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IDProjectCategoryView StatusLast Update
0001552OpenFOAM[All Projects] Bugpublic2015-03-02 22:50
Reporteruser158Assigned Tohenry 
PrioritynormalSeverityminorReproducibilityhave not tried
Status resolvedResolutionfixed 
PlatformGNU/LinuxOSUbuntuOS Version14.04
Product Version 
Fixed in Version 
Summary0001552: Wrong calculation of shear rate for the Bingham model in the driftFluxFoam solver (previous settlingFoam)
DescriptionIn the driftFluxFoam solver, the "BinghamPlastic.C" file, the shear rate for the Bingham viscoplastic model is calculated as "mag(fvc::grad(U_))", which is wrong.
The shear rate should be calculated as "sqrt(2.0)*mag(symm(fvc::grad(U_)))", as is done in viscosityModel.C for example.

Note: The provided value of the parameter "yieldStressCoeff" is set relative to the current error. Thus, if the suggested correction is made, its value must at least be multiplied with sqrt(2) (additional finer adjustment is likely necessary).
Additional InformationClear theoretical background about the shear rate (i.e. why it is as is) can for example be found in the paper "Effect of the hydrodynamic pressure on shaft torque for a 4-blades vane rheometer, International Journal of Heat and Fluid Flow", 2014, doi:10.1016/j.ijheatfluidflow.2014.06.001
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2015-03-02 22:50

manager   ~0003948

Resolved by commit 7d4f8d7aac8ba020dac4c9883a48fd0bd02fce07

Issue History

Date Modified Username Field Change
2015-03-02 19:47 user158 New Issue
2015-03-02 22:50 henry Note Added: 0003948
2015-03-02 22:50 henry Status new => resolved
2015-03-02 22:50 henry Resolution open => fixed
2015-03-02 22:50 henry Assigned To => henry