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anuargimenez August 13, 2022 13:08

p initial residual always 1 in rhoPimpleFoam
 
Hi,

I am running a simulation using rhoPimpleFoam and AMI, and at each time step the initial pressure residual always remains at 1.

Here you can see an example:
Code:

Courant Number mean: 4.83737e-08 max: 0.000103041
deltaT = 0.000119048
Time = 0.000119048

PIMPLE: Iteration 1
AMI: Creating addressing and weights between 50424 source faces and 50424 target faces
AMI: Patch source sum(weights) min/max/average = 0.995592, 1, 0.999994
AMI: Patch target sum(weights) min/max/average = 0.995604, 1, 0.999994
GAMG:  Solving for pcorr, Initial residual = 1, Final residual = 0.000714785, No Iterations 47
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
smoothSolver:  Solving for Ux, Initial residual = 1, Final residual = 0.00297523, No Iterations 2
smoothSolver:  Solving for Uy, Initial residual = 1, Final residual = 0.00106849, No Iterations 2
smoothSolver:  Solving for Uz, Initial residual = 1, Final residual = 0.00282929, No Iterations 2
- selecting all cells
- selected 11197318 cell(s) with volume 6.83952e-06
- selecting all cells
- selected 11197318 cell(s) with volume 6.83952e-06
smoothSolver:  Solving for h, Initial residual = 1, Final residual = 0.000281533, No Iterations 1
- selecting all cells
- selected 11197318 cell(s) with volume 6.83952e-06
GAMG:  Solving for p, Initial residual = 1, Final residual = 2.84356e-06, No Iterations 100
pressureControl: p max 9.24171e+09
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 6.94491e-10, global = 1.59976e-13, cumulative = 1.59976e-13
GAMG:  Solving for p, Initial residual = 1, Final residual = 6.61374e-06, No Iterations 100
pressureControl: p max 9.24157e+09
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 1.61504e-09, global = 1.07506e-12, cumulative = 1.23503e-12
GAMG:  Solving for p, Initial residual = 1, Final residual = 1.25426e-05, No Iterations 100
pressureControl: p max 9.24152e+09
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 3.06263e-09, global = -4.51817e-13, cumulative = 7.83217e-13
PIMPLE: Iteration 2
smoothSolver:  Solving for Ux, Initial residual = 0.249918, Final residual = 0.000997765, No Iterations 2
smoothSolver:  Solving for Uy, Initial residual = 0.0644488, Final residual = 0.000122414, No Iterations 2
smoothSolver:  Solving for Uz, Initial residual = 0.251148, Final residual = 0.000954186, No Iterations 2
- selecting all cells
- selected 11197318 cell(s) with volume 6.83952e-06
- selecting all cells
- selected 11197318 cell(s) with volume 6.83952e-06
smoothSolver:  Solving for h, Initial residual = 0.160909, Final residual = 4.6518e-05, No Iterations 1
- selecting all cells
- selected 11197318 cell(s) with volume 6.83952e-06
GAMG: Solving for p, Initial residual = 1, Final residual = 1.94859e-05, No Iterations 100
pressureControl: p max 9.16088e+09
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 5.10553e-09, global = 4.74236e-12, cumulative = 5.52557e-12
GAMG:  Solving for p, Initial residual = 1, Final residual = 2.75255e-05, No Iterations 100
pressureControl: p max 9.1609e+09
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 7.21149e-09, global = -6.78828e-13, cumulative = 4.84675e-12
GAMG: Solving for p, Initial residual = 1, Final residual = 8.70879e-06, No Iterations 100
pressureControl: p max 9.16084e+09
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 2.28158e-09, global = -7.81905e-13, cumulative = 4.06484e-12
PIMPLE: Iteration 3
smoothSolver:  Solving for Ux, Initial residual = 0.130021, Final residual = 0.000634088, No Iterations 2
smoothSolver:  Solving for Uy, Initial residual = 0.0683342, Final residual = 9.66028e-05, No Iterations 2
smoothSolver:  Solving for Uz, Initial residual = 0.130765, Final residual = 0.000607738, No Iterations 2
- selecting all cells
- selected 11197318 cell(s) with volume 6.83952e-06
- selecting all cells
- selected 11197318 cell(s) with volume 6.83952e-06
smoothSolver:  Solving for h, Initial residual = 0.0627407, Final residual = 1.7988e-05, No Iterations 1
- selecting all cells
- selected 11197318 cell(s) with volume 6.83952e-06
GAMG:  Solving for p, Initial residual = 1, Final residual = 4.00594e-05, No Iterations 100
pressureControl: p max 9.13797e+09
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 1.05944e-08, global = 1.41599e-11, cumulative = 1.82247e-11
GAMG:  Solving for p, Initial residual = 1, Final residual = 1.67696e-05, No Iterations 100
pressureControl: p max 9.13789e+09
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 4.43483e-09, global = 5.08035e-13, cumulative = 1.87328e-11
GAMG:  Solving for p, Initial residual = 1, Final residual = 8.36599e-06, No Iterations 100
pressureControl: p max 9.13784e+09
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 2.2124e-09, global = -2.48692e-12, cumulative = 1.62459e-11
PIMPLE: Iteration 4
smoothSolver:  Solving for Ux, Initial residual = 0.0825004, Final residual = 0.000471153, No Iterations 2
smoothSolver:  Solving for Uy, Initial residual = 0.0919697, Final residual = 0.000142687, No Iterations 2
smoothSolver:  Solving for Uz, Initial residual = 0.0830071, Final residual = 0.000452445, No Iterations 2
- selecting all cells
- selected 11197318 cell(s) with volume 6.83952e-06
- selecting all cells
- selected 11197318 cell(s) with volume 6.83952e-06
smoothSolver:  Solving for h, Initial residual = 0.029692, Final residual = 8.45077e-06, No Iterations 1
- selecting all cells
- selected 11197318 cell(s) with volume 6.83952e-06
GAMG:  Solving for p, Initial residual = 1, Final residual = 7.91552e-06, No Iterations 100
pressureControl: p max 9.13357e+09
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 2.08725e-09, global = 2.54129e-12, cumulative = 1.87872e-11
GAMG:  Solving for p, Initial residual = 1, Final residual = 1.14643e-05, No Iterations 100
pressureControl: p max 9.13351e+09
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 3.02292e-09, global = -1.36014e-12, cumulative = 1.7427e-11
GAMG:  Solving for p, Initial residual = 1, Final residual = 9.96948e-06, No Iterations 100
pressureControl: p max 9.13354e+09
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 2.62873e-09, global = -4.63862e-12, cumulative = 1.27884e-11

I am new to transient simulations and the PIMPLE algorithm. Is this normal? If not, how can it be corrected?

Thank you,
Anuar


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