This function is based on the kinetic theory of gases under the following assumptions [Present1958]:
function D 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/p0 "Specific volume" annotation( Dialog(__Dymola_label = "<html><i>v</i></html>")); output Q.Diffusivity D "Diffusivity" annotation( Dialog(__Dymola_label = "<html><i>D</i></html>")); end D;