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April 29, 2011, 21:42 
volume fraction = nan

#1 
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Anonymous
Join Date: Feb 2010
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The liquid phase volume fraction is too large during interDyMFoam run. What should I do?
Thanks, Centre of mass: (3.99998969769 0.199999365532 0.00194121622769) Linear velocity: (0.00807274666396 0.000116891215473 1.22736927321) Angular velocity: (50.7400957943 350.884852997 0.162897658258) Centre of mass: (3.99998969769 0.199999365532 0.00194121622769) Linear velocity: (0.00807274666396 0.000116891215473 1.22736927321) Angular velocity: (50.7400957943 350.884852997 0.162897658258) GAMG: Solving for cellDisplacementx, Initial residual = 1, Final residual = 7.59907279221e06, No Iterations 4 GAMG: Solving for cellDisplacementy, Initial residual = 1, Final residual = 7.48199156032e06, No Iterations 4 GAMG: Solving for cellDisplacementx, Initial residual = 1, Final residual = 7.59907279221e06, No Iterations 4 GAMG: Solving for cellDisplacementz, Initial residual = 1, Final residual = 6.28747292815e06, No Iterations 4 GAMG: Solving for cellDisplacementy, Initial residual = 1, Final residual = 7.48199156032e06, No Iterations 4 GAMG: Solving for cellDisplacementz, Initial residual = 1, Final residual = 6.28747292815e06, No Iterations 4 Execution time for mesh.update() = 14.83 s time step continuity errors : sum local = 4.34625791759e11, global = 2.0984282934e13, cumulative = 4.55449681311e06 Execution time for mesh.update() = 14.84 s time step continuity errors : sum local = 4.34625791759e11, global = 2.0984282934e13, cumulative = 4.55449681311e06 GAMGPCG: Solving for pcorr, Initial residual = 1, Final residual = 7.16391976148e06, No Iterations 8 time step continuity errors : sum local = 3.11362494258e16, global = 5.34853518262e18, cumulative = 4.55449681311e06 MULES: Solving for alpha1 Liquid phase volume fraction = nan Min(alpha1) = 1.44928608738e+296 Max(alpha1) = 1.18486320879e+296 GAMGPCG: Solving for pcorr, Initial residual = 1, Final residual = 7.16391976148e06, No Iterations 8 time step continuity errors : sum local = 3.11362494258e16, global = 5.34853518262e18, cumulative = 4.55449681311e06 MULES: Solving for alpha1 MULES: Solving for alpha1 Liquid phase volume fraction = nan Min(alpha1) = 9067.86973555 Max(alpha1) = 873794.676324 Liquid phase volume fraction = nan Min(alpha1) = 1.44928608738e+296 Max(alpha1) = 1.18486320879e+296 MULES: Solving for alpha1 MULES: Solving for alpha1 Liquid phase volume fraction = nan Min(alpha1) = 21395657433.6 Max(alpha1) = 3942543.65753 Liquid phase volume fraction = nan Min(alpha1) = 9067.86973555 Max(alpha1) = 873794.676324 MULES: Solving for alpha1 Liquid phase volume fraction = nan Min(alpha1) = 21395657433.6 Max(alpha1) = 3942543.65753 

