Problem running settlingFoam
 

I used the dahl tutorial as a starter.

Changed the geometry, to make the inlet smaller rather than occupying the wholeof the left hand face, the outlet at the top right rather than the bottom right, and set the geometry to create a baffle at the top surface.

When run it crashes! Any suggestions as to what to try?

Output:

Courant Number mean: 1.9503e-005 max: 0.135083
deltaT = 0.00011219
Time = 0.01466623371571942

diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for Alpha, Initial residual = 6.94518e-005, Final residual = 3.31266e-014, No Iterations 1
Solid phase fraction = 8.00299e-010 Min(Alpha) = -3.86902e-193 Max(Alpha) = 0.0029
DICPCG: Solving for p_rgh, Initial residual = 2.36688e-008, Final residual = 2.36688e-008, No Iterations 0
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 1.03624e-013, global = -3.79501e-015,cumulative = 1.59011e-014
DICPCG: Solving for p_rgh, Initial residual = 4.92649e-012, Final residual = 4.92649e-012, No Iterations 0
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 1.04815e-013, global = -5.03788e-015,cumulative = 1.08632e-014
DICPCG: Solving for p_rgh, Initial residual = 7.68714e-013, Final residual = 7.68714e-013, No Iterations 0
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 1.02267e-013, global = -6.45012e-015,cumulative = 4.4131e-015
DILUPBiCG: Solving for epsilon, Initial residual = 0.185361, Final residual = 1.27635e-009, No Iterations 4
bounding epsilon, min: -3.88225 max: 11.4251 average: 0.000481464
DILUPBiCG: Solving for k, Initial residual = 0.0474388, Final residual = 5.60305e-011, No Iterations 5
bounding k, min: -115.223 max: 338.428 average: 0.147732
ExecutionTime = 4.824 s ClockTime = 5 s

Courant Number mean: 2.38851e-005 max: 0.236126
deltaT = 0.000134628
Time = 0.01480086132362708

diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for Alpha, Initial residual = 6.23682e-005, Final residual = 5.43706e-014, No Iterations 1
Solid phase fraction = 8.0811e-010 Min(Alpha) = -7.20353e-192 Max(Alpha) = 0.0029
DICPCG: Solving for p_rgh, Initial residual = 1.64528e-008, Final residual = 1.64528e-008, No Iterations 0
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 7.09954e-014, global = -1.15096e-014,cumulative = -7.09655e-015
DICPCG: Solving for p_rgh, Initial residual = 4.73684e-012, Final residual = 4.73684e-012, No Iterations 0
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 6.78167e-014, global = -6.00684e-015,cumulative = -1.31034e-014
DICPCG: Solving for p_rgh, Initial residual = 7.61297e-013, Final residual = 7.61297e-013, No Iterations 0
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 7.1786e-014, global = -1.26679e-014, cumulative = -2.57713e-014
DILUPBiCG: Solving for epsilon, Initial residual = 0.206386, Final residual = 8.21281e-011, No Iterations 4
bounding epsilon, min: -7.68824 max: 19.5526 average: 0.000304606
DILUPBiCG: Solving for k, Initial residual = 0.0648693, Final residual = 2.92731e-009, No Iterations 4
bounding k, min: -228.936 max: 581.509 average: 0.15149
ExecutionTime = 4.989 s ClockTime = 5 s

Courant Number mean: 6.65539e-005 max: 0.933005
deltaT = 7.21472e-005
Time = 0.0148730084942251

diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for Alpha, Initial residual = 5.48342e-005, Final residual = 3.57752e-014, No Iterations 1
Solid phase fraction = 8.12297e-010 Min(Alpha) = -6.04098e-191 Max(Alpha) = 0.0029
DICPCG: Solving for p_rgh, Initial residual = 5.73158e-008, Final residual = 5.73158e-008, No Iterations 0
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 7.1374e-014, global = 1.94634e-015, cumulative = -2.3825e-014
DICPCG: Solving for p_rgh, Initial residual = 4.9524e-012, Final residual = 4.9524e-012, No Iterations 0
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 7.22832e-014, global = -1.77565e-015,cumulative = -2.56006e-014
DICPCG: Solving for p_rgh, Initial residual = 7.44481e-013, Final residual = 7.44481e-013, No Iterations 0
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 7.00685e-014, global = 1.27875e-015, cumulative = -2.43219e-014
DILUPBiCG: Solving for epsilon, Initial residual = 0.218753, Final residual = 7.83109e-011, No Iterations 4
bounding epsilon, min: -13.1321 max: 33.4159 average: 0.000173824
DILUPBiCG: Solving for k, Initial residual = 0.1047, Final residual = 4.01982e-009, No Iterations 4
bounding k, min: -392.676 max: 997.905 average: 0.158028
ExecutionTime = 5.154 s ClockTime = 5 s

