This function is based on based on NASA CEA [McBride1996, Svehla1995]
Although specific volume is an input to this function, the result is independent of specific volume.
function eta extends Modelica.Icons.Function; input Q.TemperatureAbsolute T = 298.15*U.K "Temperature" annotation( Dialog(__Dymola_label = "<html><i>T</i></html>")); input Q.VolumeSpecific v = 298.15*U.K/U.atm "Specific volume"; output Q.Resistivity eta "Fluidity" annotation( Dialog(__Dymola_label = "<html>η</html>")); end eta;