Temperature dependent model for some volume or mass fraction
This property must be a medium property. It can be used for media with a phase change of the fluid in the pore space. Then, there is a temperature dependent (volume or mass) fraction for one of the two phases. The other one is immediately given by the remaining fraction. The fraction is computed based on a phase transition spread over a temperature interval following a sigmoid line:
\frac{1 - S_r}{1 + \exp(k (T - T_\mathrm{c}))}
Parameter S_r is residual saturation, representing the amount of liquid water remaining after the water-ice phase transition is complete. The parameter k controlling the steepness of the phase change and T_\mathrm{c} as the characteristic temperature where the phase change is centered around (melting temperature) are forwarded to a sigmoid function.
No additional info.
Used in no end-to-end test cases.