April 30, 2011, 00:01 

#2 
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Anonymous
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after reducing timestep, tried both GAMGPCG and DICPCG for solving pcorr and still cannot fix this. solution gives singularity when solving pcorr.
Centre of mass: (1.50001686526 0.499972308524 0.493779071806) Linear velocity: (0.00249152243223 0.00491296145985 0.845915059591) Angular velocity: (8.1941654618 6.9633990245 0.737810296966) Centre of mass: (1.50001686526 0.499972308524 0.493779071806) Linear velocity: (0.00249152243223 0.00491296145985 0.845915059591) Angular velocity: (8.1941654618 6.9633990245 0.737810296966) GAMG: Solving for cellDisplacementx, Initial residual = 1, Final residual = 3.96337485906e06, No Iterations 6 GAMG: Solving for cellDisplacementx, Initial residual = 1, Final residual = 3.96337485906e06, No Iterations 6 GAMG: Solving for cellDisplacementy, Initial residual = 1, Final residual = 3.72427537902e06, No Iterations 6 GAMG: Solving for cellDisplacementy, Initial residual = 1, Final residual = 3.72427537902e06, No Iterations 6 GAMG: Solving for cellDisplacementz, Initial residual = 1, Final residual = 8.96207859635e06, No Iterations 6 GAMG: Solving for cellDisplacementz, Initial residual = 1, Final residual = 8.96207859635e06, No Iterations 6 Execution time for mesh.update() = 17.76 s time step continuity errors : sum local = 1.01648889068e10, global = 3.98753833131e12, cumulative = 6.73971151269e09 Execution time for mesh.update() = 17.74 s time step continuity errors : sum local = 1.01648889068e10, global = 3.98753833131e12, cumulative = 6.73971151269e09 DICPCG: Solving for pcorr, Initial residual = 1, Final residual = 9.96719754608e07, No Iterations 255 DICPCG: Solving for pcorr, Initial residual = 1, Final residual = 9.96719754608e07, No Iterations 255 DICPCG: Solving for pcorr: solution singularity DICPCG: Solving for pcorr: solution singularity DICPCG: Solving for pcorr: solution singularity time step continuity errors : sum local = inf, global = inf, cumulative = inf DICPCG: Solving for pcorr: solution singularity time step continuity errors : sum local = inf, global = inf, cumulative = inf MULES: Solving for alpha1 MULES: Solving for alpha1 Liquid phase volume fraction = inf Min(alpha1) = inf Max(alpha1) = 1.83985404514e+287 Liquid phase volume fraction = inf Min(alpha1) = inf Max(alpha1) = 1.83985404514e+287 MULES: Solving for alpha1 MULES: Solving for alpha1 Liquid phase volume fraction = nan Min(alpha1) = 52.2330190268 Max(alpha1) = 29.9036740755 Liquid phase volume fraction = nan Min(alpha1) = 52.2330190268 Max(alpha1) = 29.9036740755 MULES: Solving for alpha1 MULES: Solving for alpha1 Liquid phase volume fraction = nan Min(alpha1) = 504.821905808 Max(alpha1) = 387.19735435 Liquid phase volume fraction = nan Min(alpha1) = 504.821905808 Max(alpha1) = 387.19735435 

April 30, 2011, 11:33 

#3 
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Anonymous
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At timestep=0, it works fine but iteration blows up at next timestep. DT=0.005s. I am posting a link to the image at t=0.
http://www.cfdonline.com/Forums/mem...imestep0.html Thank you for any response. 

April 30, 2011, 12:01 

#4 
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Bruno Santos
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Hi VirtualiCFD,
I only have a very limited understanding of how interFoam and interDyMFoam work, but basically here's what could be wrong:
Best regards, Bruno
__________________


