to support the evaporation of the solvent from the wax film and the changes in
viscosity caused by the reduction in solvent content.
BUG: filmViscosityModel::thixotropicViscosity: Corrected sign of impingement rate
to compensate for rhoSp having the wrong sign
BUG: surfaceFilmModels::waxSolventEvaporation: Corrected handling of impingement
ENH: surfaceFilmModels::waxSolventViscosity: Changed mixing to mole-fraction based
ENH: surfaceFilmModels::thermoSingleLayer: Added call to solveContinuity before updateSubmodels
to allow sub-models to solve transport equations for conserved properties