e.g. in transportProperties

phases (air water);

twoPhaseEulerFoam: Remove k from the Reynolds stress because there is only a single pressure in the system
and to avoid the generation of flow from the gradient of k the pressure gradient must balance the k term in
each U equation

twoPhaseEulerFoam/kEpsilon.H: Correct the handling of the phase-fraction and make the equations phase-intensive