See example below:

EOS WATER
SURFACE_DENSITY 1004.0 kg/m^3
REFERENCE_DENSITY 1000
REFERENCE_PRESSURE 1.0D7
WATER_COMPRESSIBILITY 4.6D-10
END
END


Note that in the example described above, the IFC67 default model is used for the enthalpy, because no other models are specified.

The density is computed as:

$\rho(P)=ρ_{ ref }\left[1+ X_c + \frac{X_c^2}{2} \right]$

where:

$\begin{split}\begin{split} &X_C &= C(P-P_{\mbox{ref}}) \\ &ρ_{ref} &= \mbox{reference density [kg/m^3]} \\ &P_{ref} &= \mbox{reference reference pressure [Pa]} \\ &C &= \mbox{water compressibility [1/Pa] } \end{split}\end{split}$

Units cannot be entered and the values must be entered in the units reported above.