April 30, 2011, 12:32 

#5 
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Anonymous
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Hi Bruno, thank you for your prompt response.
After reducing deltaT from 0.005s to 0.0025s and now I checkMesh the geometry and the new mesh now has some problems. I will try to fix it and post the progress here. Create time Create polyMesh for time = 0 Time = 0 Mesh stats points: 767593 faces: 2204098 internal faces: 2137246 cells: 719444 boundary patches: 6 point zones: 0 face zones: 0 cell zones: 0 Overall number of cells of each type: hexahedra: 701651 prisms: 3585 wedges: 0 pyramids: 0 tet wedges: 32 tetrahedra: 0 polyhedra: 14176 Checking topology... Boundary definition OK. Point usage OK. Upper triangular ordering OK. Face vertices OK. Number of regions: 1 (OK). Checking patch topology for multiply connected surfaces ... Patch Faces Points Surface topology sidewall 20480 20930 ok (nonclosed singly connected) inlet 4096 4225 ok (nonclosed singly connected) outlet 4096 4225 ok (nonclosed singly connected) floor 10240 10465 ok (nonclosed singly connected) ceiling 10240 10465 ok (nonclosed singly connected) floatingObject 17700 19883 ok (closed singly connected) Checking geometry... Overall domain bounding box (4 2 3) (8 3 4) Mesh (nonempty, nonwedge) directions (1 1 1) Mesh (nonempty) directions (1 1 1) Boundary openness (7.93596913354e16 2.25264336087e16 1.5514796242e15) OK. Max cell openness = 3.04515531184e16 OK. Max aspect ratio = 4.39517096183 OK. Minumum face area = 4.29684081531e05. Maximum face area = 0.0085458594. Face area magnitudes OK. Min volume = 1.240235887e06. Max volume = 0.000640939455. Total volume = 418.630237694. Cell volumes OK. Mesh nonorthogonality Max: 55.9891415978 average: 3.848649819 Nonorthogonality check OK. Face pyramids OK. Max skewness = 2.29577137119 OK. Mesh OK. Time = 0.005 Checking geometry... Overall domain bounding box (4 2 3) (8 3 4) Mesh (nonempty, nonwedge) directions (1 1 1) Mesh (nonempty) directions (1 1 1) Boundary openness (7.83532651411e16 2.26932595494e16 1.54953377682e15) OK. Max cell openness = 4.32512283352e16 OK. Max aspect ratio = 4.20723431263 OK. Minumum face area = 4.2968408155e05. Maximum face area = 0.00893658472989. Face area magnitudes OK. Min volume = 1.22476329522e06. Max volume = 0.000668814291826. Total volume = 418.630237804. Cell volumes OK. Mesh nonorthogonality Max: 58.6431968444 average: 3.90508611734 Nonorthogonality check OK. ***Error in face pyramids: 3 faces are incorrectly oriented. <<Writing 3 faces with incorrect orientation to set wrongOrientedFaces Max skewness = 2.32252294916 OK. Failed 1 mesh checks. End 

May 2, 2011, 03:56 

#6 
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Anton Kidess
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Your time step might still be too large. I'd aim for a maximum Courant number of 0.2 (deltaT = 1e05 maybe? depends on your setup, which you have told us nothing about), and from there increase the time step a bit if it runs smoothly.


May 2, 2011, 19:45 

#7 
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Anonymous
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Hi Anton,
I greatly appreciate your reply. In fact, I have stopped working on this case due to its complex geometry to begin with and after several failed attempts over the last weekend. In fact, I've just started with a much simpler and different geometry mesh to see if I can get over with this issue. As you see from my log message below, now I encountered difficulty as my timestep is getting smaller and smaller. I've posted some setting for the information. http://www.cfdonline.com/Forums/ope...nonstop.html I will try lower Co number at 0.2 and let you know the progress. 

