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IDProjectCategoryView StatusDate SubmittedLast Update
0000412OpenFOAMBugpublic2012-02-03 11:072012-02-03 13:17
Reporterlinnemann Assigned Touser2 
PrioritynormalSeveritymajorReproducibilityalways
Status resolvedResolutionno change required 
Platformx86_64OSCentOSOS Version5.4
Summary0000412: Using MRF solver in conjunction with AMI leads to mass imbalance
DescriptionWhen using MRFSimpleFoam on a simple case with two AMI pairs there is no mass balance over the pairs. This is a severe problem and should be addressed ASAP or inform users to avoid MRF in conjunction with AMI's.

Mass output using simplefunctionobjects and MRFSimpleFoam (m^3/h)
MassFlows: inlet = -6.15535 AMI1_1 = 6.15531 AMI1_2 = -1.01369 AMI2_1 = -5.03995 AMI2_2 = 1.01368 outlet = 5.04

Mass output using simplefunctionobjects and simpleFoam (m^3/h)
MassFlows: inlet = -5.03961 AMI1_1 = 5.03968 AMI1_2 = -5.0465 AMI2_1 = -5.03999 AMI2_2 = 5.04648 outlet = 5.04
Steps To ReproduceRun the case in the link below with MRFSimpleFoam and then simpleFoam, monitor the massflow using simplefunctionobjects from the swak4foam project.

http://dl.dropbox.com/u/15968063/OF21_AMI_massFlow.tar.gz
TagsNo tags attached.

Activities

linnemann

2012-02-03 11:11

reporter  

AMI1_1_vs_AMI_1_2.png (32,881 bytes)   
AMI1_1_vs_AMI_1_2.png (32,881 bytes)   

user15

2012-02-03 11:53

  ~0001011

when you say monitor the massflow it sounds like you are looking at a non-converged solution. Are you doing that?

linnemann

2012-02-03 11:58

reporter   ~0001012

Last edited: 2012-02-03 12:31

 Hi, this is the last iteration on a fully converged case 2000itt.

You could also sample phi on the converged case, it will give you the same result.

Edit

Added picture of massflow from paraview on the two AMI sides, using this formula in the python calculator.

area(inputs[0])*dot(inputs[0].CellData['U'],norm(inputs[0].CellData['U']))

linnemann

2012-02-03 12:30

reporter  

AMI1_1_vs_AMI_1_2_MassFlow.png (134,994 bytes)   
AMI1_1_vs_AMI_1_2_MassFlow.png (134,994 bytes)   

user2

2012-02-03 12:44

  ~0001017

Thanks for the report.

However, when using AMI with MRF, the AMI patches should be added to the non-rotating patches in the constant/MRFZones dictionary, i.e. for your case:

    nonRotatingPatches (AMI1_1 AMI1_2 AMI2_1 AMI2_2);

Also for info, you can generate the mass flux output using the standard OF function objects - using the faceSource object and the 'sum' operation on 'phi'

linnemann

2012-02-03 13:06

reporter   ~0001019

Hi

Thx for the swift reply, I just tested and it indeed fixes the issue.

Please close the bug per my request.

Issue History

Date Modified Username Field Change
2012-02-03 11:07 linnemann New Issue
2012-02-03 11:11 linnemann File Added: AMI1_1_vs_AMI_1_2.png
2012-02-03 11:53 user15 Note Added: 0001011
2012-02-03 11:58 linnemann Note Added: 0001012
2012-02-03 12:30 linnemann File Added: AMI1_1_vs_AMI_1_2_MassFlow.png
2012-02-03 12:31 linnemann Note Edited: 0001012
2012-02-03 12:44 user2 Note Added: 0001017
2012-02-03 13:06 linnemann Note Added: 0001019
2012-02-03 13:17 user2 Status new => resolved
2012-02-03 13:17 user2 Fixed in Version => 2.1.x
2012-02-03 13:17 user2 Resolution open => no change required
2012-02-03 13:17 user2 Assigned To => user2