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IDProjectCategoryView StatusLast Update
0001382OpenFOAM[All Projects] Bugpublic2015-02-13 09:22
ReporterprojectionistAssigned Tohenry 
PrioritynormalSeverityminorReproducibilityalways
Status resolvedResolutionfixed 
PlatformLinuxOSUbuntuOS Version14.04
Product Version 
Fixed in Version 
Summary0001382: IATE: possible sign error at the randomCoalescence IATESource model
DescriptionIn the IATE model, there are 3 contributions from bubble-bubble interaction. These are 'breakage due to turbulent impact (TI)','coalescence through random collision driven by turbulent eddies (RC)' and 'coalescence due to wake entrainment (WE)'.
For the transport equation of interfacial area concentration the first effect (TI) acts as a source and the other two (RC and WE) act as a sink. Breakage decreases bubble size and thus increases the interfacial area, whereas, coalescence increases bubble size and decreases interfacial area.
Consequently, the term modelling (TI) has to have a different sign as the terms for (RC and WE).
Steps To ReproduceThe right hand side of the kappaEqn is -fvm::SuSp(R, kappai_) and R is defines as R -= sources_[j].R();
So both minus signs cancel out and we can look at the R() methods in the daughter classes of IATEsource.

Here is a brief summary of what is implemented (Build: 2.3.x-2a185786c1f3)

TI: R[celli] = (1.0/3.0)* /* other stuff*/
RC: R[celli] = 12*phi()* /* other stuff*/
WE: R() { return (-12)*phi()* /* other stuff */

This shows, that TI and RC act as a source and only WE as sink.

For the implementation to obey Ishii et al. RC has to act as a sink, thus it should say

RC: R[celli] = (-12.0)*phi()* /* other stuff*/



Please have a look on the source models for the IATE model to check if my findings are correct.
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henry

2015-02-13 09:22

manager   ~0003754

Thanks for the bug-report and correction
Resolved by commit b17c4b7e0430f8af751cbc6ac95d479ea1c52929

Issue History

Date Modified Username Field Change
2014-08-25 21:00 projectionist New Issue
2015-02-13 09:22 henry Note Added: 0003754
2015-02-13 09:22 henry Status new => resolved
2015-02-13 09:22 henry Resolution open => fixed
2015-02-13 09:22 henry Assigned To => henry