June 9, 2015, 09:41 

#8 
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Join Date: May 2011
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Hi,
I am using interphaseChangeFoam and I did include T field to the solver. It is running with deltaT=1e6 in tutorial geometry but it is running with so small time step and Courant Number (see below) in the wavy pipe geometry and after several time steps Courant Number becomes 1e+20... i do not understand why it is running in one case and not in another one? Code:
Courant Number mean: 1.49926e28 max: 1.81888e26 deltaT = 8.39642e30 Time = 2.12243e29 Max interFaceArea: 1.01863e11 m2 Max Heat transfer coefficient: 951.326 W/m2/K DILUPBiCG: Solving for alpha1, Initial residual = 1.34882e05, Final residual = 1.81609e22, No Iterations 1 Max interFaceArea: 1.01863e11 m2 Max Heat transfer coefficient: 951.326 W/m2/K Max Condensation Rate = 0.206548 kg/m3/s Total Condensation Rate = 3.88296e08 kg/s Liquid phase volume fraction = 0.0001 Min(alpha1) = 0.0001 Max(alpha1) = 0.0001 PIMPLE: iteration 1 GAMG: Solving for p_rgh, Initial residual = 5.75304e10, Final residual = 5.75304e10, No Iterations 0 time step continuity errors : sum local = 3.59822e28, global = 3.59822e28, cumulative = 1.80246e+14 GAMG: Solving for p_rgh, Initial residual = 5.75304e10, Final residual = 5.75304e10, No Iterations 0 time step continuity errors : sum local = 3.59822e28, global = 3.59822e28, cumulative = 1.80246e+14 GAMG: Solving for p_rgh, Initial residual = 5.75304e10, Final residual = 5.75304e10, No Iterations 0 time step continuity errors : sum local = 3.59822e28, global = 3.59822e28, cumulative = 1.80246e+14 PIMPLE: iteration 2 GAMG: Solving for p_rgh, Initial residual = 5.75304e10, Final residual = 5.75304e10, No Iterations 0 time step continuity errors : sum local = 3.59822e28, global = 3.59822e28, cumulative = 1.80246e+14 GAMG: Solving for p_rgh, Initial residual = 5.75304e10, Final residual = 5.75304e10, No Iterations 0 time step continuity errors : sum local = 3.59822e28, global = 3.59822e28, cumulative = 1.80246e+14 GAMGPCG: Solving for p_rgh, Initial residual = 5.75304e10, Final residual = 5.75304e10, No Iterations 0 time step continuity errors : sum local = 3.59822e28, global = 3.59822e28, cumulative = 1.80246e+14 DILUPBiCG: Solving for T, Initial residual = 9.24264e06, Final residual = 1.30498e22, No Iterations 1 ExecutionTime = 20.05 s ClockTime = 20 s Courant Number mean: 1.79911e28 max: 2.18266e26 deltaT = 1.00757e29 Time = 3.13e29 Max interFaceArea: 1.01863e11 m2 Max Heat transfer coefficient: 951.326 W/m2/K DILUPBiCG: Solving for alpha1, Initial residual = 1.748e05, Final residual = 2.78871e22, No Iterations 1 Max interFaceArea: 1.01863e11 m2 Max Heat transfer coefficient: 951.326 W/m2/K Max Condensation Rate = 0.206548 kg/m3/s Total Condensation Rate = 3.88296e08 kg/s Liquid phase volume fraction = 0.0001 Min(alpha1) = 0.0001 Max(alpha1) = 0.0001 PIMPLE: iteration 1 GAMG: Solving for p_rgh, Initial residual = 5.75304e10, Final residual = 5.75304e10, No Iterations 0 time step continuity errors : sum local = 4.31787e28, global = 4.31787e28, cumulative = 1.80246e+14 GAMG: Solving for p_rgh, Initial residual = 5.75304e10, Final residual = 5.75304e10, No Iterations 0 time step continuity errors : sum local = 4.31787e28, global = 4.31787e28, cumulative = 1.80246e+14 GAMG: Solving for p_rgh, Initial residual = 5.75304e10, Final residual = 5.75304e10, No Iterations 0 time step continuity errors : sum local = 4.31787e28, global = 4.31787e28, cumulative = 1.80246e+14 PIMPLE: iteration 2 GAMG: Solving for p_rgh, Initial residual = 5.75304e10, Final residual = 5.75304e10, No Iterations 0 time step continuity errors : sum local = 4.31787e28, global = 4.31787e28, cumulative = 1.80246e+14 GAMG: Solving for p_rgh, Initial residual = 5.75304e10, Final residual = 5.75304e10, No Iterations 0 time step continuity errors : sum local = 4.31787e28, global = 4.31787e28, cumulative = 1.80246e+14 GAMGPCG: Solving for p_rgh, Initial residual = 5.75304e10, Final residual = 5.75304e10, No Iterations 0 time step continuity errors : sum local = 4.31787e28, global = 4.31787e28, cumulative = 1.80246e+14 DILUPBiCG: Solving for T, Initial residual = 5.98267e06, Final residual = 9.28524e23, No Iterations 1 ExecutionTime = 24.43 s ClockTime = 25 s Courant Number mean: 2.15893e28 max: 2.61919e26 deltaT = 1.20908e29 Time = 4.33909e29 Thanks in advance! Kanarya 

June 12, 2015, 18:15 

#9 
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Bruno Santos
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Quick answer: Sorry, but you've not provided enough information to diagnose anything Please follow the guidelines: http://www.cfdonline.com/Forums/ope...gethelp.html


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