Courant Number mean: 4.61272e-005 max: 0.741969
deltaT = 4.86186e-005
Time = 0.01492162712802586

diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for Alpha, Initial residual = 4.88762e-005, Final residual = 2.96102e-014, No Iterations 1
Solid phase fraction = 8.15118e-010 Min(Alpha) = -4.46907e-190 Max(Alpha) = 0.0029
DICPCG: Solving for p_rgh, Initial residual = 1.26235e-007, Final residual = 1.65974e-008, No Iterations 1
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 9.10545e-014, global = -1.78692e-015,cumulative = -2.61088e-014
DICPCG: Solving for p_rgh, Initial residual = 2.9157e-008, Final residual = 2.9157e-008, No Iterations 0
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 8.877e-014, global = -1.67383e-015, cumulative = -2.77826e-014
DICPCG: Solving for p_rgh, Initial residual = 1.2226e-007, Final residual = 2.39142e-008, No Iterations 4
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 6.73634e-014, global = -2.09113e-015,cumulative = -2.98738e-014
DILUPBiCG: Solving for epsilon, Initial residual = 0.999197, Final residual = 2.81609e-009, No Iterations 4
bounding epsilon, min: -71803.7 max: 37125.2 average: 5.96835
DILUPBiCG: Solving for k, Initial residual = 2.61743e-006, Final residual = 2.41308e-010, No Iterations 2
bounding k, min: -1.13808e+006 max: 599613 average: 260.734
ExecutionTime = 5.325 s ClockTime = 5 s

... DELETED ...

Courant Number mean: -57.4098 max: 66990.1
deltaT = 1.27948e-017
Time = 0.01492348511484738

diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for Alpha, Initial residual = 1.61014e-021, Final residual = 1.61014e-021, No Iterations 0
Solid phase fraction = 8.08671e-010 Min(Alpha) = 0 Max(Alpha) = 0.0029
DICPCG: Solving for p_rgh, Initial residual = 1, Final residual = 123.894, No Iterations 1001
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = -1.24575e+028, global = -9.67212e+026, cumulative = -2.04296e+037
DICPCG: Solving for p_rgh, Initial residual = 8.43499e-023, Final residual = 8.43499e-023, No Iterations 0


Backtrace:
ZN10StackTraceC1Ev [0x6c58160e+62]
module: d:\blueCFD-SingleCore-2.1\OpenFOAM-2.1\platforms\linuxmingw-w64DPOpt\lib\libstack_trace.dll
(No symbol) [0x2c1ec60]
RtlCaptureContext [0x7755b6f0+0]
module: C:\windows\system32\kernel32.dll
ZN4Foam11fileMonitor15fileStateNames_E [0x6d9af580+1536]
module: d:\blueCFD-SingleCore-2.1\OpenFOAM-2.1\platforms\linuxmingw-w64DPOpt\lib\libOpenFOAM.dll

Went back to just the dahl geometry. Changed it so that the inlet & outlet were 10 cm slots at the top of a 3m deep tank, rather than the original where the inlet was the full 3m and the outlet 10cm at the base of the tank.

Had the same problem of the run failing. Currently trying a higher inlet velocity than the original, to reflect the smaller inlet area. Oddly, that seems to have *improved* matters. But would still appreciate any insights available.

Hi Jeremy,

Two things, which I notice:

1. You are not solving for the momentum equation, but only for the pressure. This is different from the original dahl-tutorial (OF2.2.0), so you have changed something besides the geometry.

2. You turbulence equations go unbounded, so I would start with the following steps:
a. Solve without turbulence to verify that the boundary conditions on p and U are sane.
b. Add turbulence, but use the upwind scheme. Especially on the convective term.

If 2a is successful, then 2b would probably give you stability. Once you have that, you can start playing around with higher-order schemes.

Kind regards,

Niels

Part of the problem appears to be that I had meshes with overlapping faces. Because I did not use mergePatchPairs I inadvertently created internal walls where I should have flow exchange between the regions. I'm seeing how that progresses me. I have gone back to the dahl case and am adding my changes bit by bit - first the change to the location of the inlets/outlets. Then split the mesh up, in readiness to add a second outlet.

Not sure how I specify a 50:50 flow split in openFoam! Last time I did this, with STAR-CD, I think I could just specify the flow split directly. I'm guessing I set the velocity in one outlet as uniform, so that I can fix the volumetric flow going through that.