function velocityOfSound_ph extends Modelica.Icons.Function; input SI.Pressure p "Pressure"; input SI.SpecificEnthalpy h "Specific enthalpy"; input Integer phase = 0 "2 for two-phase, 1 for one-phase, 0 if not known"; input Integer region = 0 "If 0, region is unknown, otherwise known and this input"; output SI.Velocity v_sound "Speed of sound"; end velocityOfSound_ph;