View Issue Details
|ID||Project||Category||View Status||Date Submitted||Last Update|
|0001552||OpenFOAM||[All Projects] Bug||public||2015-03-02 19:47||2015-03-02 22:50|
|Priority||normal||Severity||minor||Reproducibility||have not tried|
|Fixed in Version|
|Summary||0001552: Wrong calculation of shear rate for the Bingham model in the driftFluxFoam solver (previous settlingFoam)|
|Description||In 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 Information||Clear 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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