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IDProjectCategoryView StatusLast Update
0001841OpenFOAMBugpublic2022-05-18 11:10
Reporteruser1226Assigned Towill  
Status resolvedResolutionfixed 
PlatformGNU/LinuxOSUbuntuOS Version14.04
Fixed in Versiondev 
Summary0001841: Abnormal Courant number and abnormal phase fractions in /multiphase/multiphaseInterDyMFoam/laminar/mixerVesselAMI2D
DescriptionMultiphaseInterDyMFoam has been executed for the case of mixerVesselAMI2D for the first time, the calculation has been terminated at Time=0.411847, though that endTime is set to 5 [s]. (Case1)
I started to investigate the cause by changing the time step (deltaT) and when deltaT=5e-7 (for Case1, deltaT=1e-6) the calculation continued to Time=1.13274. (Case2) But I soon realised that it does not matter how small deltaT is: even though deltaT=1e-9, the calculation is terminated at around Time=0.4.
Then I compared the "alphas" of two cases (Case1 and Case2) using ParaView time by time and I found that air adjoining water seems to penetrate the impeller for Case 1 (See attached GIF file). For Case2, no such penetration is found.
The calculation log of the both cases, however, show abnormal Courant number and phase fractions before the run is terminated.
Steps To ReproduceWhen I tried 2 phases (air and water) instead of 4 phases, I could reproduce a similar phenomenon: abnormal Courant number and abnormal phase fractions before termination of calculation.
So I guess, so far, that the combination of handling multiphase fluids with large difference of densities (1 kg/m^3 for air and 1000 kg/m^3 for water) and AMI interacts each other. In fact, I did not have such problem when I executed /multiphaseInterFoam/laminar/mixerVessel2D.
Additional InformationThe calculation of /multiphaseInterFoam/laminar/mixerVessel2D is normally ended: normal Courant number and normal phase fraction



2015-08-28 11:31


mixerVesselAMI2D_Case1.gif (204,488 bytes)   
mixerVesselAMI2D_Case1.gif (204,488 bytes)   


2015-08-28 11:39

manager   ~0005310

This problem relates to the non-convervation problems with AMI for multiphase flow which have been reported and discussed here many times.


2022-05-18 11:10

manager   ~0012592

Numerical issues with AMI-based patch couplings have been resolved by the new Non-Conformal Coupled (NCC) development. See the following commit for explanation, and instructions for how to use NCC and convert cases from AMI.

Issue History

Date Modified Username Field Change
2015-08-28 11:31 user1226 New Issue
2015-08-28 11:31 user1226 File Added: mixerVesselAMI2D_Case1.gif
2015-08-28 11:39 henry Note Added: 0005310
2015-08-29 15:01 wyldckat Tag Attached: AMI
2022-05-18 11:10 will Assigned To => will
2022-05-18 11:10 will Status new => resolved
2022-05-18 11:10 will Resolution open => fixed
2022-05-18 11:10 will Fixed in Version => dev
2022-05-18 11:10 will Note Added: 0012592