chtMultiRegionFOAM derived fvPatchFields
 

Hello,

I don't understand something about the solidWallMixedTemperatureCoupled boundary condition.

"// Both sides agree on
// - temperature : (myKDelta*fld + nbrKDelta*nbrFld)/(myKDelta+nbrKDelta)
// - gradient : (temperature-fld)*delta
// We've got a degree of freedom in how to implement this in a mixed bc.
// (what gradient, what fixedValue and mixing coefficient)
// Two reasonable choices:
// 1. specify above temperature on one side (preferentially the high side)
// and above gradient on the other. So this will switch between pure
// fixedvalue and pure fixedgradient
// 2. specify gradient and temperature such that the equations are the
// same on both sides. This leads to the choice of
// - refGradient = zero gradient
// - refValue = neighbour value
// - mixFraction = nbrKDelta / (nbrKDelta + myKDelta())
"

I don't understand the second choice (which is implemented). Why fixing theses values for refGradient, refValue and mixFraction leads to the similitude of the equations on both sides ?

Thanks,

Gilles