPE — floating point exception |
| 139 | SIGSEGV — memory / corrupted mesh |
| 137 | SIGKILL — out of memory (OOM killer) |
| 255 | MPI error / decomposition mismatch |